Stand-level bird response to experimental forest management in the Missouri Ozarks

Abstract

Long-term landscape-scale experiments allow for the detection of effects of silviculture on bird abundance. Manipulative studies allow for strong inference on effects and confirmation of patterns from observational studies. We estimated bird-territory density within forest stands (2.89–62 ha) for 19 years of the Missouri Ozark Forest Ecosystem Project (MOFEP), a 100-year experiment designed to study the effects of even-age and uneven-age management on wildlife. We spot-mapped territories of 15 species in 228 stands for 5 years before treatment and 14 years after treatment to assess the effects of stand-level silvicultural treatments (clearcut, select cut, thin, and no-harvest) applied within even-age, uneven-age, or no-harvest (control) management sites and year on avian territory density. We used 2 a priori contrasts to compare pre-treatment bird densities with densities during early (3–5 yr) and late (12–14 yr) post-treatment periods. The interaction of silvicultural treatment and year had significant effects on the densities of all 15 species. Densities of hooded warbler (Setophaga citrina), indigo bunting (Passerina cyanea), prairie warbler (Setophaga discolor), and yellow-breasted chat (Icteria virens) increased significantly 3–5 years post-treatment with the greatest changes in clearcuts, but densities 12–14 years post-treatment did not differ from pre-treatment densities. Densities of Acadian flycatcher (Empidonax virescens), wood thrush (Hylocichla mustelina), and especially ovenbird (Seiurus aurocapilla) had significant decreases in clearcut stands after treatment and lesser decreases in select cut or thin stands post-treatment. Densities of black-and-white warbler (Mniotilta varia), eastern wood-pewee (Contopus virens), and Kentucky warbler (Geothlypis formosa) increased in clearcut, thin, and select cut stands, but these increases were short-lived and sporadic by year after treatment. Densities of Acadian flycatcher and ovenbird remained lower in clearcut stands than no-harvest stands 13 years post-treatment. The results of this manipulative experiment were mostly consistent with our predictions of bird response to common silvicultural treatments in these forests. Managers can use these species-specific responses to silvicultural treatment to guide management decisions for target species or to balance management practices in a landscape to meet the needs of multiple species. © 2014 The Wildlife Society.