Southwest Idaho vernal pool and playa faunal inventory and condition assessment

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The authors collected baseline information on fauna inhabiting or seasonally using vernal pools and playas in southwestern Idaho. They used a Rapid Assessment Method to evaluate the ecological condition of surveyed sites. Ecological and vegetation classification and estimates of vernal pool and playa distribution were conducted concurrently and detailed in a companion report (Murphy 2012, U12MUR01IDUS). Surveys targeted waterfowl, shorebirds, specific aquatic invertebrate groups, and amphibians. Ecological condition was estimated by measuring the number and severity of physical disturbances within pool boundaries and in a 50-meter buffer around wetland habitats. The authors evaluated 90 vernal pools and playas during 2008-2009 and performed faunal surveys at 39 sites. Waterfowl and shorebirds were observed at 20 sites, including pools that were dry or nearly so. Invertebrate surveys focused on the large branchiopod crustaceans in the Anostracan and Notostracan orders. Anostracan (fairy) shrimp occupied nearly all inundated sites and 3 Branchinecta and 1 Eubranchipus species were identified. Branchinecta constricta, a new Idaho record, represents a range extension of >500 km. Notostracan (tadpole) shrimp occurred at 9 sites. Amphibians were infrequently observed and vouchered at only 7 locations. These surveys indicate widespread occupancy of vernal pools and playas in southwest Idaho by a diverse community of aquatic invertebrates and birds and by localized but important breeding populations of amphibians. Approximately 73% of playas surveyed were minimally or lightly disturbed, compared to 32% of vernal pools. Livestock grazing was widespread. Impacts from excavated livestock water reservoirs and nonnative plant invasion were locally severe.

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ELECTRONIC FILE - Zoology

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U12WEE01IDUS.pdf