The effect of multiple resource additions on community structure and ecosystem processes.

The Sevilleta LTER is a participant in the Nutrient Network (NutNet).

NutNet is an international research network comprised of more than 40 grassland sites worldwide all of which are using the same experimental design and measurement protocols to address the following questions: 1) How general is our current understanding of productivity-diversity relationships? 2) To what extent are plant production and diversity co-limited by multiple nutrients in herbaceous-dominated communities? 3) Under what conditions do grazers or fertilization control plant biomass, diversity, and composition? To answer these question, we have established at the Sevilleta five replicates of each of the following fertilization treatments in a fully crossed design: control, annual N addition (10gm-2), annual P addition (20gm-2), annual K addition (10gm-2) and all possible combinations.

NutNet has two main goals. The first is to collect data from a broad range of sites in a consistent manner to allow direct comparisons of environment-productivity-diversity relationships among systems around the world. This is currently occurring at each site in the network and, when these data are compiled, will allow us to provide new insights into several important, unanswered questions in ecology. The second goal is to implement a cross-site experiment requiring only nominal investment of time and resources by each investigator, but quantifying community and ecosystem responses in a wide range of herbaceous-dominated ecosystems (i.e., desert grasslands to arctic tundra).