The National Academies

NCHRP 25-25/Task 100 [Pending]

Compilation of Existing Data on Northern Long-Eared and Other Cave-Dwelling Bat Habitat and the Roadside Environment
[ NCHRP 25-25 (Research for the AASHTO Committee on Environment and Sustainability) ]

  Project Data
Funds: $125,000
Contract Time: 12 months
Staff Responsibility: Lori L. Sundstrom



The Indiana bat (Myotis sodalis) is a federally listed endangered species, and the Northern long-eared bat [Myotis septentrionalis] (NLEB) is a species proposed for Federal listing under the Endangered Species Act of 1973 (ESA). These species' ranges include most of the eastern U.S. The Indiana Bat is found in 22 states, and has been considered endangered since 1967. The NLEB is found in 39 states; it was proposed for listing as endangered under the ESA in October 2013. The listing is anticipated to become final in April 2015.


Research on the biology and ecology of the Indiana bat has been conducted since the late 1960s. Over the years, a great deal of survey information has been collected across the multiple states where it occurs. These surveys have often employed acoustic monitoring or mist netting to capture bats to demonstrate the presence or absence of the Indiana bat as part of Section 7 consultation under the ESA. During these surveys, data on other bat species, including the NLEB and other cave-dwelling bats have also been recorded.


Both the Indiana bat and the NLEB can be found roosting singly or in colonies in trees, caves and mines throughout the summer months and use caves and mines as hibernacula during the winter months. The populations of these bats are declining as a result of white-nose syndrome, a deadly fungal disease that is spreading across the U.S. (USFWS 2014b). There is little information compiled on the particular characteristics of wooded areas that the NLEB may use in the summer months, making it difficult to determine the potential impact on the species of construction projects such as lane additions or shoulder widening that involves tree removal along long linear distances.


This research is urgent because of the impending listing of the NLEB as a federal endangered species in 39 states. Additional species such as the little brown bat (Myotis lucifugus) and the tri-colored bat (Perimyotis subflavus) may be added to the federal list as well. The listing of these species will dramatically affect the workload of highway agencies in their efforts to evaluate impacts of tree removals on bats. Tree removal is commonly required for both construction and maintenance along roadsides; so many projects are affected by the possibility of informal and formal consultation with USFWS.


Research Objective:


The objective of this research is to produce information that will assist state departments of transportation (DOTs) in discussions with the US Fish and Wildlife Service (USFWS) as both agencies work toward clarifying the regulatory process and identifying strategies for streamlining compliance with the Endangered Species Act (ESA).  This will include (1) the creation of a database of existing survey data where NLEB and other cave dwelling bats were successfully detected during surveys for Indiana bats from the 22 states where the Indiana bat is listed, and (2) conducting an analysis of the observations to obtain useful information regarding the NLEB and other bats’ important habitat characteristics and use of groups of trees and wooded areas in close proximity to roads.  Readily available survey data collected for Indiana bats will be compiled and an analysis of the data collected on other bat species—other bat species that were detected during the surveys—will be conducted to determine what else can be learned about the NLEB and other cave-dwelling bats, particularly regarding their use of roadside environments. Based upon this information, potential mitigation strategies will be identified.

To create a link to this page, use this URL: