APPENDIX I: Projects that clear ≥20 acres of contiguous forest or fragment a connective corridor between two or more suitable forest patches

Indiana bats and northern long-eared bats (NLEB) are forest dependent and require large, contiguous1 forested tracts for roosting, commuting and foraging. The Service defines suitable roosting habitat for Indiana bats as forest patches with trees of 5 inches in diameter at breast height (DBH) or larger, and suitable roosting habitat for NLEB as forest patches with trees of 3 inches DBH or larger. However, early successional habitat with small diameter trees may be used as important foraging and/or commuting habitat by listed bats. Projects that clear ≥20 acres of contiguous forest have potential to adversely affect or indirectly take federally listed bats even if the clearing is done during the inactive season, due to the extensive removal of available habitat. Therefore, projects that clear ≥20 acres of contiguous forest warrant project-specific consideration and coordination with the Service. 

Based on life history information and available literature for Indiana bats (e.g., average foraging distances and occupied forest patch sizes), the Service believes that it is unlikely that an isolated forest stand of 10 acres or less would provide sufficient resources for an Indiana bat (click here for more information). However, available data indicate that Indiana bats may infrequently use isolated forest patches as small as 5.6 acres (Keith Lott, personal communication). The Michigan Ecological Services Field Office believes a conservative minimum patch size of 5 acres is appropriate for Indiana bats and NLEB. Although listed bats rarely traverse non-forested areas of 1000 feet or more, they are frequently observed using vegetated corridors, such as tree lines, to travel among suitable forest patches. Because they may connect important foraging and roosting habitats, removal of forested corridors (regardless of size/area of corridor, as long as it connects suitable forest patches) could severely fragment available habitat and result in adverse effects or indirect take of listed bats. Therefore, projects that remove connective corridors between forest patches warrant project-specific consideration and coordination with the Service. (For more information, refer to the Indiana Bat Section 7 Section 7
Section 7 Consultation The Endangered Species Act (ESA) directs all Federal agencies to work to conserve endangered and threatened species and to use their authorities to further the purposes of the Act. Section 7 of the Act, called "Interagency Cooperation," is the mechanism by which Federal agencies ensure the actions they take, including those they fund or authorize, do not jeopardize the existence of any listed species.

Learn more about Section 7 and Section 10 Guidance for Wind Energy Projects, available here).