Breeding Bird Assemblages Inhabiting Riparian Buffer Strips in Newfoundland, Canada

Abstract

Throughout most of the North American boreal forest, riparian buffer strips are left during clearcutting. Although this practice is considered a means to reduce adverse effects of timber harvesting on terrestrial fauna, little research has been conducted to quantify the extent to which buffer strips are used by wildlife. We compared breeding bird assemblages (grouped into 5 habitat guilds) in undisturbed shoreline habitats with those in 20-50-m-wide riparian buffer strips in balsam fir (Abies balsamea) forests on insular Newfoundland, Canada. Total avian abundance was higher along buffer strips than undisturbed shorelines because of a greater abundance of ubiquitous species and species associated with clearcut edge habitats. Abundances of forest generalist, interior forest, and riparian species were similar between buffers and controls. Riparian buffer strips provided habitat for a diverse avian assemblage and maintained many riparian and woodland species in areas of intensive clearcutting. Counts of riparian species did not increase in wider buffers, likely due to their association with habitats adjacent to water, which do not increase in proportion to strip width. Total numbers of interior forest birds, many species of which may be declining in northeastern North America, may increase in wider buffers, but these species were rare even in the widest strips sampled (40-50 m) when compared to local interior forest habitat. Furthermore, 3 of 6 species in the interior forest guild were not observed in any buffer strip. While riparian conservation is essential, separate but complementary conservation strategies clearly are required to protect riparian and interior forest species.