Risch Anita Christina

Impacts of different-sized herbivores on above- and belowground productivity in alpine grasslands

Project Number: CH-4452
Project Type: Master
Project Duration: 02/01/2010 - 11/30/2010 project completed
Funding Source: other ,
Project Leader: Prof. Anita Christina Risch
Head of Animal Ecology
Ökologie der Lebensgemeinschaften
Zürcherstrasse 111
8903 Birmensdorf
Phone: ; +41 (0) 44 739 21 11
FAX: +41 (0) 44 739 22 15
e-Mail: anita.risch(at)wsl.ch

related to this project.
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Research Areas:

general biology

Herbivores can be key determinants and important regulators for grassland processes. Consumption rates and therefore grazing intensity of herbivores are shown to be related to their body size. While small herbivores require high quality forage and can exist with low quantities, larger herbivores need high quantity and can better exploit low quality. A large-scale exclusion experiment, in the Swiss National Park (SNP), was established in 2009 that assesses the impacts of different-sized herbivores on subalpine grasslands of different productivity. This thesis focuses on changes in above- and belowground biomass after the first season of herbivore exclusion. In nutrient rich short-grass communities, large herbivores were shown to have large negative effects on aboveground biomass, whereas they had only little effect on changes in tall-grass. There was a slight trend in terms of herbivore exclusion on belowground biomass, which was decreasing with decreasing size of herbivores. Finally, the data suggests that succession is depleted in the presence of large herbivores. Large herbivores promote diverse landscape patterns and thus diversity of plants and animals. For conservation management it is suggested that there is no need for human induced regulations of large herbivore densities in SNP. However, short-term observations make it difficult to predict future states and may lead to misinterpretation. To better understand the complexity of the grassland system and thus to be able to predict impacts of differentsized herbivores on its functions, there is a need to focus on the whole ecosystem over a longer time-scale, which will be done in subsequent studies from Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) and SNP.

Stoffel Bigna 2010: Impacts of different-sized herbivores on above- and belowground productivity in alpine grasslands. Master thesis, ETH Zürich.
pdf Masterthesis

Last update: 7/18/17
Source of data: ProClim- Research InfoSystem (1993-2020)
Update the data of project: CH-4452

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