Bat Community Management Plan 2024 and Monitoring 2002-2019

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.

For the monitoring dataset, we compiled bat survey data from sampling sites throughout San Diego County in southern California from 2002-2019. Survey methods included ANABAT bat detectors, the unaided ear, day roost surveys and exit counts, and night roost surveys. All surveys were led by or included D. Stokes. Surveys were conducted with permission from private landowners and public land managers in areas where species were historically known or had the potential to occur based on habitat preferences. The study area in which surveys were conducted, San Diego County, spans a wide array of habitat types, including woodland, forest, coastal sage scrub, chaparral, and desert habitats, and apart from the desert, is generally characterized by a moderate Mediterranean climate. Elevation

Monitoring
Vertebrate Species
completed
Project Focus

Pallid bat, Townsend's big-eared bat

San Diego Association of Governments

Robert N. Fisher; Amy Vandergast; Drew Stokes

San Diego Natural History Museum; U.S. Geological Survey, Western Ecological Research Center

Sarah McCutcheon

Kris Preston

Brian Myers; Drew Stokes

Project Protocol
Bat survey data 2002-2019 Sampling Protocol

This file contains detailed information on the bat sampling protocol used for the data compilation between 2002-2019.

roost surveys, mist-netting, acoustic surveys
150.92KB Bat survey data 2002-2019 sampling protocol.pdf
File name Lead Author Year Type
Bat Management in San Diego County Myers, Brian; Stokes, Drew; Preston, Kris; Fisher, Robert N.; Vandergast, Amy 2022 powerpoint presentation
Bat virome study and ties to emerging infectious diseases Fisher, Robert N. 2022 powerpoint presentation
DRAFT Final report for focused pallid bat (Antrozous pallidus) and Townsend's big-eared bat (Corynorhinus townsendii) surveys in San Diego County, California San Diego Natural History Museum 2018 report
Quantification of threats to bats at localized spatial scales for conservation and management Myers, Brian; Stokes, Drew; Preston, Kris; Fisher, Robert N.; Vandergast, Amy journal article
Recording - May 2022 SDMMP Management and Monitoring Coordination Meeting Fisher, Robert N.; Vandergast, Amy; Myers, Brian 2022 recording
Project Files