Bats have had a PR problem for millennia. They have been maligned as omens of evil, carriers of disease and many people just simply fear or hate them.
Despite this perception, the fact remains that bats are extremely important to every ecosystem they inhabit, they are critical components of the agricultural industry and they have a significant, positive impact on public health (despite unfounded fears of disease). In an agriculturally intensive region like the Southern Tier, the economic benefits of bats are important to consider.
Insectivorous bat species reduce the potential for mosquito-borne illness by consuming pathogen-spreading insects. They control crop-destroying pests as well as insects that impact natural areas. For example, little brown (Myotis lucifugus) and big brown bats (Eptesicus fuscus) consume large numbers of mosquitos.
In a 2002 study, a colony of 150 big brown bats was estimated to control the following number of agricultural pests in just one year: 600,000 cucumber beetles; 33,000,000 rootworms; 335,000 stink bugs; 194,000; scarab beetles; and 158,000 leafhoppers. This equates to a decrease in insect populations of more than 225,000 per bat annually. The impact of this one species of bat affects crop harvests of cucumbers, corn, soybeans, cotton, potatoes, apples, as well as lawn and nursery industries by driving pest populations down.
A 2011 study estimated that bats provide $22.9 billion annually in ecosystem services in the United States, with many agricultural counties of the nation benefiting between $20 million and $73 million annually. Bats provide the bulk of their services in the early part of the growing season, which can result in delayed use of toxic agricultural pesticides. Delaying pesticide use also means financial savings to the farmer who uses less chemicals. Around 70% of the world’s more than 1,400 bat species are insectivores, so parallels with this level of insect control are found across the globe.
A major issue affecting bat populations in eastern North America is white-nose syndrome (WNS), which is caused by the non-native fungus Psuedogymnoascus destructans. This disease has killed nearly 6 million bats in the northeastern U.S., including Western New York, and has caused one of the most precipitous declines in wildlife in modern history.
Wind turbines, through direct collisions and barotrauma, kill hundreds of thousands to millions of bats annually in the U.S., a level of mortality on par with WNS.
Both sources of mortality affect the two main groups of bats here differently. Wind energy predominately kills tree-dwelling migratory bats. For example, hoary bats (Lasiurus cinereus) are expected to see 90% declines in coming years attributed to wind-energy-related mortality. WNS affects cave-hibernating species, causing 90-99% declines in the last decade. This is why the northern long-eared bat (Myotis septentrionalis) is listed as threatened under the Endangered Species Act. It is now extremely rare here, but there remain documented colonies of this species in the area. Northern long-eared bats are also killed by wind turbines.
Plans to develop a large-scale wind-energy facility in Farmersville, Freedom, Centerville, Rushford and Arcade — a 106-square-mile project area — put these colonies at risk.
There are nine documented maternity roost sites in seven unique locations within the project area. A maternity roost for bats is where females congregate annually during the summer season to communally raise their pups. These roosts are an extremely critical component for a rare species like the northern long-eared bat. The fact that there are documented roost sites still in Cattaraugus and Allegany counties is cause for joy — however these bats are in jeopardy.
The declines of such important mammals should be concerning to all. Love them or hate them, the fact remains that humans cannot survive without them. As the preeminent bat biologist and photographer, Dr. Merlin Tuttle, has said, “We should fear a world without bats more than we should fear bats themselves.”
Many of our favorite crops are dependent on bats, and the insects they control destroy our food resources and impact public health. You don’t have to want them to live in your home with you to appreciate that.
The proposed Alle-Catt wind energy facility is projected to kill between 26,000-39,500 bats. These beleaguered species’ populations cannot sustain that rate of mortality, and we ignore this fact at our own peril.
(Jonathan Townsend is a doctoral student in the Department of Geography, University at Buffalo, and he’s manager of conservation and restoration at the Roger Tory Peterson Institute of Natural History.)