Evolutionary resistance: Does adaptation stabilise plant community structure and function under climate change?

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Globally, we depend on grasslands to support biodiversity and agricultural productivity, offer recreational areas, and provide a wide range of other valuable ecosystem services. For example, the UK dairy industry, which is worth ~£4.27 billion per year, depends entirely on grasslands. At the same time, grasslands are among the most altered and least protected ecosystems, and they are now being to the imminent effects of climate change: warming, drought, flooding.Grassland organisms may ultimately cope with climate change by adapting, via evolution, where environmental change selects for individuals of a species that have advantageous characteristics (specific 'phenotypes'). This adaptive response stems from both changes in phenotype, and changes in the way organisms express their characteristics in a new environment (called 'phenotypic plasticity). Both aspects increase the likelihood that organisms will thrive in the new environment. Both of these components of evolution can buffer populations against the adverse effects of climate change. However, we do not know how evolutionary change will alter communities of coexisting species or the important ecosystem processes that underpin the important benefits of grasslands to our society. This study focuses on species-rich grasslands, which have a high conservation value, and are an iconic feature of UK landscapes. They can contain more than 40 plant species per square metre and any of these coexisting species may evolve when exposed to climate change. Nobody knows how these adaptive changes in component species could influence grassland plant communities and the ecosystem as a whole, and whether they will allow grasslands to remain relatively unchanged ("resistant") during climate change. This is because, to date, most scientists have studied climate-driven evolution in single isolated species, which does not allow us to assess how adaptation could influence interactions among co-existing species. Our research will address this by studying climate-driven evolutionary change in plant communities in a natural grassland. For over two decades, we have exposed a species-rich grassland near Buxton, UK, to simulated climate change (warming, increased rainfall, and drought). Our research has shown very little change in the diversity and abundance of grassland plant species subjected to different climate treatments, meaning that the plant community is resistant to change. However, we have also shown that some of the plant species are adapting to the climate treatments, raising the possibility that evolution itself is the source of resistance to climate change and could explain the stability of the plant community in this species-rich grassland. Building on our previous work, our overarching goal is to use the Buxton climate experiment as a model to understand how evolutionary changes allow grassland plants to resist climate change at the community and ecosystem levels. In doing so, we aim to determine how species diversity contributes to the services that grasslands provide, and to better understand (and predict) threats to grasslands under climate change. We have designed a set of experiments to examine how evolutionary adaptation to climate changes in individual plants influences the stability of plant communities and important ecosystem processes. Over three years, we will measure i) the strength and direction of evolution in 16 coexisting plant species, ii) use mathematical modelling to predict climate impacts on grasslands and iii) test for these impacts using targeted experiments at Buxton. This will involve constructing model ecosystems, and measuring species responses, plant phenotypes, and ecosystem processes in the climate treatments. Our research will provide a unique, evolutionary view of how plants, and their phenotypes, contribute to the stability of grasslands and ecosystem processes during climate change.