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Michael L. Casazza

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The San Francisco Bay estuary is highly urbanized, but it supports the largest remaining extent of tidal salt marshes on the west coast of North America as well as a diverse native bird community. San Francisco Bay tidal marshes are occupied by more than 113 bird species that represent 31 families, including five subspecies from three families that we denote as tidal-marsh obligates. To better identify the niche of bird species in tidal marshes, we present a review of functional groups based on foraging guilds and habitat associations. Foraging guilds describe the method by which species obtain food from tidal marshes, while habitat associations describe broad areas within the marsh that have similar environmental...
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This report reviews the available literature on giant gartersnakes (Thamnophis gigas) to compile existing information on this species and identify knowledge gaps that, if addressed, would help to inform conservation efforts for giant gartersnakes. Giant gartersnakes comprise a species of semi-aquatic snake precinctive to wetlands in the Central Valley of California. The diversion of surface water and conversion of wetlands to agricultural and other land uses resulted in the loss of more than 90 percent of natural giant gartersnake habitats. Because of this habitat loss, giant gartersnakes are now listed by the United States and California Endangered Species Acts as Threatened. Most extant populations occur in...
Categories: Publication; Types: Citation; Tags: Open-File Report
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Identifying links between micro-habitat selection and wildlife reproduction is imperative to population persistence and recovery. This information is particularly important for landscape species such as greater sage-grouse (Centrocercus urophasianus; sage-grouse). Although this species has been widely studied, because environmental factors can affect sage-grouse populations, local and regional studies are crucial for developing viable conservation strategies. We studied the habitat-use patterns of 71 radio-marked sage-grouse inhabiting an area affected by wildfire in the Virginia Mountains of northwestern Nevada during 2009–2011 to determine the effect of micro-habitat attributes on reproductive success. We measured...
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Rigorous analysis and management of animal populations requires that observers account for limitations inherent to the detection of those populations and the individuals within them. Researchers are usually unable to see every individual of a population or to even detect some entire populations. Ignoring this imperfect detectability can bias estimates of population characteristics, such as probability of occurrence, abundance, survival, recruitment, and population growth rate. Furthermore, the precision with which these population characteristics are estimated is dependent on detection probabilities (the probability that at least one individual of a species is detected during a survey, given that the species occurs...
Categories: Publication; Types: Citation; Tags: Open-File Report
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