Our Approach
NABat monitoring relies on an extensive community of partners across the continent who use standardized protocols, developed by NABat, to gather data through acoustic surveys, summer roost counts, and winter hibernacula surveys. These data are used to assess changes in bat populations at local, regional, and range-wide scales. Our protocols were consciously designed to accommodate variation in resources, personnel, and locations, providing clear but adaptable guidance for bat monitoring efforts in the U.S., Canada, and Mexico. It is important to note that the diversity of North American bats encompasses a range of life histories and behaviors, so the appropriate protocol will vary based on species groups, season, and geographic region. For example: counting bats at a winter hibernaculum is appropriate for species that hibernate in large groups, but other monitoring approaches may work better for species that hibernate individually or in regions where hibernacula locations are unknown.
Our Purpose
To create a continent-wide program to monitor bats at local to range-wide scales that will provide reliable data to promote effective conservation and long-term viability of bat populations across the continent.
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Our Goals
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Measure indices of bat species abundance at multiple spatial scales
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Assess changes in species distribution
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Provide regular analyses and reporting on the status of North American bats
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Our Monitoring Methods
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Mobile acoustic surveys along driving transects
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Acoustic surveys at stationary points
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External roost counts
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Internal winter hibernaculum counts
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Internal maternity colony counts
Photo credit: USFWS
Our Sample Design
NABat monitoring follows a master sample approach in which North America is divided into a series of 10 x 10 km (100 km ) grid cell frameworks. The generalized random-tessellation stratified (GRTS) survey design algorithm then assigns a spatially balanced and randomized ordering (GRTS order) to each 100 km cell within its respective framework. This probabilistic sampling design provides flexibility to researchers and accommodates common problems with long-term monitoring efforts like loss of access and changes in available resources by allowing sample site additions and deletions.
Grid cells are prioritized numerically; the lower the number, the higher the sampling priority. Cells can then be selected for monitoring following the GRTS order, ensuring both randomization and spatial balance. Monitoring within this standardized framework allows statistical inference to non-surveyed locations and ensures the validity of analyses at regional and range-wide scales using data collected by dozens of partners across the North American continent.
Partners are also encouraged to submit compatible legacy data (collected prior to the establishment of NABat) and found data (collected outside the formal survey design). NABat will use appropriate statistical techniques to integrate these data into syntheses of regional status and trends.
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Our History
Our History
Bats make up the second largest order of mammals, Chiroptera, and comprise one-fifth of all mammalian species. They perform numerous ecosystem services (insect suppression, pollination, seed dispersal) and provide enormous economic benefits by consuming agricultural pests. There are 47 bat species in the U.S. and Canada, eight of which are listed as Federally endangered or threatened. Another 18 are deemed species of concern within the states. Altogether, more than half the bat species in the U.S. and Canada are of current conservation concern.
Despite the importance of bats and growing concern about their status, prior to 2015 there was no program to conduct standardized monitoring of bat species across multiple taxa in North America. The need for such a program had been recognized for many years, but the discovery of white-nose syndrome (WNS), an emerging fungal disease, in the winter of 2006 renewed interest in the project. In the following years, the rapid spread of WNS and its associated mortality further prioritized the need to understand population trends where the disease was already present and to establish baseline data in uninfected areas. Furthermore, the National WNS Response Plan specifically called for the development of monitoring plans to determine differences in susceptibility among species and to identify which species are most vulnerable to extinction due to WNS.
It soon became evident that others in the bat research and management community were tackling similar issues, particularly the increase in bat fatalities associated with large industrial wind turbines. Because factors like WNS and wind turbines affect bat populations across political borders, it was determined that a comprehensive bat monitoring program for all 46 species shared among the United States, Canada, and Mexico was required. By monitoring population and distribution trends across North America, NABat will not only provide information about the impacts of WNS, but also inform land managers and policymakers about the impacts of wind energy development, climate change, habitat loss, and other unanticipated threats that may arise in the future.
Coordination Team
Brian Reichert
NABat Program Coordinator
Jordi Segers
NABat Coordinator Canada
Bethany Straw
NABat Assistant Program Coordinator
Dane Smith
Technical Outreach Coordinator
Jaclyn Martin
Technical Outreach Coordinator
Ben Gotthold
Computer Scientist
James Cox
Technical Monitoring Liaison
Brad Udell
Data Analyst
Our Team
NABat is a collaborative partnership to systematically document bat populations across North America. Our partners include local, federal, state, and provincial agencies, non-governmental organizations, and universities who are collecting monitoring data across the continent.
Core Planning Team
Jeremy Coleman
U.S. Fish and Wildlife Service
Jon Reichard
U.S. Fish and Wildlife Service
Kathi Irvine
U.S. Geological Survey
Wayne Thogmartin
U.S. Geological Survey
Susan Loeb
U.S Forest Service
Ted Weller
U.S. Forest Service
Tom Rodhouse
National Park Service
Michelle Verant
National Park Service
Mylea Bayless
Bat Conservation International
Winifred Frick
Bat Conservation International
Frank Quamen
Bureau of Land Management
Charles Francis
Canadian Wildlife Service
Cori Lausen
Wildlife Conservation Society, Canada
Eric Britzke
ERDC Environmental Laboratory
