Functional and phylogenetic assembly in a Chinese tropical tree community across size classes, spatial scales and habitats

Abstract

Summary1. Increasingly, ecologists are using functional and phylogenetic approaches to quantify the relative importance of stochastic, abiotic filtering and biotic filtering processes shaping the pattern of species co-occurrence. A remaining challenge in functional and phylogenetic analyses of tropical tree communities is to successfully integrate the functional and phylogenetic structure of tree communities across spatial and size scales and habitats in a single analysis. 2. We analysed the functional and phylogenetic structure of tree assemblages in a 20-ha tropical forest dynamics plot in south-west China. Because the influence of biotic interactions may become more apparent as cohorts age, on local scales, and in resource-rich environments, we perform our analyses across three size classes, six spatial scales and six distinct habitat types, using 10 plant functional traits and a molecular phylogeny for the >400 tree taxa found in the plot. 3. All traits, except leaf area and stem-specific resistance, had significant, albeit weak phylogenetic signal. For canopy species, phylogenetic clustering in small and medium size classes turned to phylogenetic overdispersion in the largest size class and this change in dispersion with size was found in each habitat type and across all spatial scales. On fine spatial scales, functional dispersion changed from clustering to overdispersion with increasing size classes. However, on larger spatial scales assemblages were functionally clustered for all size classes and habitats. 4. Phylogenetic and functional structure across spatial and size scales and habitats gave strong support for a deterministic model of species co-occurrence rather than for a neutral model. The results also support the hypothesis that abiotic determinism is more important at larger scales, while biotic determinism is more important on smaller scales within habitats.

How to design trait-based analyses of community assembly mechanisms: Insights and guidelines from a literature review

“…sidered different spatial scales as part of their experimental design and only detected functional signatures associated with limiting similarity at their smallest sampling scales while environmental filtering dominates at the largest ones (e.g. Kraft and Ackerly, 2010;Yang et al, 2014). However, these general assumptions require considering the specific spatial scale of abiotic environmental het- The position of the papers on the ordination plan is shown by different colors, depending on the type of organism (bottom left caption) while the response variables are in bold capital letters (bottom right caption).…”

Evolutionary heritage influences Amazon tree ecology

“…For example, if a selected trait has significant PS, the relatedness of species can help us to understand the underlying mechanisms that drive community structure [5–7]. The presence of significant PS also suggests that the sum of phylogenetic distances among species that occur within a community (i.e.…”

Ontogenetic trait variation influences tree community assembly across environmental gradients

“…However, mechanistic inferences based on patterns of functional diversity are complicated by the fact that trait variation can emerge through a combination of interspecific trait variation, intraspecific trait variation across environmental gradients (Jung et al 2010, Violle et al 2012, and intraspecific trait variation across ontogenetic stages (Poorter 2007, Yang et al 2014). Yet, most studies of trait-based assembly have focused on interspecific trait variation typically measured at a single ontogenetic stage (e.g., Ackerly 2009, Spasojevic andSuding 2012) or extracted from floras or trait databases with limited information on intraspecific trait variation (e.g., Schamp andAarssen 2009, Liu et al 2013).…”

“…More recently, ecologists have incorporated intraspecific trait variation into this framework by comparing how traits of individual species vary across environments (e.g., Fernandez-Going et al 2012, Spasojevic et al 2014 or by partitioning trait variation within and among species to help infer the relative importance of different assembly mechanisms (e.g., Messier et al 2010, Violle et al 2012, Hulshof et al 2013. In contrast, little is known about how ontogenetic trait variation influences community assembly across environmental gradients (e.g., Poorter 2007, Yang et al 2014. If assembly mechanisms vary in their relative importance across ontogenetic stages Peart 2000, Comita et al 2007), community-wide patterns of functional diversity may mask the signature of abiotic and biotic mechanisms during community assembly.…”