Winter warming facilitates range expansion: cold tolerance of the butterfly Atalopedes campestris

摘要

Our ability to predict ecological and evolutionary responses to climate change requires an understanding of the mechanistic links between climate and range limits. The warming trend over the past half-century has generated numerous opportunities to develop much-needed case studies of these links. Species that are only limited by climatic factors are likely to shift range quickly during periods of warming. Such species directly impact recipient communities and indicate trends that will become more widespread. Because minimum temperature (T min) is rising at twice the rate of maximum temperature, species with this range-limiting factor may be especially responsive to global warming. In this study, I test the hypothesis that rising T min has directly affected the range of a skipper butterfly. Atalopedes campestris has moved northward rapidly this century, recently colonizing eastern Washington where January T min has risen 3°C in 50 years. The results show that: A. campestris' range lies completely within the −4°C January average minimum isotherm, and that recently colonized areas were below this threshold earlier this century.