Dr. Monica G.Turner
Department of Zoology
University of Wisconsin
430 Lincoln Dr.
Madison, WI 53706
Landscape Ecology Lab
My current research is focused on how enhanced nutrient supply and climatic change (manipulation of snow conditions and temperature) drives plant parasite interactions and ecosystem change. I am working in an area with very low N background deposition (~2kg ha-1 yr-1) which enables us to study initial responses of strictly N limited ecosystems. My main study areas are a boreal mire, Degerö Stormyr (64º11’N, 19º33’E; 270 m a. s. l.) and a very nutrient poor pine heath, likewise being situated in the area. Due to strong nitrogen limitation both systems show a considerable time lag in response. Yet, after 8 years of N addition the experiment at the boreal mire shows striking changes in plant dominance. Especially the close Sphagnum carpet had collapsed.
In order to achieve a better understanding of driving factors of ecosystem change following enhanced N supply I have studied the interactions between parasitic fungi infecting the dwarf shrubs. My ongoing work addresses physiological responses of the disappearing Sphagnum. The results from combined studies, a transect study – along a nitrogen deposition gradient in Sweden – and experimental data from Degerö Stormyr are now used to clarify causes of the observed Sphagnum decline associated with enhanced nitrogen deposition.
Wiedermann, M. M., U. Gunnarsson, L. Ericson, and A. Nordin. 2009. Ecophysiological adjustment of two Sphagnum species in response to anthropogenic nitrogen deposition. New Phytologist 181: 208-217. (pdf)
Wiedermann, M. M., U. Gunnarsson, M. B. Nilsson, A. Nordin, and L. Ericson. 2008. Can small-scale experiments predict ecosystem response? An example from peatlands. Oikos. doi:10.1111/j.1600-0706.2008.17129.x. (pdf)
Wiedermann M. M. 2008. Responses of peatland vegetation to enhanced nitrogen. PhD Thesis, Umeå University, Umeå, Sweden. (pdf)
Wiedermann M. M., A. Nordin, U. Gunnarsson, M. B. Nilsson, L. Ericson. 2007. Global change shifts vegetation and plant-parasite interactions in a boreal mire. Ecology 88: 454-464. (pdf)
Bowman, W. D., J. R. Gartner, K. Holland, and M. Wiedermann. 2006. Nitrogen critical loads for alpine vegetation and terrestrial ecosystem response: Are we there yet? Ecological Applications 16:1183-1193.