From diversity indices to community assembly processes: a test with simulated data

Authored by T Muenkemueller, Bello F de, C N Meynard, D Gravel, S Lavergne, D Mouillot, N Mouquet, W Thuiller

Date Published: 2012

DOI: 10.1111/j.1600-0587.2011.07259.x

Sponsors: European Union French National Research Agency (ANR) French National Center for Scientific Research (CNRS)

Platforms: No platforms listed

Model Documentation: Other Narrative Flow charts

Model Code URLs: Model code not found

Abstract

Ecological theory suggests that spatial distribution of biodiversity is strongly driven by community assembly processes. Thus the study of diversity patterns combined with null model testing has become increasingly common to infer assembly processes from observed distributions of diversity indices. However, results in both empirical and simulation studies are inconsistent. The aim of our study is to determine with simulated data which facets of biodiversity, if any, may unravel the processes driving its spatial patterns, and to provide practical considerations about the combination of diversity indices that would produce significant and congruent signals when using null models. The study is based on simulated species assemblages that emerge under various landscape structures in a spatially explicit individual-based model with contrasting, predefined assembly processes. We focus on four assembly processes (species-sorting, mass effect, neutral dynamics and competition colonization trade-off) and investigate the emerging species distributions with varied diversity indices (alpha, beta and gamma) measured at different spatial scales and for different diversity facets (taxonomic, functional and phylogenetic). We find that 1) the four assembly processes result in distinct spatial distributions of species under any landscape structure, 2) a broad range of diversity indices allows distinguishing between communities driven by different assembly processes, 3) null models provide congruent results only for a small fraction of diversity indices and 4) only a combination of these diversity indices allows identifying the correct assembly processes. Our study supports the inference of assembly processes from patterns of diversity only when different types of indices are combined. It highlights the need to combine phylogenetic, functional and taxonomic diversity indices at multiple spatial scales to effectively infer underlying assembly processes from diversity patterns by illustrating how combination of different indices might help disentangling the complex question of coexistence.

Tags

Limiting similarity Ecological communities Beta diversity Species abundance Niche Neutral theory Spatial variation Functional diversity Phylogenetic structure Unified approach