Journal
JOURNAL OF WILDLIFE MANAGEMENT
Volume 75, Issue 5, Pages 1094-1102Publisher
WILEY-BLACKWELL
DOI: 10.1002/jwmg.151
Keywords
bats; bat detectors; canyon bat; Chiroptera; monitoring; Parastrellus hesperus; probability-based survey; spatially balanced sampling; survey design
Funding
- National Park Service Upper Columbia Basin Network
- John Day Fossil Beds National Monument
- National Oceanic and Atmospheric Administration (NOAA) Northwest Fisheries Science Center
Ask authors/readers for more resources
Acoustic surveys are widely used for describing bat occurrence and activity patterns and are increasingly important for addressing concerns for habitat management, wind energy, and disease on bat populations. Designing these surveys presents unique challenges, particularly when a probabilistic sample is required for drawing inference to unsampled areas. Sampling frame errors and other logistical constraints often require survey sites to be dropped from the sample and new sites added. Maintaining spatial balance and representativeness of the sample when these changes are made can be problematic. Spatially balanced sampling designs recently developed to support aquatic surveys along rivers provide solutions to a number of practical challenges faced by bat researchers and allow for sample site additions and deletions, support unequal-probability selection of sites, and provide an approximately unbiased local neighborhood-weighted variance estimator that is efficient for spatially structured populations such as is typical for bats. We implemented a spatially balanced design to survey canyon bat (Parastrellus hesperus) activity along a stream network. The spatially balanced design accommodated typical logistical challenges and yielded a 25% smaller estimated standard error for the mean activity level than the usual simple random sampling estimator. Spatially balanced designs have broad application to bat research and monitoring programs and will improve studies relying on model-based inference (e. g., occupancy models) by providing flexibility and protection against violations of the independence assumption, even if design-based estimators are not used. Our approach is scalable and can be used for pre- and post-construction surveys along wind turbine arrays and for regional monitoring programs. (C) 2011 The Wildlife Society.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available