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In a rapidly changing world, where species conservation needs vary by local habitat, concentrated conservation efforts at small spatial scales can be critical. Bats provide an array of value to the ecosystems they inhabit; many bat species are also of conservation concern. San Diego County, California, contains 22 of the 41 bat species that occur in the United States, 16 of which are on conservation watchlists. Thus, management of bat communities in San Diego County is a pressing need. Because bats exploit vast areas of the landscape and historical sampling strategies have shifted over time, a standardized way of prioritizing areas of the landscape for management would provide an integral asset to bat conservation. We leveraged long-term bat community survey data from sampling areas across San Diego County to prioritize areas with the most management need. We calculated two types of scores: species scores and threat scores. Species scores incorporated richness and conservation status, and threat scores included landscape level threats that bats could encounter. We found that urbanization, the presence of artificial lights, and areas sampled on unconserved land were all significantly associated with decreases in species richness. Further, using species and threat scores, each sampling area was placed into one of four conservation categories, in order from greatest to least conservation need, ranging from highest priority (high species score, high threat score) to lowest (low species score, low threat score). Additionally, we focused on sampling areas in which Townsend’s big-eared bat (Corynorhinus townsendii) and/or pallid bat (Antrozous pallidus) occurred. These two species are of exceptional conservation concern in San Diego County and across the western United States. We identified urbanization, the presence of artificial lights, and areas sampled on unconserved land as threats that were all significantly associated with the absence of Townsend’s big-eared bat, but not pallid bat. The strategy, methodology, and solutions proposed in our study should assist bat conservation and management efforts wherever bats occur, and can be extended to other species that require conservation attention.

Presentation for the May 25, 2022 SDMMP Management and Monitoring Coordination Meeting.

Recording from the May 25, 2022 SDMMP Management and Monitoring Coordination Meeting. Presentations from Brian Myers (California Polytechnic State University, Pomona) and Amy Vandergast (USGS) - "Integrating 20 years of site-specific bat surveys to help inform a regional bat management plan"; and Robert Fisher (USGS) - "Bat virome study and ties to emerging infectious diseases".

Very little information exists on the status or distribution of either species, particularly in the North County MSCP area. Therefore, San Diego County-wide surveys for these species were needed to document where they were found and what their current population status was. Obtaining this information would allow for more informed consideration of the conservation planning and management of these species in the North County plan. This would also allow habitat models to be developed for the target species to aid in future planning.

We conducted a bat species inventory of the Multiple Species Conservation Program (MSCP) area in San Diego County, California. The study began in the early summer of 2002 and terminated in the winter of 2003. We used a variety of bat survey techniques including ultrasonic bat detectors, mist-nets, hand-nets, unaided ears (audible), and spotlights to document both foraging and roosting bats within and immediately adjacent to the Multi-Habitat Preserve area. We conducted a total of 80 surveys at 27 foraging bat sites and 28 surveys of 18 potential bat roosting sites. We detected 16 bat species including five species of local concern at various sites within the study area during both foraging and roosting bat surveys. Other information provided by this study includes demographics, reproductive states, and injuries of captured bats, seasonal activity and richness patterns of bats in the study area, watershed associations of bats in the study area, and detection success of the various bat survey techniques used. We present specific recommendations for bat management and long-term monitoring strategies.

We investigated the role of large-scale wildfires on the community composition and structure of foraging bats within San Diego County, California. In October and November of 2003, large–scale wildfires burned nearly 130,000 hectares of San Diego County. To assess the potential impacts of these fires on the native bat communities, we conducted surveys at eleven sites within each of our two study areas, Rancho Jamul Ecological Reserve - Hollenbeck Canyon Wildlife Area and Santa Ysabel Open Space Preserve. At each study area a subset of these sites was sampled before the fires (2001- 2003) and a subset after the fires (2005-2006). Our pre-fire sampling efforts included five survey techniques: active-Anabat, mist-netting, roost, visual, and audible. These same five techniques were employed during the first year of post-fire sampling, 2005. In 2006, we altered our survey methods by discontinuing mist-netting and began using passive-Anabat monitoring stations instead of an actively monitored station.

The goal of this project is to increase the suitability of roosting habitat for Townsend’s big-eared bat (MSP Category SO (Significant occurrence(s) at risk of loss from MSPA)) by installing a gate in the entrance of a mine and controlling the existing erosion threat there. The project also includes creation of interpretive materials to increase community awareness about these sensitive species and the habitats upon which they rely