Climate Change Response Science Focus Area

Experimental work under the Response SFA will focus on the identification of critical response functions for terrestrial organisms, communities, and ecosystems. Both direct and indirect effects of these experimental perturbations will be analyzed to develop and refine models needed for full Earth system analyses. Response SFA research will be organized around a climate change manipulation focusing on the combined response of multiple levels of warming at ambient or elevated CO2 (eCO2) levels. The experiment will provide a platform for testing mechanisms controlling vulnerability of organisms and ecosystems to important climate change variables (e.g., thresholds for organism decline or mortality, limitations to regeneration, biogeochemical limitations to productivity). The experiment will evaluate the response of existing biological communities to a range of warming levels from ambient to +8 C. The ambient, +4 C and +8 C warming treatments will also be conducted at eCO2 (in the range of 800 to 900 ppm). The experiment will be conducted in a Picea mariana [black spruce]# Sphagnum spp. forest in northern Minnesota. This ecosystem located at the southern extent of the spatially expansive boreal peatland forests is considered to be especially vulnerable to climate change and to have important feedbacks on the atmosphere and climate. This science plan for the Response SFA also describes support for core long-term tracking of the hydrologic, biogeochemical and biological response of the Walker Branch Watershed to inter-annual climatic variations.