Genetic structure and adaptation at a dynamic range margin

我们目前正处于全球变暖的时期，这对世界各地的物种分布产生了巨大的影响。许多物种的北部范围边界正在发生地理扩张，而其南部外围分布的范围边缘则受到生境不适宜以及人为活动和生物压力增加导致的隔离加剧的影响。这些分布变化将对生物多样性和生态过程产生深远的影响，需要在种群水平上详细了解范围变化的原因和后果。这个项目将研究飞鼠（Glaucomys sp.），它们在安大略省经历了一个重要的“自然实验”。南方鼯鼠在10年的时间里将它们的活动范围扩大了大约200公里，然而，在2003- 2004年，寒冷的冬天和食物不足的综合影响使它们的数量在一年内减少了等量的距离。该项目将调查任何幸存的南方鼯鼠种群或可能已经适应了当地急性气候事件的南北杂交飞鼠。候选适应基因可能参与温度调节，促进局部适应较冷的冬季在山脉前缘或任何幸存的口袋将被表征。我们还将研究变暖趋势和栖息地破碎化对飞鼠的协同效应，因为它们在发达的安大略省景观中扩张。在接下来的几十年里，增加我们对气候变暖和越来越随机的恶劣天气条件（如2003-04年安大略省冬季）对野生动物种群范围扩大和当地适应的综合影响的理解将是很重要的。

We are currently in a period of global warming that is having dramatic effects on species distributions worldwide. Geographic expansions of northern range boundaries are occurring for many species, while the range margins at their southern peripheral distribution are impacted by less suitable habitat and increased isolation resulting from anthropogenic activities and increased biotic stress. These distributional changes will have profound effects on biodiversity and ecological processes and require a detailed understanding of the causes and consequences of range shifts at the population level. This project will study flying squirrels (Glaucomys sp.) that have undergone an important "natural experiment" in Ontario. Southern flying squirrels expanded their range by approximately 200 km over a 10-year period, however, in 2003-04, the combined effects of a cold winter and low food caused the population to contract by an equivalent distance in one year. This project will survey any surviving southern flying squirrel populations or hybrid northern x southern flyers that may have been adapted to the acute local climatic event. Candidate adaptive genes potentially involved in thermoregulation that promoted local adaptation to the colder winter at the range front or in any surviving pockets will be characterized. We will also examine the synergistic effects of warming trends and habitat fragmentation on flying squirrels as they expand through the developed Ontario landscape. It will be important over the next few decades to increase our understanding the combined effects of climatic warming and increasingly random harsh weather conditions, such as the 2003-04 Ontario winter, on range expansions and local adaptation in wildlife populations.