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.
|Autori:||Benedetti Cecchi, Lisandro; Bertocci, I; Vaselli, S; Maggi, E; Bulleri, Fabio|
|Titolo:||Neutrality and the Response of Rare Species to Environmental Variance|
|Anno del prodotto:||2008|
|Digital Object Identifier (DOI):||10.1371/journal.pone.0002777|
|Appare nelle tipologie:||1.1 Articolo in rivista|