Climate driven phenotypic change: macroecology meets quantitative genetics

From aardvarks to zooplankton, how will life on earth be affected by climate change? The answer to this question has enormous implications for predicting how the world may look in fifty or a hundred years time. Yet, worryingly, scientists do not know the answer. What we do know is that species have evolved to adapt to climate change in the past and, on this basis, it seems reasonable to predict that evolution by natural selection might play an important role in the current climate crisis. But if climate change is as rapid as anticipated, we might find that even the fittest members of a species may not be fit enough. I will use a fellowship to address three main aims that will help in predicting species' responses to climate change. Most species are made up of many populations inhabiting different geographic areas and varying in phenotype, with phenotype often correlating with temperature or rainfall. We can use the present-day patterns in these correlations to see whether populations will need to evolve to a changed climate of the future. For example, walk through a wood in southern England during April and you might see a blanket of bluebells, but in the colder Scottish Highlands you'd need to wait another month to see this. Temperatures fluctuate from year to year, so that in some years the spring temperature in the Highlands may rise as high as that normally seen in the south. In these years, we can observe whether the Highland bluebells flower as early as is the norm for southern populations; if they do not, we can infer that populations are adapted to the temperatures that they experience in an average year. Such locally adapted populations will be rendered less well adapted if temperatures change. I will use observations of phenology collected by citizen scientists and collated by the Woodland Trust and British Trust for Ornithology (BTO) to gain the first insights into whether local adaptation is responsible for geographic differences in the timing of spring events for a host of plant and bird species. I will then ask whether plasticity or local adaptation can be predicted on the basis of the characteristics of species or environmental conditions. Natural selection operates when the phenotypes of 'fit' individuals differ from those of less fit individuals. To calculate phenotypic survival selection for a wild population, we need to measure a trait for lots of individuals and we need to know which individuals survive and perish. Most studies that measure selection do so at just one location. This is unfortunate because, in order to predict how a species will evolve, we need to know how selection varies among locations and over time. For over half a century bird ringers across Britain have caught birds, measuring the wing length of each one and submitting these data to the BTO. I will use these measurements for the blue tit - the most often caught bird - to estimate how selection on wing length varies in space and time and test whether aspects of climate drives selection. If a population has adapted to its local climate, how will selection act if the climate changes? One possibility is that, across the whole population, survival will decrease, but there are other possibilities and, to distinguish these, I will conduct a plant experiment. I will also look at birds to test whether species with nesting times that are adapted to local conditions are especially prone to population decline. Another consequence of climate change is that species may respond differently, disrupting inter-species interactions. I will compare communities composed of plant, butterfly and bird species, to identify cases where climate change may cause most disruption to interactions among species. The ways in which different species and populations adapt and respond to their environmental conditions fascinates me, and gaining a proper understanding of these processes and their consequences has become urgent.