Department of Biology, Trent University, 2140 East Bank Drive, Peterborough, ON, Canada, K9J 7B8, USA.
Glob Chang Biol. 2014 Apr;20(4):1126-35. doi: 10.1111/gcb.12469. Epub 2013 Dec 18.
Understanding the effects of climate change on species' persistence is a major research interest; however, most studies have focused on responses at the northern or expanding range edge. There is a pressing need to explain how species can persist at their southern range when changing biotic interactions will influence species occurrence. For predators, variation in distribution of primary prey owing to climate change will lead to mismatched distribution and local extinction, unless their diet is altered to more extensively include alternate prey. We assessed whether addition of prey information in climate projections restricted projected habitat of a specialist predator, Canada lynx (Lynx canadensis), and if switching from their primary prey (snowshoe hare; Lepus americanus) to an alternate prey (red squirrel; Tamiasciurus hudsonicus) mitigates range restriction along the southern range edge. Our models projected distributions of each species to 2050 and 2080 to then refine predictions for southern lynx on the basis of varying combinations of prey availability. We found that models that incorporated information on prey substantially reduced the total predicted southern range of lynx in both 2050 and 2080. However, models that emphasized red squirrel as the primary species had 7-24% lower southern range loss than the corresponding snowshoe hare model. These results illustrate that (i) persistence at the southern range may require species to exploit higher portions of alternate food; (ii) selection may act on marginal populations to accommodate phenotypic changes that will allow increased use of alternate resources; and (iii) climate projections based solely on abiotic data can underestimate the severity of future range restriction. In the case of Canada lynx, our results indicate that the southern range likely will be characterized by locally varying levels of mismatch with prey such that the extent of range recession or local adaptation may appear as a geographical mosaic.
了解气候变化对物种存续的影响是一个主要的研究兴趣；然而，大多数研究都集中在北部或扩展范围的边缘的反应上。迫切需要解释为什么当生物相互作用的变化会影响物种的存在时，物种可以在其南部范围中存续。对于捕食者来说，由于气候变化导致主要猎物分布的变化，将导致分布不匹配和局部灭绝，除非它们的饮食改变为更广泛地包括替代猎物。我们评估了在气候预测中增加猎物信息是否会限制加拿大猞猁（Lynx canadensis）这一专业捕食者的预测栖息地，如果捕食者从其主要猎物（雪兔；Lepus americanus）转向替代猎物（红松鼠；Tamiasciurus hudsonicus），是否会缓解南部范围边缘的范围限制。我们的模型预测了每个物种到 2050 年和 2080 年的分布情况，然后根据猎物供应的不同组合来完善对南部猞猁的预测。我们发现，纳入猎物信息的模型大大减少了 2050 年和 2080 年南部猞猁的总预测范围。然而，强调红松鼠为主要物种的模型比相应的雪兔模型的南部范围损失低 7-24%。这些结果表明：（i）在南部范围的存续可能需要物种利用更高比例的替代食物；（ii）选择可能作用于边缘种群，以适应允许更多利用替代资源的表型变化；（iii）仅基于非生物数据的气候预测可能低估未来范围限制的严重程度。就加拿大猞猁而言，我们的结果表明，南部范围可能具有与猎物局部不同程度的不匹配，因此范围退缩或局部适应的程度可能表现为地理镶嵌。
