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  • 1
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    Wiley-Blackwell
    Publication Date: 2018-02-28
    Description: The atmospheric abundance of the non-methane volatile organic compounds (NMVOCs) ethane, propane, and butane increased during the industrial era. In addition to weak absorption and emission of longwave radiation, these gases influence the atmospheric radiative balance indirectly, mainly as precursors for ozone (O 3 ), and through reaction with the hydroxyl radical (OH), which leads to less OH and thereby longer atmospheric lifetime of methane (CH 4 ). In this study, we have calculated lifetimes, direct and indirect radiative forcing (RF), and global warming potentials (GWPs) for the three compounds, using a self-consistent methodology. Results show net RF per unit emission of 1.0, 0.9, and 0.6 mW m −2 (Tg year −1 ) −1 for ethane, propane, and butane, respectively. For all compounds, the direct effect is considerably smaller than the indirect effects (6% or less of the total). The indirect O 3 and CH 4 effects are approximately of the same magnitude. Net GWPs for a 100-year time horizon are 10 for ethane and propane, and 7 for butane, whereof the direct GWPs are 〈1 for all compounds. The net GWPs are generally higher than previous estimates, mainly because our calculations include emissions for a full year rather than one season. For the compounds studied here, 100-year GWP values do not differ substantially between each compound, considering the large uncertainties involved, and this may indicate that using values representative for a lump of NMVOCs may be sufficient. However, the climate effects may differ more between NMVOC compounds other than alkanes, such as alkenes and aromatics. Ethane is the non-methane hydrocarbon with the longest lifetime and highest abundance in the atmosphere. We have calculated lifetimes, direct and indirect radiative forcing (RF), and global warming potentials (GWPs), using a consistent methodology. Results show that the direct RF efficiency of ethane, propane, and butane is lower than previous estimates, while the net GWP is higher than before, due to stronger indirect effects on ozone and methane.
    Electronic ISSN: 1530-261X
    Topics: Geosciences , Physics
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  • 2
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    Wiley-Blackwell
    Publication Date: 2018-03-06
    Description: By extending the previously proposed heuristic parameterization, the author derived an analytical equation computing the overlap areas between the precipitation (or radiation) areas and the cloud areas in a cloud system consisting of cumulus and stratus. The new analytical equation is accurate and much more efficient than the previous heuristic equation, which suffers from the truncation error in association with the digitalization of the overlap areas. Global test simulations with the new analytical formula in an offline mode showed that the maximum cumulus overlap simulates more surface precipitation flux than the random cumulus overlap. On the other hand, the maximum stratus overlap simulates less surface precipitation flux than random stratus overlap, which is due to the increase in the evaporation rate of convective precipitation from the random to maximum stratus overlap. The independent precipitation approximation (IPA) marginally decreases the surface precipitation flux, implying that IPA works well with other parameterizations. In contrast to the net production rate of precipitation and surface precipitation flux that increase when the cumulus and stratus are maximally and randomly overlapped, respectively, the global mean net radiative cooling and longwave cloud radiative forcing (LWCF) increase when the cumulus and stratus are randomly overlapped. On the global average, the vertical cloud overlap exerts larger impacts on the precipitation flux than on the radiation flux. The radiation scheme taking the subgrid variability of water vapor between the cloud and clear portions into account substantially increases the global mean LWCF in tropical deep convection and midlatitude storm track regions.
    Electronic ISSN: 1942-2466
    Topics: Geography , Geosciences
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  • 3
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    Wiley-Blackwell
    Publication Date: 2018-03-06
    Description: Ocean-Waves-Atmosphere (OWA) exchanges are not well represented in current Numerical Weather Prediction (NWP) systems, which can lead to large uncertainties in tropical cyclone track and intensity forecasts. In order to explore and better understand the impact of OWA interactions on tropical cyclone modelling, a fully coupled OWA system based on the atmospheric model Meso-NH, the oceanic model CROCO and the wave model WW3 and called MSWC was designed and applied to the case of tropical cyclone Bejisa (2013-2014). The fully coupled OWA simulation shows good agreement with the literature and available observations. In particular, simulated significant wave height is within 30 cm of measurements made with buoys and altimeters. Short-term (〈 2 days) sensitivity experiments used to highlight the effect of oceanic waves coupling showlimited impact on the track, the intensity evolution and the turbulent surface fluxes of the tropical cyclone. However, it is also shown that using a fully coupled OWA system is essential to obtain consistent sea salt emissions. Spatial and temporal coherence of the sea state with the 10m-wind speed are necessary to produce sea salt aerosol emissions in the right place (in the eyewall of the tropical cyclone) and with the right size distribution, which is critical for cloud microphysics.
    Electronic ISSN: 1942-2466
    Topics: Geography , Geosciences
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  • 4
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: A homogenization algorithm for randomly distributed microstructures is applied to develop a mass diffusion model for dry snow. Homogenization is a multi-scale approach linking constituent behavior at the microscopic level—amongst ice and air—to the macroscopic material—snow. Principles of continuum mechanics at the microscopic scale describe water vapor diffusion across an ice grain's surface to the air-filled pore space. Volume averaging and a localization assumption scale up and down, respectively, between microscopic and macroscopic scales. The model yields a mass diffusivity expression at the macroscopic scale that is, in general, a 2 nd order tensor parameterized by both bulk and microstructural variables. The model predicts a mass diffusivity of water vapor through snow that is less than that through air. Mass diffusivity is expected to decrease linearly with ice volume fraction. Potential anisotropy in snow's mass diffusivity is captured due to the tensor representation. The tensor is built from directional data assigned to specific, idealized microstructural features. Such anisotropy has been observed in the field and laboratories in snow morphologies of interest such as weak layers of depth hoar and near-surface facets.
    Electronic ISSN: 1942-2466
    Topics: Geography , Geosciences
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  • 5
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: Deficiencies in the parameterizations of convection used in global climate models often lead to a distorted representation of the simulated rainfall intensity distribution (i.e., too much rainfall from weak rain rates). While encouraging improvements in high percentile rainfall intensity have been found as the horizontal resolution of the Community Atmosphere Model is increased to ∼25 km, we demonstrate no corresponding improvement in the moderate rain rates that generate the majority of accumulated rainfall. Using a statistical framework designed to emphasize links between precipitation intensity and accumulated rainfall beyond just the frequency distribution, we show that CAM cannot realistically simulate moderate rain rates, and cannot capture their intensification with climate change, even as resolution is increased. However, by separating the parameterized convective and large-scale resolved contributions to total rainfall, we find that the intensity, geographic pattern and climate change response of CAM's large-scale rain rates are more consistent with observations (TRMM 3B42), superparameterization and theoretical expectations, despite issues with parameterized convection. Increasing CAM's horizontal resolution does improve the representation of total rainfall intensity, but not due to changes in the intensity of large-scale rain rates, which are surprisingly insensitive to horizontal resolution. Rather, improvements occur through an increase in the relative contribution of the large-scale component to the total amount of accumulated rainfall. Analysis of sensitivities to convective timescale and entrainment rate confirm the importance of these parameters in the possible development of scale-aware parameterizations, but also reveal unrecognized trade-offs from the entanglement of precipitation frequency and total amount.
    Electronic ISSN: 1942-2466
    Topics: Geography , Geosciences
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  • 6
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: The gravitational effects of the atmosphere and subsurface water are significant obstacles to observing gravity variations on the sub-μGal (1 μGal = 10 nm/s 2 ) scale. The goal of this study is to detect changes in gravity that are caused by mass redistributions deep underground related to seismological phenomena by reducing environmental gravity effects using multiple gravimeters below- and aboveground, which we term a “vertical gravimeter array”. Based on an evaluation of the responses to atmospheric effects and rainfall events identified in observations made with individual relative gravimeters, the vertical gravimeter array succeeds in stacking the target signals from deep underground and in reducing errors due to rainfall or free groundwater and atmospheric effects. To enable accurate interpretation, we introduce a physical approach that is based on attraction and loading deformation effects for atmospheric reduction using state-of-the-art gridded weather data products. Changes in the water levels of confined groundwater can be regarded as a signal from deep underground, and a response coefficient of approximately −15 μGal/m was obtained. In addition, the response coefficient of the free groundwater level was determined to be approximately 5 μGal/m. Such array observations are expected to contribute to monitoring crustal activity and hydrological studies.
    Electronic ISSN: 2333-5084
    Topics: Geosciences , Physics
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  • 7
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: Landslides have been observed in different terrestrial environments and also on planets, satellites, and asteroids. Long runout landslides are strongly dependent on the initial mass position, material and slope path properties, topographic relief, and presence of volatiles. Therefore, landslides represent a means for the description of rock properties and environment of deposition prevailing at the time of occurrence, and may assist understanding the geological and climatological history of the planetary surfaces. Concerning Mars, previous studies have concentrated on Valles Marineris, where among the largest and longest landslides have been observed. Using different imagery, we present and analyse an original database of 3,118 Martian landslides of deposit area greater than 0.1 km 2 throughout the planet between 60°n and 60°S, resulting in a dataset far richer than previously done. After a distinction is made between different typologies of landslides, their position and the statistical distribution of their geometrical properties are examined. Large landslides cluster along the Noctis Labyrinthus – Valles Marineris – Margaritifer Terra system. Rock avalanches within craters are widespread, but no significant large landslides have been found at latitudes higher than 40°S and 46°N. The magnitude-frequency distribution follows a power-law with scaling exponent ranging between 1.02 and 1.57, for the entire dataset, and varies according to the geomorphological settings, the landslide typology, and mobility. A volume-area power law relationship (exponent: 1.12-1.24) is proposed, based on the reconstruction of 222 landslide geometries, and compared to those for similar terrestrial landslides (1.39). Similarities with respect to terrestrial landslide, distribution with respect to impact craters and impact energy, and cryosphere extent are also discussed.
    Electronic ISSN: 2333-5084
    Topics: Geosciences , Physics
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  • 8
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: Mounting evidence has indicated that engaging in extrapair copulations (EPCs) might be maladaptive or detrimental to females. It is unclear why such nonadaptive female behavior evolves. In this study, we test two hypotheses about the evolution of female EPC behavior using population genetic models. First, we find that both male preference for allocating extra effort to seek EPCs and female pursuit behavior without costs can be maintained and remain polymorphic in a population via frequency-dependent selection. However, both behaviors cannot evolve when females with pursuit behavior suffer from a decline in male parental care. Second, we present another novel way in which female pursuit behavior can evolve; indirect selection can act on this behavior through a ratchet-like mechanism involving oscillating linkage disequilibria between the target EPC pursuit locus and two other loci determining male mate choice and a female sexual signal. Although the overall positive force of such indirect selection is relatively weak, our results suggest that it may still play a role in promoting the evolution of female EPC behavior when this behavior is nonadaptive (i.e., it is neutral) or only somewhat maladaptive (e.g., males only occasionally lower parental care when their mates pursue EPCs). Little is known about the evolution of nonadaptive female extrapair copulation (EPC) behavior. We find that such a behavior can be maintained and remain polymorphic in a population via frequency-dependent selection when there is no cost for females. Also, indirect selection can act on this behavior through a ratchet-like mechanism involving oscillating linkage disequilibria between the target EPC pursuit locus and two other loci determining male mate choice and a female sexual signal.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 9
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: Evolutionary theory predicts that parents should invest equally in the two sexes. If one sex is more costly, a production bias is predicted in favour of the other. Two well-studied causes of differential costs are size dimorphism, in which the larger sex should be more costly, and sex-biased helping in cooperative breeders, in which the more helpful sex should be less costly because future helping “repays” some of its parents’ investment. We studied a bird species in which both processes should favor production of males. Female riflemen Acanthisitta chloris are larger than males, and we documented greater provisioning effort in more female-biased broods indicating they are likely costlier to raise. Riflemen are also cooperative breeders, and males provide more help than females. Contrary to expectations, we observed no male bias in brood sex ratios, which did not differ significantly from parity. We tested whether the lack of a population-wide pattern was a result of facultative sex allocation by individual females, but this hypothesis was not supported either. Our results show an absence of adaptive patterns despite a clear directional hypothesis derived from theory. This appears to be associated with a suboptimal female-biased investment ratio. We conclude that predictions of adaptive sex allocation may falter because of mechanistic constraint, unrecognized costs and benefits, or weak selection. Evolutionary theory predicts that if one sex is costlier to produce, offspring sex ratios should be biased in favour of the other. Here, we show that rifleman females are likely to be costlier to produce, because they are larger, require more provisioning effort and are less likely to help their parents raise future offspring. Despite this, we find that offspring sex ratios are not biased in favour of males and discuss possible reasons for this.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 10
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: Many studies demonstrated the importance of facilitative effect by nurse plant on seedling establishment. Few studies evaluated the negative effects of consumers on plant establishment under nurse plants by dealing with them during multiple demographic processes. We investigated the balance between the facilitative effect and negative effects of consumers during multiple demographic processes in Malawi in southeastern Africa. We chose Ficus natalensis as a nurse plant and compared it with three other microsites in tropical woodlands: Brachystegia floribunda (a dominant woodland species), Uapaca kirkiana (a woodland species), and a treeless site. We quantified the seed rain, postdispersal seed predation, germination, and seedling survival of Syzygium guineense ssp. afromontanum (a common forest species). Within each microsite, we quantified the overall probability of recruitment. We also measured seedling abundance of S. guineense ssp. afromontanum . We found that Ficus natalensis exerted both positive and negative impacts on the establishment of S. guineense ssp. afromontanum . Ficus natalensis facilitated seed deposition, seed germination, and seedling survival. On the other hand, seed removal at postdispersal stage was highest under F. natalensis . Interestingly, B. floribunda also had positive effects on germination and seedling survival, but not on seed deposition. When we excluded the seed arrival stage from our estimation of the recruitment probability, the highest value was found under B. floribunda , not under F. natalensis . When we included the seed arrival stage, however, the order of recruitment probability between F. natalensis and B. floribunda was reversed. The probability was one order of magnitude higher under F. natalensis than under B. floribunda . Our estimation of the probability which included the seed arrival stage was consistent with natural patterns of S. guineense ssp. afromontanum establishment. Despite the presence of opposite effects, the net effects of F. natalensis on S. guineense ssp. afromontanum recruitment in tropical woodlands can be positive. Through experiment, we found that nurse plant exerted opposing effects on establishment of beneficiary species by facilitating seed deposition, seed germination, and seedling survival and by simultaneously increasing the risk of seed predation. Based on above experiments, we estimated the transition probability. According to the estimation, we found the net effect of nurse plant on the establishment can be facilitative.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 11
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: Ecotypic differentiation in the tussock-forming sedge Eriophorum vaginatum has led to the development of populations that are locally adapted to climate in Alaska's moist tussock tundra. As a foundation species, E. vaginatum plays a central role in providing topographic and microclimatic variation essential to these ecosystems, but a changing climate could diminish the importance of this species. As Arctic temperatures have increased, there is evidence of adaptational lag in E. vaginatum , as locally adapted ecotypes now exhibit reduced population growth rates. Whether there is a physiological underpinning to adaptational lag is unknown. Accordingly, this possibility was investigated in reciprocal transplant gardens. Tussocks of E. vaginatum from sites separated by ~1° latitude (Coldfoot: 67°15′N, Toolik Lake: 68°37′, Sagwon: 69°25′) were transplanted into the Toolik Lake and Sagwon sites and exposed to either an ambient or an experimental warming treatment. Five tussocks pertreatment combination were measured at each garden to determine photosynthetic capacity (i.e., V cmax and J max ) and dark respiration rate ( R d ) at measurement temperatures of 15, 20, and 25°C. Photosynthetic enhancements or homeostasis were observed for all ecotypes at both gardens under increased growth temperature, indicating no negative effect of elevated temperature on photosynthetic capacity. Further, no evidence of thermal acclimation in R d was observed for any ecotype, and there was little evidence of ecotypic variation in R d . As such, no physiological contribution to adaptational lag was observed given the increase in growth temperature (up to ~2°C) provided by this study. Despite neutral to positive effects of increased growth temperature on photosynthesis in E. vaginatum , it appears to confer no lasting advantage to the species. As Arctic temperatures have risen, the foundation species Eriophorum vaginatum has begun to exhibit adaptational lag. The physiological underpinning to this process was examined, and we found that increased growth temperature had neutral to positive effects on photosynthetic capacity and respiration. Over the range of growth temperatures examined in this study (up to 2°C), no negative physiological effects were observed.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 12
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: Admixture is the hybridization between populations within one species. It can increase plant fitness and population viability by alleviating inbreeding depression and increasing genetic diversity. However, populations are often adapted to their local environments and admixture with distant populations could break down local adaptation by diluting the locally adapted genomes. Thus, admixed genotypes might be selected against and be outcompeted by locally adapted genotypes in the local environments. To investigate the costs and benefits of admixture, we compared the performance of admixed and within-population F1 and F2 generations of the European plant Lythrum salicaria in a reciprocal transplant experiment at three European field sites over a 2-year period. Despite strong differences between site and plant populations for most of the measured traits, including herbivory, we found limited evidence for local adaptation. The effects of admixture depended on experimental site and plant population, and were positive for some traits. Plant growth and fruit production of some populations increased in admixed offspring and this was strongest with larger parental distances. These effects were only detected in two of our three sites. Our results show that, in the absence of local adaptation, admixture may boost plant performance, and that this is particularly apparent in stressful environments. We suggest that admixture between foreign and local genotypes can potentially be considered in nature conservation to restore populations and/or increase population viability, especially in small inbred or maladapted populations. The costs and benefits of admixture between native Purple loosestrife populations were tested in a reciprocal transplant experiment with three sites in Europe. Our results show that in the absence of local adaptation, admixture can lead to heterosis in both F1 and F2 hybrid generations. This positive effect of admixture was most apparent in more stressful environments.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 13
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: River flow fluctuation has an important influence on riparian vegetation dynamics. A temporally segmented stochastic model focusing on a same-aged population is developed for the purpose of describing both spatial and temporal dynamics of riparian vegetation. In the model, the growth rate of population, rather than carrying capacity, is modeled as the random variable. This model has explicit physical meaning. The model deduces a process-based solution. From the solution process, the probability density of spatial distribution can be derived; therefore, the spatial distribution of population abundance can be described. The lifespan of a same-aged population and the age structure of the species-specific population can also be studied with the aid of this temporally segmented model. The influence of correlation time of river flow fluctuation is also quantified according to the model. The calibration of model parameters and model application are discussed. The model provides a computer-aided method to simulate and predict vegetation dynamics during river flow disturbances. Meanwhile, the model is open and allows for more accurate and concrete modeling of growth rate. Because of the Markov property involved in the process-based solution, the model also has the ability to deal with cases of nonstationary disturbances. The model provides a computer-aided method to simulate and predict vegetation dynamics during river flow disturbances. Meanwhile, the model is open and allows for more accurate and concrete modeling of growth rate and has the ability to deal with cases of nonstationary disturbances.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 14
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: Global species counts are a key measure of biodiversity and associated metrics of conservation. It is both scientifically and practically important to know how many species exist, how many undescribed species remain, and where they are found. We modify a model for the number of undescribed species using species description data and incorporating taxonomic information. We assume a Poisson distribution for the number of species described in an interval and use maximum likelihood to estimate parameter values of an unknown intensity function. To test the model's performance, we performed a simulation study comparing our method to a previous model under conditions qualitatively similar to those related to mammal species description over the last two centuries. Because our model more accurately estimates the total number of species, we predict that 5% of mammals remain undescribed. We applied our model to determine the biogeographic realms which hold these undescribed species. We modify a model for the number of undiscovered species using species description data and incorporating taxonomic information. We performed a simulation study to determine how our model performed in comparison with the original model. Because our model more accurately estimates the total number of species, we predict that 5% of mammals remain undiscovered.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 15
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: Penguins are a monophyletic group in which many species are found breeding sympatrically, raising questions regarding how these species coexist successfully. Here, the isotopic niche of three sympatric pygoscelid penguin species was investigated at Powell Island, South Orkney Islands, during two breeding seasons (austral summers 2013–2014 and 2015–2016). Measurements of carbon (δ 13 C) and nitrogen (δ 15 N) stable isotope ratios were obtained from blood (adults) or feather (chicks) samples collected from Adélie Pygoscelis adeliae , chinstrap P. antarctica , and gentoo P. papua penguins. Isotopic niche regions (a proxy for the realized trophic niches) were computed to provide estimates of the trophic niche width of the studied species during the breeding season. The isotopic niche regions of adults of all three species were similar, but gentoo chicks had noticeably wider isotopic niches than the chicks of the other two species. Moderate to strong overlap in isotopic niche among species was found during each breeding season and for both age groups, suggesting that the potential for competition for shared food sources was similar during the two study years, although the actual level of competition could not be determined owing to the lack of data on resource abundance. Clear interannual shifts in isotopic niche were seen in all three species, though of lower amplitude for adult chinstrap penguins. These shifts were due to variation in carbon, but not nitrogen, isotopic ratios, which could indicate either a change in isotopic signature of their prey or a switch to an alternative food web. The main conclusions of this study are that (1) there is a partial overlap in the isotopic niches of these three congeneric species and that (2) they responded similarly to changes that likely occurred at the base of their food chain between the 2 years of the study. We provide evidence for a moderate to strong overlap in isotopic niche among three species of pygoscelid penguins breeding in sympatry, over two nonconsecutive years. Additionally, clear interannual shifts in isotopic niche occurred in all three species which pointed toward a change in isotopic signature of the lower trophic levels in the food chain rather than a change in the type of prey consumed.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 16
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: Diet regulation behavior can mediate the consequences of imbalanced diets for animal well-being, particularly for captive species that have little dietary choice. Dasyurids (carnivorous marsupials) are of conservation concern in Australia, and many species are in captive breeding programmes. However, their nutrient targets and dietary regulation behaviors are poorly understood, a limitation that may decrease the breeding success and well-being of captive animals. We tested how dietary protein content influenced the intake and utilization of nutrients, physical activity, and body mass of fat-tailed dunnarts Sminthopsis crassicaudata . Twelve adult dunnarts from six sibling pairs (one female and one male per pair) were provided ad libitum access to three diets in a repeated measures design: cat food, cat food supplemented with raw lean beef (1:1), and cat food supplemented with cooked lean beef (1:1). Food intake, activity level, and fecal output were measured daily. Dunnarts significantly decreased food intake, increased protein digestion, and physical activity, but body mass was unchanged when on the high-protein diet compared to the normal cat food diet. These observations suggest a capacity of dunnarts to maintain constant body mass using a dynamic balance of feeding, digestion, and activity. We also found a significant effect of family, with differences between families as large as the difference between the diet treatments, suggesting a genetic component to diet selection. The nutrient regulation responses of dunnarts to high-protein diets and the strong family effects provide important messages for the management of populations of small carnivores, including the aspects of dietary manipulation and conservation of genetic diversity. When challenged with diets with different protein components, the small marsupial carnivore, Sminthopsis crassicaudata, moderated food intake and increased activity when on a high-protein diet, but body mass did not change. Surprisingly, there was a large effect of their genetic background on activity and food consumption; this effect was as large as the effect from the diets and sends a cautionary message about assumptions concerning food consumption in captive and wild animals.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 17
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: Trade-offs associated with sexual size dimorphism (SSD) are well documented across the Tree of Life. However, studies of SSD often do not consider potential investment trade-offs between metabolically expensive structures under sexual selection and other morphological modules. Based on the expectations of the expensive tissue hypothesis, investment in one metabolically expensive structure should come at the direct cost of investment in another. Here, we examine allometric trends in the ontogeny of oyster toadfish ( Opsanus tau ) to test whether investment in structures known to have been influenced by strong sexual selection conform to these expectations. Despite recovering clear changes in the ontogeny of a sexually selected trait between males and females, we find no evidence for predicted ontogenetic trade-offs with metabolically expensive organs. Our results are part of a growing body of work demonstrating that increased investment in one structure does not necessarily drive a wholesale loss of mass in one or more organs. Organisms are faced with a finite energy budget with which to accumulate biomass in developing tissues, raising the question of how sexual selection imposes trade-offs in organ investment. We test the expectations of the expensive tissue hypothesis (ETH) across the ontogeny of oyster toadfishes, a species in which males are under strong sexual selection for a metabolically expensive acoustic repertoire that involves maintaining the fastest twitching muscles of any vertebrates. However, despite finding clear evidence of sexual dimorphism, we failed to recover any evidence supporting the expectations of the ETH.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 18
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: Passeriformes is the largest and most diverse avian order in the world and comprises the Passeri and Tyranni suborders. These suborders constitute a monophyletic group, but differ in their ecology and history of occupation of South America. We investigated the influence of biogeographic history on functional and phylogenetic diversities of Passeri and Tyranni in forest and savanna habitats in the Brazilian Amazon. We compiled species composition data for 34 Passeriformes assemblages, 12 in savannas and 22 in forests. We calculated the functional (Rao's quadratic entropy, FD Q ) and phylogenetic diversities (mean pairwise distance, MPD, and mean nearest taxon distance, MNTD), and the functional beta diversity to investigate the potential role of biogeographic history in shaping ecological traits and species lineages of both suborders. The functional diversity of Passeri was higher than for Tyranni in both habitats. The MPD for Tyranni was higher than for Passeri in forests; however, there was no difference between the suborders in savannas. In savannas, Passeri presented higher MNTD than Tyranni, while in forest areas, Tyranni assemblages showed higher MNTD than Passeri. We found a high functional turnover (~75%) between Passeri and Tyranni in both habitats. The high functional diversity of Passeri in both habitats is due to the high diversity of ecological traits exhibited by species of this group, which enables the exploitation of a wide variety of resources and foraging strategies. The higher Tyranni MPD and MNTD in forests is likely due to Tyranni being older settlers in this habitat, resulting in the emergence and persistence of more lineages. The higher Passeri MNTD in savannas can be explained by the existence of a larger number of different Passeri lineages adapted to this severe habitat. The high functional turnover between the suborders in both habitats suggests an ecological strategy to avoid niche overlap. We investigated the functional and phylogenetic diversity of Passeriformes (Passeri and Tyranni suborders) in Amazonian, and the functional beta diversity. The patterns of functional and phylogenetic diversity were a result of both the biogeographic history of each bird group, the occurrence within each habitat type, as well as the different ecological strategies shown by the species.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 19
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: The concept of niche partitioning has received considerable theoretical attention at the interface of ecology and evolution of infectious diseases. Strain theory postulates that pathogen populations can be structured into distinct nonoverlapping strains by frequency-dependent selection in response to intraspecific competition for host immune space. The malaria parasite Plasmodium falciparum presents an opportunity to investigate this phenomenon in nature, under conditions of high recombination rate and extensive antigenic diversity. The parasite's major blood-stage antigen, Pf EMP1, is encoded by the hyperdiverse var genes. With a dataset that includes thousands of var DBLα sequence types sampled from asymptomatic cases within an area of high endemicity in Ghana, we address how var diversity is distributed within isolates and compare this to the distribution of microsatellite allelic diversity within isolates to test whether antigenic and neutral regions of the genome are structured differently. With respect to var DBLα sequence types, we find that on average isolates exhibit significantly lower overlap than expected randomly, but that there also exists frequent pairs of isolates that are highly related. Furthermore, the linkage network of var DBLα sequence types reveals a pattern of nonrandom modularity unique to these antigenic genes, and we find that modules of highly linked DBLα types are not explainable by neutral forces related to var recombination constraints, microsatellite diversity, sampling location, host age, or multiplicity of infection. These findings of reduced overlap and modularity among the var antigenic genes are consistent with a role for immune selection as proposed by strain theory. Identifying the evolutionary and ecological dynamics that are responsible for the nonrandom structure in P. falciparum antigenic diversity is important for designing effective intervention in endemic areas. In this study, we test the hypothesis of niche partitioning to reduce trait overlap within a local community of Plasmodium falciparum strains. We examine patterns of diversity within the parasite's major blood-stage antigen, which is likely the playing field for parasite competition over host immune space. We observe reduced overlap among isolates and modularity among antigenic types—indications that niche partitioning is promoting the coexistence of distinct strains within this highly endemic community despite recombination through high multiplicity of infection.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 20
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: Southwest China is an important biodiversity hotspot. The interactions among the complex topography, climate change, and ecological factors in the dry-hot valley areas in southwest China may have profoundly affected the genetic structure of plant species in this region. In this study, we determined the effects of the Tanaka Line on genetic variation in the wild Bombax ceiba tree in southwest China. We sampled 224 individuals from 17 populations throughout the dry-hot valley regions. Six polymorphic expressed sequence tag–simple sequence repeat primers were employed to sequence the PCR products using the first-generation Sanger technique. The analysis based on population genetics suggested that B. ceiba exhibited a high level of gene diversity ( H E : 0.2377–0.4775; I : 0.3997–0.7848). The 17 populations were divided into two groups by cluster analysis, which corresponded to geographic characters on each side of the Tanaka Line. In addition, a Mantel test indicated that the phylogeographic structure among the populations could be fitted to the isolation-by-distance model ( r 2  = .2553, p  〈 .001). A barrier test indicated that there were obstacles among populations and between the two groups due to complex terrain isolation and geographic heterogeneity. We inferred that the Tanaka Line might have promoted the intraspecific phylogeographic subdivision and divergence of B. ceiba . These results provide new insights into the effects of the Tanaka Line on genetic isolation and population differentiation of plant species in southwest China. In the study, we used six pairs of EST-SSR primers to explore population structure and diversity of B .  cieba wild populations from both sides of Tanaka Line. Moreover, we used the Sanger sequencing of PCR products to make the results more accurate and reliable.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 21
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: The reproductive stages of the life cycle are crucial in explaining the distribution patterns of plant species because of their extreme vulnerability to environmental conditions. Despite reported evidence that seed germination is related to habitat macroclimatic characteristics, such as mean annual temperature, the effect of this trait in controlling plant species distribution has not yet been systematically and quantitatively evaluated. To learn whether seed germination can predict species distribution along altitude gradients, we examined germination data of 36 Rhododendron species in southeastern Tibet originating from contrasting altitudes, habitats, plant heights, seed masses, and phylogenies. Germination varied significantly with altitude, habitat, plant height, and phylogeny and was higher in the light than in the dark. Germination percentage was highest at 10:20°C in the light and 15:25°C in the dark. As altitude increased, germination percentages first rose and then decreased, being highest at 3,500–4,000 m. Germination percentage and rate were highest on rocky slopes, increasing as seed mass and plant height rose. Variations in germination percentage and rate were not significant at subgenera, section, and subsection levels, but they were significant at species level. The results suggested that the relationship between germination and altitude may provide insights into species distribution patterns. Further, germination patterns are a result of long-term evolution as well as taxonomic constraints. The reproductive stages of the life cycle are crucial in explaining the distribution patterns of plant species because of their extreme vulnerability to environmental conditions. Phylogeny, habitat together with biological and ecological factors can influence germination of 36 subalpine Rhododendron species from the eastern Tibetan Plateau.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 22
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 23
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: Resource selection functions (RSFs) are tremendously valuable for ecologists and resource managers because they quantify spatial patterns in resource utilization by wildlife, thereby facilitating identification of critical habitat areas and characterizing specific habitat features that are selected or avoided. RSFs discriminate between known-use resource units (e.g., telemetry locations) and available (or randomly selected) resource units based on an array of environmental features, and in their standard form are performed using logistic regression. As generalized linear models, standard RSFs have some notable limitations, such as difficulties in accommodating nonlinear (e.g., humped or threshold) relationships and complex interactions. Increasingly, ecologists are using flexible machine-learning methods (e.g., random forests, neural networks) to overcome these limitations. Herein, we investigate the seasonal resource selection patterns of mule deer ( Odocoileus hemionus ) by comparing a logistic regression framework with random forest (RF), a popular machine-learning algorithm. Random forest (RF) models detected nonlinear relationships (e.g., optimal ranges for slope and elevation) and complex interactions which would have been very challenging to discover and characterize using standard model-based approaches. Compared with standard RSF models, RF models exhibited improved predictive skill, provided novel insights about resource selection patterns of mule deer, and, when projected across a relevant geographic space, manifested notable differences in predicted habitat suitability. We recommend that wildlife researchers harness the strengths of machine-learning tools like RF in addition to “classical” tools (e.g., mixed-effects logistic regression) for evaluating resource selection, especially in cases where extensive telemetry data sets are available. Resource selection functions (RSFs, which discriminate between used and available habitats on the basis of environmental features) are widely used by ecologists and resource managers but traditional approaches (generalized linear models) have limited power to detect and characterize nonlinear responses and complex interactions. Using a population of GPS-collared migratory mule deer in Nevada, USA, as a case study, we contrasted a classical RSF approach (mixed-effects logistic regression) with a more flexible machine-learning approach (random forest). The machine-learning approach provided important insights about seasonal resource selection patterns of mule deer that would have been difficult or impossible to achieve using classical RSF methods, leading us to conclude that machine-learning methods can complement and extend classical RSF approaches, especially in cases where extensive telemetry data sets are available.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 24
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: A human-made environmental disaster due to the shipwrecked of Costa Concordia cruise vessel on the Tuscan Island of Giglio (Italy) coast and the possible pollutants release has been feared, so requiring the activation of removal operations and the monitoring of the marine environment. In the present study, the seagrass Posidonia oceanica (L.) Delile was used as a bioindicator for the impact of the Costa Concordia accident on the marine and coastal habitat. Different P. oceanica samples were collected in the shipwrecked site under different light conditions. Using high-performance thin-layer chromatography, metabolic analysis of the samples was carried out in order to highlight possible changes in the secondary metabolism due to the permanent shading and the presence of pollutant traces. Moreover, sample mutagenicity, as a consequence of the possible absorption of environmental toxicants leaked by the wreck, was assessed by the Ames test. The results highlighted the permanence of the Concordia-induced alteration in the plant secondary metabolites. However, absorption of chemical pollutants and carcinogens was not reported; this point was confirmed by the lack of mutagenic effects found for the samples tested. Our results clearly evidence that the environmental impact of Costa Concordia wreck and removal operations on P. oceanica was mainly due to the lack of light in the marine habitat. Present methodological approach, which combines metabolomic and genetic ecotoxicological analysis, could represent a suitable strategy to evaluate the impact of human disasters on the ecosystem and to monitor the environmental changes.
    Electronic ISSN: 2150-8925
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 25
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: Spatial variation in fish densities across river networks suggests that the influence of food and habitat resources on assemblages varies greatly throughout watersheds. Conceptual models predict that in situ primary production should vary with river characteristics, but the influence of autochthonous resource availability on the capacity for river reaches to support fish is poorly understood. We estimated primary production throughout the South Fork and Middle Fork of the John Day River, Oregon, by measuring diel cycles in dissolved oxygen (DO) during July 2013. Using these data, we (1) evaluated the extent to which juvenile salmonid abundance and resource limitation correlated with areas of high gross primary production (GPP), (2) developed models to predict GPP from both site-level measurements and remotely sensed data, and (3) made predictions of GPP across the entirety of the Middle Fork John Day River (MFJD) network and assessed the utility of these spatially continuous predictions for describing variation fish densities at broad scales. We produced reliable estimates of GPP at sites where DO loggers were deployed using measurements of solar exposure, water temperature, and conductivity measured at each site, as well as surrogates for these data estimated from remote sensing data sources. Estimates of GPP across fish sampling sites explained, on average, 58–63% of the variation in juvenile salmonid densities during the summer sampling period, and 51–83% during the fall sampling period, while continuous network predictions of GPP explained 44% of the variation in fish densities across 29 km of the MFJD. Further, GPP explained nearly half of the variation in juvenile steelhead dietary resource limitation, as inferred from bioenergetics modeling results. These results comprise a first effort at quantifying variation in autochthonous production across an entire river network and, importantly, provide a much-needed food-web context for guiding more effective fish and habitat management.
    Electronic ISSN: 2150-8925
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 26
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: Sea scallops ( Placopecten magellanicus ) live along the Northwest Atlantic continental shelf and are aggregated over a broad range of spatial scales (m 2 –10 5  km 2 ). However, little is known about the spatial distribution of local scallop neighborhoods, the scale at which spawning, intra-specific competition, and predator–prey interactions occur. We surveyed 30,995 km 2 of Georges Bank and the Great South Channel annually from 2003 to 2010 counting the number of scallops in 54,016 locally replicated 3.24-m 2 quadrats with underwater video. There were about 4 billion scallops occupying 11,200 km 2 of the study area in concentrations from 1 to 41 scallops per scallop. Scallop spatial distribution switched from dispersed to aggregated at a concentration of 3–4 scallops in every year. High concentrations (〉3) occurred in 11% but were only persistent in 4% (449 km 2 ) of scallop habitat. There were 13 persistent high-concentration aggregations (7–217 km 2 ), and all but two occurred on gravel-dominated sediments left by prehistoric glacial retreat. Model-derived benthic boundary shear stresses in the persistent aggregations averaged two times higher than in scallop habitat, but the seabed was about two times more stable because it had significantly less sand and more granule–pebble and cobble sediment. The area occupied by scallops each year varied little (9%) despite a 49% increase in total scallop abundance between 2005 and 2007, suggesting Georges Bank scallops have a proportional density population structure. Most scallops occurred alone or at low concentrations (≤2) where fertilization success is probably poor. The persistent high-concentration aggregations we identified may be critical for successful reproduction and sustainable harvest. Observing organisms at scales corresponding to their individual interactions reveals important processes shaping their landscape-scale spatiotemporal distributions. These processes are obscured by the methods typically employed to estimate abundances of commercial fishery species. The spatiotemporal structure of sea scallop distribution has important implications for the design of abundance surveys and the assumptions underlying stock assessment methods. These should be investigated. Finally, this work suggests that natural disturbance (sediment stability) may play a substantial role in shaping spatiotemporal distributions and dynamics of benthic marine populations.
    Electronic ISSN: 2150-8925
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 27
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: Knowledge of how zooplankton can utilize cyanobacteria to sustain their nitrogen (N) demand for essential compounds like amino acids (AAs) is a key to predicting responses of higher trophic levels in terms of production and food web structure to future enhanced water column stratification. We explored the natural abundances of bulk N and AA-specific nitrogen isotopes (δ 15 N) in particulate organic matter and mesozooplankton size-fraction samples from three vertically separated water bodies in the central Baltic Sea during two summertime cyanobacteria blooms. The combination of plankton community and isotope data together with environmental variables helped to identify a mechanism of diazotrophic AA supply (synthesized during N 2 fixation) for mesozooplankton, that largely depended on the sea surface temperature which regulated the access to the diazotrophic N-based food web in the surface water (SW). We found that in the warmer summer, thermophilic cladocerans (e.g., Bosmina spp.) benefited most from diazotrophic AAs in the SW (19.8°C), while only in the colder summer, temperate copepods (e.g., Temora longicornis ) ascended from the subjacent winter water into the SW (16.2°C) and incorporated diazotrophic AAs. Trophic position estimates based on the phenylalanine and glutamic acid δ 15 N signatures revealed that the diazotrophic AA supply into mesozooplankton was mainly indirect via feeding on mixo- and heterotrophic diets. Significantly enriched δ 15 N signatures in phenylalanine in the deep mesozooplankton (mainly copepods of Pseudo- and Paracalanus spp.) from the bottom water (BW) that was a region of the suboxic zone point to a reliance on a local food web. Mesozooplankton in the BW was feeding on diets of heterotrophic origin and probably profited from the heterotrophic re-synthesis of AAs originating from sinking organic matter, as well as from the indirect incorporation of de novo synthesized AAs that most likely originated from chemoautotrophic bacteria or archaea communities in the suboxic zone. Our findings suggest that indirect feeding on diazotrophs and chemoautotrophs will be principal ways of amino acid supply for zooplankton in future enhanced stratified aquatic systems. Only a relatively small increase in temperature may restrict temperate key species from diazotrophic N-based food webs in the mixed layer.
    Electronic ISSN: 2150-8925
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 28
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: Terrestrial organic matter (TOM) constitutes an important source of energy in many aquatic environments. This is the first study to compare the consumption of terrestrial leaves ( Alnus rubra ) to high-quality ( Nereocystis luetkeana ) and low-quality ( Fucus gardneri ) sources of drift kelp and low-quality seagrass ( Phyllospadix spp.) in pools of the rocky intertidal zone on Cape Arago, Oregon, USA. On average, 1.02 kg ash-free dry mass (AFDM) per day of TOM was transported by small forested streams during fall leaf abscission to the rocky intertidal zone in small pocket bays. Leaves of A. rubra (red alder) varied in wrack from negligible (12 g AFDM/m 2 ) on some beaches to the primary source of detritus on others (256 g AFDM/m 2 ). Long-term feeding experiments (months) showed that consumption rates of A. rubra in the spring (19.7% of the initial pack biomass) and in the fall (52% of the initial pack biomass) were intermediate between those of N. luetkeana (fully consumed) and Phyllospadix spp. (never 〉10% consumed of the initial pack biomass). Long-term experiments also showed that conditioned fall-shed leaves of A. rubra were consumed at a faster rate (52.3% of initial pack biomass) than spring-shed leaves of A. rubra (16.8% of initial pack biomass). Short-term feeding experiments again showed that consumption of A. rubra in the spring (18.6% of initial pack biomass over 3 d) and fall (16.7% over 7 d) was intermediate between N. luetkeana (57.3% consumed over 3 d in the spring and 60.7% over 7 d in the fall) and Phyllospadix spp. (〈1% consumed in the spring). Except for Phyllospadix spp., consumption rates followed polyphenolic concentrations in that, N. luetkeana (418 mg/mL) 〉  A. rubra (3415 mg/mL) 〉  F. gardneri (8098 mg/mL). Phyllospadix spp. was rarely consumed despite a fairly low concentration of phenolics (800 mg/mL). In the temperate zone, leaves of A .  rubra may constitute an important source of energy during the fall and winter when more nutritious marine resources dieback, such as single-celled algae and kelp (e.g., N. luetkeana ).
    Electronic ISSN: 2150-8925
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 29
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: The policy term green infrastructure highlights the need to maintain functional ecosystems as a foundation for sustainable societies. Because forests are the main natural ecosystems in Europe, it is crucial to understand the extent to which forest landscape management delivers functional green infrastructures. We used the steep west–east gradient in forest landscape history, land ownership, and political culture within northern Europe's Baltic Sea Region to assess regional profiles of benefits delivered by forest landscapes. The aim was to support policy-makers and planners with evidence-based knowledge about the current conditions for effective wood production and biodiversity conservation. We developed and modeled four regional-level indicators for sustained yield wood production and four for biodiversity conservation using public spatial data. The western case study regions in Sweden and Latvia had high forest management intensity with balanced forest losses and gains which was spatially correlated, thus indicating an even stand age class distribution at the local scale and therefore long-term sustained yields. In contrast, the eastern case study regions in Belarus and Russia showed spatial segregation of areas with forest losses and gains. Regarding biodiversity conservation indicators, the west–east gradient was reversed. In the Russian, Belarusian, and Latvian case study regions, tree species composition was more natural than in Sweden, and the size of contiguous areas without forest loss was larger. In all four case study regions, 54–85% of the total land base consisted of forest cover, which is above critical fragmentation thresholds for forest landscape fragmentation. The results show that green infrastructures for wood production and biodiversity conservation are inversely related among the four case study regions, and thus rival. While restoration for biodiversity conservation is needed in the west, intensified use of wood and biomass is possible in the east. However, a cautious approach should be applied because intensification of wood production threatens biodiversity. We discuss the barriers and bridges for spatial planning in countries with different types of land ownership and political cultures and stress the need for a landscape approach based on evidence-based collaborative learning processes that include both different academic disciplines and stakeholders that represent different sectors and levels of governance.
    Electronic ISSN: 2150-8925
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 30
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: Foundation species are locally abundant and uniquely control associated biodiversity, whereas dominant species are locally abundant but are thought to be replaceable in ecological systems. It is important to distinguish foundation from dominant species to direct conservation efforts. Long-term studies that remove abundant species while measuring community dynamics have the potential to (1) aid in the identification of foundation vs. dominant species and, (2) once a foundation species is identified, determine how long its effects persist within a community after its loss. Long-term data on ant assemblages within two canopy-manipulation experiments—the Harvard Forest Hemlock Removal Experiment (HF-HeRE) and the Black Rock Future of Oak Forests Experiment (BRF-FOFE)—provide insights into how ant assemblages change and reassemble following the loss of Tsuga canadensis or Quercus spp. Previous research documented foundation species effects on ants in the HF-HeRE for up to four years after T. canadensis loss. Six additional years of data at HF-HeRE presented for the first time here show that removal of T. canadensis resulted in taxonomic and some measures of functional shifts in ant assemblages that persisted for ten years, further supporting the hypothesis that T. canadensis is a foundation species at Harvard Forest. In contrast, ant assemblages at BRF-FOFE varied little regardless of whether oaks or other tree species were removed from the canopy, suggesting that Quercus species do not act as foundation species at Black Rock Forest. Deer and moose exclosures within each experiment also allowed for comparisons between effects on ants of foundation or dominant tree species relative to effects of large herbivores. At HF-HeRE, effects of T. canadensis were stronger than effects of large herbivores on taxonomic and functional diversity of ant assemblages. At BRF-FOFE, in contrast, effects of Quercus species were weaker than effects of large herbivores on ant taxonomic diversity and some measures of ant functional diversity. These findings illustrate the importance of distinguishing between the roles of irreplaceable foundation species and replaceable dominant ones in forested ecosystems along with other drivers of biodiversity (e.g., herbivory).
    Electronic ISSN: 2150-8925
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 31
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: In pediatric cancer, we advocate for trio sequencing of the child and its parents. This method can have substantial implications for cancer prevention in parents and siblings and even in more distant family members. It does not only help to identify a putative classical cancer predisposition syndrome in the index patient, but also detects the combinatorial effect of two independent risk variants in the same signaling pathway. This type of inheritance pattern could contribute to explaining the early occurrence of cancer in children and young adults and thereby inform early diagnosis, screening and preventive measures. From identifying a putative classical cancer predisposition syndrome in the index patient, trio-sequencing can also detect a potential combinatorial effect of two independent risk variants in the same signaling pathway. M. Kuhlen and A. Borkhardt explain here why they advocate for it.
    Print ISSN: 1757-4676
    Electronic ISSN: 1757-4684
    Topics: Medicine
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  • 32
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: Terrestrial primary production is a fundamental ecological process and a crucial component in understanding the flow of energy through trophic levels. The global MODIS gross primary production (GPP) and net primary production (NPP) products (MOD17) are widely used for monitoring GPP and NPP at coarse resolutions across broad spatial extents. The coarse input datasets and global biome-level parameters, however, are well-known limitations to the applicability of the MOD17 product at finer scales. We addressed these limitations and created two improved products for the conterminous United States (CONUS) that capture the spatiotemporal variability in terrestrial production. The MOD17 algorithm was utilized with medium resolution land cover classifications and improved meteorological data specific to CONUS in order to produce: (a) Landsat derived 16-day GPP and annual NPP at 30 m resolution from 1986 to 2016 (GPP L 30 and NPP L 30 , respectively); and (b) MODIS derived 8-day GPP and annual NPP at 250 m resolution from 2001 to 2016 (GPP M 250 and NPP M 250 respectively). Biome-specific input parameters were optimized based on eddy covariance flux tower-derived GPP data from the FLUXNET2015 database. We evaluated GPP L 30 and GPP M 250 products against the standard MODIS GPP product utilizing a select subset of representative flux tower sites, and found improvement across all land cover classes except croplands. We also found consistent interannual variability and trends across NPP L 30 , NPP M 250 , and the standard MODIS NPP product. We highlight the application potential of the production products, demonstrating their improved capacity for monitoring terrestrial production at higher levels of spatial detail across broad spatiotemporal scales. We produced two higher resolution primary production datasets, using better input data than currently existing datasets. These products more closely match the scale of many ecological processes and management activities, and will facilitate better understandings of production dynamics. Our products correspond well with other production datasets at multiple scales. The products fill a critical gap in our ability to monitor and assess terrestrial production dynamics in relation to many ecological processes and land use change. As production is a foundational ecological process and ecosystem service, understanding these dynamics is critical for environmental sustainability.
    Electronic ISSN: 2056-3485
    Topics: Architecture, Civil Engineering, Surveying , Biology
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  • 33
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    Wiley-Blackwell
    Publication Date: 2018-03-09
    Description: The management of conflicts between wildlife conservation and agricultural practices often involves the implementation of strategies aimed at reducing the cost of wildlife impacts on crops. Vital to the success of these strategies is the perception that changes in management efforts are synchronised relative to changes in impact levels, yet this expectation is never evaluated. We assess the level of synchrony between time series of population counts and management effort in the context of conflicts between agriculture and five populations of large grazing birds in northern Europe. We reveal inconsistent patterns of synchrony and asynchrony between changes in population counts and impact management effort relating to population harvesting, monetary payments or scaring practices. This variation is likely due to differing management aims, the existence of lags between management decisions and population monitoring, and the inconsistent use of predictive models across case studies. Overall, our findings highlight the need for more adaptive and timely responses of management to changes in target species numbers so as not to unexpectedly increase social conflicts and jeopardise the status of wildlife populations. This article is protected by copyright. All rights reserved
    Print ISSN: 1755-263X
    Electronic ISSN: 1755-263X
    Topics: Biology
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  • 34
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    Wiley-Blackwell
    Publication Date: 2018-03-09
    Electronic ISSN: 2049-6060
    Topics: Geosciences
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  • 35
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    Wiley-Blackwell
    Publication Date: 2018-03-12
    Description: No abstract is available for this article.
    Electronic ISSN: 2333-5084
    Topics: Geosciences , Physics
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  • 36
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    Wiley-Blackwell
    Publication Date: 2018-03-13
    Description: Temperature is one of most the important environmental factors that affect the ontogenesis of organisms. In this study, we incubated Chinese soft-shelled turtle eggs at 28°C (control temperature, C treatment), a temperature with a 16°C cold shock and a 36°C heat shock twice per week (S treatment) or a ramp-programmed temperature of 29 ± 9°C (with 12 hr (+) and 12 hr (−) every day) (F treatment). The incubation period, hatching success, hatchling weight, and locomotor performance were significantly different between the controls and the different heat treatment groups. The pathogen challenge results illustrated that hatchlings from the S treatment group were more resistant to bacterial infection, whereas hatchlings from the F treatment group were more vulnerable. We used RNA-seq quantification analysis to identify differentially expressed genes (DEGs) of hatchlings in the S treatment group. Based on the functional annotation results for the DEGs, 9 genes were chosen to verify the RNA-seq results. The background expression of DEGs was also analyzed for the three treatments, as was the regulation of the pathogen challenge. The results showed that 8 DEGs were related to the immune response after pathogen challenge and that temperature was an important factor in differential regulation of the immunity pathways. Hatchling traits and locomotor performance were affected by incubation temperature. Incubation temperature affected immune response of hatchlings after pathogen challenge. RNA-seq quantification analysis was used to obtain DEGs related with temperature and immunity.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 37
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    Wiley-Blackwell
    Publication Date: 2018-03-13
    Description: Enchytraeus albidus is a terrestrial earthworm widespread along the coasts of northern Europe and the Arctic. This species tolerates freezing of body fluids and survives winters in a frozen state. Their acclimatory physiological mechanisms behind freeze tolerance involve increased fluidity of membrane lipids during cold exposure and accumulation of cryoprotectants (glucose) during the freezing process. Gene regulatory processes of these physiological responses have not been studied, partly because no gene expression tools were developed. The main aim of this study was to understand whether the freeze tolerance mechanisms have a transcriptomic basis in E. albidus . For that purpose, first the transcriptome of E. albidus was assembled with RNAseq data. Second, two strains from contrasting thermal environments (Germany and Greenland) were compared by mapping barcoded RNAseq data onto the assembled transcriptome. Both of these strains are freeze tolerant, but Greenland is extremely freeze tolerant. Results showed more plastic responses in the Greenland strain as well as higher constitutive expression of particular stress response genes. These altered transcriptional networks are associated with an adapted homeostasis coping with prolonged freezing conditions in Greenland animals. Previously identified physiological alterations in freeze-tolerant strains of E. albidus are underpinned at the transcriptome level. These processes involve anion transport in the hemolymph, fatty acid metabolism, metabolism, and transport of cryoprotective sugars as well as protection against oxidative stress. Pathway analysis supported most of these processes, and identified additional differentially expressed pathways such as peroxisome and Toll-like receptor signaling. We propose that the freeze-tolerant phenotype is the consequence of genetic adaptation to cold stress and may have driven evolutionary divergence of the two strains. We studied transcriptional regulatory networks underlying cold tolerance in a natural Enchytraeus albidus population from Greenland as compared to a freeze-sensitive reference population. Constitutive overexpression of stress response genes as well as increased transcriptional plasticity of genes involved in cold tolerance-associated physiological processes seem to have shaped genetic adaptation to prolonged freezing conditions.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 38
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    Wiley-Blackwell
    Publication Date: 2018-03-13
    Description: Sepsis-associated encephalopathy (SAE), characterized as diffuse brain dysfunction and neurological manifestations secondary to sepsis, is a common complication in critically ill patients and can give rise to poor outcome, but understanding the molecular basis of this disorder remains a major challenge. Given the emerging role of G protein-coupled receptor 2 (GRK2), first identified as a G protein-coupled receptor (GPCR) regulator, in the regulation of non-GPCR-related molecules contributing to diverse cellular functions and pathology, including inflammation, we tested the hypothesis that GRK2 may be linked to the neuropathogenesis of SAE. When mouse MG6 microglial cells were challenged with lipopolysaccharide (LPS), GRK2 cytosolic expression was highly upregulated. The ablation of GRK2 by small interfering RNAs (siRNAs) prevented an increase in intracellular reactive oxygen species generation in LPS-stimulated MG6 cells. Furthermore, the LPS-induced upregulation of inducible nitric-oxide synthase expression and increase in nitric oxide production were negated by GRK2 inhibitor or siRNAs. However, GRK2 inhibition was without effect on overproduction of tumor necrosis factor-α, interleukin (IL)-6, and IL-1β in LPS-stimulated MG cells. In mice with cecal ligation and puncture-induced sepsis, treatment with GRK2 inhibitor reduced high levels of oxidative and nitrosative stress in the mice brains, where GRK2 expression was upregulated, alleviated neurohistological damage observed in cerebral cortex sections, and conferred a significant survival advantage to CLP mice. Altogether, these results uncover the novel role for GRK2 in regulating cellular oxidative and nitrosative stress during inflammation and suggest that GRK2 may have a potential as an intriguing therapeutic target to prevent or treat SAE. This article is protected by copyright. All rights reserved.
    Print ISSN: 0022-3042
    Electronic ISSN: 1471-4159
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  • 39
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    Wiley-Blackwell
    Publication Date: 2018-03-13
    Description: Epigenetic modifications through methylation of DNA and acetylation of histones modulate neuronal gene expression and regulate long-term memory. Earlier we demonstrated that scopolamine-induced decrease in memory consolidation is correlated with enhanced expression of hippocampal DNA methyltransferase 1 (DNMT1) and histone deacetylase 2 (HDAC2) in mice. DNMT1 and HDAC2 act together by recruiting a co-repressor complex and deacetylating the chromatin. The catalytic activity of HDACs is mainly dependent on its incorporation into multiprotein co-repressor complexes, among which SIN3A-HDAC2 co-repressor is widely studied to regulate synaptic plasticity. However, the involvement of co-repressor complex in regulating memory loss or amnesia is unexplored. The present study examines the role of co-repressor SIN3A in scopolamine-induced amnesia through epigenetic changes in the hippocampus. Scopolamine treatment remarkably enhanced hippocampal SIN3A expression in mice. To prevent such increase in SIN3A expression, we used hippocampal infusion of SIN3A-siRNA and assessed the effect of SIN3A silencing on scopolamine-induced amnesia. Silencing of SIN3A in amnesic mice reduced the binding of HDAC2 at neuronal immediate early genes (IEGs) promoter, but did not change the expression of HDAC2. Further, it increased acetylation of H3K9 and H3K14 at neuronal IEGs (Arc, Egr1, Homer1 and Narp) promoter, prevented scopolamine-induced downregulation of IEGs and improved consolidation of memory during novel object recognition task. These findings together suggest that SIN3A has a critical role in regulation of synaptic plasticity and might act as a potential therapeutic target to rescue memory decline during amnesia and other neuropsychiatric pathologies. This article is protected by copyright. All rights reserved.
    Print ISSN: 0022-3042
    Electronic ISSN: 1471-4159
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  • 40
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    Wiley-Blackwell
    Publication Date: 2018-03-13
    Description: Hemopexin (Hpx) binds heme with extraordinary affinity, and after haptoglobin may provide a second line of defense against the toxicity of extracellular hemoglobin (Hb). In this series of experiments, the hypothesis that Hpx protects neurons from Hb neurotoxicity was evaluated in murine primary cultures containing neurons and glial cells. Contrary to hypothesis, Hpx increased neuronal loss due to micromolar concentrations of Hb by 4-12-fold, as measured by LDH release assay; conversely, the neurotoxicity of hemin was completely prevented. The endogenous fluorescence of Hpx was quenched by Hb, consistent with transfer of Hb-bound heme to Hpx. This was associated with precipitation of globin chains, as detected by immunostaining and fluorescent Hb labeling. A portion of this precipitate attached firmly to cells and could not be removed by multiple washes. Concomitant treatment with haptoglobin (Hp) prevented globin precipitation and most of the increase in neuronal loss. Hpx weakly attenuated the increase in culture non-heme iron produced by Hb treatment, quantified by ferrozine assay. However, Hb-Hpx toxicity was iron-dependent, and was blocked by deferoxamine and ferrostatin-1. Upregulation of cell ferritin expression, a primary cell defense against Hb toxicity, was not observed on Western blots of culture lysates that had been concomitantly treated with Hpx. These results suggest that Hpx destabilizes Hb in the absence of haptoglobin, leading to globin precipitation and exacerbation of iron-dependent oxidative cell injury. Combined therapy with hemopexin plus haptoglobin may be preferable to hemopexin alone after CNS hemorrhage. This article is protected by copyright. All rights reserved.
    Print ISSN: 0022-3042
    Electronic ISSN: 1471-4159
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  • 41
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    Wiley-Blackwell
    Publication Date: 2018-03-13
    Description: The indirect pathway striatal medium spiny projection neurons (iMSNs) are critical to motor and cognitive brain functions. These neurons express a high level of cAMP-increasing adenosine A2a receptors (A2aRs). However, the potential effects of cAMP production on iMSN spiking activity have not been established, and recording identified iMSNs in freely moving animals is challenging. Here we show that in the transgenic mice expressing cAMP-producing G protein G s -coupled designer receptor exclusively activated by designer drug (Gs-DREADD) in iMSNs, the baseline spike firing in MSNs is normal, indicating DREADD expression does not affect the normal physiology of these neurons. Intraperitoneal (IP) injection of the DREADD agonist clozapine-N-oxide (CNO; 2.5 mg/kg) increased the spike firing in 50% of the recorded MSNs. However, CNO did not affect MSN firing in Gs-DREADD negative mice. We also found that CNO injection inhibited the spike firing of globus pallidus external segment (GPe) neurons in Gs-DREADD positive mice, further indicating CNO excitation of iMSNs. Temporally coincident with these effects on spiking firing in the indirect pathway, CNO injection selectively inhibited locomotion in D2 Gs-DREADD mice. Taken together, our results strongly suggest that cAMP production in iMSNs can increase iMSN spiking activity and cause motor inhibition, thus addressing a long-standing question about the cellular functions of the cAMP-producing A2aRs in iMSNs. This article is protected by copyright. All rights reserved.
    Print ISSN: 0022-3042
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  • 42
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    Wiley-Blackwell
    Publication Date: 2018-03-13
    Description: The evidence of gut microbiota-mediated modulation of brain function has been widely recognized from studies using germ-free rodents or animals with oral antibiotic-induced microbiota depletion. Since the number of bacteria in the large intestine greatly exceeds that found within the small intestine, large intestinal microbiota may play a crucial role in the modulation of brain function. In the present study, twelve piglets (12.08 ± 0.28 kg) fitted with a T-cannula at the distal ileum were fed a standard diet and randomly assigned to two groups (n=6) for ileal infusion of either saline (control group) or antibiotics (antibiotic group). After 25-days of infusion, ileal and fecal microbiota, serum amino acids and neurotransmitters, and hypothalamic transcriptomics were analyzed. Whilst the antibiotic infusion did not change the proximal ileal microbial composition, it markedly altered the fecal microbial composition and increased aromatic amino acid (AAAs) metabolism ( P 〈0.05), suggesting the infusion specifically targeted large intestinal microbes. Concentrations of AAAs were likewise decreased in the blood and hypothalamus ( P 〈0.05) by antibiotic infusion. Antibiotic infusion further decreased concentrations of hypothalamic 5-HT and dopamine, in line with AAAs being their precursors. Furthermore, an upregulation in gene expressions of neurotransmitter transporters and synthetases was observed ( q 〈0.001). In conclusion, the ileal-antibiotic infusion altered neurotransmitter expression in the porcine hypothalamus and this effect occurred simultaneously with changes in both the large intestinal microbiota, and AAAs in large intestine, blood and hypothalamus. These findings indirectly indicate that large intestinal microbiota affects hypothalamic neurotransmitter expressions. This article is protected by copyright. All rights reserved.
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  • 43
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    Wiley-Blackwell
    Publication Date: 2018-03-13
    Description: Biomarkers for α-synuclein are needed for diagnosis and prognosis in Parkinson's disease (PD). Endogenous auto-antibodies to α-synuclein could serve as biomarkers for underlying synucleinopathy, but previous assessments of auto-antibodies have shown variability and inconsistent clinical correlations. We hypothesized that auto-antibodies to α-synuclein could be diagnostic for PD and explain its clinical heterogeneity. To test this hypothesis, we developed an enzyme-linked immunosorbent assay for measuring α-synuclein auto-antibodies in human samples. We evaluated 69 serum samples (16 healthy controls (HC) and 53 PD patients) and 145 CSF samples (52 HC and 93 PD patients) from our Institution. Both serum and CSF were available for 24 participants. Males had higher auto-antibody levels than females in both fluids. CSF auto-antibody levels were significantly higher in PD patients as compared to HC, whereas serum levels were not significantly different. CSF auto-antibody levels did not associate with amyloid-β 1-42 , total tau, or phosphorylated tau. CSF auto-antibody levels correlated with performance on the Montreal Cognitive Assessment, even when controlled for CSF amyloidβ 1-42 . CSF hemoglobin levels, as a proxy for contamination of CSF by blood during lumbar puncture, did not influence these observations. Using recombinant α-synuclein with N- and C-terminal truncations, we found that CSF auto-antibodies target amino acids 100 through 120 of α-synuclein. We conclude that endogenous CSF auto-antibodies are significantly higher in PD patients as compared to HC, suggesting that they could indicate the presence of underlying synucleinopathy. These auto-antibodies associate with poor cognition, independently of CSF amyloidβ 1-42 ., and target a select C-terminal region of α-synuclein. This article is protected by copyright. All rights reserved.
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  • 44
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    Wiley-Blackwell
    Publication Date: 2018-03-14
    Electronic ISSN: 1942-2466
    Topics: Geography , Geosciences
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  • 45
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    Wiley-Blackwell
    Publication Date: 2018-03-16
    Description: Payments for ecosystem services (PES) are expected to promote ecological restoration while simultaneously improving human livelihoods. As an adaptive management tool, PES programs should be dynamic and adjusted according to changing natural and socio-economic contexts. Taking the implementation of China's famous ecological restoration policy known as the Grain for Green Program (GGP) in the Wolong National Nature Reserve as an example, we analyzed changes in the livelihood capitals and strategies of local households that had participated in the GGP over a 10-year period and discussed the implications of these changes for the next stage of the program's implementation. Data were collected from a locally implemented questionnaire in both 2004 and 2015. We found that local livelihood capitals and strategies had experienced dramatic change over the 10-year period. Natural capital decreased and was unequally distributed among local respondents. In terms of financial capital, despite that agricultural and nonagricultural income increased, compensation from the GGP decreased and did not keep pace with increasing cost of cropland, household income and more broadly national economic development and inflation. Regarding human capital, the local labor force is facing huge transformational pressures. In particular, there is a increase in the supply of local labor force aged between 21 and 40 and the implications of this for the future of the GGP should be given more attention. The findings have demonstrated that: Some changes in participants’ livelihood were expected by the GGP but were not evenly distributed among the participants; and PES programs are embedded in changing and multi-dimensional socio-economic contexts, and so their design and implementation must be coordinated with other related policies if they are to achieve long-term success. Participants’ livelihoods have changed much in 10 years since Grain for Green Program implementation. These changes would feedback on the program itself and its sustainability in the long term. Payment for ecosystem service should be adjusted according to changing situations.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 46
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    Wiley-Blackwell
    Publication Date: 2018-03-16
    Description: Changes in microclimate, soil physicochemical properties, understory vegetation cover, diversity, and composition as well as soil microbial community resulting from silvicultural practices are expected to alter soil food webs. Here, we investigated whether and how contrasting-sized canopy openings affect soil nematode community within a 30 year-aged spruce plantation. The results indicated that the responses of soil nematodes to canopy opening size were dependant on their feeding habit. The abundance of total nematodes and that of free-living nematodes was negatively correlated with soil bulk density, whereas the abundance of omnivore–predators was negatively correlated with soil bulk density and shrubs cover, respectively. The ratio of the sum abundance of predators and omnivores to the plant parasites’ abundance, Simpson's dominance index, Pielou's evenness index, and sigma maturity index, maturity index (MI), MI 2-5 , basal index, enrichment index, and structure index was sensitive to alteration in canopy opening size. Multivariate analysis indicated that thinning-induced gap size resulted in contrasting nematode assemblages. In conclusion, soil nematodes should be integrated as an indicator to monitor soil multifunctionality change due to thinning. The responses of soil nematodes to gap size varied with the guilds of nematodes. Fine root biomass was positively related to abundance of total nematodes and plant parasites, while total microbial biomass, gap size, and soil water content were positively correlated to omnivore–predators abundance. The Pielou's evenness index, structure index, and the ratio of predatory to parasites were sensitive to gap size change. Means with the same letter are not different at the 5% level of significance based on the Tukey’s honestly significant difference tests.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 47
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    Wiley-Blackwell
    Publication Date: 2018-03-07
    Description: Biogenic volatile organic compounds (BVOCs) are major precursors of both ozone and secondary organic aerosols (SOA) in the troposphere and represent a non-negligible portion of the carbon fixed by primary producers, but long-term ecosystem scale measurements of their exchanges with the atmosphere are lacking. In this study the fluxes of 46 ions corresponding to 36 BVOCs were continuously monitored along with the exchanges of mass (carbon dioxide, water vapour) and energy (sensible and latent heat) for an entire year in a poplar ( Populus ) short-rotation crop (SRC), using the eddy covariance methodology. BVOC emissions mainly consisted of isoprene, acetic acid and methanol. Total net BVOC emissions were 19.20 kg C ha −1 yr −1 , which represented 0.63% of the net ecosystem exchange (NEE), resulting from −23.59 Mg C ha −1 yr −1 fixed as CO 2 and 20.55 Mg C ha −1 yr −1 respired as CO 2 from the ecosystem. Isoprene emissions represented 0.293% of NEE, being emitted at a ratio of 1:1709 mol isoprene per mol of CO 2 fixed. Based on annual ecosystem-scale measurements this study quantified for the first time that BVOC carbon emissions were lower than previously estimated in other studies (0.5-2% of NEE) on poplar trees. Furthermore, the seasonal and diurnal emission patterns of isoprene, methanol and other BVOCs provided a better interpretation of the relationships with ecosystem CO 2 and water vapour fluxes, with air temperature, vapour pressure deficit and photosynthetic photon flux density. This article is protected by copyright. All rights reserved.
    Print ISSN: 1757-1693
    Electronic ISSN: 1757-1707
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 48
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    Wiley-Blackwell
    Publication Date: 2018-03-09
    Description: Genomic studies have been used to identify genes underlying many important plant secondary metabolic pathways. However, genes for salicinoid phenolic glycosides (SPGs)—ecologically important compounds with significant commercial, cultural, and medicinal applications—remain largely undescribed. We used a linkage map derived from a full-sib population of hybrid cottonwoods ( Populus spp.) to search for quantitative trait loci (QTL) for the SPGs salicortin and HCH-salicortin. SSR markers and primer sequences were used to anchor the map to the V3.0 P. trichocarpa genome. We discovered 21 QTL for the two traits, including a major QTL for HCH-salicortin ( R 2  = .52) that colocated with a QTL for salicortin on chr12. Using the V3.0 Populus genome sequence, we identified 2,983 annotated genes and 1,480 genes of unknown function within our QTL intervals. We note ten candidate genes of interest, including a BAHD-type acyltransferase that has been potentially linked to Populus SPGs. Our results complement other recent studies in Populus with implications for gene discovery and the evolution of defensive chemistry in a model genus. To our knowledge, this is the first study to use a full-sib mapping population to identify QTL intervals and gene lists associated with SPGs. Salicinoid phenolic glycosides (SPGs) are important secondary metabolites with numerous ecological, commercial, and ethnobotanical applications. However, the pathways controlling the expression of SPGs remain conspicuously underscribed. Here, discuss 25 quantitative trait loci (QTL) associated with the salicinoid phenolic gylcosides, salicortin and HCH-salicortin, and a number of potential candidate genes that occur within our QTL intervals.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 49
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    Wiley-Blackwell
    Publication Date: 2018-03-09
    Description: In article number 1700124 , Pedro M. Martins, Senentxu Lanceros-Méndez, and co-workers show for the first time the immobilization of photocatalytic titanium dioxide (TiO 2 ) nanoparticles in a polymer (PVDF) onto the surface of polymeric optical fibers, which can be applied in environmental decontamination. The optical fibers not only act as a material of light transportation but also an immobilization matrix for the PVDF/TiO 2 composite, thus radiation and the photocatalytic effect are provided by the same material. The immobilization of TiO 2 in the polymer improves the stability of the coating and consequently its reusability, which is important for practical applications. As light is transmitted through the fibers until the end tip, remote environments deployed of light access, as it is the case of soil and deep water, can be reached and decontaminated. This work combines the practicability of the optical fibers to transport radiation, the chemical resilience of the PVDF coating, and the catalytic properties of TiO 2 into a single material.
    Electronic ISSN: 2056-6646
    Topics: General, Interdisciplinary , Energy, Environment Protection, Nuclear Power Engineering
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  • 50
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    Wiley-Blackwell
    Publication Date: 2018-03-09
    Electronic ISSN: 2056-6646
    Topics: General, Interdisciplinary , Energy, Environment Protection, Nuclear Power Engineering
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  • 51
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    Wiley-Blackwell
    Publication Date: 2018-03-12
    Description: Ongoing controversy over logging the ancient Białowieża Forest in Poland symbolizes a global problem for policies and management of the increasing proportion of the earth's intact forest that is subject to post-disturbance logging. We review the extent of, and motivations for, post-disturbance logging in protected and unprotected forests globally. An unprecedented level of logging in protected areas and other places where green-tree harvest would not normally occur is driven by economic interests and a desire for pest control. To avoid failure of global initiatives dedicated to reducing the loss of species, five key policy reforms are necessary: (1) salvage logging must be banned from protected areas; (2) forest planning should address altered disturbance regimes for all intact forests to ensure that significant areas remain undisturbed by logging; (3) new kinds of integrated analyses are needed to assess the potential economic benefits of salvage logging against its ecological, economic, and social costs; (4) global and regional maps of natural disturbance regimes should be created to guide better spatio-temporal planning of protected areas and undisturbed forests outside reserves; and (5) improved education and communication programs are needed to correct widely-held misconceptions about natural disturbances. This article is protected by copyright. All rights reserved
    Print ISSN: 1755-263X
    Electronic ISSN: 1755-263X
    Topics: Biology
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  • 52
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    Wiley-Blackwell
    Publication Date: 2018-03-13
    Description: Building resilience to natural disturbances is a key to managing forests for adaptation to climate change. To date, most climate adaptation guidance has focused on recommendations for frequent-fire forests, leaving few published guidelines for forests that naturally experience infrequent, stand-replacing wildfires. Because most such forests are inherently resilient to stand-replacing disturbances, and burn severity mosaics are largely indifferent to manipulations of stand structure (i.e., weather-driven, rather than fuel-driven fire regimes), we posit that pre-fire climate adaptation options are generally fewer in these regimes relative to others. Outside of areas of high human value, stand-scale fuel treatments commonly emphasized for other forest types would undermine many of the functions, ecosystem services, and other values for which these forests are known. For stand-replacing disturbance regimes, we propose that (1) managed wildfire use (e.g., allowing natural fires to burn under moderate conditions) can be a useful strategy as in other forest types, but likely confers fewer benefits to long-term forest resilience and climate adaptation, while carrying greater socio-ecological risks; (2) reasoned fire exclusion (i.e., the suppression component of a managed wildfire program) can be an appropriate strategy to maintain certain ecosystem conditions and services in the face of change, being more ecologically justifiable in long-interval fire regimes and producing fewer of the negative consequences than in frequent-fire regimes; (3) low-risk pre-disturbance adaptation options are few, but the most promising approaches emphasize fundamental conservation biology principles to create a safe operating space for the system to respond to change (e.g., maintaining heterogeneity across scales and minimizing stressors); and (4) post-disturbance conditions are the primary opportunity to implement adaptation strategies (such as protecting live tree legacies and testing new regeneration methods), providing crucial learning opportunities. This approach will provide greater context and understanding of these systems for ecologists and resource managers, stimulate future development of adaptation strategies, and illustrate why public expectations for climate adaptation in these forests will differ from those for frequent-fire forests.
    Electronic ISSN: 2150-8925
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 53
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    Wiley-Blackwell
    Publication Date: 2018-03-13
    Description: Behavioral responses of prey to predation risk can affect lower trophic levels. White-tailed deer ( Odocoileus virginianus ; hereafter deer) increase vigilance in response to coyote ( Canis latrans ) presence, but vigilance responses to spatiotemporal variation in coyote abundance are unknown. Therefore, we examined the relationship between deer foraging behavior and coyote abundance on two 2000-ha study areas in Georgia, USA, during 2010–2013. We used baited camera traps during fall and winter to quantify deer behavior (i.e., feeding or vigilant) and estimated coyote abundance using fecal genotyping to noninvasively mark and recapture individuals. During 2011 and 2012, coyote removals were implemented on each study area. Coyote abundance (i.e., predation risk) varied spatiotemporally and was a predictor of foraging behavior during at least one season for all sex-age classes of deer except juveniles. Adult males were more sensitive to predation risk in winter, after the breeding season, whereas adult females were sensitive to predation risk during both seasons, but more so during fall when offspring are at greater risk. Yearling males were more sensitive to predation risk than adult males, and juveniles were least sensitive to predation risk, likely because of inexperience and high energetic demands. Reproductive chronology explained sex-specific and seasonal antipredator responses to predation risk, but there was a non-linear relationship between indirect predator effects and direct predation risk for some sex-age classes. Our results suggest deer detect and respond behaviorally to variation in coyote abundance. Due to the widespread distribution of deer and their interactions at multiple trophic levels, the ecological implications of this finding may be wide-reaching.
    Electronic ISSN: 2150-8925
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 54
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    Wiley-Blackwell
    Publication Date: 2018-03-13
    Description: With wildlife populations in decline, understanding their distributions across the landscape are needed for management and conservation efforts, particularly in remote or hazardous regions. We used indigenous local knowledge to inform species distribution models (SDMs) to predict the distribution of 38 wildlife species historically documented in Somaliland, one of the most isolated, data-poor regions in Africa. We conducted 195 interviews with agro-pastoral men and women in 2016 and 2017 throughout Somaliland based on the environmental range captured by performing a Multivariate Environmental Similarity Surface (MESS) analysis. Respondents were asked if each species (1) occurred in the vicinity, and if they did, (2) whether it was common, rare, extirpated, or unknown. We tested two commonly used SDMs, Maxent and boosted regression trees (BRTs), to map the potential distribution of wildlife using interview data. We present detailed case studies of two species of high conservation priority: cheetah ( Acinonyc jubatus ) and African wild ass ( Equus africanus somaliensis ). More than half of the respondents reported the presence of 25 of the wildlife species in the survey. Additionally, we developed Maxent models for all surveyed wildlife known to develop a species richness map. The least reported species known to have inhabited Somaliland in recent decades were lion ( Panthera leo ), African wild ass, and Somali wild dog ( Lycaon pictus somalicus ). Surprisingly, 177 of respondents reported the presence of cheetah, which was presumed by many to be extirpated from Somaliland. Given the high number of reports, coupled with the BRT model results and evaluations, it may be that cheetahs persist throughout Somaliland. Unfortunately, our results also suggest that African wild ass may have been extirpated from Somaliland. Our models carry the uncertainties of the raw data, but provide habitat suitability maps to guide future targeted surveys. Our methods and results demonstrate that integrating indigenous local knowledge with SDMs may be an essential tool for the conservation of wildlife in data-poor regions.
    Electronic ISSN: 2150-8925
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 55
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    Wiley-Blackwell
    Publication Date: 2018-03-13
    Description: Molybdenum disulfide (MoS 2 ), a type of transition metal dichalcogenide material, has emerged as an important class among 2D systems. When 2D MoS 2 materials are reduced to 0D quantum dots (QDs), they introduce new optical properties that point to several potential technological advantages in electronic, magnetic, optical, and catalytic properties. In this study, a simple way to produce chiral MoS 2 QDs from MoS 2 nanopowder is presented using l (+)-ascorbic acid as a reducing agent. The calculated quantum yield of QDs is 11.06%. Experimental results reveal that the size of QDs is uniformly monodispersed (2–3 nm) and have a blue emissive fluorescence peak and circular dichroism (CD) peak located at 420 and 330 nm, respectively. Furthermore, a dual-mode detection system based on fluorescence and chirality is performed using as-synthesized MoS 2 QDs, where QDs are conjugated with anti-hemagglutinin antibodies of avian influenza virus and made into an immunobridge in the presence of target virus and anti-neuraminidase antibodies conjugated magnetic nanoparticles (MNPs). The photoluminescence and CD spectra of unconjugated QDs after separated magnetochirofluorescent (MNPs-QDs) nanohybrids by external magnets enables influenza virus A (H5N1) detection with the limit of detection value of 7.35 and 80.92 pg mL −1 , respectively. A dual-mode biosensing detection system based on fluorescence and chirality of MoS 2 quantum dots for avian influenza viruses is described.
    Electronic ISSN: 2056-6646
    Topics: General, Interdisciplinary , Energy, Environment Protection, Nuclear Power Engineering
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  • 56
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    Wiley-Blackwell
    Publication Date: 2018-03-14
    Description: Ectotherms tend to grow faster, but reach a smaller size when reared under warmer conditions. This temperature-size rule (TSR) is a widespread phenomenon. Despite the generality of this pattern, no general explanation has been found. We therefore tested the relative importance of two proposed mechanisms for the TSR: (1) a stronger increase in development rate relative to growth rate at higher temperatures, which would cause a smaller size at maturity, and (2) resource limitation placing stronger constraints on growth in large individuals at higher temperatures, which would cause problems with attaining a large size in warm conditions. We raised Daphnia magna at eight temperatures to assess their size at maturity, asymptotic size, and size of their offspring. We used three clonal lines that differed in asymptotic size and growth rate. A resource allocation model was developed and fitted to our empirical data to explore the effect of both mechanisms for the TSR. The genetic lines of D. magna showed different temperature dependence of growth and development rates resulting in different responses for size at maturity. Also, at warm temperatures, growth was constrained in large, but not in small individuals. The resource allocation model could fit these empirical data well. Based on our empirical results and model explorations, the TSR of D. magna at maturity is best explained by a stronger increase in development rate relative to growth rate at high temperature, and the TSR at asymptotic size is best explained by a size-dependent and temperature-dependent constraint on growth, although resource limitation could also affect size at maturity. In conclusion, the TSR can take different forms for offspring size, size at maturity, and asymptotic size and each form can arise from its own mechanism, which could be an essential step toward finding a solution to this century-old puzzle. Scientists have known that ectotherms tend to reach larger sizes when they grow in colder environments. We now identified three distinct patterns in this phenomenon and discuss how these patterns could be regulated by different physiological mechanisms. We use a novel resource allocation model to describe these patterns and to test the hypothesized mechanisms underlying them.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 57
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    Wiley-Blackwell
    Publication Date: 2018-03-14
    Description: Global change is affecting primary productivity in forests worldwide, and this, in turn, will alter long-term carbon (C) sequestration in wooded ecosystems. On one hand, increased primary productivity, for example, in response to elevated atmospheric carbon dioxide (CO 2 ), can result in greater inputs of organic matter to the soil, which could increase C sequestration belowground. On other hand, many of the interactions between plants and microorganisms that determine soil C dynamics are poorly characterized, and additional inputs of plant material, such as leaf litter, can result in the mineralization of soil organic matter, and the release of soil C as CO 2 during so-called “priming effects”. Until now, very few studies made direct comparison of changes in soil C dynamics in response to altered plant inputs in different wooded ecosystems. We addressed this with a cross-continental study with litter removal and addition treatments in a temperate woodland (Wytham Woods) and lowland tropical forest (Gigante forest) to compare the consequences of increased litterfall on soil respiration in two distinct wooded ecosystems. Mean soil respiration was almost twice as high at Gigante (5.0 μmol CO 2  m −2  s −1 ) than at Wytham (2.7 μmol CO 2  m −2  s −1 ) but surprisingly, litter manipulation treatments had a greater and more immediate effect on soil respiration at Wytham. We measured a 30% increase in soil respiration in response to litter addition treatments at Wytham, compared to a 10% increase at Gigante. Importantly, despite higher soil respiration rates at Gigante, priming effects were stronger and more consistent at Wytham. Our results suggest that in situ priming effects in wooded ecosystems track seasonality in litterfall and soil respiration but the amount of soil C released by priming is not proportional to rates of soil respiration. Instead, priming effects may be promoted by larger inputs of organic matter combined with slower turnover rates. Taken together, results of our cross-continental study with litter removal and addition treatments in a temperate woodland (Wytham Woods) and lowland tropical forest (Gigante forest) for comparing consequences of increased litterfall on soil respiration in two distinct wooded ecosystems showed that mean soil respiration was almost twice as high at Gigante than at Wytham but surprisingly, litter manipulation treatments had a greater and more immediate effect on soil respiration at Wytham. Importantly, despite higher soil respiration rates at Gigante, priming effects were stronger and more consistent at Wytham. Our results suggest that in situ priming effects in wooded ecosystems track seasonality in litterfall and soil respiration but the amount of soil C released by priming is not proportional to rates of soil respiration.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 58
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    Wiley-Blackwell
    Publication Date: 2018-03-14
    Description: Species composition is constrained by two upper-level processes in ecological contexts where the dispersion of organisms is not severely limited, namely selection and ecological drift. This intuitive framework has motivated a constant flow of empirical models for linking the species matrix to the local environmental descriptors, in which the environment rarely explains more than 30–40% of the variation in species composition. In most cases, researchers only approximate the environmental axes that drive fitness differences between species, as the list of measured descriptors reflect both logistical constraints and hypothesis-driven questions. Moreover, contextual factors, such as the species pool size (SPS) and the spatial extent of the sampled area, could moderate species–environment associations through sampling effects and dispersal limitations. This study's objective was to quantify the influence of contextual factors (i.e., related to the circumstances in which the study was conducted) on the species–environment association strength on the basis of a synthesis of 156 models of forest bird communities. Our results reveal that factors related to the SPS and the number of independent environmental axes studied affect our capacity to detect selection, whereas spatial factors such as the study's spatial extent and latitude are less important determinants. The study context explains almost a third of the observed variation in the strength of the species–environment association. We conclude that strong species–environment associations can be found for properly designed studies of forest bird communities, which raises the question of whether ecologists have underestimated the importance of selection in community assembly processes.
    Electronic ISSN: 2150-8925
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 59
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    Wiley-Blackwell
    Publication Date: 2018-03-14
    Description: Management, environment, and agroecosystem type are key factors influencing photosynthetic carbon (C) uptake and C use efficiency (CUE), calculated as the ratio of net ecosystem production to gross ecosystem production (NEP:GEP). Current literature has mainly emphasized annual C balance in studies involving multiple years with continuous monitoring of ecosystem C fluxes, yet CUE has not been thoroughly analyzed during the growing season, particularly in paired comparisons of contrasting types of pasture under semiarid conditions. From 2009 through 2013, we used eddy covariance method to determine daily, seasonal, and annual C budgets in rainfed alfalfa ( Medicago sativa L.) and grass ecosystems subjected to periodic harvest (haying) near Mandan, North Dakota, USA. We found consistently higher magnitudes of C fluxes (ecosystem respiration [ER], NEP, GEP) and hay production in alfalfa than grassland. Leaf area and canopy nitrogen content per unit land area were key driving factors for daily, seasonal, and annual differences in C fluxes between agroecosystems. Net ecosystem C balance indicated C losses occurred through haying in both ecosystems, though no changes in soil C stocks were detected in either ecosystem over the course of the study. Mean NEP:GEP ratios (±standard error) during periods of steady carbon dioxide (CO 2 ) uptake before and after haying were 0.43 ± 0.01 and 0.26 ± 0.03 for alfalfa and grassland, respectively, implying more efficient C use in the former. Moreover, alfalfa had consistently greater CUE than grassland despite variations in sunlight, temperature, and precipitation within and between growing seasons. Ratios of ER to GEP were also repeatedly lower in alfalfa than grassland in all five growing seasons. Under drought conditions, we infer alfalfa roots accessed water in the soil profile unavailable to more shallow-rooted grass species. Overall, hayed alfalfa was more efficient and tolerant than grassland in assimilating and using atmospheric CO 2 under variable intra- and inter-seasonal conditions. Outcomes from this study suggest the inclusion of alfalfa in unirrigated crop rotations can sustain high CUE, C uptake, and hay production while mitigating C losses in a semiarid environment.
    Electronic ISSN: 2150-8925
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 60
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    Wiley-Blackwell
    Publication Date: 2018-03-14
    Description: Termite mounds perform important roles in savanna ecosystems, generating heterogeneity and influencing ecosystem processes across multiple trophic levels. However, the influence the environment and neighboring termite colonies have on mound spatial patterning and structure is poorly understood, despite the profound implications such dynamics can have on ecosystems. To better understand these drivers, we mapped the spatial distribution and size of active and inactive Macrotermes mounds in eight 1-km 2 plots on contrasting geologies, nutrient-rich granite and nutrient-poor basalt, in a semi-arid Zimbabwean savanna. Although mound density was not significantly different between basalt (5.5 mounds/ha) and granite (6.1 mounds/ha), termite mound structural attributes and spatial distribution patterns varied greatly between geologies. Mound size distributions differed between the geologies and mounds were 2.6 times taller and 3.9 times wider and had 15 times greater lateral surface area on granite. Subsequently, 6% of the total landscape was covered by mounds on granite compared with only 0.4% on basalt. On granite, large mounds exhibited significant over-dispersion at scales below 30 m, signifying density-dependent thinning. Furthermore, small mounds were clustered around large mounds, likely a result of the budding of new colonies comprising fully fledged castes less vulnerable to competition. In contrast, random patterning was evident on comparably homogenous basalt. Our results demonstrate the powerful influence geological substrate has on mound spatial patterning and structure, suggesting that the importance of termite mounds for ecosystem functioning is more pronounced on nutrient-poor granitic substrates than basalts because of the pronounced over-dispersion, which maximizes mound production per unit area, and much larger mound sizes here.
    Electronic ISSN: 2150-8925
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 61
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    Wiley-Blackwell
    Publication Date: 2018-03-14
    Description: For organisms with complex life cycles, climate change can have both direct effects and indirect effects that are mediated through plastic responses to temperature and that carry over beyond the developmental environment. We examined multiple responses to environmental warming in a dragonfly, a species whose life history bridges aquatic and terrestrial environments. We tested larval survival under warming and whether warmer conditions can create carry-over effects between life history stages. Rearing dragonfly larvae in an experimental warming array to simulate increases in temperature, we contrasted the effects of the current thermal environment with temperatures +2.5° and +5°C above ambient, temperatures predicted for 50 and 100 yr in the future for the study region. Aquatic mesocosms were stocked with dragonfly larvae ( Erythemis collocata ), and we followed survival of larvae to adult emergence. We also measured the effects of warming on the timing of the life history transition to the adult stage, body size of adults, and the relative size of their wings, an aspect of morphology key to flight performance. There was a trend toward reduced larval survival with increasing temperature. Warming strongly affected the phenology of adult emergence, advancing emergence by up to a month compared with ambient conditions. Additionally, our warmest conditions increased variation in the timing of adult emergence compared with cooler conditions. The increased variation with warming arose from an extended emergence season with fewer individuals emerging at any one time. Altered emergence patterns such as we observed are likely to place individuals emerging outside the typical season at greater risk from early and late season storms and will reduce effective population sizes during the breeding season. Contrary to expectations for ectotherms, body size was unaffected by warming. However, morphology was affected: at +5°C, dragonflies emerging from mesocosms had relatively smaller wings. This provides some of the first evidence that the effects of climate change on animals during their growth can have carry-over effects in morphology that will affect performance of later life history stages. In dragonflies, relatively smaller wings are associated with reduced flight performance, creating a link between larval thermal conditions and adult dispersal capacity.
    Electronic ISSN: 2150-8925
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 62
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    Wiley-Blackwell
    Publication Date: 2018-03-14
    Description: Interacting effects of climate change and livestock grazing on semi-arid grassland ecosystems have not been well studied, especially on a long-term basis. This paper analyzes changes in plant community composition in relation to grazing intensity and climate change based on repeated monitoring along long-term grazing intensity gradients in three Mongolian ecological zones over 20 yr. We synthesized our findings into state-and-transition models of vegetation change, contributing to our understanding of ecological dynamics in relation to management and environmental change, and to the development of tools for resilience-based rangeland management. In the mountain steppe (MS), community composition was driven largely by climate, and transitions from one community to another were associated with climate change or combined climate and grazing effects. The MS experienced the largest number of long-term transitions (14 of 15 plots) over 20 yr. In the steppe (ST), grazing intensity was the strongest influence on community composition, but transitions between communities from the early 1990s to 2013 were most strongly correlated with climate change. Ten of the 15 ST plots transitioned to other communities over 20 yr. Community composition in the desert steppe (DS) was unrelated to either grazing intensity or climate change and only six of 15 plots transitioned permanently over 20 yr. The MS appears most vulnerable to climate-induced community change, as others have suggested. Some degraded ST communities are resilient to climate change, while ST communities on drier sites are vulnerable to grazing-induced community changes. Our findings illustrate the utility of state-and-transition models as a means to synthesize and depict plant community dynamics in relation to climate and management factors. These models identify communities that may be growing rarer or more common under the combined effects of climate change and grazing, and highlight species and communities that may be useful conservation targets or indicators of climate- or grazing-induced change.
    Electronic ISSN: 2150-8925
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 63
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    Wiley-Blackwell
    Publication Date: 2018-03-14
    Description: Environmental factors strongly influence the ecology and evolution of vector-borne infectious diseases. However, our understanding of the influence of climatic variation on host–parasite interactions in tropical systems is rudimentary. We studied five species of birds and their haemosporidian parasites ( Plasmodium and Haemoproteus ) at 16 sampling sites to understand how environmental heterogeneity influences patterns of parasite prevalence, distribution, and diversity across a marked gradient in water availability in northern South America. We used molecular methods to screen for parasite infections and to identify parasite lineages. To characterize spatial heterogeneity in water availability, we used weather-station and remotely sensed climate data. We estimated parasite prevalence while accounting for spatial autocorrelation, and used a model selection approach to determine the effect of variables related to water availability and host species on prevalence. The prevalence, distribution, and lineage diversity of haemosporidian parasites varied among localities and host species, but we found no support for the hypothesis that the prevalence and diversity of parasites increase with increasing water availability. Host species and host × climate interactions had stronger effects on infection prevalence, and parasite lineages were strongly associated with particular host species. Because climatic variables had little effect on the overall prevalence and lineage diversity of haemosporidian parasites across study sites, our results suggest that independent host–parasite dynamics may influence patterns in parasitism in environmentally heterogeneous landscapes. Our work focuses on the ecology and evolution of host–pathogen interactions in relation to environmental heterogeneity. We aimed to understand the role of water-related climatic variables on the prevalence, diversity, and distribution of avian malaria parasites in northern South America across a steep climatic gradient. We studied five codistributed bird species with contrasting ecologies and evolutionary histories. We took advantage of field methods in ecology and ornithology, molecular screening of parasites, and statistical methods to examine relationships between parasitic infections and climatic data derived from remote-sensed variables.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 64
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    Wiley-Blackwell
    Publication Date: 2018-03-14
    Description: Organisms commonly experience significant spatiotemporal variation in their environments. In response to such heterogeneity, different mechanisms may act that enhance ecological performance locally. However, depending on the nature of the mechanism involved, the consequences for populations may differ greatly. Building on a previous model that investigated the conditions under which different adaptive mechanisms (co)evolve, this study compares the ecological and evolutionary population consequences of three very different responses to environmental heterogeneity: matching habitat choice (directed gene flow), adaptive plasticity (associated with random gene flow), and divergent natural selection. Using individual-based simulations, we show that matching habitat choice can have a greater adaptive potential than plasticity or natural selection: it allows for local adaptation while protecting genetic polymorphism despite global mating or strong environmental changes. Our simulations further reveal that increasing environmental fluctuations and unpredictability generally favor the emergence of specialist genotypes but that matching habitat choice is better at preventing local maladaptation by individuals. This confirms that matching habitat choice can speed up the genetic divergence among populations, cause indirect assortative mating via spatial clustering, and hence even facilitate sympatric speciation. This study highlights the potential importance of directed dispersal in local adaptation and speciation, stresses the difficulty of deriving its operation from nonexperimental observational data alone, and helps define a set of ecological conditions which should favor its emergence and subsequent detection in nature. Organisms commonly experience significant spatiotemporal variation in their environment, and populations can respond to this via different mechanisms that enhance individual local performance. Using individual-based simulation modeling, we compared the ecological and evolutionary population consequences of matching habitat choice (directed gene flow) with those of more familiar mechanisms: adaptive plasticity (associated with random gene flow) and divergent natural selection. We confirm that matching habitat choice can speed up local adaptation and genetic divergence among populations and can cause indirect assortative mating via spatial clustering and hence facilitate sympatric speciation.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 65
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    Wiley-Blackwell
    Publication Date: 2018-03-15
    Description: Tolerance may lessen when wildlife adversely impacts people. Models from psychology can help elucidate how people make judgements, why they act accordingly, and whether beliefs and norms influence support for policy and intervention. Working in a globally important region for tigers, we estimated hunting prevalence for this endangered species and three sympatric taxa using methods for asking sensitive questions. We also investigated the relative strength of ethnicity and social-psychological predictors in influencing intention to hunt. Men's behavioural intention and perceptions differed by species: pro-conservation values were most prevalent for tiger, weakest for wild boar. Perceived behavioural control was the strongest predictor of hunting-intention; affect and injunctive norms were also important. The prominence of affect in determining intention suggests increasing environmental knowledge is unlikely to curb hunting. However, existing norms could be leveraged to incentivise behaviour-change. Integrating behaviour-change models into conservation science is crucial where strategies require changes in people's actions. This article is protected by copyright. All rights reserved
    Print ISSN: 1755-263X
    Electronic ISSN: 1755-263X
    Topics: Biology
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  • 66
    Publication Date: 2018-03-15
    Description: Currently, human society is predominantly powered by fossil fuels—coal, oil and natural gas—yet also ultimately depends on goods and services provided by biodiversity. Fossil fuel extraction impacts biodiversity indirectly through climate change and by increasing accessibility, and directly through habitat loss and pollution. In contrast to the indirect effects, quantification of the direct impacts has been relatively neglected. To address this, we analyse the potential threat to 〉 37,000 species and 〉 200,000 protected areas globally from the locations of present and future fossil fuel extraction in marine and terrestrial environments. Sites that are currently exploited have higher species richness and endemism than unexploited sites, whereas known future hydrocarbon activities will predominantly move into less biodiverse locations. We identify 181 ‘high-risk’ locations where oil or gas extraction suitability coincides with biodiversity importance, making conflicts between extraction and conservation probable. In total, protected areas are located on US$3-15 trillion of unexploited hydrocarbon reserves, posing challenges and potentially opportunities for protected area management and sustainable financing. This article is protected by copyright. All rights reserved
    Print ISSN: 1755-263X
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  • 67
    Publication Date: 2018-03-15
    Description: Metastatic castration-resistant prostate cancer (mCRPC) is a lethal form of treatment-resistant prostate cancer and poses significant therapeutic challenges. Deregulated receptor tyrosine kinase (RTK) signalling mediated by loss of tumour suppressor Sprouty2 (SPRY2) is associated with treatment resistance. Using pre-clinical human and murine mCRPC models, we show that SPRY2 deficiency leads to an androgen self-sufficient form of CRPC. Mechanistically, HER2-IL6 signalling axis enhances the expression of androgen biosynthetic enzyme HSD3B1 and increases SRB1-mediated cholesterol uptake in SPRY2-deficient tumours. Systemically, IL6 elevated the levels of circulating cholesterol by inducing host adipose lipolysis and hepatic cholesterol biosynthesis. SPRY2-deficient CRPC is dependent on cholesterol bioavailability and SRB1-mediated tumoral cholesterol uptake for androgen biosynthesis. Importantly, treatment with ITX5061, a clinically safe SRB1 antagonist, decreased treatment resistance. Our results indicate that cholesterol transport blockade may be effective against SPRY2-deficient CRPC. Tumour-induced IL6 modulates host lipid metabolism to drive treatment-resistant castration-resistant prostate cancer (CRPC). Blocking tumoral cholesterol uptake using SRB1 antagonist or restoring systemic cholesterol homeostasis using statins decreases treatment resistance.
    Print ISSN: 1757-4676
    Electronic ISSN: 1757-4684
    Topics: Medicine
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  • 68
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    Wiley-Blackwell
    Publication Date: 2018-03-15
    Description: Understanding how factors that vary in spatial scale relate to population abundance is vital to forecasting species responses to environmental change. Stream and river ecosystems are inherently hierarchical, potentially resulting in organismal responses to fine-scale changes in patch characteristics that are conditional on the watershed context. Here, we address how populations of two salamander species are affected by interactions among hierarchical processes operating at different scales within a rapidly changing landscape of the southern Appalachian Mountains. We modeled reach-level occupancy of larval and adult black-bellied salamanders ( Desmognathus quadramaculatus ) and larval Blue Ridge two-lined salamanders ( Eurycea wilderae ) as a function of 17 different terrestrial and aquatic predictor variables that varied in spatial extent. We found that salamander occurrence varied widely among streams within fully forested catchments, but also exhibited species-specific responses to changes in local conditions. While D. quadramaculatus declined predictably in relation to losses in forest cover, larval occupancy exhibited the strongest negative response to forest loss as well as decreases in elevation. Conversely, occupancy of E. wilderae was unassociated with watershed conditions, only responding negatively to higher proportions of fast-flowing stream habitat types. Evaluation of hierarchical relationships demonstrated that most fine-scale variables were closely correlated with broad watershed-scale variables, suggesting that local reach-scale factors have relatively smaller effects within the context of the larger landscape. Our results imply that effective management of southern Appalachian stream salamanders must first focus on the larger scale condition of watersheds before management of local-scale conditions should proceed. Our findings confirm the results of some studies while refuting the results of others, which may indicate that prescriptive recommendations for range-wide management of species or the application of a single management focus across large geographic areas is inappropriate.
    Electronic ISSN: 2150-8925
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 69
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    Wiley-Blackwell
    Publication Date: 2018-01-13
    Print ISSN: 0007-9235
    Electronic ISSN: 1542-4863
    Topics: Medicine
    Published by Wiley-Blackwell on behalf of American Cancer Society.
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  • 70
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    Wiley-Blackwell
    Publication Date: 2018-01-13
    Description: Phenotypic and genetic variation are present in all species, but lineages differ in how variation is partitioned among populations. Examining phenotypic clustering and genetic structure within a phylogeographic framework can clarify which biological processes have contributed to extant biodiversity in a given lineage. Here, we investigate genetic and phenotypic variation among populations and subspecies within a Neotropical songbird complex, the White-collared Seedeater ( Sporophila torqueola ) of Central America and Mexico. We combine measurements of morphology and plumage patterning with thousands of nuclear loci derived from ultraconserved elements (UCEs) and mitochondrial DNA to evaluate population differentiation. We find deep levels of molecular divergence between two S. torqueola lineages that are phenotypically diagnosable: One corresponds to S. t. torqueola along the Pacific coast of Mexico, and the other includes S. t. morelleti and S. t. sharpei from the Gulf Coast of Mexico and Central America. Surprisingly, these two lineages are strongly differentiated in both nuclear and mitochondrial markers, and each is more closely related to other Sporophila species than to one another. We infer low levels of gene flow between these two groups based on demographic models, suggesting multiple independent evolutionary lineages within S. torqueola have been obscured by coarse-scale similarity in plumage patterning. These findings improve our understanding of the biogeographic history of this lineage, which includes multiple dispersal events out of South America and across the Isthmus of Tehuantepec into Mesoamerica. Finally, the phenotypic and genetic distinctiveness of the range-restricted S. t. torqueola highlights the Pacific Coast of Mexico as an important region of endemism and conservation priority. We examined phenotypic and genomic differentiation within a widespread Neotropical songbird. We found deep molecular divergence between two subspecies groups: One restricted to western Mexico, and the other in eastern Mexico and Central America. We find that these two lineages are not sister species, suggesting a revised biogeographic history of repeated dispersal out of South America and hidden endemism in western Mexico.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 71
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    Wiley-Blackwell
    Publication Date: 2018-01-17
    Description: The clear evidence of the accumulating impacts of anthropogenic actions on the Earth system is driving researchers to look to historical data as a resource for understanding the present and predicting the future. In the conservation science literature, using historical sources usually refers to data mining ‘the past’ using the scientific methods of historical ecology. This paper considers the often overlooked methodological challenges of sourcing and interpreting historical data. A schema is provided for conservation scientists, summarising the kinds of questions and metadata required to work rigorously with historical data. This will improve the accuracy of the data we use to construct trends to inform our understanding of the conservation status of particular species and ecosystems. It will also deepen our understanding of the interplays of factors influencing policy and management in particular social-ecological contexts. This article is protected by copyright. All rights reserved
    Print ISSN: 1755-263X
    Electronic ISSN: 1755-263X
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  • 72
    Publication Date: 2018-01-17
    Description: Targeting phylogenetic diversity (PD) in systematic conservation planning is an efficient way to minimize losses across the Tree of Life. Considering representation of genetic diversity below and above species level, also allows robust analyses within systems where taxonomy is in flux. We use dense sampling of phylogeographic diversity for eleven lizard genera, to demonstrate how PD can be applied to a policy-ready conservation planning problem. Our analysis bypasses named taxa, using genetic data directly to inform conservation decisions. We highlight areas that should be prioritised for ecological management, and also areas that would provide the greatest benefit if added to the multi-sector conservation estate. We provide a rigorous and effective approach to represent the spectrum of genetic and species diversity in conservation planning. This article is protected by copyright. All rights reserved
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  • 73
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    Wiley-Blackwell
    Publication Date: 2018-01-14
    Description: Mating systems have broad impacts on how sexual selection and mate choice operate within a species, but studies of mating behavior in the laboratory may not reflect how these processes occur in the wild. Here, we examined the mating behavior of the neotropical butterfly Heliconius erato in the field by releasing larvae and virgin females and observing how they mated. H. erato is considered a pupal-mating species (i.e., males mate with females as they emerge from the pupal case). However, we observed only two teneral mating events, and experimentally released virgins were almost all mated upon recapture. Our study confirms the presence of some pupal-mating behavior in H. erato , but suggests that adult mating is likely the prevalent mating strategy in this species. These findings have important implications for the role of color pattern and female mate choice in the generation of reproductive isolation in this diverse genus. Heliconius erato is thought to be one of a few species of butterfly which display an unusual mating system known as pupal mating: males wait on the developing pupae of females and mate with them upon emergence. Using experiments and observations with natural populations, we find that while H. erato do engage in pupal mating in the wild, it is rare: adult-mating is likely the prevalent mode of mating. Our finding that most couplings occur between adults suggests that color pattern is likely an important factor driving assortative mating and speciation in this adaptively radiating species.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 74
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    Wiley-Blackwell
    Publication Date: 2018-01-14
    Description: Environmental differences influence the evolutionary divergence of mating signals through selection acting either directly on signal transmission (“sensory drive”) or because morphological adaptation to different foraging niches causes divergence in “magic traits” associated with signal production, thus indirectly driving signal evolution. Sensory drive and magic traits both contribute to variation in signal structure, yet we have limited understanding of the relative role of these direct and indirect processes during signal evolution. Using phylogenetic analyses across 276 species of ovenbirds (Aves: Furnariidae), we compared the extent to which song evolution was related to the direct influence of habitat characteristics and the indirect effect of body size and beak size, two potential magic traits in birds. We find that indirect ecological selection, via diversification in putative magic traits, explains variation in temporal, spectral, and performance features of song. Body size influences song frequency, whereas beak size limits temporal and performance components of song. In comparison, direct ecological selection has weaker and more limited effects on song structure. Our results illustrate the importance of considering multiple deterministic processes in the evolution of mating signals. Sensory drive and magic traits both contribute to variation in acoustic signal structure, yet we have limited understanding of the relative role of these direct and indirect processes during signal evolution. Using phylogenetic analyses across 276 species of ovenbirds (Aves: Furnariidae), we compared the extent to which song evolution was related to the direct influence of habitat characteristics and the indirect effect of body size and beak size, two potential magic traits in birds. We find that indirect ecological selection, via diversification in putative magic traits, explains variation in temporal, spectral, and performance features of song, whereas direct ecological selection has weaker and more limited effects on song structure.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 75
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    Wiley-Blackwell
    Publication Date: 2018-01-17
    Description: Plant ecologists require spatial information on functional soil properties but are often faced with soil classifications that are not directly interpretable or useful for statistical models. Sand and clay content are important soil properties because they indicate soil water-holding capacity and nutrient content, yet these data are not available for much of the landscape. Remotely sensed soil radiometric data offer promise for developing statistical models of functional soil properties applicable over large areas. Here, we build models linking radiometric data for an area of 40,000 km 2 with soil physicochemical data collected over a period of 30 years and demonstrate a strong relationship between gamma radiometric potassium ( 40 K), thorium (²³²Th), and soil sand and clay content. Our models showed predictive performance of 43% with internal cross-validation (to held-out data) and ~30% for external validation to an independent test dataset. This work contributes to broader availability and uptake of remote sensing products for explaining patterns in plant distribution and performance across landscapes. Soil texture and chemistry significantly explained deviation in remote-sensed gamma-radiometric Th and K. Percent sand and clay particles in A Horizon were the most influential variables. Gamma-radiometric Th and and K, with environmental data, moderately predicted sand and clay %.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 76
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    Wiley-Blackwell
    Publication Date: 2018-01-17
    Description: The response of tropical forests to global warming is one of the largest uncertainties in predicting the future carbon balance of Earth. To determine the likely effects of elevated temperatures on tropical forest understory plants and soils, as well as other ecosystems, an infrared (IR) heater system was developed to provide in situ warming for the Tropical Responses to Altered Climate Experiment (TRACE) in the Luquillo Experimental Forest in Puerto Rico. Three replicate heated 4-m-diameter plots were warmed to maintain a 4°C increase in understory vegetation compared to three unheated control plots, as sensed by IR thermometers. The equipment was larger than any used previously and was subjected to challenges different from those of many temperate ecosystem warming systems, including frequent power surges and outages, high humidity, heavy rains, hurricanes, saturated clayey soils, and steep slopes. The system was able to maintain the target 4.0°C increase in hourly average vegetation temperatures to within ± 0.1°C. The vegetation was heterogeneous and on a 21° slope, which decreased uniformity of the warming treatment on the plots; yet, the green leaves were fairly uniformly warmed, and there was little difference among 0–10 cm depth soil temperatures at the plot centers, edges, and midway between. Soil temperatures at the 40–50 cm depth increased about 3°C compared to the controls after a month of warming. As expected, the soil in the heated plots dried faster than that of the control plots, but the average soil moisture remained adequate for the plants. The TRACE heating system produced an adequately uniform warming precisely controlled down to at least 50-cm soil depth, thereby creating a treatment that allows for assessing mechanistic responses of tropical plants and soil to warming, with applicability to other ecosystems. No physical obstacles to scaling the approach to taller vegetation (i.e., trees) and larger plots were observed. An infrared heater system was designed, installed, and tested over tropical forest understory vegetation in Puerto Rico. Larger plots and a higher degree of warming required using 4–8 times larger equipment than used for this application before, and the location involved challenges from power surges and outages, high humidity, steep slope, weak soils, and hurricanes. The system maintained the target 4°C rise in temperature of the heated plots above that of the controls when power was available, the uniformity of the treatment was satisfactory, and significant soil warming of 2.6°C on average to a depth of 50 cm was achieved with minimal soil drying.
    Electronic ISSN: 2045-7758
    Topics: Biology
    Published by Wiley-Blackwell
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  • 77
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    Wiley-Blackwell
    Publication Date: 2018-01-17
    Description: The endosymbiotic bacterium Wolbachia infects a wide range of arthropods and their relatives. It is an intracellular parasite transmitted through the egg from mother to offspring. Wolbachia can spread and persist through various means of host reproductive manipulation. How these different mechanisms of host manipulation evolved in Wolbachia is unclear. Which host reproductive phenotype is most likely to be ancestral and whether evolutionary transitions between some host phenotypes are more common than others remain unanswered questions. Recent studies have revealed multiple cases where the same Wolbachia strain can induce different reproductive phenotypes in different hosts, raising the question to what degree the induced host phenotype should be regarded as a trait of Wolbachia . In this study, we constructed a phylogenetic tree of Wolbachia and analyzed the patterns of host phenotypes along that tree. We were able to detect a phylogenetic signal of host phenotypes on the Wolbachia tree, indicating that the induced host phenotype can be regarded as a Wolbachia trait. However, we found no clear support for the previously stated hypothesis that cytoplasmic incompatibility is ancestral to Wolbachia in arthropods. Our analysis provides evidence for heterogeneous transition rates between host phenotypes. This study uses comparative methods to analyze the evolution of Wolbachia -induced host reproductive phenotypes along the phylogenetic tree of Wolbachia . Our results show that Wolbachia -induced host reproductive phenotypes can be regarded as a Wolbachia trait and provide novel insights into ancestral states and evolutionary transition rates of Wolbachia 's host manipulation.
    Electronic ISSN: 2045-7758
    Topics: Biology
    Published by Wiley-Blackwell
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  • 78
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    Wiley-Blackwell
    Publication Date: 2018-01-17
    Description: Understanding the origins and introduction pathways of invasive species is a fundamental issue for invasion biology, which is necessary for predicting and preventing future invasion. Once an invasive species is established in a new location, this location could serve as a stepping-stone for further invasions. However, such “stepping-stone” effect has not been widely investigated. Using the published literature and records, we compiled the first found locations of 127 top invasive species in China. Our study showed that the most common landing spots of these invasive species were Hong Kong (22 species) and Taiwan (20 species), which accounted for one-third of the invasive species in China. Our analysis revealed that the invasive species in mainland China were more likely to transport from Hong Kong than Macau, a neighboring region with a similar area and colonial history. Similarly, more invasive species were also first landed on Taiwan than Hainan, a nearby island sharing similar climate conditions. Together, our findings indicate that Hong Kong and Taiwan are the most important stepping-stones for invasive species to the mainland of China and suggesting that the increasing trade exchange of China's coastal ports constitutes a potential risk for the spread of more invasive species. We suppose that they would be the future stepping-stones for invasive species to the mainland of China and these coastal ports regions where improved biosecurity is needed now. It can be concluded that Taiwan and Hong Kong are stepping-stones for invasive species to the mainland of China. Then group comparisons between Taiwan and Hainan, and between Hong Kong and Macao are conducted to find out that colonial rule and economical and trade activities are the driving forces for alien species invasion and that islands are more susceptible to species invasion than continents.
    Electronic ISSN: 2045-7758
    Topics: Biology
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  • 79
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    Wiley-Blackwell
    Publication Date: 2018-01-17
    Description: Fluctuations in marine populations often relate to the supply of recruits by oceanic currents. Variation in these currents is typically driven by large-scale changes in climate, in particular ENSO (El Nino Southern Oscillation). The dependence on large-scale climatic changes may, however, be modified by early life history traits of marine taxa. Based on eight years of annual surveys, along 150 km of coastline, we examined how ENSO influenced abundance of juvenile fish, coral spat, and canopy-forming macroalgae. We then investigated what traits make populations of some fish families more reliant on the ENSO relationship than others. Abundance of juvenile fish and coral recruits was generally positively correlated with the Southern Oscillation Index (SOI), higher densities recorded during La Niña years, when the ENSO-influenced Leeuwin Current is stronger and sea surface temperature higher. The relationship is typically positive and stronger among fish families with shorter pelagic larval durations and stronger swimming abilities. The relationship is also stronger at sites on the coral back reef, although the strongest of all relationships were among the lethrinids ( r  = .9), siganids ( r  = .9), and mullids ( r  = .8), which recruit to macroalgal meadows in the lagoon. ENSO effects on habitat seem to moderate SOI–juvenile abundance relationship. Macroalgal canopies are higher during La Niña years, providing more favorable habitat for juvenile fish and strengthening the SOI effect on juvenile abundance. Conversely, loss of coral following a La Niña-related heat wave may have compromised postsettlement survival of coral dependent species, weakening the influence of SOI on their abundance. This assessment of ENSO effects on tropical fish and habitat-forming biota and how it is mediated by functional ecology improves our ability to predict and manage changes in the replenishment of marine populations. Abundance of juvenile fish and coral recruits was generally positively correlated with the Southern Oscillation Index (SOI), with higher densities recorded during La Niña years. The relationship is typically positive and stronger among fish families with shorter pelagic larval durations and stronger swimming abilities. ENSO effects on habitat seem to moderate SOI–juvenile abundance relationship.
    Electronic ISSN: 2045-7758
    Topics: Biology
    Published by Wiley-Blackwell
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  • 80
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    Wiley-Blackwell
    Publication Date: 2018-01-17
    Description: The importance and prevalence of phylogenetic tracking between hosts and dependent organisms caused by co-evolution and shifting between closely related host species have been debated for decades. Most studies of phylogenetic tracking among phytophagous insects and their host plants have been limited to insects feeding on a narrow range of host species. However, narrow host ranges can confound phylogenetic tracking (phylogenetic tracking hypothesis) with host shifting between hosts of intermediate relationship (intermediate hypothesis). Here, we investigated the evolutionary history of the Enchenopa binotata complex of treehoppers. Each species in this complex has high host fidelity, but the entire complex uses hosts across eight plant orders. The phylogenies of E. binotata were reconstructed to evaluate whether (1) tracking host phylogeny; or (2) shifting between intermediately related host plants better explains the evolutionary history of E. binotata . Our results suggest that E. binotata primarily shifted between both distant and intermediate host plants regardless of host phylogeny and less frequently tracked the phylogeny of their hosts. These findings indicate that phytophagous insects with high host fidelity, such as E. binotata , are capable of adaptation not only to closely related host plants but also to novel hosts, likely with diverse phenology and defense mechanisms. Although with high host fidelity and a wide range of host usage (across eight host orders), we found that host shifting, regardless of the host plant relationship, played a more important role than coevolution with hosts in the evolutionary history of Enchenopa binotata treehoppers. This result is fascinating it is not only unsupportive to coevolut