Berdanier, Aaron B., authorKlein, Julia Anne, advisorKnapp, Alan K., 1956-, committee memberBurke, Ingrid C., committee member2007-01-032007-01-032010http://hdl.handle.net/10217/38381Department Head: N. LeRoy Poff.Life in high-elevation ecosystems is hard. Ecosystem functions such as aboveground net primary production (ANPP) are constrained by short growing seasons and patchy resource availability. I quantified ANPP responses to changes in these variables by combining global, regional, and local observations with simple models. I observed a consistent, linear increase in ANPP with growing season length (4 g/m2/d) at local and regional scales. I also found a nonlinear, asymptotic increase in ANPP with soil moisture across sites, despite variation in space, time, and plant species composition. I hypothesized that this soil moisture limitation may be partially mediated by nitrogen availability based on leaf-level observations from Niwot Ridge, CO. Finally, I compared a set of competing models relating ANPP to growing season length and soil moisture. I found that the combined influence of these variables was modeled best with a cumulative limitation by soil moisture. This model offers a simple basis for predicting the response of high-elevation ANPP to changes in these climatic constraints.masters thesesengCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.Mountain ecology -- ColoradoVegetation and climate -- ColoradoMountain plants -- ColoradoText