Environmental and biotic drivers of soil microbial β‐diversity across spatial and phylogenetic scales

Soil microbial communities play a key role in ecosystem functioning but still little is known about the processes that determine their turnover (β‐diversity) along ecological gradients. Here, we characterize soil microbial β‐diversity at two spatial scales and at multiple phylogenetic grains to ask how archaeal, bacterial and fungal communities are shaped by abiotic processes and biotic interactions with plants. We characterized microbial and plant communities using DNA metabarcoding of soil samples distributed across and within eighteen plots along an elevation gradient in the French Alps. The recovered taxa were placed onto phylogenies to estimate microbial and plant β‐diversity at different phylogenetic grains (i.e. resolution). We then modeled microbial β‐diversities with respect to plant β‐diversities and environmental dissimilarities across plots (landscape scale) and with respect to plant β‐diversities and spatial distances within plots (plot scale). At the landscape scale, fungal and archaeal β‐diversities were mostly related to plant β‐diversity, while bacterial β‐diversities were mostly related to environmental dissimilarities. At the plot scale, we detected a modest covariation of bacterial and fungal β‐diversities with plant β‐diversity; as well as a distance–decay relationship that suggested the influence of ecological drift on microbial communities. In addition, the covariation between fungal and plant β‐diversity at the plot scale was highest at fine or intermediate phylogenetic grains hinting that biotic interactions between those clades depends on early‐evolved traits. Altogether, we show how multiple ecological processes determine soil microbial community assembly at different spatial scales and how the strength of these processes change among microbial clades. In addition, we emphasized the imprint of microbial and plant evolutionary history on today's microbial community structure.     

Beyond taxonomic diversity patterns: how do α, β and γ components of bird functional and phylogenetic diversity respond to environmental gradients across France?

Aim To test how far can macroecological hypotheses relating diversity to environmental factors be extrapolated to functional and phylogenetic diversities, i.e. to the extent to which functional traits and evolutionary backgrounds vary among species in a community or region. We use a spatial partitioning of diversity where regional or γ‐diversity is calculated by aggregating information on local communities, local or α‐diversity corresponds to diversity in one locality, and turnover or β‐diversity corresponds to the average turnover between localities and the region. Location France. Methods We used the Rao quadratic entropy decomposition of diversity to calculate local, regional and turnover diversity for each of three diversity facets (taxonomic, phylogenetic and functional) in breeding bird communities of France. Spatial autoregressive models and partial regression analyses were used to analyse the relationships between each diversity facet and environmental gradients (climate and land use). Results Changes in γ‐diversity are driven by changes in both α‐ and β‐diversity. Low levels of human impact generally favour all three facets of regional diversity and heterogeneous landscapes usually harbour higher β‐diversity in the three facets of diversity, although functional and phylogenetic turnover show some relationships in the opposite direction. Spatial and environmental factors explain a large percentage of the variation in the three diversity facets (>60%), and this is especially true for phylogenetic diversity. In all cases, spatial structure plays a preponderant role in explaining diversity gradients, suggesting an important role for dispersal limitations in structuring diversity at different spatial scales. Main conclusions Our results generally support the idea that hypotheses that have previously been applied to taxonomic diversity, both at local and regional scales, can be extended to phylogenetic and functional diversity. Specifically, changes in regional diversity are the result of changes in both local and turnover diversity, some environmental conditions such as human development have a great impact on diversity levels, and heterogeneous landscapes tend to have higher diversity levels. Interestingly, differences between diversity facets could potentially provide further insights into how large‐ and small‐scale ecological processes interact at the onset of macroecological patterns.     

Do body size and diet breadth affect partitioning of species diversity? A test with forest Lepidoptera

Two of the major themes resulting from recent macroecological research are the central roles that body size and niche breadth may play as determinants of species geographical distribution. Unanswered questions, however, linger regarding how similarities in body size or niche breadth affect the allocation of α‐ and β‐diversity across spatial scales. Using data on moth diversity in the eastern deciduous forest of North America, we tested the predictions that smaller‐bodied and diet‐restricted species would have lower levels of α‐diversity within forest stands and greater β‐diversity at higher sampling scales compared to larger or more generalist species. Moths were sampled using a nested sampling design consisting of three hierarchical levels: 20 forest stands, 5 sites and 3 ecoregions. Body size for 492 species was estimated as mean forewing length, and diet breadth was assessed from the published literature. Moth species were then classified according to body size (small or large) or diet breadth (generalist or restricted), and partitioning was conducted on each group. Diversity partitions for large‐ and small‐bodied species yielded similar patterns. When observed diversity components differed from those derived from our null model, a consistent pattern was observed: α‐diversity was greater than expected, β‐diversity among forest stands was less than expected, and β‐diversity among sites and ecoregions was higher than expected. In contrast, diet‐restricted moths contributed significantly less to stand‐level α‐diversity than generalist feeders. Furthermore, specialists contributed to a greater proportion of β‐diversity across scales compared to generalist moths. Because absolute measures of β‐diversity among stands were greater for generalists than for restricted feeders, we suggest that regional β‐diversity of forest moths may be influenced by several possible factors: intraspecific aggregation of diet‐restricted species, local fluctuations in population size of eruptive generalists and small geographical distributions of generalist moths than predicted by the geographical extent of putative host plants     

Using rarity to infer how dendritic network structure shapes biodiversity in riverine communities

Dispersal of organisms connects physical localities, but the strength of connection varies widely. Variability in the influence of dispersal can be predictable in sharply defined networks like river systems because some sections of the network are more isolated, leading to different balances of local (i.e. environmental filtering, species interactions) and regional (i.e. dispersal‐driven) processes in structuring communities. We examined the influence of spatial isolation on the relative contributions of α‐ and β‐diversity to regional (γ) diversity, and examined how that influence differed between common and rare species in stream macroinvertebrate communities. One explanation for rarity on a regional scale is that common species are habitat generalists while rare species are specialists. Therefore, common species should be influenced more by dispersal‐driven processes while rare species should be more influenced by local processes. We predicted that for rare taxa, β‐diversity should represent a higher fraction of γ‐diversity in isolated headwaters but that differences between rare and common taxa with regard to the contribution of β‐diversity to γ‐diversity should be less distinct in well‐connected mainstem habitats. To test these predictions, we used macroinvertebrate communities from 634 sites across 22 watersheds. Regardless of rarity, β‐ and γ‐diversity were higher in headwaters compared to mainstems. However, α‐diversity was similar regardless of isolation for rare assemblages. But contrary to our predictions, common assemblages of predators and herbivores did exhibit differences in α‐diversity between locations. Our predictions were strongly supported for two guilds of consumers, the detritivores and collectors, but less so for herbivores and predators. However, these results make sense considering differences in life histories between the groups. For detritivores and collectors, species turnover (β‐diversity) was higher in isolated regions in river networks, and rarity exacerbated this effect, resulting in higher regional diversity of rare species, supporting the general theory that rarity reflects habitat specialization.     

Not all non‐natives are equally unequal: reductions in herbivore β‐diversity depend on phylogenetic similarity to native plant community

Effects of host plant α‐ and β‐diversity often confound studies of herbivore β‐diversity, hindering our ability to predict the full impact of non‐native plants on herbivores. Here, while controlling host plant diversity, we examined variation in herbivore communities between native and non‐native plants, focusing on how plant relatedness and spatial scale alter the result. We found lower absolute magnitudes of β‐diversity among tree species and among sites on non‐natives in all comparisons. However, lower relative β‐diversity only occurred for immature herbivores on phylogenetically distinct non‐natives vs. natives. Locally in that comparison, non‐native gardens had lower host specificity; while among sites, the herbivores supported were a redundant subset of species on natives. Therefore, when phylogenetically distinct non‐natives replace native plants, the community of immature herbivores is likely to be homogenised across landscapes. Differences in communities on closely related non‐natives were subtler, but displayed community shifts and increased generalisation on non‐natives within certain feeding guilds.     

BIODIVERSITY RESEARCH: Diversity and distribution of macroinvertebrates in lentic habitats in massively altered landscapes in south‐eastern Australia

Aim We investigated whether faunas of lentic macroinvertebrates differed among two landscape types: (1) those that are largely covered in forests (presumed to be in a more pre‐human‐impact condition) and (2) those that are completely cleared for agricultural exploitation (massively altered). Location Five pairs of landscapes (each pair referred to as a region) – one of each landscape type – across a 30,000 km² region of north‐central Victoria, Australia. Methods Each individual waterbody was surveyed three times (austral spring 2006, autumn 2007, and spring 2007) for invertebrates. Waterbodies were characterized by measurements of static (e.g. abutting vegetation cover) and labile (e.g. pH) variables. Data were analysed using hierarchical Bayesian models of species richness, α‐ and β‐diversities and functional feeding groups. Assemblage composition was related to landscape and in‐waterbody characteristics. Results Neither measured, nor asymptotic estimates of, species richness differed among landscape types, notwithstanding consistent differences in in‐waterbody habitat characteristics among waterbodies in the two landscape types. There were no discernible differences in patterns of α‐ and β‐diversities at landscape scales relating to landscape type. Habitat diversity of waterbodies at the landscape scale did not affect β‐diversity, although distinct waterbodies within landscapes tended to have more distinct faunas. Main conclusions The lentic macroinvertebrate faunas are relatively homogeneous over the entire region, with little differentiation between wooded and cleared landscapes. The regional fauna may be a homogenized subset of native species, possibly arising from the huge numerical predominance of lentic habitats in agricultural landscapes producing ‘spill‐over’ effects into forested landscapes. Of taxa more frequently found in one or other landscape type, trophic group diversity was greater in forested landscapes.     

Comparative responses of termite functional and taxonomic diversity to land‐use change

1. While it is clear that land‐use change significantly impacts the taxonomic dimension of soil biodiversity, how the functional dimension responds to land‐use change is less well understood. 2. This study examined how the transformation of primary forests into rubber tree monocultures impacts individual termite species and how this change is reflected in termite taxonomic and functional α‐diversity (within site) and β‐diversity (among sites). 3. Overall, individual species responded strongly to land‐use change, whereby only 11 of the 27 species found were able to tolerate both habitats. These differences caused a 27% reduction in termite taxonomic richness and reduced taxonomic β‐diversity in rubber plantations compared with primary forests. The study also revealed that the forest conversion led to a shift in some termite species with smaller body size, shorter legs and smaller mandibular traits. Primary forests exhibited higher functional richness and functional β‐diversity of termite species, indicating that functional traits of termite species in rubber plantations are more evenly distributed. 4. The present study suggests that forest conversion does not merely decrease taxonomic diversity of termites, but also exerts functional trait filtering within some termite species. The results affirm the need for biodiversity assessments that combine taxonomic and functional indicators when monitoring the impact of land‐use change.     

The tangled link between β‐ and γ‐diversity: a Narcissus effect weakens statistical inferences in null model analyses of diversity patterns

Understanding the structure of and spatial variability in the species composition of ecological communities is at the heart of biogeography. In particular, there has been recent controversy about possible latitudinal trends in compositional heterogeneity across localities (β‐diversity). A gradient in the size of the regional species pool alone can be expected to impose a parallel gradient on β‐diversity, but whether β‐diversity also varies independently of the size of the species pool remains unclear. A recently suggested methodological approach to correct latitudinal β‐diversity gradients for the species pool effect is based on randomization null models that remove the effects of gradients in α‐ and γ‐diversity on β‐diversity. However, the randomization process imposes constraints on the variability of α‐diversity, which in turn force γ‐ and β‐diversity to become interdependent, such that any change in one is mirrored in the other. We argue that simple null model approaches are inadequate to discern whether correlations between α‐, β‐ and γ‐diversity reflect processes of ecological interest or merely differences in the size of the species pool among localities. We demonstrate that this kind of Narcissus effect may also apply to other metrics of spatial or phylogenetic species distribution. We highlight that Narcissus effects may lead to artificially high rejection rates for the focal pattern (Type II errors) and caution that these errors have not received sufficient attention in the ecological literature.     

Adaptability of the semi‐invariant natural killer T‐cell receptor towards structurally diverse CD1d‐restricted ligands

The semi‐invariant natural killer (NK) T‐cell receptor (NKTcr) recognises structurally diverse glycolipid antigens presented by the monomorphic CD1d molecule. While the α‐chain of the NKTcr is invariant, the β‐chain is more diverse, but how this diversity enables the NKTcr to recognise diverse antigens, such as an α‐linked monosaccharide (α‐galactosylceramide and α‐galactosyldiacylglycerol) and the β‐linked trisaccharide (isoglobotriaosylceramide), is unclear. We demonstrate here that NKTcrs, which varied in their β‐chain usage, recognised diverse glycolipid antigens with a similar binding mode on CD1d. Nevertheless, the NKTcrs recognised distinct epitopic sites within these antigens, including α‐galactosylceramide, the structurally similar α‐galactosyldiacylglycerol and the very distinct isoglobotriaosylceramide. We also show that the relative roles of the CDR loops within the NKTcr β‐chain varied as a function of the antigen. Thus, while NKTcrs characteristically use a conserved docking mode, the NKTcr β‐chain allows these cells to recognise unique aspects of structurally diverse CD1d‐restricted ligands.     

Correlating species and spectral diversities using hyperspectral remote sensing in early‐successional fields

Advances in remote sensing technology can help estimate biodiversity at large spatial extents. To assess whether we could use hyperspectral visible near‐infrared (VNIR) spectra to estimate species diversity, we examined the correlations between species diversity and spectral diversity in early‐successional abandoned agricultural fields in the Ridge and Valley ecoregion of north‐central Virginia at the Blandy Experimental Farm. We established plant community plots and collected vegetation surveys and ground‐level hyperspectral data from 350 to 1,025 nm wavelengths. We related spectral diversity (standard deviations across spectra) with species diversity (Shannon–Weiner index) and evaluated whether these correlations differed among spectral regions throughout the visible and near‐infrared wavelength regions, and across different spectral transformation techniques. We found positive correlations in the visible regions using band depth data, positive correlations in the near‐infrared region using first derivatives of spectra, and weak to no correlations in the red‐edge region using either of the two spectral transformation techniques. To investigate the role of pigment variability in these correlations, we estimated chlorophyll, carotenoid, and anthocyanin concentrations of five dominant species in the plots using spectral vegetation indices. Although interspecific variability in pigment levels exceeded intraspecific variability, chlorophyll was more varied within species than carotenoids and anthocyanins, contributing to the lack of correlation between species diversity and spectral diversity in the red‐edge region. Interspecific differences in pigment levels, however, made it possible to differentiate these species remotely, contributing to the species‐spectral diversity correlations. VNIR spectra can be used to estimate species diversity, but the relationships depend on the spectral region examined and the spectral transformation technique used.     

Spatial and temporal homogenisation of freshwater macrofaunal communities in ditches

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Biodiversity of soft-sediment benthic communities from Italian transitional waters

Aim For conservation purposes, it is important to understand the forces that shape biodiversity in transitional waters (TWs) and to evaluate the effects of small‐scale latitudinal changes. To this end, we analysed data on soft‐sediment macroinvertebrates from nine Italian TWs in order to (1) investigate the structure and distribution of the benthic fauna and their relationships with environmental and geographical variables, and (2) examine species richness and β‐diversity at various spatial scales. Location European Transition Waters Ecoregion 6. Methods Using a data set collected along a 7° latitudinal cline between 45°28′ N and 39°56′ N, we used Spearman’s rank correlation analysis to evaluate the relationships between species richness and both environmental and geographical variables, and linear regression analysis to show the relationships between α‐, β‐ and γ‐diversity. Three measures were used to assess β‐diversity: Whittaker’s β_W, and two similarity indices, namely the Bray‐Curtis similarity index and Δ_s. Using multivariate analyses, we determined the similarity in composition of the benthic community between sites and compared the biotic ordination with abiotic (geographical and environmental) characteristics. Results Two hundred and sixty‐eight species were recorded from 46 sites. Of these, 53.4% were restricted to one TW. Annelida was the dominant taxonomic group, followed by Crustacea and Mollusca. The α‐diversity was highly variable (5–87 species) and was correlated with latitude. The γ‐diversity, measured at the TW scale, was correlated significantly with α‐diversity. The β‐diversity increased with spatial scale and habitat heterogeneity. In the community pattern identified by multivariate analysis, TWs were segregated by latitude and biogeography, and this reflected different climatic conditions. Main conclusions We found that α‐diversity increased when moving from higher to lower latitudes, and that it depended on both regional and local factors. In addition, we detected latitudinal variations in the extent of regional influence on local species richness. The observed distribution pattern of TW faunas depended mostly on climate type. We suggest that the distribution of annelidan species could be used as a proxy for assessing general community patterns for Italian TWs.     

Alpine cushion plants inhibit the loss of phylogenetic diversity in severe environments

Biotic interactions can shape phylogenetic community structure (PCS). However, we do not know how the asymmetric effects of foundation species on communities extend to effects on PCS. We assessed PCS of alpine plant communities around the world, both within cushion plant foundation species and adjacent open ground, and compared the effects of foundation species and climate on alpha (within‐microsite), beta (between open and cushion) and gamma (open and cushion combined) PCS. In the open, alpha PCS shifted from highly related to distantly related with increasing potential productivity. However, we found no relationship between gamma PCS and climate, due to divergence in phylogenetic composition between cushion and open sub‐communities in severe environments, as demonstrated by increasing phylo‐beta diversity. Thus, foundation species functioned as micro‐refugia by facilitating less stress‐tolerant lineages in severe environments, erasing a global productivity – phylogenetic diversity relationship that would go undetected without accounting for this important biotic interaction.     

A TLC bioautographic method for the detection of α‐ and β‐glucosidase inhibitors in plant extracts

Introduction – Bioautographic assays using TLC play an important role in the search for active compounds from plants. A TLC assay has previously been established for the detection of β‐glucosidase inhibitors but not for α‐glucosidase. Nonetheless, α‐glucosidase inhibition is an important target for therapeutic agents against of type 2 diabetes and anti‐viral infections. Objective – To develop a TLC bioautographic method to detect α‐ and β‐glucosidase inhibitors in plant extracts. Methodology – The enzymes α‐ and β‐d ‐glucosidase were dissolved in sodium acetate buffer. After migration of the samples, the TLC plate was sprayed with enzyme solution and incubated at room temperature for 60 min in the case of α‐d ‐glucosidase, and 37°C for 20 min in the case of β‐d ‐glucosidase. For detection of the active enzyme, solutions of 2‐naphthyl‐α‐D‐glucopyranoside or 2‐naphthyl‐β‐D‐glucopyranoside and Fast Blue Salt were mixed at a ratio of 1 : 1 (for α‐d ‐glucosidase) or 1 : 4 (for β‐d ‐glucosidase) and sprayed onto the plate to give a purple background colouration after 2–5 min. Results – Enzyme inhibitors were visualised as white spots on the TLC plates. Conduritol B epoxide inhibited α‐d ‐glucosidase and β‐d ‐glucosidase down to 0.1 µg. Methanol extracts of Tussilago farfara and Urtica dioica after migration on TLC gave enzymatic inhibition when applied in amounts of 100 µg for α‐glucosidase and 50 µg for β‐glucosidase. Conclusion – The screening test was able to detect inhibition of α‐ and β‐glucosidases by pure reference substances and by compounds present in complex matrices, such as plant extracts. Copyright © 2009 John Wiley & Sons, Ltd.     

Importance of temporal variability at different spatial scales for diversity of floodplain aquatic communities

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停止人为去除植物功能群后的高寒草甸多样性恢复过程与群落构建

已有大量研究利用功能性状或系统发育来推断群落构建机制, 然而不同过程可能会导致相似的格局。本文基于对甘南高寒草甸植物功能群去除处理后群落恢复过程的跟踪调查, 对比了物种多样性、功能多样性和系统发育多样性的动态变化, 并分析了物种定殖与消失过程对功能多样性和系统发育多样性变化的影响。结果表明: 去除不同数量功能群的群落中: (1)包括物种丰富度(SR)、Shannon-Wiener指数(H°)和Simpson指数(D)在内的传统物种多样性均随时间快速上升并与自然群落趋同, 不同群落的均匀度指数(J)随时间呈增加趋势并趋于相似; 功能多样性(FD)与系统发育多样性(PD)呈现出与物种多样性相似的动态变化趋势, 而平均配对距离(MPD/MPD_a、MFD/MFD_a)则向中等程度聚集。(2)不同群落的功能群和物种组成在短期内均恢复到与自然群落非常相似的程度。(3)物种定殖与消失过程的功能格局是群落恢复过程中趋同效应的主要驱动力。本研究揭示了高寒草甸植物功能群去除停止后群落短期内快速恢复的过程, 说明在小尺度且周边具有大范围未退化草甸的情况下, 无论物种多样性、功能多样性还是系统发育多样性都具有较快的恢复能力, 同时说明了利用群落系统发育多样性格局来推断群落构建机制的局限性。     

Genetic and community similarities are correlated in endemic-rich springs of the northern Chihuahuan Desert

Aim Species diversity and genetic diversity within a taxon are intrinsic parts of global biodiversity. These two levels of biodiversity can show strong correlation due to a variety of reasons (i.e. parallel processes affecting both communities and populations, genotypes of a numerically or functionally dominant species affecting community composition, a species assemblage selecting for a particular genotype by affecting its selection regime). We examined correlations between species and genetic biodiversity in four isolated endemic‐rich spring systems in a hot desert and their potential link to environmental variables and physical isolation. Location Chihuahuan Desert spring systems in the Pecos River basin of New Mexico and Texas, USA. Methods We compared species richness of fish and benthic macroinvertebrate communities to within‐population allelic richness of amphipods (monophyletic Gammarus spp.) and Pecos gambusia (Gambusia nobilis) using Mantel tests. We also compared pairwise community similarities with pairwise genetic identities of populations among the same groups. We tested correlations among diversity, similarity and environmental variables after controlling for the effects of spatial distances using partial Mantel tests. We partitioned genetic and species diversity into three spatial scales (i.e. individual springs, individual spring systems, the entire region) using AMOVA and partition . Results We found strong correlations between invertebrate species richness and mosquitofish allelic richness. We found even stronger correlations of amphipod and gambusia genetic identities with fish and invertebrate community similarities; these were best explained by geographic distance rather than abiotic environmental factors. Most of the taxa and communities exhibited the largest proportion of diversity at the regional level. Main conclusions Our results suggest that drift and migration are the mechanisms that best explain our observations, and although α‐diversity among genes and species may not be strongly correlated, the pattern of species and allelic complementarity among these groups seems to be concordant at the regional level.     

Phylogenetic community structure metrics and null models: a review with new methods and software

Competitive exclusion and habitat filtering influence community assembly, but ecologists and evolutionary biologists have not reached consensus on how to quantify patterns that would reveal the action of these processes. Currently, at least 22 α‐diversity and 10 β‐diversity metrics of community phylogenetic structure can be combined with nine null models (eight for β‐diversity metrics), providing 278 potentially distinct approaches to test for phylogenetic clustering and overdispersion. Selecting the appropriate approach for a study is daunting. First, we describe similarities among metrics and null models across variance in phylogeny size and shape, species abundance, and species richness. Second, we develop spatially explicit, individual‐based simulations of neutral, competitive exclusion, or habitat filtering community assembly, and quantify the performance (type I and II error rates) of all 278 metric and null model combinations against each assembly process. Many α‐diversity metrics and null models are at least functionally equivalent, reducing the number of truly unique metrics to 12 and the number of unique metric + null model combinations to 72. An even smaller subset of metric and null model combinations showed robust statistical performance. For α‐diversity metrics, phylogenetic diversity and mean nearest taxon distance were best able to detect habitat filtering, while mean pairwise phylogenetic distance‐based metrics were best able to detect competitive exclusion. Overall, β‐diversity metrics tended to have greater power to detect habitat filtering and competitive exclusion than α‐diversity metrics, but had higher type 1 error in some cases. Across both α‐ and β‐diversity metrics, null model selection affected type I error rates more than metric selection. A null model that maintained species richness, and approximately maintained species occurrence frequency and abundance across sites, exhibited low type I and II error rates. This regional null model simulates neutral dispersal of individuals into local communities by sampling from a regional species pool. We introduce a flexible new R package, metricTester, to facilitate robust analyses of method performance.     

Altitude effects on spatial components of vascular plant diversity in a subarctic mountain tundra

Environmental gradients are caused by gradual changes in abiotic factors, which affect species abundances and distributions, and are important for the spatial distribution of biodiversity. One prominent environmental gradient is the altitude gradient. Understanding ecological processes associated with altitude gradients may help us to understand the possible effects climate change could have on species communities. We quantified vegetation cover, species richness, species evenness, beta diversity, and spatial patterns of community structure of vascular plants along altitude gradients in a subarctic mountain tundra in northern Sweden. Vascular plant cover and plant species richness showed unimodal relationships with altitude. However, species evenness did not change with altitude, suggesting that no individual species became dominant when species richness declined. Beta diversity also showed a unimodal relationship with altitude, but only for an intermediate spatial scale of 1 km. A lack of relationships with altitude for either patch or landscape scales suggests that any altitude effects on plant spatial heterogeneity occurred on scales larger than individual patches but were not effective across the whole landscape. We observed both nested and modular patterns of community structures, but only the modular patterns corresponded with altitude. Our observations point to biotic regulations of plant communities at high altitudes, but we found both scale dependencies and inconsistent magnitude of the effects of altitude on different diversity components. We urge for further studies evaluating how different factors influence plant communities in high altitude and high latitude environments, as well as studies identifying scale and context dependencies in any such influences.     

Climate and plant structure determine the spatiotemporal butterfly distribution on a tropical mountain

Mountains are among the most powerful natural gradients for testing ecological and evolutionary responses of biota to environmental influences because differences in climate and plant structure occur over short spatial scales. We describe the spatiotemporal distribution patterns and drives of fruit‐feeding butterfly diversity in the mountainous region of Serra do Cipó, Minas Gerais, Brazil. Seven elevations from 822 to 1,388 m a.s.l. were selected for evaluating the effects of abiotic factors and vegetation characteristics on butterfly diversity. A total of 44 fruit‐feeding butterfly species were recorded in a two‐year study. Species richness (local and regional) of fruit‐feeding butterflies decreased with increasing elevation. The interaction between temperature or humidity and precipitation influenced the abundance and β‐diversity of butterflies in the elevation gradient, whereas β‐diversity decreased with increasing plant richness. Butterfly richness (local and regional) and β‐diversity varied with the sampling period, with fewer species in July (2012 and 2013), the dry period, as expected for Neotropical insects. β‐Diversity in space and time was due to species replacement (turnover), indicating that butterfly composition differs throughout the mountain and over time. In summary, climate and plant richness largely influence butterfly diversity in the elevational gradient. Climatic changes in conjunction with increasing anthropic impacts on mountainous regions of southeast Brazil will likely influence the community of mountaintop butterflies in the Espinhaço Mountain Range. Abstract in Portuguese is available with online material.