Department of Biology, University of Ottawa, Ottawa, Ontario, Canada K1N 6N5.
Proc Biol Sci. 2020 Nov 25;287(1939):20202061. doi: 10.1098/rspb.2020.2061.
Climate change is contributing to the widespread redistribution, and increasingly the loss, of species. Geographical range shifts among many species were detected rapidly after predictions of the potential importance of climate change were specified 35 years ago: species are shifting their ranges towards the poles and often to higher elevations in mountainous areas. Early tests of these predictions were largely qualitative, though extraordinarily rapid and broadly based, and statistical tests distinguishing between climate change and other global change drivers provided quantitative evidence that climate change had already begun to cause species' geographical ranges to shift. I review two mechanisms enabling this process, namely development of approaches for accounting for dispersal that contributes to range expansion, and identification of factors that alter persistence and lead to range loss. Dispersal in the context of range expansion depends on an array of processes, like population growth rates in novel environments, rates of individual species movements to new locations, and how quickly areas of climatically tolerable habitat shift. These factors can be tied together in well-understood mathematical frameworks or modelled statistically, leading to better prediction of extinction risk as climate changes. Yet, species' increasing exposures to novel climate conditions can exceed their tolerances and raise the likelihood of local extinction and consequent range losses. Such losses are the consequence of processes acting on individuals, driven by factors, such as the growing frequency and severity of extreme weather, that contribute local extinction risks for populations and species. Many mechanisms can govern how species respond to climate change, and rapid progress in global change research creates many opportunities to inform policy and improve conservation outcomes in the early stages of the sixth mass extinction.
气候变化导致物种广泛重新分布，越来越多的物种正在消失。35 年前，人们预测气候变化的潜在重要性后，许多物种的地理分布范围迅速发生变化：物种向两极和山区高处迁移。尽管这些预测早期的检验很大程度上是定性的，但速度非常快，范围非常广泛，并且区分气候变化和其他全球变化驱动因素的统计检验提供了定量证据，表明气候变化已经开始导致物种的地理分布范围发生变化。我回顾了两种促成这一过程的机制，即发展用于解释有助于范围扩展的扩散的方法，以及确定改变持久性并导致范围损失的因素。在范围扩展的背景下，扩散取决于一系列过程，例如在新环境中的种群增长率、物种个体向新地点移动的速度以及气候适宜栖息地变化的速度。这些因素可以在理解良好的数学框架中联系在一起，或者通过统计学建模，从而更好地预测随着气候变化物种灭绝的风险。然而，物种越来越多地暴露在新的气候条件下，可能超过它们的耐受性，并增加局部灭绝的可能性，从而导致范围缩小。这种损失是个体作用过程的结果，由极端天气的频率和严重程度增加等因素驱动，这些因素增加了种群和物种局部灭绝的风险。许多机制可以控制物种对气候变化的反应，全球变化研究的快速进展为在第六次大规模灭绝的早期阶段为政策提供信息和改善保护结果创造了许多机会。
