| There is a pressing need to incorporate remote methodologies, such as remote sensing and geographical information systems, in the assessment and monitoring of watersheds. Faced with the recovery and maintenance of imperiled species, particularly anadromous Pacific salmon, resource managers in northern California's coastal watersheds are increasingly challenged to utilize readily available spatial data in a proficient and sound manner. Standardized methods to examine watershed processes, cumulative effects, and identify critical habitats are few and largely site-specific. This research documents geospatial methods to estimate stream condition, measure relative land use disturbance, and isolate critical habitats as they relate to the anadromous salmonids, aquatic habitats and riparian forests of the Navarro River watershed in southern Mendocino County, California.; The development of RipTopo, a riparian-topographic stream shading model, and calibration to watershed conditions generated site-specific habitat estimates and indicated streams in need of restoration to achieve potential ecological condition. These stream shading conditions were incorporated into a watershed-wide assessment of land use disturbance, in which road networks, land subdivision, timber harvesting, and removal of riparian canopy were used to gauge current distributions of steelhead (Oncorhynchus mykiss) and coho salmon (Oncorhynchus kisutch). Coho have experienced a range contraction in the Navarro River watershed; based on results of this research, it appears that, when compared to steelhead, coho are disproportionately affected by land use disturbance. Negative effects from land use disturbance were identified by pairing cumulative and discrete, localized watersheds within a spatial framework to examine relative differences in salmonid response. Ultimately, highway and seasonal road densities, as well as variability in shade and riparian forest structure, were significant negative predictors in coho distribution.; Observations from the spatial analytical framework were used in turn to predict critical aquatic habitats in need of protection in the Navarro River watershed. Lastly, hyperspectral data were evaluated as a diagnostic screening tool to identify intact riparian canopies through an estimated leaf area index and to isolate infestations of non-native riparian vegetation. Any comprehensive effort to promote restoration and conservation of northern California's coastal watersheds will require a spatial framework, incorporation of readily available data, and standardized methods of inquiry. This study provides one such example. |
