An experimental test of the area-heterogeneity tradeoff

Eyal Ben-Hur*, Ronen Kadmon

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

A fundamental property of ecosystems is a tradeoff between the number and size of habitats: as the number of habitats within a fixed area increases, the average area per habitat must decrease. This tradeoff is termed the “area-heterogeneity tradeoff.” Theoretical models suggest that the reduction in habitat sizes under high levels of heterogeneity may cause a decline in species richness because it reduces the amount of effective area available for individual species under high levels of heterogeneity, thereby increasing the likelihood of stochastic extinctions. Here, we test this prediction using an experiment that allows us to separate the effect of the area-heterogeneity tradeoff from the total effect of habitat heterogeneity. Surprisingly, despite considerable extinctions, reduction in the amount of effective area available per species facilitated rather than reduced richness in the study communities. Our data suggest that the mechanism behind this positive effect was a decrease in the probability of deterministic competitive exclusion. We conclude that the area-heterogeneity tradeoff may have both negative and positive implications for biodiversity and that its net effect depends on the relative importance of stochastic vs. deterministic drivers of extinction in the relevant system. Our finding that the area-heterogeneity tradeoff may contribute to biodiversity adds a dimension to existing ecological theory and is highly relevant for understanding and predicting biodiversity responses to natural and anthropogenic variations in the environment.

Original languageAmerican English
Pages (from-to)4815-4822
Number of pages8
JournalProceedings of the National Academy of Sciences of the United States of America
Volume117
Issue number9
DOIs
StatePublished - 3 Mar 2020

Bibliographical note

Publisher Copyright:
© 2020 National Academy of Sciences. All rights reserved.

Keywords

  • Ecological drift hypothesis
  • Habitat heterogeneity
  • Mesocosm experiment
  • Metacommunity ecology
  • Species richness

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