Bats - San Diego Co. [ds105]

These data will be valuable for comparison of current versus historical distribution of bat species, provide baseline data for biological monitoring of San Diego County, including the NCCP preserve system, and aid in future conservation planning. DATA ASSUMPTIONS AND LIMITATIONS: All data were collected by the primary field researcher, Drew Stokes. During 2002-2005 surveys, single Anabat II bat detectors were used during active acoustic monitoring portions of surveys. Anabats were placed in fixed survey locations on any particular survey date, and were usually oriented upwards at a 45-degree angle and pointed towards predicted flight path of bats. During 2006 surveys, passive monitoring anabats were used instead of the active units. During 2002-2005 surveys, mist-nets were placed over bodies of water that were not too broad to be covered by the length of a mist-net, and were not too deep to stand in. Mist-nets were also placed blocking vegetation flyways and tunnels. Mist-nets were not used during 2006 surveys. Data were not collected on nights characterized by extreme cold, wind, or precipitation. No estimates of bat abundance were made during these surveys, nor should there be any inferences of bat abundance made from these data. This is because bats were not marked during capture, so mark/re-capture information needed to make estimates of abundance is not available. In addition, it was not possible to estimate bat abundance based on Anabat recordings because it was not possible to determine how many individual bats were producing the vocalizations recorded with the Anabat (i.e., 100 recorded bat vocalization files could have been produced by 100 different individual bats, or simply one individual recorded 100 times). Anabat recordings do, however, provide an index of bat activity. Positional accuracy of individual locations is limited by accuracy of satellite GPS locations, observer error, and possible data entry errors. Although, all reasonable attempts have been made to limit these factors, positional accuracy for any individual point should not necessarily be considered minimal. The appropriateness of multiple scales of inference, is the end-users responsibility to justify and the originators assume no responsibility for incorrect or misleading uses of this data KNOWN CAVEATS OF THE DATA: Identification of bat vocalizations is a subjective process and requires experience and/or access to a bat vocalization reference library. All identification of recorded bat vocalizations was performed by the primary field researcher, Drew Stokes, who has been using the Anabat II bat detector system since 1996, and has been developing a reference library of known bat vocalizations based on hand releases of known individuals, recordings at known bat roosts, and visual observations of bats recorded simultaneously with Anabat. Anabat II bat detectors do not record all bat species with the same efficacy. Passive anabat units typically have a smaller cone of reception because the microphone is housed within PVC piping, and therefore, may not record bat vocalizations as effectively as actively monitored units. Some bat species produce low intensity vocalizations, and may not be recorded with Anabat detectors as readily as species that produce high intensity vocalizations. Reports that provide further explanation of this dataset can be accessed at: https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=16387 https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=17011 https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=17014 (Login required in order to see documents.)

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