1. Department of Biology, Campus Box 1137, Washington University, St. Louis, Missouri 63130, USA
2. Department of Biological Sciences, Union College, Schenectady, New York 12308, USA
3. Division of Amphibians and Reptiles, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA
4. Department of Biology, Barnard College, 3009 Broadway, New York 10027, USA
5. Instituto de Ecología y Sistemática, CITGMA, Carretera de Varona km 3.5, Boyeros, La Habana 10800, Apartado Postal 8029, Cuba
6. Department of Biology, Villanova University, Villanova, Pennsylvania 19085, USA
7. Present address: Department of Biological Sciences, Vanderbilt University, VU Station B 351634 Nashville Tennesee 37235, USA

Correspondence to: Jonathan B. Losos¹ Email: losos@biology2.wustl.edu

Abstract

Niche conservatism—the tendency for closely related species to be ecologically similar—is widespread^{1, 2, 3}. However, most studies compare closely related taxa that occur in allopatry³; in sympatry, the stabilizing forces that promote niche conservatism^{4, 5}, and thus inhibit niche shifts, may be countered by natural selection favouring ecological divergence to minimize the intensity of interspecific interactions^{6, 7}. Consequently, the relative importance of niche conservatism versus niche divergence in determining community structure has received little attention⁷. Here, we examine a tropical lizard community in which species have a long evolutionary history of ecological interaction. We find that evolutionary divergence overcomes niche conservatism: closely related species are no more ecologically similar than expected by random divergence and some distantly related species are ecologically similar, leading to a community in which the relationship between ecological similarity and phylogenetic relatedness is very weak. Despite this lack of niche conservatism, the ecological structuring of the community has a phylogenetic component: niche complementarity only occurs among distantly related species, which suggests that the strength of ecological interactions among species may be related to phylogeny, but it is not necessarily the most closely related species that interact most strongly.