PARENT SESSION
Oral Session # 88: Plant Ecology VII: Communities.
Presiding: N Turrill Welch
Friday, August 8. 8:30 AM to 12:00 PM, SITCC Meeting Room 100.
Latitudinal patterns of net primary production and the compensatory effects of leaf stoichiometry.
Kerkhoff, Andrew*,1, Enquist, Brian1, Elser, James2, Fagan, William3, 1 University of Arizona, Tucson, AZ2 Arizona State University, Tempe, AZ3 University of Maryland, College Park, MD
ABSTRACT- Vegetation canopies, via primary production, are the energetic and material drivers of all terrestrial ecosystems. A growing body of research suggests that many biological and ecological process rates, including primary production, may be largely controlled by a small number of factors, including body size, temperature, and C:N:P stoichiometry. However, interrelationships among site temperature, standing biomass, and organismal stoichiometry (as well as many other factors) complicate our ability to make predictions about global patterns of productivity. For example, ecologists generally consider the tropics to be substantially more productive than temperate, boreal, and arctic zones. However, adaptive changes in plant stoichiometry in response to colder environments and shorter growing seasons may obscure, or even eliminate the expected latitudinal gradient in productivity. Here, we develop a simple model integrating allometric, kinetic, and stoichiometric principles to generate testable predictions concerning the biogeography of net primary production and plant stoichiometry. Global patterns of productivity and leaf stoichiometry generally support the predictions made by the model. Specifically, trends in productivity expected on the basis of temperature appear to be moderated by compensatory changes in the nutrient content (especially P) of higher latitude plants. The principles underlying metabolic scaling theory and ecological stoichiometry provide a mechanistic basis for scaling productivity estimates "from leaf to globe" and for developing a predictive theoretical ecosystem ecology.
Key words: metabolic scaling, ecological stoichiometry, macroecology