Effects of silvicultural treatments on Cerulean Warbler (Dendroica cerulea) abundance in southern Indiana

摘要

The Cerulean Warbler (Dendroica cerulea), a once common summer inhabitant and breeder in southern Indiana, has declined at both the local and continental population levels. Because Cerulean Warblers tend to nest in large deciduous trees, they are especially at risk due to deforestation of mature tree stands. Few studies have examined the effects of specific silvicultural practices (i.e., group and single tree selection harvesting methods) on the distribution and abundance of the Cerulean Warbler. During the summers of 2005 and 2006, Cerulean Warblers were surveyed within the Morgan-Monroe and Yellowwood state forests, as well as the Hoosier National Forest in southern Indiana. Three treatment types were surveyed; unharvested reference sites (stands 35-100+ years old) were compared with single tree selection treatments and treatments where a combination of group and single tree selection was used (stands 2-30 years old). Mean bird abundance was estimated from bird surveys to determine if trends exists between silvicultural regimes and Cerulean Warbler abundance. Cerulean Warblers were located in all treatment types, with no significant differences (p =0.654) in abundance among treatment types examined (unharvested - 0.36, single tree - 0.46, group and single tree combination - 0.36). These results suggest that uneven-age management practices, such as single tree and group selection harvesting, provide suitable breeding habitat for Cerulean Warblers.