Rapid responses of British butterflies to opposing forces of climate and habitat change.

摘要: Habitat degradation and climate change are thought to be altering the distributions abundances of animals plants throughout world, but their combined impacts have not been assessed for any species assemblage1,2,3,4. Here we evaluated changes in distribution sizes 46 butterflies that approach northern climatic range margins Britain—where habitat opposing forces. These insects might expected responded positively warming over past 30 years, yet three-quarters them declined: negative responses loss outweighed positive warming. Half were mobile generalists increased sites this period (consistent with a explanation), whereas other 89% specialists declined size limitation). Changes population closely matched distributions. The dual forces modification likely cause decline, leaving biological communities reduced numbers dominated by widespread generalists.