Bat activity and roost-site selection on an intensively managed pine landscape with forested corridors in the Lower Coastal Plain of South Carolina

Abstract

I used ultrasonic acoustic detectors and radiotelemetry to investigate relationships between bats and forested corridors on an intensively managed landscape in the Lower Coastal Plain of South Carolina. I modeled bat activity and roost-site selection with logistic regression and used Akaike’s Information Criteria for small samples (AICc) to evaluate and select the most parsimonious model or set of models. Using Anabat II detectors, I recorded 16,235 bat echolocation call sequences from 320 sites along 32 pairs of corridor systems. I compared models relating occupancy of 6 bat species to site-level characteristics. My results indicated higher occupancy rates for all species along edge compared to interior corridor or adjacent stands. Although I found few differences among species with respect to site-level characteristics, bat activity was positively related with corridor overstory height and negatively related to adjacent stand age. Using radiotelemetry, I tracked 53 adult evening bats (Nycticeius humeralis) to 75 summer roosts. Evening bats roosted in a variety of structures, including cavities in hardwood trees and fork-topped loblolly pines (Pinus taeda). Approximately 40% of male and 20% of female roosts were located in corridor stands. Both male and female evening bats tended to select roost-sites in mixed-pine hardwood stands. I also radiotracked 27 adult Seminole (Lasiurus seminolus) bats to 90 summer roosts. Seminole bats roosted exclusively in the canopy of live loblolly pines. Over 60% of both male and female roosts were located in corridor stands. Proximity to edge was negatively related to both male and female Seminole bats. I tracked 20 male Seminole bats to 71 winter roosts of varying structures, including pine needle clusters and leaf litter. On warmer nights, male Seminole bats selected taller trees in mature forest stands, but when minimum nightly temperatures were <4û C, bats typically roosted on or near the forest floor in mid-rotation stands. Although I found similarities with respect to bat activity along corridor systems, roost-site selection differed between sex, species and season. Overall, results suggest a positive response by bats to forested corridors on an intensively managed pine landscape.