Anu Eskelinen, Post-doctoral ResearcherResearch interests
I am currently a post-doctoral researcher in Susan Harrison’s lab in UC Davis. In general, I am interested in determining how biotic ecosystem components such as herbivory and plant species properties (traits), and abiotic environmental conditions interact to determine plant community composition and diversity. I am also interested in how feedbacks between vegetation and soil processes/functioning contribute to drive plant community dynamics and ecosystem functioning.
My current research topics include:
1. Global change in low-productivity serpentine grasslands of California: the role of multiple human impacts, resident plant traits and plant-soil interactions
Due to global change, substantial changes are expected in the amount and timing of rainfall in the Californian region, with one of the most significant effects being an extension of the duration of spring rainfall. At the same time, native serpentine flora encounters atmospheric nitrogen deposition from automobile exhaust which is suggested to contribute to the invasion of serpentine habitats by exotic species, thus leading to the degradation of the native serpentine flora. However, many plants occurring on serpentine soils show characteristics of conservative nutrient use, which have been suggested to restrict their ability to respond to resource enrichment. In this project we investigate experimentally how changes in precipitation and nutrient availability affect plant communities in Californian serpentine grasslands, and what is the role of plant functional traits and plant-soil feedbacks in mediating community responses.
Project in collaboration with Prof. Susan Harrison, Prof. Kate Scow (UC Davis, US), and David Hooper (Western Washington University, US).
2. Global change in low-productivity tundra ecosystems: interactions between herbivory, climate warming and productivity
Plant growth in tundra is generally regarded severely nutrient-limited partly owing to low nutrient mineralization rates at low temperatures, and climate warming-induced changes in mineralization rates and growing season length are expected to lead to considerable shifts in plant species composition, productivity and diversity. While constrained by harsh environmental conditions, plants in tundra ecosystems also face intensive grazing by mammalian herbivores, such as reindeer, caribou and microtine rodents. Resent findings indicate that changes in vegetation induced by global warming may interact with mammalian herbivory and be more complex than previous studies suggest. Using experimental approach this project aims to disentangle what are the interactive effects of climate warming and grazing on tundra vegetation. This research project is carried out in Fennoscandian tundra in north-western Finland.
Project in collaboration with Dr. Johan Olofsson and PhD student Elina Kaarlejärvi (University of Umeå, Sweden).
3. Vegetation-soil-microbe interactions in relation to herbivory and soil fertility in tundra
Some plant traits may be especially important in determining both community response to environmental change and the effect of that change on ecosystem processes. Especially those traits that affect litter and organic matter quality may influence the composition and activity of soil microbial communities and soil nutrient cycling, thereby feeding back to the productivity and composition of vegetation. This projects aims to disentangle how changes in plant communities in response to herbivory and multiple environmental factors are reflected in soil and microbial communities and is the responsiveness of vegetation and its effect on soil and microbes dependent on resident vegetation properties. This research project is also conducted in Fennoscandian tundra in north-western Finland.
Project in collaboration with Dr. Sari Stark and Dr. Minna Männistö (Finnish Forest Research Institute, Finland).
Virtanen, R., Eskelinen, A. and Harrison, S. 2014. Bryophyte diversity in Californian grasslands in relation to substrate quality, exotic vascular plants and disturbance. Biodiversity and Conservation, in press.
Saccore, P., Pyykkönen, T., Eskelinen, A. & Virtanen, R. 2014. Environmental perturbation, grazing pressure and soil wetness jointly drive mountain tundra toward divergent alternative states. Journal of Ecology, in press.
Stark, S., Männistö, M. & Eskelinen, A. 2014. When do grazers accelerate or decelerate soil carbon and nitrogen cycling in tundra? – A test of theory on grazing effects in fertile and infertile habitats. Oikos, in press.
Eskelinen, A. & Harrison, S. 2013. Exotic plant invasions under enhanced rainfall are constrained by soil nutrients and competition. Ecology, in press.
Stark, S., Männistö, M. & Eskelinen, A. 2014. Nutrient availability and pH jointly constrain microbial extracellular enzyme activities in nutrient-poor tundra soils. Plant and Soil, in press.
Eskelinen, A. & Harrison, S. 2014. Exotic plant invasions under enhanced rainfall are constrained by soil nutrients and competition. Ecology 95: 682-692.
Kaarlejärvi, E., Eskelinen, A. & Olofsson, J. 2013. Herbivory prevents lowland plants benefiting from warmer and more fertile conditions at high altitudes. Functional Ecology, in press.
Eskelinen, A. & Harrison, S. & Tuomi, M. 2012. Plant traits mediate
consumer and nutrient control on plant community productivity and diversity.
Ecology 93: 2705-2718.
Stark, S. & Eskelinen, A. Männistö, M. 2012. Regulation of microbial community composition and activity by soil nutrient availability, soil pH, and herbivory in the tundra. Ecocystems 15:18-33.
Ruotsalainen, A. & Eskelinen, A. 2011. Root fungal symbionts interact with mammalian herbivory, soil nutrient availability, and specific habitat conditions. Oecologia 166: 807 - 817.
Eskelinen, A. 2010. Resident functional composition mediates the impacts of nutrient enrichment and neighbour removal on plant immigration rates. Journal of Ecology 98: 540 – 550.
Eskelinen, A., Stark, S. & Männistö, M. 2009. Links between plant community composition, soil organic matter quality and microbial communities in contrasting tundra habitats. Oecologia 161: 113 – 123.
Eskelinen, A. 2008. Herbivore and neighbour effects on tundra plants depend on species identity, nutrient availability and local environmental conditions. Journal of Ecology 96: 155 – 165.
Eskelinen, A. & Oksanen, J. 2006. Changes in the abundance, composition and species richness of mountain vegetation in relation to summer grazing by reindeer. Journal of Vegetation Science 17: 245 – 254.
Eskelinen. A. & Virtanen, R. 2005. Local and regional processes in low-productive mountain plant communities: the roles of seed and microsite limitation in relation to grazing. Oikos 110: 360 – 368.
Virtanen, R., Eskelinen, A. & Gaare, E. 2003. Historical changes in species composition, abundance and diversity of alpine plant communities in Norway and Finland. In: Nagy, L., Grabherr, G., Körner, C. & Thompson, D.B.A. (eds.). Alpine Biodiversity in Europe. Ecological Studies Vol. 167. Springer Verlag, Berlin Heidelberg. pp. 411 – 422.