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Monitoring at large geographic scales requires a framework for understanding relationships between components and processes of an ecosystem and the human activities that affect them. We created a conceptual model that is centered on ecosystem processes, considers humans as part of ecosystems, and serves as a framework for selecting attributes for monitoring(More)
Foraging behaviour, stream habitat use and food habits of a population of the aquatic, Oregon garter snake were studied in the field during the spring and summer of 1987 and 1988. Continuous records of behaviour and habitat use were obtained for each snake. Adults foraged more actively and in a wider variety of stream habitats than juveniles or neonates.(More)
of the herpetofauna of a northern California watershed: linking species patterns to landscape processes. Á/ Ecography 28: 521 Á/536. Ecosystems are rapidly being altered and destabilized on a global scale, threatening native biota and compromising vital services provided to human society. We need to better understand the processes that can undermine(More)
Widespread alteration of natural hydrologic patterns by large dams combined with peak demands for power and water delivery during summer months have resulted in frequent aseasonal flow pulses in rivers of western North America. Native species in these ecosystems have evolved with predictable annual flood-drought cycles; thus, their likelihood of persistence(More)
Rangewide phylogeography and landscape genetics of the Western U.S. endemic frog Rana boylii (Ranidae): implications for the conservation of frogs and rivers Abstract Genetic data are increasingly being used in conservation planning for declining species. We sampled both the ecological and distributional limits of the foothill yellow-legged frog, Rana(More)
Lack of rearing habitat for stream-dwelling juvenile steelhead (Oncorhynchus mykiss) during summer low-flow conditions is considered to be the primary factor limiting these populations in the Pacific Northwest. Fishery managers have commonly focused on changing low-complexity stream reaches into habitat more favorable to juvenile steelhead through(More)
  • Arnold Schwarzenegger Governor, Joseph O 'hagan, +7 authors Sarah Yarnell
  • 2008
DISCLAIMER This report was prepared as the result of work sponsored by the California Energy Commission. It does not necessarily represent the views of the Energy Commission, its employees or the State of California. The Energy Commission, the State of California, its employees, contractors and subcontractors make no warrant, express or implied, and assume(More)
Amphibians are experiencing a precipitous global decline, and population stability on public lands with multiple uses is a key concern for managers. In the Sierra Nevada Mountains (California, USA), managers have specifically identified livestock grazing as an activity that may negatively affect Yosemite toads due to the potential overlap of grazing with(More)
structural components associated with older forests were the best predictors of increased numbers of salamanders. Analyses of microhabitat associations indicated that large, well-decayed logs were the most heavily used woody debris, though use of particular size-and decay-classes varied among salamander species. Harvesting forests without immediately(More)