Calculating climate effects on birds and mammals: Impacts on biodiversity,conservation, population parameters, and global community structure

This paper describes how climate variation in time and space can constrain community structure on a global scale. We explore body size scaling and the energetic consequences in terms of absorbed mass and energy and expended m ass and energy. We explain how morphology, specific physiological propertie s, and temperature dependent behaviors are key variables that link individu al energetics to population dynamics and community structure. This paper describes an integrated basic principles model for mammal energe tics and extends the model to bird energetics. The model additions include molar balance models for the lungs and gut. The gut model couples food inge sted to respiratory gas exchanges and evaporative water loss from the respi ratory system. We incorporate a novel thermoregulatory model that yields me tabolic calculations as a function of temperature. The calculations mimic e mpirical data without regression. We explore the differences in the quality of insulation between hair and feathers with our porous media model for in sulation. For mammals ranging in size from mice to elephants we show that calculated metabolic costs are in agreement with experimental data, We also demonstrat e how we can do the same for birds ranging in size from hummingbirds to ost riches, We show the impact of changing posture and changing air temperature s on energetic costs for birds and mammals, We demonstrate how optimal body size that maximizes the potential for growth and reproduction changes with changing climatic conditions and with diet quality. Climate and diet may p lay important roles in constraining community structure (collection of func tional types of different body sizes) at local and global scales, Thus, mul tiple functional types may coexist in a locality in part because of the tem poral and spatial variation in climate and seasonal food variation. We illu strate how the models can be applied in a conservation and biodiversity con text to a rare and endangered species of parrot, the Orange-bellied Parrot of Australia and Tasmania.