Short-term effects of timber harvest on abundance territory characteristics, and pairing success of Ovenbirds in riparian buffer strips

In managed forests, riparian buffer strips typically are maintained to prot ect water quality. If properly designed, buffer strips also may act as wild life reserves. However, forest managers have lacked the information to deve lop standards for buffer strips to maximize benefits for wildlife species. We assessed the conservation potential of 20-, 100-, and 200-m wide buffers for an area-sensitive songbird in boreal mixed-wood forest in Alberta. We measured abundance, territory characteristics, and pairing success of Ovenb irds (Seiurus aurocapillus) at treatment and control lakes one year before and after upland timber harvest. After harvest, Ovenbirds were absent from 20-m buffer strips. Harvesting did not significantly influence abundance or territory size in 100-m or 200-m buffers, although territories generally b ecame narrower. Postharvest territory position did not change in 200-m buff ers, but territories in 100-m strips shifted lakeward and included more hab itat adjacent to the riparian edge than before harvest. Despite this shift in territory position, males that occupied 100-m strips successfully attrac ted mates. High availability of regional forest cover may have muted the mo re pronounced effects of habitat alteration observed in other studies. Our research is among the first to evaluate individual behavioral responses to the creation of forest edges. Our data indicate that 20-m buffer strips do not support breeding Ovenbirds, whereas 100- and 200-m buffers retain Ovenb irds during the year following harvest. Longterm harvest effects may differ from those we monitored and require study, particularly as timber extracti on increases in the boreal mixed-wood ecoregion.