Abstract

Management shortcuts in conservation biology, like the umbrella species concept, have been debated worldwide. Umbrella species have been used to identify and delineate protective areas, but habitat requirements of umbrella species can also provide tangible targets in ecological restoration. In Sweden, forest habitats have been restored for the white-backed woodpecker (WBW, Dendrocopos leucotos) under the assumption that it will benefit other habitat-associated (background) species. In this thesis, the umbrella species concept was evaluated based on the response of wood-inhabiting (saproxylic) beetles to forest restoration for the WBW. The WBW is a top-predator in saproxylic food webs associated with broadleaved trees, but it is also critically endangered in Sweden because of commercial forestry practices that disadvantage broadleaved trees and reduce dead wood availability. Spruce trees (Norway spruce, Picea abies) were selectively harvested during forest restoration to make way for broadleaved trees like birch (Betula spp.) and European aspen (Populus tremula). Some broadleaved trees were also killed to create high-stumps (snags) and downed logs. Commercially managed forests were compared with restored forests; either directly in comparative studies, or before and after forest restoration. Two types of flight-intercept traps were used to catch saproxylic beetles: IBL2-traps and trunk-window traps. Results presented in this thesis show that habitat requirements of an umbrella species can be used to guide forest restoration. There were many beneficiary species at the stand-level. Commercially managed and restored forests were inhabited by different communities of saproxylic beetles, and species positively associated with broadleaved trees and sun-exposed substrates were particularly responsive. This was reflected by an increased species richness and abundance. Several near-threatened and vulnerable species were also attracted to substrates created for the WBW. This shows that efforts to bring back the WBW can benefit other resource-limited groups of conservation concern. Saproxylic beetles might even facilitate restoration efforts since many important prey species for the WBW were attracted to restored sites. Umbrella species, like the WBW, will require landscape-level efforts to recover. This is a strength of the umbrella species concept, but also a weakness since landscape-level efforts are time consuming. The WBW is still struggling in Sweden, and failed attempts to re-establish viable populations might undermine conservation incentives. Early signs of progress, however, are sometimes provided by less demanding species, like many saproxylic beetles in this thesis. Background species can also provide much needed examples of restoration success at the stand-level.

Keywords

Broadleaved trees; Forest; Management; Restoration; Saproxylic beetles; Sweden; Umbrella species; White-backed Woodpecker

Published in

ISBN: 978-91-576-9271-9, eISBN: 978-91-576-9272-6
Publisher: Department of Wildlife, Fish, and Environmental Studies, Swedish University of Agricultural Sciences

SLU Authors

• Bell, David

  • Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Forest Science
Ecology


Permanent link to this page (URI)

https://res.slu.se/id/publ/65584