Bergmann's rule and body size in mammals.

摘要: Aim: To describe the geographical pattern of mean body size non-volant mammals Nearctic and Neotropics evaluate influence five environmental variables that are likely to affect gradients. Location: The Western Hemisphere. Methods: We calculated (average log mass) values in 110 × km cells covering continental Neotropics. also generated cell averages for annual temperature, range elevation, their interaction, actual evapotranspiration, global vegetation index its coefficient variation. Associations between were tested with simple correlations ordinary least squares multiple regression, complemented spatial autocorrelation analyses split-line regression. evaluated relative support each multiple-regression model using AIC. Results: Mean increases north is negatively correlated temperature. In contrast, across largest tropical subtropical lowlands smaller Andes, generating a positive correlation Finally, temperature nonlinearly related both regions, linear regression found thresholds marking clear shifts these relationships (Nearctic 10.9 °C; 12.6 °C). increase sizes decreasing strongest northern Nearctic, whereas decrease mountains dominates gradients warmer parts regions. Main conclusions: confirm previous work finding strong broad-scale Bergmann trends cold macroclimates but not areas. For latter regions (i.e. southern Neotropics), our suggest local patterns mammal variation influenced part by mesoscale climatic existing mountainous A explanation reduced habitat limit presence larger-sized mammals.