MAYFLIES, BIODIVERSITY AND CLIMATE CHANGE

摘要

Mayflies (Ephemeroptera) are an ancient order of insects that are globally distributed in both northern and southern hemispheres and have survived major environmental shifts. Despite the problems associated with selection processes operating in both terrestrial and aquatic environments, mayflies have successfully colonized a wide range of freshwater habitats from the tropics to the arctic, a somewhat greater range than other hemimetabolic aquatic insects such as the Plecoptera and Odonata. While manyspecies of Ephemeroptera require specific environmental cues, others display considerable flexibility in life cycle length and timing in relation to environmental changes. This is particularly apparent in arctic and alpine species. Climate change scenarios predict rapid shifts across many environmental gradients, including temperature and the frequency and magnitude of floods and droughts. Changes in the mayfly fauna are hypothesized in the light of the environmental tolerances, life cycle plasticity and the dispersal mechanisms of present day mayflies. During periods of rapid environmental transition certain species traits will be beneficial. Generalists will do better; specialists with strict environmental limits and poor powers of dispersal may become extinct.