Theses and Dissertations Collection

Legacy fire suppression in the Lake Tahoe Basin has led to accumulation of forest litter, which may represent an important source of phosphorus contributing to eutrophication and reduced clarity in the Lake. The distribution and dynamics of soil phosphorus in the Basin’s forests is not fully understood. In Chapter 2, the response of three labile soil phosphorus fractions to seasonality, ecosystem, and parent material is examined between two neighboring watersheds in a site-specific analysis. In Chapter 3, relationships of different environmental, mineral soil, and organic horizon properties with several pools of soil phosphorus are described around the Basin. Results showed that 1) parent material influences the magnitude of labile soil phosphorus concentrations, 2) ecosystem type is a major driver for source of labile phosphorus, and 3) organic forms comprise the majority of soil phosphorus readily lost to surface waters. Effective mitigation of phosphorus accumulation in watershed soils should use parent material and ecosystem type to prioritize forest management strategies.