ECOLOGICAL AND BIOLOGICAL CHARACTERISTICS EXPLAIN THE RESPONSE OF SPECIES TO RECENT CLIMATIC CHANGES
Species have evolved to live within certain temperature ranges, and many of them might simply be unable to adapt to the rapidly changing, probably unsuitable new climatic conditions and thus will be threatened with extinction. A variety of studies have stated that species displaying certain intrinsic characteristics are more vulnerable to extinction to climate warming than others, and authors have often assigned species to risk categories according to these characteristics based on expert opinion. However, the assumption of a relationship between species' characteristics and their response to climate change has never been validated against observed data. In this study we performed a meta-analysis of documented (published) responses of mammals and birds to past climate change to relate changes in climatic variables, such as annual temperature and annual precipitation, to changes in geographic distribution, abundance, body size, time of migration, and other life-history traits of mammal and bird species globally. We conducted a statistical analysis on the relationships between the type of response and each selected trait by building partitioning classification models and multinomial logistic regressions, and we found that intrinsic characteristics like activity patterns and reproductive traits play an important role in determining the responses of mammals, while those of birds depend primarily on external factors like the extent of the breeding range and the temperature experienced by the species in the area in which they live. This is the first study investigating the quantitative relationship and the causality between biological and ecological characteristics of birds and mammals, and their observed responses to climate change. Additionally, this study may provide a data-driven validation of the expert-based criteria so far used to assess extinction risk from climate change of species based on their intrinsic characteristics.