No abstract

M7e conipared bat activity levels in the Coaslal Plain of South Carolina atnong 5 habitat types: forested riparian areas, clearcuts, young pine plat~tations, mature pine plantations, and pine savannas. We used time-expansion I-adio-microphones and integrated detectors to simultaneously monitor bat activity at 3 heights (30, 10, 2 mj in each habitat type. Variation in vegetative clutter among sanipling heights and arnttng habitat types allowed us to examine the differential effect of forest vegetation on the spatial activity patterns of clutter-adapted and openadapted bat species. Moreover, monitoring activit~~ at 30, 10, and 2 m permitted us to also compare bat activity above and below the forest canopy. We detected calls of 5 species 01-species groups: eastern red/Seminole bats (Lasiums bo~-ealis/ L. seminol'us) , eastern pipistrelles (Pipistrellus subfivus) , evening bats (iz5cticpiu~ hu?nerulis), big brown bats (Eptesicus fuscus), and hoary bats (Lasiul-us cinrrius). At 2 and 10 m, bat activity was concentrated in riparian areas, whereas we detected relatively low levels of bat activity in upland habitats at those heights. Activity was more evenly distributed across the landscape at 30 m. Bat activity levels above the forest canopy were almost 3 times greater than within or below the canopy. We detected significantly greater activity levels of 2 open-adapted species (hoary and big brown bats) above rather than within or be lo^^^ the forest canopy. However, activity levels of 2 clutter-adapted species (eastern red,'Seminole bats and eastern pipistrelles) did not differ above, within, or below the forest canopy Despite classification as a clutter-adapted species, evening bat activity was greater above rather than within or below the forest canopy. We believe our results highlight the importance of riparian areas as foraging habitat for bats in pine-dominated landscapes in the southeastern United Slates. Although acoustical surveys conducted below forest canopies can provide useful intitmiation about species composition and relative activity levels of bats that forage in cluttered environments, our results sl~owing activity above canopy suggest that such data may not accurately reflect relative activity of bats adapted to forage in more open conditions, and therefore may provide an inaccurate picture of bat community assemblage and foraging habitat use. JOURNAL OF WILDLIFE MANAGEMENT

During 2001, we used active acoustical sampling (Anabat I/) to survey foraging habitat relationships of bats on the Savannah River Site (SRS) in the upper Coastal Plain of South Carolina. Using an a priori information-theoretic approach, we conducted logistic regression analysis to examine presence of individual bat species relative to a suite of microhabitat, stand, and landscape-level features such as forest structural metrics, forest type, proximity to riparian zones and Carolina bay wetlands, insect abundance, and weather. There was considerable empirical support to suggest that the majority of the activity of bats across most of the 6 species occurred at smaller, stand-level habitat scales that combine measures of habitat clutter (e.g., declining forest canopy cover and basal area), proximity to riparian zones, and insect abundance. Accordingly, we hypothesized that most foraging habitat relationships were more local than landscape across this relatively large area for generalist species of bats. The southeastern myotis (Myotis austroriparius) was the partial exception, as its presence was linked to proximity of Carolina bays (best-approximating model) and bottomland hardwood communities (other models with empirical support). Efforts at SRS to promote open longleaf pine (Pinus palustris) and loblolly pine (P. taeda) savanna conditions and to actively restore degraded Carolina bay wetlands will be beneficial to bats. Accordingly, our results should provide managers better insight for crafting guidelines for bat habitat conservation that could be linked to widely accepted land management and environmental restoration practices for the region.