Habitat fragmentation is associated with dietary shifts and microbiota variability in common vampire bats

Host ecological factors and external environmental factors are known to influence the structure of gut microbial communities, but few studies have examined the impacts of environmental changes on microbiotas in free‐ranging animals. Rapid land‐use change has the potential to shift gut microbial communities in wildlife through exposure to novel bacteria and/or by changing the availability or quality of local food resources. The consequences of such changes to host health and fitness remain unknown and may have important implications for pathogen spillover between humans and wildlife. To better understand the consequences of land‐use change on wildlife microbiotas, we analyzed long‐term dietary trends, gut microbiota composition, and innate immune function in common vampire bats (Desmodus rotundus) in two nearby sites in Belize that vary in landscape structure. We found that vampire bats living in a small forest fragment had more homogenous diets indicative of feeding on livestock and shifts in microbiota heterogeneity, but not overall composition, compared to those living in an intact forest reserve. We also found that irrespective of sampling site, vampire bats which consumed relatively more livestock showed shifts in some core bacteria compared with vampire bats which consumed relatively less livestock. The relative abundance of some core microbiota members was associated with innate immune function, suggesting that future research should consider the role of the host microbiota in immune defense and its relationship to zoonotic infection dynamics. We suggest that subsequent homogenization of diet and habitat loss through livestock rearing in the Neotropics may lead to disruption to the microbiota that could have downstream impacts on host immunity and cross‐species pathogen transmission.     

Impacts of sedimentation and nitrogen enrichment on wetland plant community development

Many factors influence which plant species are found in a particular wetland. The species pool is composed of the species present in the seed bank and species able to disperse into the wetland, and many abiotic and biotic factors interact to influence a species performance and abundance in the plant community. Anthropogenic activities produce specific stressors on wetland systems that alter these abiotic and biotic interactions, potentially altering species composition. We simulated three common wetland hydrogeomorphic (HGM) subclasses in a greenhouse to examine the effects of two stressors-sedimentation and nitrogen (N) enrichment-on the performance of 8 species grown in artificial communities. Species establishment, height, biomass, and foliar N and P concentrations were measured to explore species responses to stressors and competition, as well as the potential impacts of changes in species composition on ecosystem processes. Species were affected differently by sedimentation and N enrichment, and there were differences in overall community sensitivity to stressors between wetland subclasses. Sedimentation generally reduced seedling establishment, while N enrichment produced variable effects on height and biomass. Interspecific competition had little effect on establishment but significantly reduced most species biomass. Sedimentation generally lowered community biomass, diversity, and richness, while enrichment increased community biomass. Establishment, biomass, and foliar nutrient concentrations significantly differed between many species, suggesting that shifts in species composition may impact ecosystem processes such as nutrient cycling and carbon storage. Phalaris arundinacea, an aggressive clonal graminoid, universally dominated all wetland subclasses. This dominance across a range of environmental conditions (sedimentation, fertility, and hydrology) has important implications for both restoration and predicting the impacts of human activities on species composition. Our results suggest that, in regions where P. arundinacea is common, restoration projects that establish communities from seeds and human activities that cause vegetation removal are likely to become dominated by P. arundinacea.     

Impacts of recent climate change on terrestrial flora and fauna: Some emerging Australian examples

The effects of anthropogenic climate change on biodiversity are well known for some high‐profile Australian marine systems, including coral bleaching and kelp forest devastation. Less well‐published are the impacts of climate change being observed in terrestrial ecosystems, although ecological models have predicted substantial changes are likely. Detecting and attributing terrestrial changes to anthropogenic factors is difficult due to the ecological importance of extreme conditions, the noisy nature of short‐term data collected with limited resources, and complexities introduced by biotic interactions. Here, we provide a suite of case studies that have considered possible impacts of anthropogenic climate change on Australian terrestrial systems. Our intention is to provide a diverse collection of stories illustrating how Australian flora and fauna are likely responding to direct and indirect effects of anthropogenic climate change. We aim to raise awareness rather than be comprehensive. We include case studies covering canopy dieback in forests, compositional shifts in vegetation, positive feedbacks between climate, vegetation and disturbance regimes, local extinctions in plants, size changes in birds, phenological shifts in reproduction and shifting biotic interactions that threaten communities and endangered species. Some of these changes are direct and clear cut, others are indirect and less clearly connected to climate change; however, all are important in providing insights into the future state of terrestrial ecosystems. We also highlight some of the management issues relevant to conserving terrestrial communities and ecosystems in the face of anthropogenic climate change.     

Construction of Sand Shinnery Oak Communities of the Llano Estacado: Animal Disturbances, Plant Community Structure, and Restoration

In land restoration it is imperative to study the potential role of disturbances, biotic or abiotic, that may provide sites for colonization by specific plants. Disturbances can alter community composition by removing species or allowing others to become established. In communities where animal-generated disturbances open sites for seedling establishment, animals may have important indirect effects on several aspects of plant community structure. Animal disturbances in Quercus havardii communities of western Texas appear to open sites for colonization by herbaceous species. These animal disturbances vary in spatial distribution, density, and abiotic and biotic characteristics. The abundance of herbaceous plant seedlings is positively related to bare ground and the number of distinct disturbances. Thus, the density and the spatial distribution of these disturbances may be expected to have an important influence on the abundance and dispersion of plant species. Therefore, successful restoration efforts of sand shinnery oak communities and other similar habitats must consider the effects of animal disturbances and the role of plant-animal and plant-soil microbe interactions on plant community composition and the maintenance of plant species diversity.     

Greater variation in boreal plant community composition and community-level traits at local- than regional-scale

Questions

Rapid climate change in northern latitudes is expected to influence plant functional traits of the whole community (community-level traits) through species compositional changes and/or trait plasticity, limiting our ability to anticipate climate warming impacts on northern plant communities. We explored differences in plant community composition and community-level traits within and among four boreal peatland sites and determined whether intra- or interspecific variation drives community-level traits.

Location

Boreal biome of western North America.

Methods

We collected plant community composition and functional trait data along dominant topoedaphic and/or hydrologic gradients at four peatland sites spanning the latitudinal extent of the boreal biome of western North America. We characterized variability in community composition and community-level traits of understorey vascular and moss species both within (local-scale) and among sites (regional-scale).

Results

Against expectations, community-level traits of vascular plant and moss species were generally consistent among sites. Furthermore, interspecific variation was more important in explaining community-level trait variation than intraspecific variation. Within-site variation in both community-level traits and community composition was greater than among-site variation, suggesting that local environmental gradients (canopy density, organic layer thickness, etc.) may be more influential in determining plant community processes than regional-scale gradients.

Conclusions

Given the importance of interspecific variation to within-site shifts in community-level traits and greater variation of community composition within than among sites, we conclude that climate-induced shifts in understorey community composition may not have a strong influence on community-level traits in boreal peatlands unless local-scale environmental gradients are substantially altered.     

Lags in the response of mountain plant communities to climate change

Rapid climatic changes and increasing human influence at high elevations around the world will have profound impacts on mountain biodiversity. However, forecasts from statistical models (e.g. species distribution models) rarely consider that plant community changes could substantially lag behind climatic changes, hindering our ability to make temporally realistic projections for the coming century. Indeed, the magnitudes of lags, and the relative importance of the different factors giving rise to them, remain poorly understood. We review evidence for three types of lag: “dispersal lags” affecting plant species’ spread along elevational gradients, “establishment lags” following their arrival in recipient communities, and “extinction lags” of resident species. Variation in lags is explained by variation among species in physiological and demographic responses, by effects of altered biotic interactions, and by aspects of the physical environment. Of these, altered biotic interactions could contribute substantially to establishment and extinction lags, yet impacts of biotic interactions on range dynamics are poorly understood. We develop a mechanistic community model to illustrate how species turnover in future communities might lag behind simple expectations based on species’ range shifts with unlimited dispersal. The model shows a combined contribution of altered biotic interactions and dispersal lags to plant community turnover along an elevational gradient following climate warming. Our review and simulation support the view that accounting for disequilibrium range dynamics will be essential for realistic forecasts of patterns of biodiversity under climate change, with implications for the conservation of mountain species and the ecosystem functions they provide.     

Climate change and the future restructuring of Neotropical anuran biodiversity

Climate change is likely to impact multiple dimensions of biodiversity. Species range shifts are expected and may drive changes in the composition of species assemblages. In some regions, changes in climate may precipitate the loss of geographically restricted, niche specialists and facilitate their replacement by more widespread, niche generalists, leading to decreases in β-diversity and biotic homogenization. However, in other regions climate change may drive local extinctions and range contraction, leading to increases in β-diversity and biotic heterogenization. Regional topography should be a strong determinant of such changes as mountainous areas often are home to many geographically restricted species, whereas lowlands and plains are more often inhabited by widespread generalists. Climate warming, therefore, may simultaneously bring about opposite trends in β-diversity in mountainous highlands versus relatively flat lowlands. To test this hypothesis, we used species distribution modelling to map the present-day distributions of 2669 Neotropical anuran species, and then generated projections of their future distributions assuming future climate change scenarios. Using traditional metrics of β-diversity, we mapped shifts in biotic homogenization across the entire Neotropical region. We used generalized additive models to then evaluate how changes in β-diversity were associated with shifts in species richness, phylogenetic diversity and one measure of ecological generalism. Consistent with our hypothesis, we find increasing biotic homogenization in most highlands, associated with increased numbers of generalists and, to a lesser extent, losses of specialists, leading to an overall increase in alpha diversity, but lower mean phylogenetic diversity. In the lowlands, biotic heterogenization was more common, and primarily driven by local extinctions of generalists, leading to lower α-diversity, but higher mean phylogenetic diversity. Our results suggest that impacts of climate change on β-diversity are likely to vary regionally, but will generally lead to lower diversity, with increases in β-diversity offset by decreases in α-diversity.     

Biodiversity change under adaptive community dynamics

Compositional change is a ubiquitous response of ecological communities to environmental drivers of global change, but is often regarded as evidence of declining “biotic integrity” relative to historical baselines. Adaptive compositional change, however, is a foundational idea in evolutionary biology, whereby changes in gene frequencies within species boost population-level fitness, allowing populations to persist as the environment changes. Here, we present an analogous idea for ecological communities based on core concepts of fitness and selection. Changes in community composition (i.e., frequencies of genetic differences among species) in response to environmental change should normally increase the average fitnessof community members. We refer to compositional changes that improve the functional match, or “fit,” between organisms' traits and their environment as adaptive community dynamics. Environmental change (e.g., land-use change) commonly reduces the fit between antecedent communities and new environments. Subsequent change in community composition in response to environmental changes, however, should normally increase community-level fit, as the success of at least some constituent species increases. We argue that adaptive community dynamics are likely to improve or maintain ecosystem function (e.g., by maintaining productivity). Adaptive community responses may simultaneously produce some changes that are considered societally desirable (e.g., increased carbon storage) and others that are undesirable (e.g., declines of certain species), just as evolutionary responses within species may be deemed desirable (e.g., evolutionary rescue of an endangered species) or undesirable (e.g., enhanced virulence of an agricultural pest). When assessing possible management interventions, it is important to distinguish between drivers of environmental change (e.g., undesired climate warming) and adaptive community responses, which may generate some desirable outcomes. Efforts to facilitate, accept, or resist ecological change require separate consideration of drivers and responses, and may highlight the need to reconsider preferences for historical baseline communities over communities that are better adapted to the new conditions.     

Biotic interactions mediate the expansion of black mangrove (Avicennia germinans) into salt marshes under climate change

Many species are expanding their distributions to higher latitudes due to global warming. Understanding the mechanisms underlying these distribution shifts is critical for better understanding the impacts of climate changes. The climate envelope approach is widely used to model and predict species distribution shifts with changing climates. Biotic interactions between species, however, may also influence species distributions, and a better understanding of biotic interactions could improve predictions based solely on climate envelope models. Along the northern Gulf of Mexico coast, USA, subtropical black mangrove (Avicennia germinans) at the northern limit of its distribution grows sympatrically with temperate salt marsh plants in Florida, Louisiana, and Texas. In recent decades, freeze‐free winters have led to an expansion of black mangrove into salt marshes. We examined how biotic interactions between black mangrove and salt marsh vegetation along the Texas coast varied across (i) a latitudinal gradient (associated with a winter‐temperature gradient); (ii) the elevational gradient within each marsh (which creates different marsh habitats); and (iii) different life history stages of black mangroves (seedlings vs. juvenile trees). Each of these variables affected the strength or nature of biotic interactions between black mangrove and salt marsh vegetation: (i) Salt marsh vegetation facilitated black mangrove seedlings at their high‐latitude distribution limit, but inhibited black mangrove seedlings at lower latitudes; (ii) mangroves performed well at intermediate elevations, but grew and survived poorly in high‐ and low‐marsh habitats; and (iii) the effect of salt marsh vegetation on black mangroves switched from negative to neutral as black mangroves grew from seedlings into juvenile trees. These results indicate that the expansion of black mangroves is mediated by complex biotic interactions. A better understanding of the impacts of climate change on ecological communities requires incorporating context‐dependent biotic interactions into species range models.     

Twenty‐five years of plant community dynamics and invasion in New Zealand tussock grasslands

Understanding how plant communities respond to plant invasions is important both for understanding community structure and for predicting future ecosystem change. In a system undergoing intense plant invasion for 25 years, we investigated patterns of community change at a regional scale. Specifically, we sought to quantify how tussock grassland plant community structure had changed and whether changes were related to increases in plant invasion. Frequency data for all vascular plants were recorded on 124, permanent transects in tussock grasslands across the lower eastern South Island of New Zealand measured three times over a period of 25 years. Multivariate analyses of species richness were used to describe spatial and temporal patterns in the vegetation. Linear mixed‐effects models were used to relate temporal changes in community structure to the level and rate of invasion of three dominant invasive species in the genus Hieracium while accounting for relationships with other biotic and abiotic variables. There was a strong compositional gradient from exotic‐ to native‐dominated plant communities that correlated with increasing elevation. Over the 25 years, small‐scale species richness significantly decreased and then increased again; however, these changes differed in different plant communities. Exotic species frequency consistently increased on some transects and consistently declined on others. Species richness changes were correlated with the level of Hieracium invasion and abiotic factors, although the relationship with Hieracium changed from negative to positive over time. Compositional changes were not related to measured predictors. Our results suggest that observed broad‐scale fluctuations in species richness and community composition dynamics were not driven by Hieracium invasion. Given the relatively minor changes in community composition over time, we conclude that there is no evidence for widespread degradation of these grasslands over the last 25 years. However, because of continuing weed invasion, particularly at lower elevations, impacts may emerge in the longer term.     

Simulating small‐scale climate change effects–lessons from a short‐term field manipulation experiment on grassland arthropods

Climate change is expected to cause major consequences on biodiversity. Understanding species‐specific reactions, such as species shifts, species declines, and changes in population dynamics is a key issue to quantify large‐scale impacts of climate change on biotic communities. As it is often impossible or at least impracticable to conduct large‐scale experiments on biotic responses to climate change, studies at a smaller scale may be a useful alternative. In our study, we therefore tested responses of grassland arthropods (carabid beetles, spiders, grasshoppers) to simulated climate change in terms of species activity densities and diversity. We conducted a controlled field experiment by changing water and microclimatic conditions at a small scale (16 m²). Roof constructions were used to increase drought‐like conditions, whereas water supply was enhanced by irrigation. In all, 2 038 carabid beetles (36 species), 4 893 spiders (65 species), and 303 Orthoptera (4 species) were caught using pitfall traps from May to August, 2010. During our experiment, we created an artificial small‐scale climate change; and statistics revealed that these changes had short‐term effects on the total number of individuals and Simpson diversity of the studied arthropod groups. Moreover, our results showed that certain species might react very quickly to climate change in terms of activity densities, which in turn might influence diversity due to shifts in abundance patterns. Finally, we devised methodological improvements that may further enhance the validity of future studies.     

Elevational shifts,biotic homogenization and time lags in vegetation change during 40 years of climate warming

Many species show evidence of climate‐driven distribution shifts towards higher elevations, but given the tremendous variation among species and regions, we lack an understanding of the community‐level consequences of such shifts. Here we test for signatures of climate warming impacts using a repeat survey of semi‐permanent vegetation plots in 1970 and 2012 in a montane protected area in southern Québec, Canada, where daily maximum and minimum temperatures have increased by ∼1.6°C and ∼2.5°C over the same time period. As predicted, the abundance‐weighted mean elevations of species distributions increased significantly over time (9 m/decade). A community temperature index (CTI) was calculated as the abundance‐weighted mean of the median temperature across occurrences within each species geographic range in eastern North America. CTI did not vary significantly over time, although the raw magnitude of change (+ 0.2°C) matched the expectation based on the upward shift in distributions of 9 m/decade. Species composition of high elevation sites converged over time toward that observed at low elevation, although compositional changes at low elevation sites were more modest. As a consequence, the results of a multivariate analysis showed a decline in among‐plot compositional variability (i.e. beta diversity) over time, thus providing some of the first empirical evidence linking climate warming with biotic homogenization. Finally, plot‐scale species richness showed a marked increase of ∼25% on average. Overall, elevational distribution shifts, biodiversity change, and biotic homogenization over the past four decades have been consistent with predictions based on climate warming, although the rate of change has been relatively slow, suggesting substantial time lags in biotic responses to climate change.     

Demographic shifts in eastern US forests increase the impact of late-season drought on forest growth

While forest communities are changing as a result of global environmental change, the impacts of tree species shifts on ecosystem services such as carbon storage are poorly quantified. In many parts of the eastern United States (US), more xeric-adapted oak-hickory dominated stands are being replaced with mesic beech-maple assemblages. To examine the possible impacts of this ongoing change in forest composition, we investigated how two wide-ranging and co-occurring eastern US species – Acer saccharum (sugar maple) and Quercus alba (white oak) – respond to interannual climate variability. Using 781 tree cores from 418 individual trees at 18 locations, we found late-growing season drought reduced A. saccharum growth more than that of Q. alba. A gradient in the growth reduction across latitude was also found in A. saccharum, where southern populations of A. saccharum experienced greater reductions in growth during drought. Drought had a legacy effect on growth for both species, with drought occurring later in the growing season having a larger legacy effect. Consequently, as forests shift from oak to maple dominance, drought in the later part of the growing season is likely to become an increasingly important control on forest productivity. Thus, our findings suggest that co-occurring species are responding to environmental conditions during different times in the growing season and, therefore, the timing of drought conditions will play an important role in forest productivity and carbon sequestration as forest species composition changes. These findings are particularly important because the projected increases in potential evapotranspiration, combined with possible changes in the seasonality of precipitation could have a substantial impact on how tree growth responds to future climatic change.     

Patterns of environmental variability influence coral‐associated bacterial and algal communities on the Mesoamerican Barrier Reef

A coral's capacity to alter its microbial symbionts may enhance its fitness in the face of climate change. Recent work predicts exposure to high environmental variability may increase coral resilience and adaptability to future climate conditions. However, how this heightened environmental variability impacts coral‐associated microbial communities remains largely unexplored. Here, we examined the bacterial and algal symbionts associated with two coral species of the genus Siderastrea with distinct life history strategies from three reef sites on the Belize Mesoamerican Barrier Reef System with low or high environmental variability. Our results reveal bacterial community structure, as well as alpha‐ and beta‐diversity patterns, vary by host species. Differences in bacterial communities between host species were partially explained by high abundance of Deltaproteobacteria and Rhodospirillales and high bacterial diversity in Siderastrea radians. Our findings also suggest Siderastrea spp. have dynamic core bacterial communities that likely drive differences observed in the entire bacterial community, which may play a critical role in rapid acclimatization to environmental change. Unlike the bacterial community, Symbiodiniaceae composition was only distinct between host species at high thermal variability sites, suggesting that different factors shape bacterial versus algal communities within the coral holobiont. Our findings shed light on how domain‐specific shifts in dynamic microbiomes may allow for unique methods of enhanced host fitness.     

Pyrodiversity begets plant–pollinator community diversity

Fire has a major impact on the structure and function of many ecosystems globally. Pyrodiversity, the diversity of fires within a region (where diversity is based on fire characteristics such as extent, severity, and frequency), has been hypothesized to promote biodiversity, but changing climate and land management practices have eroded pyrodiversity. To assess whether changes in pyrodiversity will have impacts on ecological communities, we must first understand the mechanisms that might enable pyrodiversity to sustain biodiversity, and how such changes might interact with other disturbances such as drought. Focusing on plant–pollinator communities in mixed‐conifer forest with frequent fire in Yosemite National Park, California, we examine how pyrodiversity, combined with drought intensity, influences those communities. We find that pyrodiversity is positively related to the richness of the pollinators, flowering plants, and plant–pollinator interactions. On average, a 5% increase in pyrodiversity led to the gain of approximately one pollinator and one flowering plant species and nearly two interactions. We also find that a diversity of fire characteristics contributes to the spatial heterogeneity (β‐diversity) of plant and pollinator communities. Lastly, we find evidence that fire diversity buffers pollinator communities against the effects of drought‐induced floral resource scarcity. Fire diversity is thus important for the maintenance of flowering plant and pollinator diversity and predicted shifts in fire regimes to include less pyrodiversity compounded with increasing drought occurrence will negatively influence the richness of these communities in this and other forested ecosystems. In addition, lower heterogeneity of fire severity may act to reduce spatial turnover of plant–pollinator communities. The heterogeneity of community composition is a primary determinant of the total species diversity present in a landscape, and thus, lower pyrodiversity may negatively affect the richness of plant–pollinator communities across large spatial scales.     

The invasive plant species Centaurea maculosa alters arbuscular mycorrhizal fungal communities in the field

While several recent studies have described changes in microbial communities associated with exotic plant invasion, how arbuscular mycorrhizal fungi (AMF) communities respond to exotic plant invasion is not well known, despite the salient role of this group in plant interactions. Here, we use molecular methods (terminal restriction fragment length polymorphism analyses based on the large subunit of the rRNA gene) to examine AMF community structure in sites dominated by the invasive mycorrhizal forb, Centaurea maculosa Lam. (spotted knapweed), and in adjacent native grassland sites. Our results indicate that significant AMF community alteration occurs following C. maculosa invasion. Moreover, a significant reduction in the number of restriction fragment sizes was found for samples collected in C. maculosa-dominated areas, suggesting reduced AMF diversity. Extraradical hyphal lengths exhibited a significant, on average 24%, reduction in C. maculosa-versus native grass-dominated sites. As both AMF community composition and abundance were altered by C.maculosa invasion, these data are strongly suggestive of potential impacts on AMF-mediated ecosystem processes. Given that the composition of AMF communities has the potential to differentially influence different plant species, our results may have important implications for site restoration after weed invasion.     

The changing nature of plant–microbe interactions during a biological invasion

Invasive plant species can alter belowground microbial communities. Simultaneously, the composition of soil microbial communities and the abundance of key microbes can influence invasive plant success. Such reciprocal effects may cause plant–microbe interactions to change rapidly during the course of biological invasions in ways that either inhibit or promote invasive species growth. Here we use a space-for-time substitution to illustrate how effects of soil microbial communities on the exotic legume Vicia villosa vary across uninvaded sites, recently invaded sites, and sites invaded by V. villosa for over a decade. We find that soil microorganisms from invaded areas increase V. villosa growth compared to sterilized soil or live soils collected from uninvaded sites, likely because mutualistic nitrogen-fixing rhizobia are not abundant in uninvaded areas. Notably, the benefits resulting from inoculation with live soils were higher for soils from recently invaded sites compared to older invasions, potentially indicating that over longer time scales, soil microbial communities change in ways that may reduce the success of exotic species. These findings suggest that short-term changes to soil microbial communities following invasion may facilitate exotic legume growth likely because of increases in the abundance of mutualistic rhizobia, but also indicate that longer term changes to soil microbial communities may reduce the growth benefits belowground microbial communities provide to exotic species. Our results highlight the changing nature of plant–microbe interactions during biological invasions and illustrate how altered biotic interactions could contribute to both the initial success and subsequent naturalization of invasive legume species.     

Predicting future coexistence in a North American ant community

Global climate change will remodel ecological communities worldwide. However, as a consequence of biotic interactions, communities may respond to climate change in idiosyncratic ways. This makes predictive models that incorporate biotic interactions necessary. We show how such models can be constructed based on empirical studies in combination with predictions or assumptions regarding the abiotic consequences of climate change. Specifically, we consider a well‐studied ant community in North America. First, we use historical data to parameterize a basic model for species coexistence. Using this model, we determine the importance of various factors, including thermal niches, food discovery rates, and food removal rates, to historical species coexistence. We then extend the model to predict how the community will restructure in response to several climate‐related changes, such as increased temperature, shifts in species phenology, and altered resource availability. Interestingly, our mechanistic model suggests that increased temperature and shifts in species phenology can have contrasting effects. Nevertheless, for almost all scenarios considered, we find that the most subordinate ant species suffers most as a result of climate change. More generally, our analysis shows that community composition can respond to climate warming in nonintuitive ways. For example, in the context of a community, it is not necessarily the most heat‐sensitive species that are most at risk. Our results demonstrate how models that account for niche partitioning and interspecific trade‐offs among species can be used to predict the likely idiosyncratic responses of local communities to climate change.     

Invasive willows drive instream community structure

相似文献   

Agriculture erases climate‐driven β‐diversity in Neotropical bird communities

Earth is experiencing multiple global changes that will, together, determine the fate of many species. Yet, how biological communities respond to concurrent stressors at local‐to‐regional scales remains largely unknown. In particular, understanding how local habitat conversion interacts with regional climate change to shape patterns in β‐diversity—differences among sites in their species compositions—is critical to forecast communities in the Anthropocene. Here, we study patterns in bird β‐diversity across land‐use and precipitation gradients in Costa Rica. We mapped forest cover, modeled regional precipitation, and collected data on bird community composition, vegetation structure, and tree diversity across 120 sites on 20 farms to answer three questions. First, do bird communities respond more strongly to changes in land use or climate in northwest Costa Rica? Second, does habitat conversion eliminate β‐diversity across climate gradients? Third, does regional climate control how communities respond to habitat conversion and, if so, how? After correcting for imperfect detection, we found that local land‐use determined community shifts along the climate gradient. In forests, bird communities were distinct between sites that differed in vegetation structure or precipitation. In agriculture, however, vegetation structure was more uniform, contributing to 7%–11% less bird turnover than in forests. In addition, bird responses to agriculture and climate were linked: agricultural communities across the precipitation gradient shared more species with dry than wet forest communities. These findings suggest that habitat conversion and anticipated climate drying will act together to exacerbate biotic homogenization.