Changing ice-cover regimes in a warmer climate: Effects on northern aquatic ecosystems
Climate change induced regime shifts in Northern lake ecosystems
A present major scientific challenge is to understand and predict effects of climate change on lake ecosystems and the services they deliver. Globally, lakes are concentrated at northern latitudes where the magnitude of climate change is expected to be strongest. Recent advances in lake research suggest that responses of Northern lakes to global warming are fundamentally different from the expectations based on conventional knowledge. This project brings together new tools and concepts in biogeochemistry and ecology, with the aims of understanding and predicting the effects of climate change on the delivery of two major ecosystem services, fish production and the net greenhouse gas balance of Northern lakes.
Specific objectives include:
Assessment of long vs. short term effects of climate change;
Assessment of nonlinear dynamics and regime shifts; and,
Projection of responses to future climate conditions.
The project’s core is made up of a multi-scale (pond to whole-lake) experimental test of ecosystem responses to increases in temperature and precipitation/runoff. Further, we will use aDNA techniques to address past regime shifts and ecosystem resilience to climate change from paleolimnological sediment records. Finally, the project will develop process-based models to be used in the projection of future conditions in lakes at the whole ecosystem scale.
Project Dates: 2017-2021
Knut and Alice Wallenberg Foundation
David Bastviken, Linköping University
Ann-Kristin Bergström, Umeå University
Christian Bigler, Umeå University
Richard Bindler, Umeå University
Åke Brännström, Umeå University
Pär Byström, Umeå University
Sebastian Diehl, Umeå University
Isabelle Domaizon, French National Institute for Agricultural Research
Göran Englund, Umeå University
Cristian Gudasz, Umeå University
Dag Hessen, Oslo University, Norway
Jonatan Klaminder, Umeå University
Sally MacIntyre, University of California Santa Barbara, USA
Frank Peeters, University of Konstanz, Germany
André de Roos, University of Amsterdam, The Netherlands
Martin Rosvall, Umeå University
David Seekell, Umeå University
Ryan Sponseller, Umeå University
Xiau-Ru Wang, Umeå University
Marcus Klaus, Umeå University
Quantifying cryogenic soil-mixing in the tundra soil and its role for the long-term carbon cycling in the arctic
Tundra soils play an important role in the global carbon cycle. Tundra regions are warming rapidly due to the ongoing global warming, and there are concerns that this will reduce the accumulation rate of carbon in tundra soils. It is even feared, that from being a sink, these soils will instead become a significant source of carbon to the atmosphere, which will add to the currently increasing levels of greenhouse gases. In the discussion about changed carbon cycling due to changed climate in tundra regions, temperature dependent decomposition processes and changed plant productivity rates have been the main mechanisms studied although it has been suggested that soil frost processes, might be of more importance for the fat of the soil carbon pool than temperature dependent microbial processes. The objective with my research project is to test this hypothesis.
Marina Becher, Umeå University
What is a landscape characterized by grazing?- and how is it preserved in a changing climate?
In the environmental quality objective A Magnificent Mountain Landscape, it is stated that the pristine character of the mountain environment must be largely preserved, in terms of biological diversity, recreational value and natural and cultural assets. The reindeer management regime plays a central role in fulfilling these objectives, since almost the entire Swedish mountain landscape is grazed by reindeer. A more general understanding of how the current vegetation is shaped by reindeer grazing, how vegetation change when reindeer is excluded, and how these changes interact with other herbivores and climatic conditions is essential for evaluating how different reindeer management regimes will obtain the specific goals within this objective. The overall aim of this project is thus to investigate how reindeer influence the mountain vegetation in order to determine features of a landscape characterized by grazing, and evaluate how different reindeer management regimes and climate will determine future vegetation patterns and biodiversity. To achieve this we will examine how effects of excluding reindeer on vegetation vary across gradients in reindeer densities and climatic conditions in the Scandinavian mountains, and assess the importance of these findings in relationship to the environmental quality objectives.
Network: Warming and (species) Removal in Mountains (WaRM)
Rising temperatures associated with climate change is a major global political and socio-economical priority. The amount of carbon in the atmosphere regulates how much warming will occur globally, but the amount of carbon taken up and released from terrestrial ecosystems under warming remains uncertain in the models that predict future climates. Warming has a range of direct (e.g. changes in process rates) and indirect (shifts in dominant plant species, plant-soil interactions) effects on ecosystem properties and processes. In WaRM we study community and ecosystem responses to the direct and indirect effects of warming in a coordinated project that combines experimental warming and dominant plant species removal at high and low elevations among 10 globally-distributed gradients, including one in Abisko. We have five overarching objectives with this network: (1) To determine the relative influences of climate and interactions among species on biodiversity and ecosystem carbon dynamics. (2) To examine the patterns and processes that shape ecosystem function among disparate ecosystems. (3) To investigate whether the functional composition of plant communities determines how communities respond to warming and dominant species removal. (4) To assess whether functional traits can be used to improve predictions of how ecosystem function and community structure change in response to climate and climate change. (5) To leverage the results of these experiments to improve community land models to refine predictions about global carbon cycling.
WaRM Sites and PI’s
Sweden: Maja Sundqvist, Umeå University
USA: Aimee Classen and Nathan Sanders, University of Vermont
Greenland: Toke Thomas Høye, Aarhus University
Canada: Jennie McLaren, University of Texas at El Paso
Argentina: Mariano Rodriguez-Cabal, INIBIOMA, Universidad del Comahue, CONICET and M. Noelia Barríos-Garcia, CONICET, CENAC-APN
Tasmania: Mark Hovenden, University of Tasmania, Australia
New Zealand: Julie Deslippe, Victoria University of Wellington
China: Jin-Sheng He, Peking University
Switzerland: Christian Rixen, Swiss Federal Institute for Forest, Snow and Landscape Research, Sonja Wipf, WSL Institute for Snow and Avalanche Research SLF, Davos
France: Sandra Lavorel, Université Grenoble Alps
Göran Gustafssons Stiftelse för Natur och Miljö i Lappland
The Carlsberg Foundation