Catalogo Articoli (Spogli Riviste)


Ecological biogeography of North American mammals: species density and ecological structure in relation to environmental gradients
Badgley, C; Fox, DL;
Univ Michigan, Museum Paleontol, Ann Arbor, MI 48109 USA Univ Michigan Ann Arbor MI USA 48109 m Paleontol, Ann Arbor, MI 48109 USA Univ Calif Santa Cruz, Dept Earth Sci, Santa Cruz, CA 95064 USA Univ CalifSanta Cruz Santa Cruz CA USA 95064 i, Santa Cruz, CA 95064 USA
Titolo Testata:
fascicolo: 6, volume: 27, anno: 2000,
pagine: 1437 - 1467
biogeography; climatic gradients; ecological diversity; ecological structure; mammals; North America;
Tipo documento:
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Indirizzi per estratti:
Indirizzo: Badgley, C Univ Michigan, Museum Paleontol, Ann Arbor, MI 48109 USA Univ Michigan Ann Arbor MI USA 48109 , Ann Arbor, MI 48109 USA
C. Badgley e D.L. Fox, "Ecological biogeography of North American mammals: species density and ecological structure in relation to environmental gradients", J BIOGEOGR, 27(6), 2000, pp. 1437-1467


Aim To evaluate the relationship of climate and physiography to species density and ecological diversity of North American mammals,Location North America, including Mexico and Central America. Methods Species density, size structure and trophic structure of mammalianfaunas and nine environmental variables were documented for quadrats covering the entire continent. Spatial autocorrelation of species density and the environmental variables illustrated differences in their spatial structure at the continental scale. We used principal component analysis to reduce the dimensionality of the climatic variables, linear multiple regression todetermine which environmental variables best predict species density for the continent and several regions of the continent, and canonical ordinationto evaluate how well the environmental variables predict ecological structure of mammalian faunas over North America. Results In the best regression model, five environmental variables, representing seasonal extremes of temperature, annual energy and moisture, and elevation, predicted 88% of the variation in species density for the whole continent. Among different regions of North America, the environmental variables that predicted species density vary. Changes in the size and trophic structure of mammalian faunas accompany changes in species density. Redundancy analysis demonstrated that environmental variables representing winter temperature, frostfree period, potential and actual evapotranspiration, and elevation account for 77% of the variation in ecological structure. Main conclusions The latitudinal gradient in mammalian species density is strong, but most of it is explained by variation in the environmental variables. Each ecological category peaks in species richness under particular environmental conditions. The changes of greatest magnitude involve the smallest size categories (< 10 g, 11-100 g), aerial insectivores and frugivores. Species in these categories, mostly bats, increase along a gradient of decreasing winter temperature and increasing annual moisture and frostfree period, trends correlated with latitude. At the opposite end of this gradient, species in the largest size category (101-1000 kg) increase in frequency. Species in size categories 3 (101-1000 g), 5 (11-100 kg) and 6 (101-1000 kg), herbivores, and granivores increase along a longitudinal gradient of increasing annual potential evapotranspiration and elevation. Much of the spatial pattern is consistent with ecological sorting of species ranges along environmental gradients, but differential rates of speciation and extinction also may have shaped the ecological diversity of extant North American mammals.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 05/12/20 alle ore 06:23:17