LIMITS TO ADAPTATION: CAUSES, AND CONSEQUENCES FOR ECOLOGY AND ECOSYSTEM FUNCTION

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Species are increasingly faced with the challenge of coping with a changing environment caused by human disturbance or climate change. Whether they are able to cope or not is critical for biodiversity and the benefits that we get from ecosystems. The ability of species to evolve and adapt to new environmental conditions is a key factor that we need to understand if we are to predict how species will cope with a changing environment or to help mitigate the impacts of climate change. It is particularly important to understand how rapidly species can adapt, what the limits are to evolution, and how evolution of one species will affect the rest of the ecosystem with which it interacts.In this project, we will investigate these questions through a series of large scale experiments using a small crustacean called Daphnia, which has a major impact on water quality and the health of freshwater ecosystems. Our approach has several unique strengths. First, Daphnia can reproduce clonally, which means that we can manipulate the genetic diversity of populations to examine its effects on the rate and limits of adaptation. Second, we will use a system of large outdoor heated tanks - the largest such facility in Europe - to examine the response of Daphnia, and its associated ecosystem, to heat-waves, which is a key environmental challenge faced by species. Third, we will exploit the latest DNA sequencing technologies - available at a major genomics centre at Liverpool - to examine the genetic mechanisms underlying adaptation to climate change. Finally, our study is supported by recent, exciting findings from our laboratory where we have demonstrated the potential importance of two processes - plasticity and epigenetics - for adaptation. Plasticity allows individuals to change their pattern of development, growth and/or reproduction in response to the environment, and epigenetics allows these changes to be transmitted to their offspring by modifying the action of genes. These processes are central to questions about what limits the ability to adapt to environmental change, since they could allow the animals to adapt far more rapidly than they would by conventional evolution alone, in which only frequencies of genes change over time. As such, these processes may also help protect the animal populations from going extinct following an environmental change, so allowing time for the species to evolve over a longer period.The research will: i) quantify how two major influences on animals (food and temperature differences) affect many different and crucial aspects of the lives of Daphnia (phenotypic plasticity); ii) use the knowledge of this plasticity together with whether the Daphnia are adapted to local or different environments, to undertand how plasticity, genetic diversity and epigenetics determine the potential of populations to evolve; iii) understand how limitations in the potential of populations to evolve will alter the fate of other species in the community and the functioning of the whole ecosystem (e.g. by regulating water quality and blooms of harmful algae).This research will, therefore, fundamentally advance our understanding of how three different influences (genetic diversity, plasticity and epigenetics) contribute and combine to allow populations to adapt to environmental change, and how this can affect other species and ultimately the services (clean water, food, fibre, amenity) that freshwater ecosystems and their biodiversity provide. Our findings will be disseminated to the academic community, to policy-makers, to schools and to the general public.