Impact of Global Environmental Change on Animals

Global change represents a diverse assortment of human-induced environmental changes that collectively impact animals around the globe. These diverse environmental changes will necessarily have diverse biological impacts on the millions of species of animals alive today. Recent studies of fossil vertebrates suggest that human colonization and population expansion has been causing extinction over the past 10 000 years and more: even small human populations with stone-age technology can be sufficient to elevate extinction rates. These effects have been greatest for endemic and ecologically specialized animals; typically habitat destruction and introduced species rather than direct human exploitation have been the primary causes of extinction. Anticipated climate change during the coming century will alter seasonal, diurnal and latitudinal patterns of variation in temperature and precipitation. Changes in seasonal components of climate will likely be most important in determining the extent of range shifts in animals, particularly by altering the relative seasonal timing of animals and their resources or enemies. Recent evidence from butterflies, birds and other systems suggests that decadal-scale climate changes during the past century have already caused range shifts or local extinctions in some cases. Climate change will likely negatively impact animal species that are localized or habitat specialists, but will cause expanded ranges towards the poles in many generalist species, including agricultural pests. Useful predictions of climate change impacts must incorporate simultaneous effects of carbon dioxide (CO2) and seasonal temperature and precipitation. The effects of changes in climate on vector-borne diseases may depend critically on how climate alters the seasonal patterns of interactions among parasites, vectors and hosts