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Library test of multiple hypotheses for the species richness gradient of South American owls

test of multiple hypotheses for the species richness gradient of South American owls

test of multiple hypotheses for the species richness gradient of South American owls

Resource information

Date of publication
December 2004
Resource Language
ISBN / Resource ID
AGRIS:US201500220441
Pages
633-638

Many mechanisms have been proposed to explain broad scale spatial patterns in species richness. In this paper, we evaluate five explanations for geographic gradients in species richness, using South American owls as a model. We compared the explanatory power of contemporary climate, landcover diversity, spatial climatic heterogeneity, evolutionary history, and area. An important aspect of our analyses is that very different hypotheses, such as history and area, can be quantified at the same observation scale and, consequently can be incorporated into a single analytical framework. Both area effects and owl phylogenetic history were poorly associated with richness, whereas contemporary climate, climatic heterogeneity at the mesoscale and landcover diversity explained ca. 53% of the variation in species richness. We conclude that both climate and environmental heterogeneity should be retained as plausible explanations for the diversity gradient. Turnover rates and scaling effects, on the other hand, although perhaps useful for detecting faunal changes and beta diversity at local and regional scales, are not strong explanations for the owl diversity gradient.

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Authors and Publishers

Author(s), editor(s), contributor(s)

Diniz-Filho, José Alexandre Felizola
Rangel, Thiago F. L. V. B.
Hawkins, Bradford A.

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