Standard Article

Regional Influences on Local Species Composition

  1. Martin Zobel,
  2. Robert C Szava-Kovats,
  3. Meelis Pärtel

Published Online: 15 FEB 2011

DOI: 10.1002/9780470015902.a0022549



How to Cite

Zobel, M., Szava-Kovats, R. C. and Pärtel, M. 2011. Regional Influences on Local Species Composition. eLS. .

Author Information

  1. University of Tartu, Tartu, Estonia

Publication History

  1. Published Online: 15 FEB 2011


Regional influences on local species composition are considered within the context of ‘species pools’, representing sets of species that are potentially capable of coexisting in a particular community. Accumulating evidence shows that many ecological communities are not saturated with species, indicating that in addition to local biotic interactions such as predation, symbiosis and competition, regional processes such as dispersal, speciation and extinction are the important drivers of local community composition. Although current studies have been unable to reconcile completely two important difficulties – the filtering of species lists and the study of nonindependent variables – it is evident that much of the observed local variation in plant and animal diversity can be attributed to the differing sizes of species pools evolved under particular habitat conditions and to the probabilities with which the species may arrive in particular local communities.

Key Concepts:

  • Local species composition is the result of complex interactions of small-scale and regional processes.

  • Empirical relationships between diversity at local and regional scales provide an indication of the relative roles of local processes (e.g. biotic interactions) and regional processes (e.g. dispersal, speciation) in structuring ecological communities.

  • Existing evidence suggests that many ecological communities are unsaturated by species and that new species may immigrate to the community by crossing dispersal barriers.

  • Uncertainty remains with respect to methodology. Estimation of regional species pools lacks a definitive approach; both empirical and theoretical methods exist. The interpretation of local and regional species richness suffers from unresolved statistical controversy.

  • More case studies are needed to overcome these problems and provide community ecology with further empirical evidence.


  • species pool;
  • scales;
  • diversity;
  • community saturation