Avian life histories in a changing environment: a comparative study using time series and manipulation experiments

Global change is expected to result in changes in the mean, and increases in the variance, of meteorological and other environmental phenomena. In order to understand how natural populations will respond to such changes, it is crucial to first understand the responses of these species to naturally occurring fluctuations. Predictions can be derived from general life-history theory as to which species should be expected to be most vulnerable to environmental changes, and in which demographic traits those re sponses will be observed. These hypotheses will be tested in birds using two approaches, analysis of demographic time series, and interspecific comparisons of manipulation experiments. Both analysis paths will utilise exhaustive data bases that have been assembled in pre-projects. The first dataset contains time series derived from long-term studies of demographic traits and population sizes of seabirds, which are comparatively long-lived species. The second dataset contains the results of all experimenta l manipulations of life-history characters that have been performed on birds. Both approaches are carried out in a phylogenetic-comparative framework, which will enable us to separate effects of climate, geography, taxonomy and life history.