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Myotis evotis (long-eared myotis), a former Category 2 Candidate, is currently recognized by several federal and state agencies as a sensitive species, in part because very little information exists to provide evaluations on population status and viability locally or rangewide. Primary threats to M. evotis are roost disturbance (especially that leading to loss or destruction of roosting structures), habitat alteration, and toxic chemicals. Roost disturbance (especially of maternity roosts and hibernacula) can take the form of direct human contact or alternation of the roost environment. Habitat alteration refers to modification of any component of the required habitat mosaic, (e.g., presence and quality...
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The Great Basin spadefoot toad (Spea intermontana) is currently recognized by the Canadian government as a threatened species. In addition, some state agencies throughout its range recognize S. intermontana as a sensitive species, often because too little is known about it to provide evaluations on population status and viability throughout its range. In the last couple of decades, amphibians around the world have experienced population decline, range reduction, and even extinction. This observed trend has been attributed to habitat degradation and loss, chemical pollution, acid precipitation, increased ultraviolet radiation, introduced species, and pathogens, which all combine with the natural fluctuation...
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The sage thrasher (Oreoscoptes montanus), a sagebrush-steppe obligate that relies on large expanses of sagebrush-steppe for successful breeding, is recognized by Canada and several U.S. state agencies as a sensitive species that is apparently at risk based on loss or alteration of breeding habitat and decreasing population trends. In this context, habitat alteration refers to modification of any component of the required habitat mosaic, (e.g., presence and quality of tall big sagebrush (Artemesia spp.), adequate cover, and increased vertical and horizontal heterogeneity) that might directly decrease suitability for nesting habitat. Primary threats to O. montanus habitat are agricultural field cultivation,...
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