Long‐Term Effects of Group‐Selection Timber Harvesting on Abundance of Forest Birds

Abstract

Relatively few studies have examined the ecological effects of group-selection timber harvesting, and nearly all have been short-term and have lacked experimental manipulations that allow pre- and posttreatment comparisons. We have been documenting the effects of a group-selection timber harvest on bird abundance in a Maine forest for 24 years (preharvest, 1983-1987; postharvest, 1988-2006). Here we characterized the trends in bird abundance over the first 20 years of the study in the managed and control halves of the 40-ha study area. Species responses to the group-selection harvest were idiosyncratic, but in general the mature-forest bird community was retained and species dependent on early successional habitat temporarily (</=8 years) benefited. The Eastern Wood-Pewee (Contopus virens), Winter Wren (Troglodytes troglodytes), Pine Warbler (Dendroica pinus), and White-throated Sparrow (Zonotrichia albicollis) increased in abundance in the managed half of the study area following timber harvest, whereas the Veery (Catharus fuscescens) decreased. The Black-and-White Warbler (Mniotilta varia), Nashville Warbler (Vermivora ruficapilla), and Common Yellowthroat (Geothlypis trichas) responded positively to harvesting, as indicated by decreases in abundance in the control area and more protracted declines or stable abundances in the managed area. This study constitutes the longest experimental investigation to date of the effects of a group-selection harvest on birds and thus provides important information on the strength, direction, and duration of temporal changes in bird populations following forest management.