Bats in Forests Managed for Wildlife

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The Challenge: Within the Mississippi Alluvial Valley (MAV), forest managers may prescribe variable retention silvicultural treatments within bottomland hardwood forests on public lands to improve forest conditions (i.e., structural heterogeneity, species composition, and senescence) for priority wildlife species. This is referred to as wildlife-forestry silviculture. However, concerns have been voiced regarding loss of available cavities for wildlife use if hollow trees are removed or become inaccessible due to management. Of particular concern are bat species and their occurrence and use of forests subjected to wildlife-forestry silviculture.

The Science: Through assessment of bottomland forests on National Wildlife Refuges, and other public conservation lands in the MAV, we are evaluating the occurrence, and relative abundance, of bat species within forest stands after prescribed harvests to improve habitat for wildlife, and stands not subjected to harvest. Bat species are being identified through use of acoustical bat detectors. An index of flying nocturnal insects (the prey of many bat species) is concurrently being assessed. Because habitat conditions change over time after harvest, bat surveys are taking place in stands from 1 to 12 years after harvest.

The Future: Indices of bat and nocturnal insect abundance are being related their occurrence in managed forest stands relative to years after wildlife-forestry based habitat enhancement harvest. By exploring the relationship between forest habitat structure and abundances of bats and insects, we hope to develop a region-wide understanding of the effects silvicultural treatments prescribed and implemented to improve forest habitat for wildlife in bottomland hardwood forests on bat occurrence and use of these bottomland forests.