Compositional Divergence and Convergence in Local Communities and Spatially Structured Landscapes

Tancredi Caruso*, Jeff R. Powell, Matthias C. Rillig

*Corresponding author for this work

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Community structure depends on both deterministic and stochastic processes. However, patterns of community dissimilarity (e.g. difference in species composition) are difficult to interpret in terms of the relative roles of these processes. Local communities can be more dissimilar (divergence) than, less dissimilar (convergence) than, or as dissimilar as a hypothetical control based on either null or neutral models. However, several mechanisms may result in the same pattern, or act concurrently to generate a pattern, and much research has recently been focusing on unravelling these mechanisms and their relative contributions. Using a simulation approach, we addressed the effect of a complex but realistic spatial structure in the distribution of the niche axis and we analysed patterns of species co-occurrence and beta diversity as measured by dissimilarity indices (e.g. Jaccard index) using either expectations under a null model or neutral dynamics (i.e., based on switching off the niche effect). The strength of niche processes, dispersal, and environmental noise strongly interacted so that niche-driven dynamics may result in local communities that either diverge or converge depending on the combination of these factors. Thus, a fundamental result is that, in real systems, interacting processes of community assembly can be disentangled only by measuring traits such as niche breadth and dispersal. The ability to detect the signal of the niche was also dependent on the spatial resolution of the sampling strategy, which must account for the multiple scale spatial patterns in the niche axis. Notably, some of the patterns we observed correspond to patterns of community dissimilarities previously observed in the field and suggest mechanistic explanations for them or the data required to solve them. Our framework offers a synthesis of the patterns of community dissimilarity produced by the interaction of deterministic and stochastic determinants of community assembly in a spatially explicit and complex context.

Original languageEnglish
Article numberARTN e35942
Number of pages10
JournalPLoS ONE
Volume7
Issue number4
DOIs
Publication statusPublished - 26 Apr 2012

Keywords

  • NEUTRAL THEORY
  • BETA-DIVERSITY
  • ECOLOGICAL DATA
  • MULTIPLE SAMPLES
  • DISPERSAL
  • NICHE
  • BIODIVERSITY
  • NEIGHBOR MATRICES
  • SPECIES ABUNDANCE
  • NULL MODEL ANALYSIS

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

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