The habitat relationships of Swainson's hawks in
northern California were studied at several levels of
resolution: 1) distribution of hawk populations among three
adjacent geographic areas, 2) density of hawk territories
among landscapes within a single geographic area, 3)
habitats associated with individual nesting territories, and
4) selection of foraging...
This dissertation had three main objectives: 1) investigate the role of macro and micro geomorphology in determining lizard distributions in the Southern California Mojave Desert; 2) develop a spatially explicit lizard habitat model based upon geomorphology; and, 3) determine the interactive effects of geomorphology, roads, and land use in defining...
The Humboldt marten, Martes americana humboldtensis, has undergone a dramatic decline throughout its historical distribution in coastal Northwestern California. There is currently only one known population occupying an area occurring in <5% of the historical distribution of the subspecies. Conservation and management efforts to benefit this population are hampered by...
I used a comparative and experimental approach to examine nest habitat selection, reproductive success, and nest site fidelity of burrowing owls (Athene cunicularia) in a large, non-fragmented grassland in southwest California. In 1999, I compared habitat characteristics between nest sites (n = 31) and randomly selected, unoccupied burrows (n =...
The variability of coastal carbonate chemistry continues to provide significant hurdles for understanding interactions between anthropogenic and natural CO2 cycling and resultant effects on coastal acidification dynamics. Attribution of the anthropogenic component is vital for identifying the impacts of increasing atmospheric carbon on coastal habitats such as coral reefs, upwelling...
Habitats for juvenile chinook salmon (Oncorhynchus tshawytscha) were
observed at a high flow during the spring of 1989 and at a low flow during the
spring of 1991 in the lower American River of California. Parameters of
microhabitats in eight macrohabitats were measured. Mean column water velocity
and total water...
Island biogeography has strongly influenced the study of biodiversity because
archipelagos provide natural model systems for investigating patterns of diversity and the
processes that shape ecological communities. I investigated the influence of area and
isolation of islands (n = 32) in the Gulf of California, Mexico on patterns of richness,...
Reintroduction programs are increasingly being used to save animals from extinction and aid in their recovery. The California Condor (Gymnogyps californianus), one of the most endangered birds in the world, is a remarkable example of how reintroduction programs can help rapidly increase a species' population numbers and range following a...
Large burrowing owl (Aihene cunicularia) populations exist in areas of intensive agriculture in California, and pesticide exposure has been identified as a potential threat to population persistence. I evaluated breeding season use of agricultural fields by adult male owls using radio telemetry, and examined egg contaminant residues to estimate population-level...
Managing rangelands with livestock grazing is a tool that can be applied to obtain vegetation management objectives. Animals utilize available resources, which vary in quantity and quality, across the landscape. Their movements are adjusted to the spatial and temporal heterogeneity of resource distribution. Controlling livestock distribution is fundamental to economically...