Racing against change: understanding dispersal and persistence to improve species' conservation prospects

Abstract

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.

Insights into bear evolution from a Pleistocene polar bear genome

“…It has been established that widespread and rapid global climate changes have occurred at unprecedented scales in recent years (39). Associated with these climate changes are welldocumented impacts to the ecologies and life histories of plants and animals (40), including shifts in latitudinal and elevational ranges (41)(42)(43), local extinctions (44), and changes in morphologies (45). Furthermore, colonizing species have in some cases been shown to capture local adaption by hybridizing with closely related resident lineages (46).…”

Climate change drives mountain butterflies towards the summits

“…In contrast, specialized species that require very specific resources such as habitat structures, a specific climatic niche, or the presence of a particular larval food plant, may be much more negatively affected by environmental changes 16 . Dispersal behaviour also plays a central role: Species with a high degree of mobility can respond much better to environmental changes such as habitat degradation and fragmentation or shifts in climate than species with a low propensity to dispersal, which usually remain in one habitat for many generations 17 . To analyse species’ specific responses on climate change, long-term observations in combination with detailed knowledge on species’ ecology, behaviour and life-history are necessary 18 .…”

Schrödinger’s range-shifting cat: analytic predictions for the effect of asymmetric environmental performance on climate change responses

“…In principle, the parameters in the analytic model could be directly measured for natural populations (Leroux et al 2013). However, measuring dispersal rates in the field is very challenging, given the importance of rare, long distance events (Kerr 2020). The rate of dispersal and colonisation of new habitats is fundamentally unpredictable, even under tightly controlled experimental conditions (Melbourne & Hastings 2009) and so there will be hard limits to the expectations of the accuracy of any direct application of the model to a particular species.…”