Forest Succession and Maternity Day Roost Selection byMyotis septentrionalisin a Mesophytic Hardwood Forest

Alexander Silvis,W Mark Ford,Eric R Britzke,Joshua B Johnson,Nathan R Beane

doi:10.1155/2012/148106

Abstract

Conservation of summer maternity roosts is considered critical for bat management in North America, yet many aspects of the physical and environmental factors that drive roost selection are poorly understood. We tracked 58 female northern bats (Myotis septentrionalis) to 105 roost trees of 21 species on the Fort Knox military reservation in north-central Kentucky during the summer of 2011. Sassafras (Sassafras albidum) was used as a day roost more than expected based on forest stand-level availability and accounted for 48.6% of all observed day roosts. Using logistic regression and an information theoretic approach, we were unable to reliably differentiate between sassafras and other roost species or between day roosts used during different maternity periods using models representative of individual tree metrics, site metrics, topographic location, or combinations of these factors. For northern bats, we suggest that day-roost selection is not a function of differences between individual tree speciesper se, but rather of forest successional patterns, stand and tree structure. Present successional trajectories may not provide this particular selected structure again without management intervention, thereby suggesting that resource managers take a relatively long retrospective view to manage current and future forest conditions for bats.

Highlights

Prior to the onset of white-nose syndrome (WNS) in North America [1], northern bats (Myotis septentrionalis) were common in most forest types in the eastern United States and southern Canada [2,3,4,5,6,7,8,9]
Transmitters were attached to all 58 adult female northern bats; mean transmitter retention time was 4.1 days
The number of uses of an individual day roost by tagged bats ranged from 1 to 84, with a mean of 2.55 ± 0.79, where use is defined as the sum of presences of all bats using that day roost

Summary

Introduction

Prior to the onset of white-nose syndrome (WNS) in North America [1], northern bats (Myotis septentrionalis) were common in most forest types in the eastern United States and southern Canada [2,3,4,5,6,7,8,9]. Northern bat foraging activity consistently has been greatest in closed-canopy forests [5, 10,11,12,13] and maternity roosts and roost areas of live trees and/or snags are typically located in upland forests [4, 7, 11, 14, 15]. Management for Myotine bats in North America often is based on the conservation of summer maternity roosts and winter hibernacula [16, 17]. Consensus is that northern bat maternity colonies typically use snags or decaying live trees with cavities or loose/exfoliating bark and that management efforts should focus on ensuring that suitable roosts are maintained on the landscape long term [4, 7, 11]

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Discussion

Conclusion