Effect of trail users at a maternity roost of rafinesque's big-eared bats

While bat-roosting sites continue to be targets of vandalism. Hood Branch Rock Shelter in Natural Bridge State Park, Kentucky, provides habitat for Corynorhinus rafinesquii (Rafinesque's big-eared bat). The shelter lies immediately adjacent to a hiking trail (Upper Loop Trail): therefore, the bats are potentially subject to disturbance by park visitors. This study monitored the behavior patterns of park visitors using the trail for potential disturbance effects at the shelter, and compared these data to population size and activity patterns of C. rafinesquii inhabiting the shelter from March to September 1998. Data indicate that a bypass trail directed many visitors away from the entrance to the shelter, but some visitors used the trail adjacent to the shelter and exhibited behavior potentially disruptive to the bats. The shelter was occupied by a maternity colony of Corynorhinus rafinesquii from late April to mid-July, a period in which access to the shelter was restricted due to debris and washouts along the trail from a severe storm in winter 1998. However, the shelter was abandoned by the bats within two weeks after the trail was cleared of debris. Although cause and effect cannot be directly inferred from collected data, the likelihood that the bats abandoned the shelter because of human intrusion is strong. The suitability of this shelter as a maternity roost of C. rafinesquii may be jeopardized by park visitors hiking the adjacent trail, suggesting closure of the Upper Loop Trail as the most viable option for protecting C. rafinesquii in Hood Branch Rock Shelter.