Get access

Using echolocation monitoring to model bat occupancy and inform mitigations at wind energy facilities

Authors

  • Theodore J. Weller,

    Corresponding author
    1. Pacific Southwest Research Station, USDA Forest Service, 1700 Bayview Drive, Arcata, CA 95521, USA
    • Pacific Southwest Research Station, USDA Forest Service, 1700 Bayview Drive, Arcata, CA 95521, USA.
    Search for more papers by this author
  • James A. Baldwin

    1. Pacific Southwest Research Station, USDA Forest Service, 800 Buchanan Street, Albany, CA 94710-0011, USA
    Search for more papers by this author

  • Associate Editor: Amy Kuenzi.

Abstract

Fatalities of migratory bats, many of which use low frequency (<35 kHz; LowF) echolocation calls, have become a primary environmental concern associated with wind energy development. Accordingly, strategies to improve compatibility between wind energy development and conservation of bat populations are needed. We combined results of continuous echolocation and meteorological monitoring at multiple stations to model conditions that explained presence of LowF bats at a wind energy facility in southern California. We used a site occupancy approach to model nightly LowF bat presence while accounting for variation in detection probability among echolocation detectors and heights. However, we transposed the spatial and temporal axes of the conventional detection history matrix such that occupancy represented proportion of nights, rather than monitoring points, on which LowF bats were detected. Detectors at 22 m and 52 m above ground had greater detection probabilities for LowF bats than detectors at 2 m above ground. Occupancy of LowF bats was associated with lower nightly wind speeds and higher nightly temperatures, mirroring results from other wind energy facilities. Nevertheless, we found that building separate models for each season and considering solutions with multiple covariates resulted in better fitting models. We suggest that use of multiple environmental variables to predict bat presence could improve efficiency of turbine operational mitigations (e.g., changes to cut-in speeds) over those based solely on wind speed. Increased mitigation efficiencies could lead to greater use of mitigations at wind energy facilities with benefits to bat populations. © 2011 The Wildlife Society.

Get access to the full text of this article

Ancillary