Natural herbivory and simulated warming in Arctic landscape
Investigating the structure and function of the arctic landscape subjected to natural herbivory and simulated warming
Virtual satellite image of Kangerlussuaq, Greenland (670N, 500W)
Global climate change is expected to have the most significant impacts in the northern latitudes. Indeed, observed changes in vegetation, species dominance and migratory patterns are well documented throughout the arctic terrestrial landscape as a result of climatic drivers (Walther et al., 2006).
In Western Greenland, Eric Post has shown how herbivores can modify the composition and biomass of plant communities in response to warming (Post and Pedersen, 2008).
Chamber used for taking ecosystem carbon efflux measurements
Shifts in species dominance as a result of biotic (e.g herbivory) and abiotic (e.g warming) drivers may reduce the carbon sequestration potential of the arctic environment and possibly feedback to the atmosphere. In this study, we have combined simulated warming with natural herbivory by caribou and muskoxen in order to further our knowledge of the role large herbivores play in altering the structure and function of the arctic landscape. Using this approach, and in association with Eric Post from Penn State University, ENRI graduate student Sean Cahoon is conducting field measurements of carbon exchange, plant morphology, logging meteorological data and quantifying belowground nitrogen mineralization.
One of three study sites near Kangerlussuaq, Greenland.
Passive warming chambers are located within and adjacent to the animal exclosure fence.
Sean Cahoon taking carbon flux measurements inside an exclosure fence. Note ITEX chamber and meteorological station visible in the background.
Post, E. and C. Pedersen. 2008. Opposing plant community responses to warming with and without herbivores. PNAS. August 26, 2008. 105 (34): 12353-12358. www.pnas.org/cgi/doi/10.1073/pnas.0802421105.
Walther, G-R., E. Post, P. Convey, A. Menzel, C. Parmesan, T. Beebee, J-M Fromentin, O. Hoegh-Guldberg and F. Bairlein. 2002. Ecological resposnses to rrecent climate change (Review article). Nature, March 28, 2002. 416:389-395. www.nature.com.