Effects of salvage logging on avian nest survival in beetle-killed forests

Abstract

Information about the immediate and potentially prolonged impacts of salvage logging is needed to develop prescriptions that maintain forest productivity, reduce the risk of catastrophic fires, and conserve biological communities. Most salvage logging studies have investigated post-fire salvage, often clearcutting, and impacts documented in these studies may be more severe than selective logging prescriptions applied to forests affected by beetle outbreaks. We evaluated the effects of selective salvage logging on avian nest survival in beetle-killed lodgepole pine (Pinus contorta) forests on the Fremont and Winema National Forests, south-central Oregon, USA, 1997–1999. Using logistic-exposure models, we found that nest survival for weak (period nest survival: 0.64; 95% CL: 0.50, 0.75) and strong (period nest survival: 0.71; 95% CL: 0.46, 0.87) cavity nesters was significantly higher than for ground nesters (period nest survival: 0.31; 95% CL: 0.18, 0.46), while nest survival for open cup nesting birds (period nest survival: 0.57; 95% CL: 0.47, 0.66) was intermediate. We did not find significant differences in nest survival for American robin (Turdus migratorius), chipping sparrow (Spizella passerine), dark-eyed junco (Junco hyemalis), dusky flycatcher (Empidonax oberholseri), mountain chickadee (Poecile gambeli), or yellow-rumped warbler (Dendroica coronata) (these six species comprised ∼80% of the sample). Our results suggest that, unlike post-fire salvage logging, selective harvesting prescriptions after beetle outbreaks may be suitable for meeting multiple management objectives, including generating a flow of commodities and maintaining avian nest survival rates.