Leave growth of Eriophorum angustifolium and Carex rotundata was measured in a long-term experimental wet sedge tundra site near Toolik Lake, AK. Experimental treatments at each site included factorial NxP, greenhouse and shadehouse and were begun in 1989 (Toolik sites).
Data Set Results
Seasonal patterns of leaf exsertion, elongation and senescence for Eriophorum vaginatum and Carex bigelowii was measured in mesic tussock tundra sites near Toolik Lake, AK. In addition, the response of both species to NP fertilizer and to variation in site fertility (after track versus non-track areas) were also assayed and compared. The research was done over two full growing seasons.
Quadrats were harvested for aboveground biomass from eight plots within a tussock, watertrack, and snowbed community at 3 sites - acidic tundra near Toolik (site of acidic LTER plots), nonacidic tundra near Toolik Lake(site of non-acidic LTER plots), and acidic tundra near Sagwon. All vascular species were sorted, divided into new and old growth, dried, and weighed. Lichens were separated by genus in all quadrats. In half of the quadrats (n=4), mosses were separated by species. Moss and lichen data are presented by species elsewhere (see 97lgmosslichen.txt).
We use a simple model of coupled carbon and nitrogen cycles in terrestrial ecosystems to examine how explicitly representing grazers versus having grazer effects implicitly aggregated in with other biogeochemical processes in the model alters predicted responses to elevated carbon dioxide and warming. The aggregated approach can affect model predictions because grazer-mediated processes can respond differently to changes in climate from the processes with which they are typically aggregated.
We use a simple model of coupled carbon and nitrogen cycles in terrestrial ecosystems to examine how explicitly representing grazers versus having grazer effects implicitly aggregated in with other biogeochemical processes in the model alters predicted responses to elevated carbon dioxide and warming. The aggregated approach can affect model predictions because grazer-mediated processes can respond differently to changes in climate from the processes with which they are typically aggregated.