Eggers, Sönke
- Department of Ecology, Swedish University of Agricultural Sciences
- Uppsala University
Research article2014Peer reviewed
Differential demographic responses of sympatric Parids to vegetation management in boreal forest
Eggers, Sönke; Low, Matthew
Abstract
Large-scale removal of small-diameter trees (i.e. thinning from below) in boreal forest can diminish niche diversity for birds that rely on a well-developed understory for nesting and foraging. Yet, few studies have examined how reduced niche diversity in managed forests affects fitness measures in closely-related species and the ability of competing species to co-exist. We related forest thinning to population trends of the willow tit Poecile montana (declining) and its dominant competitor the crested tit Lophophanes cristatus (stable), and conducted a 3-year comparative study to determine how variation in understory spruce density differentially influences survival and reproduction in these species. In line with our prediction that crested tits would gain resource priority under conditions of reduced forest understory complexity, willow tits and their nestlings suffered a disproportionate decline in both nest and adult survival prospects relative to crested tits as understoiy spruce density declined. Willow tits also had increased numbers of tail feather fault bars with decreasing understory complexity, further supporting the idea that willow tits suffer from food shortage and increased predation risk in areas of reduced understory. The long-term population declines of willow tits in boreal forest appears linked to large scale harvest of small-diameter spruce trees that provide important understory vegetation. A patchy arrangement of different thinning treatments through 'Understory Retention Thinning' (URT) may provide a cost-effective way to restore long-term structural complexity and biodiversity in densely stocked conifer stands. (C) 2014 Elsevier B.V. All rights reserved.
Keywords
Commercial thinning; Vegetation management; Variable density thinning; Niche diversity; Social dominance; Parids
Published in
Forest Ecology and Management
2014, volume: 319, pages: 169-175
Publisher: ELSEVIER SCIENCE BV
SLU Authors
Low, Matthew
- Department of Ecology, Swedish University of Agricultural Sciences
- Department of Ecology, Swedish University of Agricultural Sciences
UKÄ Subject classification
Behavioral Sciences Biology
Zoology
Evolutionary Biology
Publication identifier
- DOI: https://doi.org/10.1016/j.foreco.2014.02.019
Permanent link to this page (URI)
https://res.slu.se/id/publ/63455