DISSERTATION RESEARCH: The effect of nitrogen deposition on plant community dynamics across local and regional scales

University Of California-Davis, Davis CA

Investigators

Abstract

Rapid urbanization of California's landscape exposes remnant oak savanna ecosystems to increasing levels of atmospheric nitrogen (N) deposition. Deposited nitrogen enters the ecosystem and exposes plants to amounts and chemical forms of N that they may not be adapted to. Nitrogen deposition is not distributed evenly across the landscape, but varies across multiple scales. This results in the heterogeneous distribution of N in soil, which may alter plant communities under increasing N inputs. The aim of this research is to investigate how N deposition interacts with environmental conditions, which vary at the regional (e.g., rainfall) and local (e.g., light) scale, to structure plant communities. A combination of observational and experimental methods will be used to understand patterns and processes by which oak savannas receive N deposition and plants respond to it. This research will study specific processes through which N deposition affects plant communities in oak savannas. Understanding dynamics of natural areas embedded within a changing landscape is critical for management and conservation efforts. Managers are concerned about the effect of N deposition on invasive species and how that affects forage quality in grazing lands. At the broader, regional scale, results can inform land-use and regulation decisions affecting N emissions and air quality.