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

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.

Policy makers:
A greater understanding of the mechanisms that either hasten extinction or underpin rapid evolutionary responses to anthropogenic stressors, and the effect that this then has on population, community and ecosystem level processes will help environment and health legislators to deliver informed conservation, medical and sustainable harvesting strategies that will mitigate or avoid anthropogenic effects, and/or protect the evolutionary processes that determine future patterns of biodiversity.

Training of scientists:
The project will train researchers in state-of-the-art 'omic techniques that are transferable to other fields such as health and medicine, stem cell technology, disease biology, agriculture, conservation, and environmental sciences. The conceptually broad and integrative nature of this project - investigating links along pathways between molecular biology and ecosystem function - will not only train researchers in several specialist areas of life and environmental sciences, but crucially also in working in multidisciplinary teams to advance a more thorough and comprehensive understanding of complex environmental challenges.

Commercial/private sector:
Understanding individual, population, community and ecosystem level responses to human-induced evolutionary change can help us to mitigate these effects in natural environments. But also, a mechanistic understanding of rapid evolutionary responses might also be used to improve responses to artificial selection used in agriculture and food industries.

Wider public:
Concepts such as contemporary evolution, phenotypic plasticity, non-genetic inheritance and epigenetics are complex topics that are poorly understood by the general public. Yet they are increasingly an everyday part of our lives, impacting on society through antibiotic and pesticide resistance, the over-harvesting of natural resources, and their implication in diseases including aging, cancer, schizophrenia and lifestyle diseases such as heart disease, diabetes, and obesity. Our work will improve the public understanding of science by introducing these topics into the public domain. Second, the wider public will also benefit from our work because incorporating rapid evolution into the management of shallow freshwaters will help to protect them and the ecosystem services that they provide, including the provision of freshwater, power-generation, regulation of waste and nutrients, retention of soil and transport and recreation.