Department of Biogeography and Global Change, National Museum of Natural Sciences, CSIC, Madrid, Spain.
Departamento de Biología y Geología, Física y Química Inorgánica, Área de Biodiversidad y Conservación, Escuela Superior de Ciencias Experimentales y Tecnología, Universidad Rey Juan Carlos, Madrid, Spain.
Glob Chang Biol. 2021 Mar;27(6):1309-1317. doi: 10.1111/gcb.15483. Epub 2021 Jan 15.
Species are reportedly shifting their distributions poleward and upward in several parts of the world in response to climate change. The extent to which other factors might play a role driving these changes is still unclear. Land-cover change is a major cause of distributional changes, but it cannot be discarded that distributional dynamics might be at times caused by other mechanisms (e.g. dispersal, ecological drift). Using observed changes in the distribution of 82 breeding birds in Great Britain between three time periods 1968-72 (t ), 1988-91 (t ) and 2007-2011 (t ), we examine whether observed bird range shifts between t -t and t -t are best explained by climate change or land-cover change, or whether they are not distinguishable from what would be expected by chance. We found that range shifts across the rear edge of northerly distributed species in Great Britain are best explained by climate change, while shifts across the leading edge of southerly distributed species are best explained by changes in land-cover. In contrast, at the northern and southern edges of Great Britain, range dynamics could not be distinguished from that expected by chance. The latter observation could be a consequence of boundary effects limiting the direction and magnitude of range changes, stochastic demographic mechanisms neither associated with climate nor land-cover change or with complex interactions among factors. Our results reinforce the view that comprehensive assessments of climate change effects on species range shifts need to examine alternative drivers of change on equal footing and that null models can help assess whether observed patterns could have arisen by chance alone.
据报道，在世界上的几个地区，物种为了应对气候变化，正在向极地和高海拔地区转移。其他因素在多大程度上可能起到推动这些变化的作用仍不清楚。土地覆盖变化是分布变化的主要原因，但不能排除分布动态有时可能是由其他机制（例如扩散、生态漂变）引起的。利用英国 82 种繁殖鸟类在三个时间段（1968-72 年（t ）、1988-91 年（t ）和 2007-2011 年（t ））之间分布变化的观测数据，我们研究了观测到的鸟类在 t -t 和 t -t 之间的范围变化是否可以用气候变化或土地覆盖变化来解释，或者它们是否与随机变化没有区别。我们发现，英国北部分布物种的范围变化最能由气候变化来解释，而南部分布物种的范围变化最能由土地覆盖变化来解释。相比之下，在英国的北部和南部边缘，范围动态与随机变化没有区别。后一种观察结果可能是边界效应限制了范围变化的方向和幅度的结果，这种边界效应限制了范围变化的方向和幅度，随机的人口统计机制既与气候变化、土地覆盖变化无关，也与因素之间的复杂相互作用无关。我们的研究结果进一步证实了这样一种观点，即全面评估气候变化对物种范围变化的影响，需要平等地考虑变化的替代驱动因素，而且零模型可以帮助评估观测到的模式是否可能仅仅是偶然产生的。
