title: Energy gradients and the geographic distribution of local ant diversity.
abstract: Geographical diversity gradients, even among local communities, can ultimately arise from geographical differences in speciation and extinction rates. We evaluated three models--energy-speciation, energy-abundance, and area--that predict how geographic trends in net diversification rates generate trends in diversity. We sampled 96 litter ant communities from four provinces: Australia, Madagascar, North America, and South America. The energy-speciation hypothesis best predicted ant species richness by accurately predicting the slope of the temperature diversity curve, and accounting for most of the variation in diversity. The communities showed a strong latitudinal gradient in species richness as well as inter-province differences in diversity. The former vanished in the temperature-diversity residuals, suggesting that the latitudinal gradient arises primarily from higher diversification rates in the tropics. However, inter-province differences in diversity persisted in those residuals--South American communities remained more diverse than those in North America and Australia even after the effects of temperature were removed.
authors.affiliation: Department of Zoology, University of Oklahoma, Norman, OK 73019, USA. mkaspari@ou.edu
authors.forename: Michael
authors.initials: M
authors.lastname: Kaspari
authors.forename: Philip S
authors.initials: PS
authors.lastname: Ward
authors.forename: May
authors.initials: M
authors.lastname: Yuan
mesh_terms: D000818:Animals; D001000:Ants; D002965:Classification; D004734:Energy Metabolism; D005843:Geography; D011157:Population Dynamics; D013696:Temperature; D014329:Tropical Climate