PLoS ONE (Jul 2008)

Neutrality and the response of rare species to environmental variance.

  • Lisandro Benedetti-Cecchi,
  • Iacopo Bertocci,
  • Stefano Vaselli,
  • Elena Maggi,
  • Fabio Bulleri

DOI
https://doi.org/10.1371/journal.pone.0002777
Journal volume & issue
Vol. 3, no. 7
p. e2777

Abstract

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Neutral models and differential responses of species to environmental heterogeneity offer complementary explanations of species abundance distribution and dynamics. Under what circumstances one model prevails over the other is still a matter of debate. We show that the decay of similarity over time in rocky seashore assemblages of algae and invertebrates sampled over a period of 16 years was consistent with the predictions of a stochastic model of ecological drift at time scales larger than 2 years, but not at time scales between 3 and 24 months when similarity was quantified with an index that reflected changes in abundance of rare species. A field experiment was performed to examine whether assemblages responded neutrally or non-neutrally to changes in temporal variance of disturbance. The experimental results did not reject neutrality, but identified a positive effect of intermediate levels of environmental heterogeneity on the abundance of rare species. This effect translated into a marked decrease in the characteristic time scale of species turnover, highlighting the role of rare species in driving assemblage dynamics in fluctuating environments.