Breeding Bird Community Continues to Colonize Riparian Buffers Ten Years after Harvest

• Published in: PloS one Vol. 10; no. 12; p. e0143241
• Main Authors: Pearson, Scott F, Giovanini, Jack, Jones, Jay E, Kroll, Andrew J
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 04.12.2015; Public Library of Science (PLoS)
• Subjects: Abundance; Alnus rubra; Animal breeding; Animals; Aquatic ecosystems; Aquatic environment; Associated species; Bayes Theorem; Bayesian analysis; Bird migration; Birds - physiology; Breeding; Buffers; Clearcutting; Communities; Conservation; Conservation of Natural Resources - methods; Ecosystem; Environmental aspects; Experimental design; Fauna; Fisheries management; Flora; Forests; Harvest; Land use; Local extinction; Logging; Natural resources; Northwestern United States; Pearson, Jack; Population decline; Pseudotsuga menziesii; Riparian areas; Riparian buffers; Riparian ecology; Riparian environments; Riparian land; River networks; Rivers; Silvicultural practices; Silviculture; Species extinction; Species richness; Terrestrial environments; Thuja plicata; Trees; Tsuga heterophylla; Northwestern United States; United States; Oregon; United States > US
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0143241

Riparian ecosystems integrate aquatic and terrestrial communities and often contain unique assemblages of flora and fauna. Retention of forested buffers along riparian habitats is a commonly employed practice to reduce potential negative effects of land use on aquatic systems. However, very few studies have examined long-term population and community responses to buffers, leading to considerable uncertainty about effectiveness of this practice for achieving conservation and management outcomes. We examined short- (1-2 years) and long-term (~10 years) avian community responses (occupancy and abundance) to riparian buffer prescriptions to clearcut logging silvicultural practices in the Pacific Northwest USA. We used a Before-After-Control-Impact experimental approach and temporally replicated point counts analyzed within a Bayesian framework. Our experimental design consisted of forested control sites with no harvest, sites with relatively narrow (~13 m) forested buffers on each side of the stream, and sites with wider (~30 m) and more variable width unharvested buffer. Buffer treatments exhibited a 31-44% increase in mean species richness in the post-harvest years, a pattern most evident 10 years post-harvest. Post-harvest, species turnover was much higher on both treatments (63-74%) relative to the controls (29%). We did not find evidence of local extinction for any species but found strong evidence (no overlap in 95% credible intervals) for an increase in site occupancy on both Narrow (short-term: 7%; long-term 29%) and Wide buffers (short-term: 21%; long-term 93%) relative to controls after harvest. We did not find a treatment effect on total avian abundance. When assessing relationships between buffer width and site level abundance of four riparian specialists, we did not find strong evidence of reduced abundance in Narrow or Wide buffers. Silviculture regulations in this region dictate average buffer widths on small and large permanent streams that range from ~22-25 m. Guidelines for this region are within the range of buffers included in our study, in which we observed no evidence for avian species loss or for a decline in species abundance (including riparian associated species).