Phylogenetic turnover during subtropical forest succession across environmental and phylogenetic scales

Although spatial and temporal patterns of phylogenetic community structure during succession are inherently interlinked and assembly processes vary with environmental and phylogenetic scales, successional studies of community assembly have yet to integrate spatial and temporal components of community structure, while accounting for scaling issues. To gain insight into the processes that generate biodiversity after disturbance, we combine analyses of spatial and temporal phylogenetic turnover across phylogenetic scales, accounting for covariation with environmental differences. We compared phylogenetic turnover, at the species‐ and individual‐level, within and between five successional stages, representing woody plant communities in a subtropical forest chronosequence. We decomposed turnover at different phylogenetic depths and assessed its covariation with between‐plot abiotic differences. Phylogenetic turnover between stages was low relative to species turnover and was not explained by abiotic differences. However, within the late‐successional stages, there was high presence‐/absence‐based turnover (clustering) that occurred deep in the phylogeny and covaried with environmental differentiation. Our results support a deterministic model of community assembly where (i) phylogenetic composition is constrained through successional time, but (ii) toward late succession, species sorting into preferred habitats according to niche traits that are conserved deep in phylogeny, becomes increasingly important.     

Discriminating ecological processes affecting different dimensions of α‐ and β‐diversity in desert plant communities

Understanding the spatial distribution of plant diversity and its drivers are major challenges in biogeography and conservation biology. Integrating multiple facets of biodiversity (e.g., taxonomic, phylogenetic, and functional biodiversity) may advance our understanding on how community assembly processes drive the distribution of biodiversity. In this study, plant communities in 60 sampling plots in desert ecosystems were investigated. The effects of local environment and spatial factors on the species, functional, and phylogenetic α‐ and β‐diversity (including turnover and nestedness components) of desert plant communities were investigated. The results showed that functional and phylogenetic α‐diversity were negatively correlated with species richness, and were significantly positively correlated with each other. Environmental filtering mainly influenced species richness and Rao quadratic entropy; phylogenetic α‐diversity was mainly influenced by dispersal limitation. Species and phylogenetic β‐diversity were mainly consisted of turnover component. The functional β‐diversity and its turnover component were mainly influenced by environmental factors, while dispersal limitation dominantly effected species and phylogenetic β‐diversity and their turnover component of species and phylogenetic β‐diversity. Soil organic carbon and soil pH significantly influenced different dimensions of α‐diversity, and soil moisture, salinity, organic carbon, and total nitrogen significantly influenced different dimensions of α‐ and β‐diversity and their components. Overall, it appeared that the relative influence of environmental and spatial factors on taxonomic, functional, and phylogenetic diversity differed at the α and β scales. Quantifying α‐ and β‐diversity at different biodiversity dimensions can help researchers to more accurately assess patterns of diversity and community assembly.     

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.     

Phylogenetic beta diversity in bacterial assemblages across ecosystems: deterministic versus stochastic processes

Increasing evidence has emerged for non-random spatial distributions of microbes, but knowledge of the processes that cause variation in microbial assemblage among ecosystems is lacking. For instance, some studies showed that deterministic processes such as habitat specialization are important, while other studies hold that bacterial communities are assembled by stochastic forces. Here we examine the relative influence of deterministic and stochastic processes for bacterial communities from subsurface environments, stream biofilm, lake water, lake sediment and soil using pyrosequencing of the 16S ribosomal RNA gene. We show that there is a general pattern in phylogenetic signal in species ecological niches across recent evolutionary time for all studied habitats, enabling us to infer the influences of community assembly processes from patterns of phylogenetic turnover in community composition. The phylogenetic dissimilarities among-habitat types were significantly higher than within them, and the communities were clustered according to their original habitat types. For communities within-habitat types, the highest phylogenetic turnover rate through space was observed in subsurface environments, followed by stream biofilm on mountainsides, whereas the sediment assemblages across regional scales showed the lowest turnover rate. Quantifying phylogenetic turnover as the deviation from a null expectation suggested that measured environmental variables imposed strong selection on bacterial communities for nearly all sample groups. For three sample groups, spatial distance reflected unmeasured environmental variables that impose selection, as opposed to spatial isolation. Such characterization of spatial and environmental variables proved essential for proper interpretation of partial Mantel results based on observed beta diversity metrics. In summary, our results clearly indicate a dominant role of deterministic processes on bacterial assemblages and highlight that bacteria show strong habitat associations that have likely emerged through evolutionary adaptation.     

Trade-offs in community ecology: linking spatial scales and species coexistence

Trade‐offs in species performances of different ecological functions is one of the most common explanations for coexistence in communities. Despite the potential for species coexistence occurring at local or regional spatial scales, trade‐offs are typically approached at a single scale. In recent years, ecologists have increasingly provided evidence for the importance of community processes at both local and regional spatial scales. This review summarizes the theoretical predictions for the traits associated with trade‐offs under different conditions and at different spatial scales. We provide a spatial framework for understanding trade‐offs, coexistence and the supportive empirical evidence. Predictions are presented that link the patterns of diversity observed to the patterns of trade‐offs that lead to coexistence at different spatial scales. Recent evidence for the evolution of trade‐offs under different conditions is provided which explores both laboratory microcosm studies and phylogenetic tests. Examining trade‐offs within a spatial framework can provide a strong approach to understanding community structure and dynamics, while explaining patterns of species diversity.     

Phylogenetic and functional dissimilarity does not increase during temporal heathland succession

Succession has been a focal point of ecological research for over a century, but thus far has been poorly explored through the lens of modern phylogenetic and trait-based approaches to community assembly. The vast majority of studies conducted to date have comprised static analyses where communities are observed at a single snapshot in time. Long-term datasets present a vantage point to compare established and emerging theoretical predictions on the phylogenetic and functional trajectory of communities through succession. We investigated within, and between, community measures of phylogenetic and functional diversity in a fire-prone heathland along a 21 year time series. Contrary to widely held expectations that increased competition through succession should inhibit the coexistence of species with high niche overlap, plots became more phylogenetically and functionally clustered with time since fire. There were significant directional shifts in individual traits through time indicating deterministic successional processes associated with changing abiotic and/or biotic conditions. However, relative to the observed temporal rate of taxonomic turnover, both phylogenetic and functional turnover were comparatively low, suggesting a degree of functional redundancy among close relatives. These results contribute to an emerging body of evidence indicating that limits to the similarity of coexisting species are rarely observed at fine spatial scales.     

Species turnover in Amazonian frogs: low predictability and large differences among forests

The factors explaining species turnover at different spatial scales have been intensively studied, but most work in Amazonia has mainly focused on plants. For animals, it is not as obvious which environmental variables most affect differences in species composition among sites. We sought to identify what causes anuran turnover in Amazonian terra firme forests, and how the effectiveness of these factors varies among regions and across spatial scales. We sampled frogs in 56 plots along ponds and streams distributed over three terra firme forest areas in Eastern Amazonia. Using multiple regressions on distance matrices, we partitioned the variation in species turnover into components explained by variation in environmental and spatial distances. This was done in parallel for each area separately, and for all areas together, to assess the consistency of results between scales and across areas at the same scale. Each community seemed to respond to a set of factors specific to that area, and the identity of the variables that emerged as significant differed among areas and scales. Both geographical distances and environmental differences had larger explanatory power at the regional scale than at the local scale. The large differences among results from different areas caution against making broad generalizations about species turnover patterns from a single community, as real differences may exist among areas.     

Plankton metacommunities in floodplain wetlands under contrasting hydrological conditions

相似文献   

Environmental variation is a major predictor of global trait turnover in mammals

Aim

To evaluate how environment and evolutionary history interact to influence global patterns of mammal trait diversity (a combination of 14 morphological and life‐history traits).

Location

The global terrestrial environment.

Taxon

Terrestrial mammals.

Methods

We calculated patterns of spatial turnover for mammalian traits and phylogenetic lineages using the mean nearest taxon distance. We then used a variance partitioning approach to establish the relative contribution of trait conservatism, ecological adaptation and clade specific ecological preferences on global trait turnover.

Results

We provide a global scale analysis of trait turnover across mammalian terrestrial assemblages, which demonstrates that phylogenetic turnover by itself does not predict trait turnover better than random expectations. Conversely, trait turnover is consistently more strongly associated with environmental variation than predicted by our null models. The influence of clade‐specific ecological preferences, reflected by the shared component of phylogenetic turnover and environmental variation, was considerably higher than expectations. Although global patterns of trait turnover are dependent on the trait under consideration, there is a consistent association between trait turnover and environmental predictive variables, regardless of the trait considered.

Main conclusions

Our results suggest that changes in phylogenetic composition are not always coupled with changes in trait composition on a global scale and that environmental conditions are strongly associated with patterns of trait composition across species assemblages, both within and across phylogenetic clades.     

The relationships between local and regional species richness and spatial turnover

Aim To determine the empirical relationships between species richness and spatial turnover in species composition across spatial scales. These have remained little explored despite the fact that such relationships are fundamental to understanding spatial diversity patterns. Location South‐east Scotland. Methods Defining local species richness simply as the total number of species at a finer resolution than regional species richness and spatial turnover as turnover in species identity between any two or more areas, we determined the empirical relationships between all three, and the influence of spatial scale upon them, using data on breeding bird distributions. We estimated spatial turnover using a measure independent of species richness gradients, a fundamental feature which has been neglected in theoretical studies. Results Local species richness and spatial turnover exhibited a negative relationship, which became stronger as larger neighbourhood sizes were considered in estimating the latter. Spatial turnover and regional species richness did not show any significant relationship, suggesting that spatial species replacement occurs independently of the size of the regional species pool. Local and regional species richness only showed the expected positive relationship when the size of the local scale was relatively large in relation to the regional scale. Conclusions Explanations for the relationships between spatial turnover and local and regional species richness can be found in the spatial patterns of species commonality, gain and loss between areas.     

Geographic Variation in Plant Community Structure of Salt Marshes: Species,Functional and Phylogenetic Perspectives

In general, community similarity is thought to decay with distance; however, this view may be complicated by the relative roles of different ecological processes at different geographical scales, and by the compositional perspective (e.g. species, functional group and phylogenetic lineage) used. Coastal salt marshes are widely distributed worldwide, but no studies have explicitly examined variation in salt marsh plant community composition across geographical scales, and from species, functional and phylogenetic perspectives. Based on studies in other ecosystems, we hypothesized that, in coastal salt marshes, community turnover would be more rapid at local versus larger geographical scales; and that community turnover patterns would diverge among compositional perspectives, with a greater distance decay at the species level than at the functional or phylogenetic levels. We tested these hypotheses in salt marshes of two regions: The southern Atlantic and Gulf Coasts of the United States. We examined the characteristics of plant community composition at each salt marsh site, how community similarity decayed with distance within individual salt marshes versus among sites in each region, and how community similarity differed among regions, using species, functional and phylogenetic perspectives. We found that results from the three compositional perspectives generally showed similar patterns: there was strong variation in community composition within individual salt marsh sites across elevation; in contrast, community similarity decayed with distance four to five orders of magnitude more slowly across sites within each region. Overall, community dissimilarity of salt marshes was lowest on the southern Atlantic Coast, intermediate on the Gulf Coast, and highest between the two regions. Our results indicated that local gradients are relatively more important than regional processes in structuring coastal salt marsh communities. Our results also suggested that in ecosystems with low species diversity, functional and phylogenetic approaches may not provide additional insight over a species-based approach.     

Multi‐scale ant diversity in savanna woodlands: an intercontinental comparison

Ecological patterns and processes are highly scale‐dependent, but few studies have used standardized methodology to examine how scale dependency varies across continents. This paper examines scale dependency in comparative ant species richness and turnover in savannas of Australia and Brazil, which are well‐matched climatically but whose ant faunas have contrasting biogeographic origins. The study was conducted in savanna woodland near Darwin in northern Australia and Uberlândia in central Brazil. The sampling design consisted of eight 400‐m line transects, four in each continent, with eight pitfall traps located on and around each of 20 trees evenly spaced along each transect. Ant richness and species turnover were compared at three spatial scales: pitfalls associated with a tree, trees within a transect and transects within a savanna. The composition of the Australian and Brazilian savanna ant faunas was broadly similar at the subfamily level, despite the very low proportion of shared genera and species. The ground and arboreal ant faunas were very distinct from each other in both savannas, but especially in Brazil. Overall ant abundance was almost three times higher in Australia than in Brazil, both on the ground and on vegetation, but overall species richness was higher in Brazil (150 species) than in Australia (93). There was no significant difference in the mean number of species per pitfall trap, but the mean species richness was significantly higher in Brazil than in Australia at both the tree and transect scales. We attribute these scale‐dependent intercontinental differences to biogeographical and historical factors in Brazil that have led to a large regional pool of arboreal species of rainforest origin. Our study underlines the importance of biogeographical context when conducting comparative analyses of community structure across biogeographical scales, and highlights the importance of process acting at regional scales in determining species richness in ant communities.     

The building of a biodiversity hotspot across a land-bridge in the Mediterranean

Many of the macroevolutionary processes that have shaped present-day phylogenetic patterns were caused by geological events such as plate tectonics and temporary land-bridges. The study of spatial patterns of phylogenetic diversity can provide insights into these past events. Here we focus on a western Mediterranean biodiversity hotspot located in the southern Iberian Peninsula and northwest Africa, two regions that are separated by the Strait of Gibraltar. We explore the spatial structure of the phylogenetic relationships within and across large-scale plant assemblages. Significant turnover in terminal lineages tends to occur between landmasses, whereas turnover in deep lineages tends to occur within landmasses. Plant assemblages in the western ecoregions of this hotspot tend to be phylogenetically overdispersed but are phylogenetically clustered on its eastern margins. We discuss our results in the light of potential scenarios of niche evolution (or conservatism) and lineage diversification. The significant turnover between landmasses suggests a common scenario of allopatric speciation that could have been facilitated by the intermittent joining of the two continents. This may have constituted an important stimulus for diversification and the emergence of this western Mediterranean biodiversity hotspot.     

Deconstructing the dimensions of alpha diversity in squamate reptiles (Reptilia: Squamata) across the Americas

Aim

Our aim is to document the dimensions of current squamate reptile biodiversity in the Americas by integrating taxonomic, phylogenetic and functional data, and assessing how this may vary across phylogenetic scales. We also explore the potential underlying mechanisms that may be responsible for the observed geographical diversity patterns.

Location

The Americas.

Time period

Present.

Major taxa

Squamate reptiles.

Methods

We used published data on the distribution, phylogeny, and body size of squamate reptiles to document the current dimensions of their alpha diversity in the Americas. We overlapped species ranges to estimate taxonomic diversity (TD) and calculated phylogenetic diversity (PD) using mean pairwise phylogenetic distance (MPD), speciation rate (DivRate) and Faith's phylogenetic index (PD). We estimated functional diversity (FD) as trait dispersion in the multivariate space using body size and leg development data. We implemented a deconstructive macroecological approach to understand how spatial mismatches between the three facets of diversity vary across phylogenetic scales, and the potential eco-evolutionary mechanisms driving these patterns across space.

Results

We found a strong latitudinal gradient of TD with a large accumulation in tropical regions. PD and FD patterns were largely similar likely due to the high phylogenetic signal in the traits used, and higher values tended to be concentrated in harsh and/or heterogeneous environments. We found differences between major clades within Squamata that display contrasting geographical patterns. Several regions across the continent shared the same spatial mismatches between dimensions across clades, suggesting that similar eco-evolutionary processes are shaping these regional reptile assemblages. However, we also found evidence that non-mutually exclusive processes can operate differently across clades.

Main conclusions

The deconstructive approach implemented here is based on a solid macroecological framework. We can extend this to other taxonomic groups to establish whether there are particularities about how different eco-evolutionary mechanisms shape biodiversity facets in a spatially explicit context.     

Functional and phylogenetic structure of forest and savanna bird assemblages across spatial scales

Ecological and evolutionary mechanisms that drive community assembly vary in space and time. However, little is known about how such mechanisms act in contrasting habitats. Here, we estimated the functional and phylogenetic structure of forest and savanna bird assemblages across different spatial scales to understand: 1) the mechanisms that govern the structure of assemblages in these habitats; 2) the relationship between phylogenetic and functional structure; and 3) the influence of species richness on the functional and phylogenetic structure of assemblages. We used a null model where forest and savanna bird species were allowed to occur in the same null assemblages and other where species were separated based on their habitats. According to the first null model, forest bird assemblages were functionally and phylogenetically clustered at all spatial scales, whereas savanna bird assemblages generally showed random functional and phylogenetic structure. These results can be explained by the low dispersal rate of forest species across of the patchy habitats and the widespread distribution of savanna species. However, in the second null model, both forest and savanna bird assemblages showed random functional and phylogenetic structure at regional and local scales. This suggests that trait‐based assembly might not play an important role in both habitats and across different spatial scales. In addition, the phylogenetic and functional structure of assemblages were not correlated, evidencing that caution is necessary when using phylogenetic relationships as a surrogate to functional distances among species. Finally, the relationships between species richness and functional and phylogenetic structure indicated that an increase in the number of species can promote both clustering and overdispersion, depending on the studied habitat and scale. Our study shows that integrating different types of habitat, spatial scales and biodiversity components in a single framework can shed light on the mechanisms that determine the community assembly.     

Does functional homogenization accompany taxonomic homogenization of British birds and how do biotic factors and climate affect these processes?

Environmental change has reshuffled communities often causing taxonomic homogenization rather than differentiation. Some studies suggest that this increasing similarity of species composition between communities is accompanied by an increase in similarity of trait composition—functional homogenization—although different methodologies have failed to come to any consistent conclusions. Functional homogenization could have a large effect on ecosystem functioning and stability. Here, we use the general definition of homogenization as “reduced spatial turnover over time” to compare changes in Simpson's beta diversity (taxonomic turnover) with changes in Rao's quadratic entropy beta diversity (functional turnover) in British breeding birds at three spatial scales. Using biotic and climatic variables, we identify which factors may predispose a site to homogenization. The change in turnover measures between two time periods, 20 years apart, was calculated. A null model approach was taken to identify occurrences of functional homogenization and differentiation independent of changes in taxonomic turnover. We used conditional autoregressive models fitted using integrated nested Laplace approximations to determine how environmental drivers and factors relating to species distributions affect changes in spatial turnover of species and functional diversity. The measurement of functional homogenization affects the chance of rejection of the null models, with many sites showing taxonomic homogenization unaccompanied by functional homogenization, although occurrence varies with spatial scale. At the smallest scale, while temperature‐related variables drive changes in taxonomic turnover, changes in functional turnover are associated with variation in growing degree days; however, changes in functional turnover become more difficult to predict at larger spatial scales. Our results highlight the multifactorial processes underlying taxonomic and functional homogenization and that redundancy in species traits may allow ecosystem functioning to be maintained in some areas despite changes in species composition.     

Measuring biodiversity to explain community assembly: a unified approach

One of the oldest challenges in ecology is to understand the processes that underpin the composition of communities. Historically, an obvious way in which to describe community compositions has been diversity in terms of the number and abundances of species. However, the failure to reject contradictory models has led to communities now being characterized by trait and phylogenetic diversities. Our objective here is to demonstrate how species, trait and phylogenetic diversity can be combined together from large to local spatial scales to reveal the historical, deterministic and stochastic processes that impact the compositions of local communities. Research in this area has recently been advanced by the development of mathematical measures that incorporate trait dissimilarities and phylogenetic relatedness between species. However, measures of trait diversity have been developed independently of phylogenetic measures and conversely most of the phylogenetic diversity measures have been developed independently of trait diversity measures. This has led to semantic confusions particularly when classical ecological and evolutionary approaches are integrated so closely together. Consequently, we propose a unified semantic framework and demonstrate the importance of the links among species, phylogenetic and trait diversity indices. Furthermore, species, trait and phylogenetic diversity indices differ in the ways they can be used across different spatial scales. The connections between large‐scale, regional and local processes allow the consideration of historical factors in addition to local ecological deterministic or stochastic processes. Phylogenetic and trait diversity have been used in large‐scale analyses to determine how historical and/or environmental factors affect both the formation of species assemblages and patterns in species richness across latitude or elevation gradients. Both phylogenetic and trait diversity have been used at different spatial scales to identify the relative impacts of ecological deterministic processes such as environmental filtering and limiting similarity from alternative processes such as random speciation and extinction, random dispersal and ecological drift. Measures of phylogenetic diversity combine phenotypic and genetic diversity and have the potential to reveal both the ecological and historical factors that impact local communities. Consequently, we demonstrate that, when used in a comparative way, species, trait and phylogenetic structures have the potential to reveal essential details that might act simultaneously in the assembly of species communities. We highlight potential directions for future research. These might include how variation in trait and phylogenetic diversity alters with spatial distances, the role of trait and phylogenetic diversity in global‐scale gradients, the connections between traits and phylogeny, the importance of trait rarity and independent evolutionary history in community assembly, the loss of trait and phylogenetic diversity due to human impacts, and the mathematical developments of biodiversity indices including within‐species variations.     

Plant species coexistence at local scale in temperate swamp forest: test of habitat heterogeneity hypothesis

It has been suggested that a heterogeneous environment enhances species richness and allows for the coexistence of species. However, there is increasing evidence that environmental heterogeneity can have no effect or even a negative effect on plant species richness and plant coexistence at a local scale. We examined whether plant species richness increases with local heterogeneity in the water table depth, microtopography, pH and light availability in a swamp forest community at three local spatial scales (grain: 0.6, 1.2 and 11.4 m). We also used the variance partitioning approach to assess the relative contributions of niche-based and other spatial processes to species occurrence. We found that heterogeneity in microtopography and light availability positively correlated with species richness, in accordance with the habitat heterogeneity hypothesis. However, we recorded different heterogeneity-diversity relationships for particular functional species groups. An increase in the richness of bryophytes and woody plant species was generally related to habitat heterogeneity at all measured spatial scales, whereas a low impact on herbaceous species richness was recorded only at the 11.4 m scale. The distribution of herbaceous plants was primarily explained by other spatial processes, such as dispersal, in contrast to the occurrence of bryophytes, which was better explained by environmental factors. Our results suggest that both niche-based and other spatial processes are important determinants of the plant composition and species turnover at local spatial scales in swamp forests.     

A phylogenetic and trait‐based analysis of community assembly in a subtropical forest in central China

Despite several decades of study in community ecology, the relative importance of the ecological processes that determine species co‐occurrence across spatial scales remains uncertain. Some of this uncertainty may be reduced by studying the scale dependency of community assembly in the light of environmental variation. Phylogenetic information and functional trait information are often used to provide potentially valuable insights into the drivers of community assembly. Here, we combined phylogenetic and trait‐based tests to gain insights into community processes at four spatial scales in a large stem‐mapped subtropical forest dynamics plot in central China. We found that all of the six leaf economic traits measured in this study had weak, but significant, phylogenetic signal. Nonrandom phylogenetic and trait‐based patterns associated with topographic variables indicate that deterministic processes tend to dominate community assembly in this plot. Specifically, we found that, on average, co‐occurring species were more phylogenetically and functionally similar than expected throughout the plot at most spatial scales and assemblages of less similar than expected species could only be found on finer spatial scales. In sum, our results suggest that the trait‐based effects on community assembly change with spatial scale in a predictable manner and the association of these patterns with topographic variables, indicates the importance of deterministic processes in community assembly relatively to random processes.