ECOGEN - Ecosystem change and species persistence over time: a genome-based approach

Will Arctic-Alpine species and ecosystems be able to resist both direct human impact and climate changes? We are concerned about this especially for cold Alpine and Arctic regions where the effect of changing climate is expected to be the most severe. With a good understanding of how species and ecosystems have endured previous climate changes and human impacts, we will be better equipped to understand and predict the tolerance limits for the changes currently occurring. We use the latest genetic methods and further develop these to reveal species and ecosystems throughout time. Lake sediments represent an archive of species that have lived in and around the lakes for millennia. We have analysed DNA from 10 lakes in northern Fennoscandia and 14 lakes in the Alps to find out how the diversity of animals and plants has changed over time. As these two regions have experienced similar changes in climate, whereas the impact of humans has been much higher in the Alps than the Arctic, we should be able to disentangle the effects of past human land-use (hunting, husbandry, burning, agriculture) from climate change, and biotic effects on species and ecosystem changes. Our first major publication from northern Fennoscandia shows that plant diversity increased through almost the entire period since the ice melted, even in periods when the climate was relatively stable. The second major publication shows that it took several thousand years from the entry of plants until the ecosystem became stable. The greatest number of plants entered the ecosystem 12-10 thousand years ago, but the ecosystem was unstable until about eight thousand years ago. After that, new species continued to enter our northern ecosystems, but these appear to have had less impact on ecosystem function and stability. Now we have also obtained usable results on mammals, and reindeer were the first to arrive about 11,100 years ago. We have also published our first article from the Alps, where we observe a clear shift in vegetation from before 6000 years ago, when vegetation mainly reflected climate changes, to the last 6000 years, when vegetation is strongly influenced by human land use. In addition, we have analyzed lake sediments from the Polar Ural and Svalbard to get a broader picture of vegetation changes. Beyond answering questions about the ability of species and ecosystems to withstand changes, we study the risk of species extinction and stability in ecosystem services. By combining what we learn about past changes with knowledge of current ecosystems, land use, and climate change, we will gain knowledge of great relevance for better management of our natural resources. We have recently published a study on how to practically use this data to simulate changes under different climate scenarios.

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There is great concern about the ability of species and ecosystems to resist both direct human impact and climate changes. Especially in cold alpine and arctic regions, the effect of changing climate is expected to be severe. While much knowledge has been gained from modern ecology and palaeoecology, the possibility to test ecological hypothesis using palaeocological data has been limited by the taxonomic resolution of pollen and scarcity of macrofossils. Recent analyses using state-of-the-art ancient DNA methodology do, however, show great promise in overcoming these limitations and open up the possibility to studying more complete species compositions of past ecosystems. In this project we aim to even further increase the information gained from palaeorecords by developing full genome techniques and quantitative DNA methods for plants and key herbivores, for which we already are compiling full genome DNA reference libraries for the Alps and northern Norway. Additionally, for both of these regions we will develop a balanced sampling design of in total 40 lakes along climate gradients and human-land-use contrasts, informed by the latest archaeological and palaeoecological knowledge and current climate variation. We will analyse environmental DNA data from these lake sediments to provide a first comprehensive assessment of how multiple drivers of ecosystem changes interact to drive ecosystem shifts, tipping points and changes in the provisioning of ecosystem services. Using state-of-the-art techniques to model species distribution, we will address key factors thought to cause time lags in species dispersal and extinction. Combining our knowledge gained from the past with data on current climate, land use and ecosystem characteristics, this project will make predictions of future changes and provide key knowledge for management and conservation priorities.