The State of the Bats in North America

Bats are fascinating animals that play essential roles in ecosystems around the world (except the Arctic, Antarctic, and some remote islands). All bat species in Canada eat insects and contribute to population control of forest and agricultural pest species. In other parts of North America (and the world), there exist bat species that consume nectar and fruit as well. These species play important roles in pollination and seed dispersal, keeping forests healthy and aiding in reforestation.

However, bats around the world are facing an increasing number of threats to their populations and many of these threats are directly caused by human influence. Understanding the threats to bats and the state of North American bat species is an important piece in knowing which bat species need additional protection and how to provide this protection.

Several bat species of eastern Canada: top left, little brown myotis; top middle eastern red bat; top right, tri-colored bat; middle left, northern myotis; middle, myotis species; middle right, eastern small-footed bat; bottom left, silver-haired bat; bottom middle, big brown bat; bottom right, hoary bat.

The Canadian Wildlife Health Cooperative, as a member of the North American Bat Conservation Alliance (NABCA), co-authored a new publication on the State of the Bats in North America. This manuscript, published in the Annals of the New York Academy of Sciences, was a collaboration between various government and non-government partners across Canada, the United States of America, and Mexico.

While species status assessments are typically limited by the availability (or lack of) published literature on species, NABCA conducted an expert elicitation to assess bat species in North America. Species’ status evaluations were conducted by 102 experts across the continent. All 17 bat species in Canada and an additional 27 unique species in the US were assessed, as well as a total of 89 of Mexico’s 142 bat species, with many species being assessed separately in two or all three countries.

NatureServe assessment methods were used to evaluate each species by country using range extent, population size, short-term population trend, and threat impact for 44 threats from the International Union for Conservation of Nature (IUCN) Threats Classification Scheme.

Silver-haired bat

Overall, the expert elicitation indicated that 53% of North American bat species are considered at risk of population decline or extinction in the next 15 years and 90% are estimated to have populations that likely decreased over the past 15 years. In Canada, 14 of the 17 bat species were considered at risk through expert assessment.

Top threats to bats identified by experts include: drought as a cause of climate change, habitat conversion for agriculture, collision with wind turbines for renewable energy production, and the fungal disease white-nose syndrome, with the last two considered to have the most significant impact on Canadian bat populations.

The push for renewable energy sources to curb global climate change is causing a dramatic increase in wind energy production. Unfortunately, collision of bats with wind turbines is a major threat to several bat species, especially those species that migrate along the paths on which these wind energy facilities are typically built. In Canada, the migratory hoary bat, eastern red bat, and silver-haired bat are most impacted by this threat. The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) has recommended to the federal government that these three species should be listed as endangered under the Species at Risk Act.

 

White-nose syndrome is caused by a fungus accidentally introduced to North America from Europe. The disease affects hibernating bat species and is found throughout almost all of the Canadian and U.S. ranges of hibernating bats. While the disease appears to be able to affect most hibernating bat species, the three species most severely affected are little brown myotis, northern myotis, and tri-colored bat; all three are federally listed as endangered under the Canadian Species at Risk Act.

The published manuscript discusses the importance of effective management of at-risk species requiring coordinated, interagency, and inter-jurisdictional efforts by cross-boundary organizations sharing a goal of species protection. The national bat health program of Canada and the white-nose syndrome response programs of the United States are an example of such cross-jurisdictional efforts that effectively mitigate major threats to at-risk bat species.

Presenting the State of the Bats in North America helps to increase our understanding of growing threats and lessons from effective conservation initiatives. Protective power through governmental species listing and targeted efforts to change public attitude towards bats are listed as valuable tools to increase support for bats across North America. The CWHC will continue to work with NABCA and partners in government, academia, and others to understand the needs of at-risk bat species and facilitate threat mitigation and recovery actions to not only prevent species extinction, but to enable bat populations and habitat in Canada to thrive.

Story and photos by Jordi Segers, National Bat Health Program Coordinator, CWHC National Office

Link to publication: https://nyaspubs.onlinelibrary.wiley.com/doi/10.1111/nyas.15225

Link to State of the bats report: https://digital.batcon.org/state-of-the-bats-report/2023-report/

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