Functional traits and environmental filtering drive community assembly in a species‐rich tropical system

Abstract

Mechanistic models of community assembly state that biotic and abiotic filters constrain species establishment through selection on their functional traits. Predicting this assembly process is hampered because few studies directly incorporate environmental measurements and scale up from species to community level and because the functional traits' significance is environment dependent. We analyzed community assembly by measuring structure, environmental conditions, and species traits of secondary forests in a species-rich tropical system. We found, as hypothesized, that community structure shaped the local environment and that strong relationships existed between this environment and the traits of the most successful species of the regeneration communities. Path and multivariate analyses showed that temperature and leaf traits that regulate it were the most important factors of community differentiation. Comparisons between the trait composition of the forest's regeneration, juvenile, and adult communities showed a consistent community assembly pattern. These results allowed us to identify the major functional traits and environmental factors involved in the assembly of dry-forest communities and demonstrate that environmental filtering is a predictable and fundamental process of community assembly, even in a complex system such as a tropical forest.

Environmental changes during secondary succession in a tropical dry forest in Mexico

“…Light availability declines sharply with the prompt growth of pioneers (Lebrija-Trejos et al 2010a). Nonetheless, because TDF has a low canopy height, a simple vertical stratification and a low leaf biomass (Bullock et al 1995, Lebrija-Trejos et al 2008, the light differential created throughout succession is much weaker than in temperate or humid tropical forests, where, for instance, only < 1% to ∼5% of full sunlight reaches the closed-canopy understorey (Canham et al 1990, Richards et al 1996, vs. 6-22% in our fallows.…”

“…Even if water is freely available, short periods with relatively mild levels of VPD (>2 kPa), as found even under closed canopies, markedly reduce photosynthetic gains of tropical drought-avoiding species (Ishida et al 2006, Shirke & Pathre 2004. Many TDF species are filtered out from early successional communities, and recruit more numerously in the shadier and moister late-successional communities (Aerts et al 2007, Lebrija-Trejos et al 2010a, Lieberman & Li 1992.…”

Environmental Filtering Process Has More Important Roles than Dispersal Limitation in Shaping Large-Scale Prokaryotic Beta Diversity Patterns of Grassland Soils

“…Previous studies suggested that species similarity has a negative relationship with environmental heterogeneity according to the deterministic process as shown in Fig. 1b [25]. In other words, the habitat specialization resulting from adaptive evolution has a crucial role in determining community composition [26,27], which is a typical deterministic process driven by environmental heterogeneity.…”

“…1a). In contrast, the deterministic process is characterized by environmental filtering, which suggests that the species with similar traits tend to exist in the same habitat, and this process is governed by the divergence of environmental conditions [25]. Previous studies suggested that species similarity has a negative relationship with environmental heterogeneity according to the deterministic process as shown in Fig.…”

Successional dynamics in Neotropical forests are as uncertain as they are predictable

“…As a result, most of our knowledge on forest succession is based on chronosequences (13), a space-for-time substitution approach that assumes that succession follows a single, largely deterministic trajectory over time. Recent studies, however, have shown that successional pathways vary widely, even among neighboring stands with similar environmental conditions and disturbance history (14)(15)(16)(17)(18). In the case of posthurricane succession in Nicaragua, such variation has been attributed to stochastic processes associated with nonequilibrium community dynamics (18).…”