RT Journal Article SR Electronic T1 Metabolism constrains bird and mammal ranges and predicts shifts in response to climate change JF bioRxiv FD Cold Spring Harbor Laboratory SP 167973 DO 10.1101/167973 A1 Lauren B. Buckley A1 Imran Khaliq A1 David L. Swanson A1 Christian Hof YR 2017 UL http://biorxiv.org/content/early/2017/07/24/167973.abstract AB Aim We test whether physiological constraints on maximum metabolic rate and the factor by which endotherms can elevate their metabolism (metabolic expansibility) govern cold range limits for mammal and bird species.Location GlobalMethods We examine metabolic expansibility at the cold range boundary (MEcrb) and its trait predictors and then use MEcrb to project range shifts for 210 mammal and 61 bird species.Results We find evidence for metabolic constraints: the distributions of metabolic expansibility at the cold range boundary peak at similar values for birds (2.7) and mammals (3.2). The right skewed distributions suggest some species have adapted to elevate or evade metabolic constraints. Mammals exhibit greater skew than birds, consistent with their diverse thermoregulatory adaptations and behaviors. Mammal and bird species that are small and occupy low trophic levels exhibit high levels of MEcrb. Mammals with high MEcrb tend to hibernate or use torpor. Predicted metabolic rates at the cold range boundaries represent large energetic expenditures (>50% of maximum metabolic rates). We project species to shift their cold range boundaries poleward by an average of 3.9° latitude by 2070.Main conclusions Our analysis suggests that metabolic constraints provide a viable mechanism for projecting cold range boundaries and range shifts in response to climate change for endotherms.