The Arctic is currently experiencing dramatic changes in response to the strong high-latitude climate warming, affecting both terrestrial and aquatic ecosystems. This will have immediate effects on ecosystem services connected to food production, climate regulation, natural resources and cultural integrity. Due to a potential reduction of tundra ecosystems and the development of newly forested areas, this will have effects on climate - i.e. warming connected to albedo increase - and on biodiversity, both at the level of species and genotypes. We use past records of ecosystem change retrieved through ancient environmental DNA from sedimentary deposits. Our current project "Future ArcTic Ecosystems (FATE)", funded in the BiodivScen action of BiodivERsA and the Belmont Forum tracks plants and herbivores through time since the Pleistocene to understand the relative impacts of climate, herbivory, and human management on Arctic ecosystems.
Impacts of (past) climate change and anthropogenic pressure on aquatic ecosystems
The last century has seen dramatic changes in aquatic ecosystems globally, with freshwater population declines of over 80% since 1970 and major restructuring of aquatic ecosystem function. After decades of pressure from direct anthropogenic impacts, such as water pollution, including excessive nutrient enrichment, freshwater ecosystems now face a number of emerging threats, among which effects of climate change will be of particular severity on a global scale. While changes in biodiversity are most visible and prominent at the level of species, i.e. through the decline of species numbers and heightened extinction rates, current developments include a loss and turnover in genetic diversity. Heightened and specific selective pressures can also act as drivers of evolutionary change. While evidence for ongoing changes is challenging to retrieve, many aquatic ecosystems look back on a dynamic history, having experienced both previous climatic changes as well as anthropogenic pressure since their respective formation. Studying past biotic assemblages and their responses to changing environmental conditions can provide information for conservation and restoration and inform predictions for the future.
Currently we are studying past ecosystem changes in Lake Constance, which went through a distinct period of eutrophication and re-oligotrophication in the second half of the 20th century and has experienced distinct periods of climatic change as well as intense and early human settlement. Within the context of the Research Training Group R3, and in cooperation with the Institute for Lake Research, the State Office for the Conservation of Monuments, as well as the Universities of Braunschweig and Bern, we are studying sediment cores covering the past centuries and reaching back to the Late Pleistocene. These analyses are additionally funded through the Baden-Württemberg Foundation.
Biodiversity monitoring with Environmental DNA
The use of environmental DNA to trace organisms and monitor biodiversity is a growing field with many practical applications - and an excellent example of a quick switch from basic science without immediately visible practical value (such as detecting mammoths in ancient sediments without visible remains) to immense impact on biodiversity conservation. We enthusiastically contribute to developing and applying eDNA-based assays for the analyses of water and sediment samples. We routinely work with metabarcoding, species-specific PCRs and quantification via ddPCR. Currently, our group is conducting work on endemic endangered crayfish in Baden-Wuerttemberg, funded through a PhD scholarship of the German Federal Environmental Foundation (Deutsche Bundesstiftung Umwelt
). We have also developed assays for a range of neobiota in Lake Constance and will be testing the distribution of their DNA in space as well as back in time through the analyses of short sediment cores.