A bunch of more than ten bats squished in a rock crevice
October 25, 2022

Helping Endangered Bats Via Compensatory Mitigation

In partnership with government agencies and private partners, The Conservation Fund supports compensatory mitigation solutions that achieve positive conservation outcomes for wildlife, including endangered bats. When infrastructure development for wind power, energy transmission and transportation projects impact the natural habitats of endangered species, The Conservation Fund can offset those impacts through land conservation and management plans that protect the most critical habitats for bats.

Growing List of Endangered Bat Species

Beyond being amazing nocturnal, echolocating, flying mammals, bats provide essential natural services such as plant pollination, seed dispersal, and insect control. Unfortunately, bat populations have been declining due to habitat destruction and disease. The primary disease of concern is white-nose syndrome, which is a fungal disease that grows on bats’ skin, disrupts their hibernation and ultimately causes starvation and death.

A cluster of Indiana bats which are listed as endangered. Photo by Daniel Istvanko

There are 48 species of bats found in the United States and its territories, of which ten are listed as endangered and one as threatened (less concern) by the U.S. Fish and Wildlife Service (USFWS) due to drastic population decreases throughout their ranges (see Table 1). Sadly, that list is growing; the northern long-eared bat was upgraded to endangered and hoary bat has been proposed for listing as endangered. Experts speculate that the little brown bat and hoary bat, two of the most common and widespread bats, will also be proposed for listing as endangered in the future.

Table 1: Bat species of special concern in the United States

What happens after a species is listed as endangered, and how does it relate to our work at The Conservation Fund?

When a species becomes listed under the Endangered Species Act (ESA), new protections extend to the species’ occupied habitat. The ESA was signed into law with broad support in 1973 to prevent the extinction of imperiled species by conserving their habitat. The law requires federal agencies to ensure that their activities or activities of the public do not destroy or modify critical habitats.

When an infrastructure project, such as energy production or transmission, is proposed, developers work with the USFWS to avoid and minimize impacts to ESA-protected and ESA-listed species; however, some impacts are unavoidable. The ESA recognizes that there may be instances where there could be incidental harm to a species, and therefore includes processes to both reduce impacts and offset the effects of project development on protected species and their habitats.

Compensatory mitigation is required to offset the unavoidable impact on the species, and that is where The Conservation Fund plays an important role by providing the best conservation benefits when compensatory mitigation is required. As a national nonprofit conservation organization, we are uniquely chartered to provide land conservation to preserve natural, cultural and historical resources while supporting economic development. Our staff routinely works with partners from local communities, federal and state agencies, and other nonprofit organizations to identify the highest priority conservation opportunities where our expertise can be used to acquire lands for permanent conservation or place conservation easements on private lands to protect the identified conservation values.

We partner in two ways to implement compensatory mitigation. Most often, we partner with the regulatory agency to implement the agency’s priority conservation projects using funding from the developer whose project impacted the protected resource. Alternatively, we have contracted with the project developer to identify a project that would achieve the best conservation outcome to meet the developer’s compensatory mitigation requirements. Either way, The Conservation Fund is a trusted partner with the regulatory agency and collaborates to implement mitigation that permanently protects land or completes other conservation projects identified in the approved mitigation plan. We work flexibly with the regulatory agency to accomplish the goals of the compensatory mitigation requirements.

An example of our work demonstrates that conserving the unique and threatened habitat that endangered bats need to thrive truly is one of the most effective ways we can support the species. The Conservation Fund helped conserve 185 acres of significant Indiana bat habitat in Hannibal, Missouri utilizing compensatory mitigation funds from a nearby pipeline development. The property is now known as the Sodalis Nature Preserve and owned by the City of Hannibal. Earlier in 2024, USFWS conducted a population census within the former underground mine at Sodalis and counted an estimated 222,000 Indiana bats, which represents a more than 23percent increase from the 180,000 bats counted in 2019. These results are proof that compensatory mitigation can achieve great results, and we are excited to continue this important conservation work.

The Conservation Fund helped conserve 185 acres of significant Indiana bat habitat in Hannibal, Missouri utilizing mitigation funds from nearby pipeline development. Now known as the Sodalis Nature Preserve, the property is owned by the City of Hannibal and home to an estimated 222,000 Indiana bats, as well as several other bat species. Photo by Steve Orr

Bat Compensatory Mitigation

So what does all that mean for endangered bats? The Conservation Fund offers several options for meeting the requirements of bat compensatory mitigation, including an in-lieu fee program, project-specific mitigation and programmatic mitigation. All three options can help to achieve the best conservation outcome through consultation with the USFWS and relevant state regulatory partners.

The Conservation Fund and the USFWS developed the Range-wide Indiana Bat and Northern Long-Eared Bat In-Lieu Fee (Bat ILF) program to provide a practical mitigation option for unavoidable adverse impacts to Indiana bats and northern long-eared bats. The Conservation Fund is actively identifying high-priority lands for conservation that can benefit the recovery of these two bat species. As The Conservation Fund pools payments from developers impacting Indiana bat and northern long-eared bat habitat, it works with project partners to secure the best available opportunities for bat habitat conservation.

The Bat ILF program covers a total of 37 states and Washington DC. There are 22 states where the ranges of the Indiana bat and northern long-eared bat overlap, and an additional 15 states and Washing DC with only northern long-eared bat range.

The Conservation Fund will remain flexible about our approach to bat compensatory mitigation because the USFWS may require a different approach to mitigation if the tricolored bat and the little brown bat are proposed to be listed as endangered. We are creating new and alternative ways to implement compensatory mitigation solutions for the tricolored and little brown bats, including project-specific and new programmatic bat mitigation plans or pooled funds.

The infrastructure permit schedule will determine which solution will be the most practical and effective. A project-specific bat compensatory mitigation plan will take less time to develop and submit as part of the proposed Habitat Conservation Plan, but other alternatives may become available. While a programmatic bat mitigation plan may require additional time to develop, it would likely provide a better and more cost-effective conservation outcome. This is because several infrastructure projects could provide compensatory mitigation fees to create an economy of scale that would allow for larger habitat acquisitions and a more strategic approach to bat conservation. The Conservation Fund can administer either project-specific or programmatic bat compensatory mitigation plans to match project mitigation requirements with the most appropriate conservation projects that have been approved by our agency partner.

The tricolored bat can be found across most of the eastern half of the U.S. roosting in trees, caves, buildings, and other man-made structures. Their biggest threat is white-nose syndrome, which has caused declines of more than 90 percent in affected tricolored bat colonies and is currently present across 59 percent of the species’ range. Photo by Daniel Istvanko

The Conservation Fund is currently working with a USFWS field office to develop a programmatic bat mitigation plan that will likely be used first to mitigate wind energy infrastructure impacts to five different bat species, including Indiana, northern long-eared, tricolored, little brown, and gray bats. The proposed bat mitigation plan would become a mechanism that could be used for acquisition, protection and restoration of habitat as well as funding research that would be critical to improving the success of these bat populations. We anticipate that this could become a successful model for matching compensatory mitigation to the best conservation outcomes for bats.

The Conservation Fund will continue to lead conservation efforts for all bat species by connecting funding from diverse sources — including compensatory mitigation, philanthropic donations, grants and partnerships — to the best available bat conservation projects. We have proven that our creative, flexible and dependable approach is critical to the changing status of species protected by the Endangered Species Act. We look forward to hearing from those who are ready to partner with us to reverse the decline of bat populations and conserve important bat habitat.

Photo credits (from top of page): Daniel Istvanko

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Close up of white fungi