The velocity of evolutionary responses of species to ecological change; testing adaptive limits in time and space

点击翻译按钮获取中文摘要

Climate change is causing the populations of some species to increase, some to remain relatively stable, and others to decline, even when the species co-exist and might be expected to exhibit comparable ecological responses (e.g., some southern species have expanded their ranges northwards, whereas others have retreated). This diversity of responses to climate change may reflect differences in their capacities to undertake evolutionary and plastic responses that determine success or failure. However, multi-species studies of historical evolutionary responses to environmental change are lacking. In the proposed research, we will use: (1) analyses of historical and present-day DNA from 30 species (10 declining, 10 stable and 10 expanding) to identify the commonality or diversity of adaptive responses to anthropogenic climate change; (2) experimental studies to tease apart plastic, epigenetic and evolutionary responses in a focal species; and (3) modelling to evaluate the contributions of evolutionary, epigenetic and plastic changes to the responses of British Lepidoptera to past and future climatic changes. Moths and butterflies represent an ideal study group because extensive datasets allow us to document the ecological (population abundance, distribution change) and plastic (phenology) responses of species to climate change over the past four decades with a precision not possible for other taxa. Their annual (or faster) generations permit rapid evolutionary change as well as plastic responses to within- and between-year variation in climatic conditions. Museum collections will enable us to assess historical levels of genetic variation within our study species prior to 20th century anthropogenic climate change. We will take advantage of recent advances in sequencing technology to quantify ancestral genetic variation in our study species, and compare this with current genomic diversity to enumerate genetic changes taking place in declining, stable and increasing species, and specifically to evaluate whether species with higher levels of genetic variation show greater ability to adapt to climate change. We will complement this multi-species analysis by evaluating the capacity of expanding, stable and declining populations of one focal species, Pararge aegeria (Speckled wood butterfly) to exhibit evolutionary change, phenotypic plasticity and epigenetic effects using experiments in which we manipulate environmental conditions during larval development (temperature, photoperiod and host-plant desiccation). These experiments will reveal if there are environmental thresholds beyond which adaptive plasticity fails, and the potential for plasticity to evolve and buffer species under future environments. We will then use dynamic simulation models that incorporate our empirical data to test the relative importance of phenotypic plasticity, epigenetic effects, and evolutionary responses in determining species' responses to climate change, and how the relative importance of these factors varies among different species and population types. Once calibrated, we can then use our models to project the responses of these species to future climate change, based on observed limits to adaptation and plasticity. Distinguishing the key factors (ecological, demographic, and genomic) that determine species' responses to environmental change, and how these depend on evolutionary responses, will allow us to identify potential conservation strategies to facilitate population persistence and growth in the face of ongoing climate change.