Overdispersion of body size in Australian desert lizard communities at local scales only: no evidence for the Narcissus effect |
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| Authors: | Daniel L Rabosky Julian Reid Mark A Cowan Jeff Foulkes |
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| Institution: | (1) Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA;(2) Cornell Lab of Ornithology, Ithaca, NY 14850, USA;(3) Fenner School of Environment and Society, Australian National University, Canberra, ACT, 0200, Australia;(4) CSIRO Sustainable Ecosystems, GPO Box 284, Canberra, ACT, 2601, Australia;(5) Department of Environment and Conservation, PO Box 51, Wanneroo, WA, 6946, Australia;(6) Department for Environment and Heritage, PO Box 1047, Adelaide, SA, 5001, Australia |
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| Abstract: | Both local and regional processes may contribute to community diversity and structure at local scales. Although many studies
have investigated patterns of local or regional community structure, few have addressed the extent to which local community
structure influences patterns within regional species pools. Here we investigate the role of body size in community assembly
at local and regional scales in Ctenotus lizards from arid Australia. Ctenotus has long been noted for its exceptional species diversity in the Australian arid-zone, and previous studies have attempted
to elucidate the processes underlying species coexistence within communities of these lizards. However, no consensus has emerged
on the role of interspecific competition in the assembly and maintenance of Ctenotus communities. We studied Ctenotus communities at several hundred sites in the arid interior of Australia to test the hypothesis that body sizes within local
and regional Ctenotus assemblages should be overdispersed relative to null models of community assembly, and we explored the relationship between
body size dispersion at local and regional scales. Results indicate a striking pattern of community-wide overdispersion of
body size at local scales, as measured by the variance in size ratios among co-occurring species. However, we find no evidence
for body size overdispersion within regional species pools, suggesting a lack of correspondence between processes influencing
the distribution of species phenotypes at local and regional scales. We suggest that size ratio constancy in Ctenotus communities may have resulted from contemporary ecological interactions among species or ecological character displacement,
and we discuss alternative explanations for the observed patterns.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. |
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| Keywords: | Character displacement Community assembly Competition Null model Regional diversity |
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