Standing deadwood for keystone bird species in the eastern boreal forest: Managing for snag dynamics

Abstract

Extensive even-aged management of the boreal forest and its consequences on the loss of late-seral stages (>100 years) is raising concerns about the future of organisms associated with standing deadwood. The considerable reduction of deadwood not only at the stand but at the landscape level is considered to be one of the principal causes of biodiversity loss in managed forest ecosystems worldwide. Ecosystem-oriented management approaches propose a fundamental change in forestry practices whereby live and dead tree retention becomes an important consideration in forest harvesting. We use woodpecker assemblages and their association with standing deadwood for both nesting and foraging to emphasize the importance of the entire range of snag degradation stages for maintenance of key ecological processes in habitat remnants of managed landscapes. We argue that bridging foraging and nesting knowledge of woodpecker's snag requirements can refine conservation objectives for deadwood retention in the boreal forest.Key words: deadwood, woodpeckers, hole-nesting community, late-seral forests, keystone species, foraging and nesting tree requirements, food webs, nest webs, snag management RÉSUMÉ L'aménagement équien de la forêt boréale transforme le couvert forestier notamment en réduisant la proportion de forêts âgées (>100 ans). Cette diminution des forêts âgées s'accompagne d'une baisse considérable du bois mort à l' échelle des peuplements et des paysages, ce qui est considérée comme l'une des principales causes de perte de diversité biologique dans les forêts aménagées à l' échelle mondiale. Les approches écosystémiques proposent un changement fondamental en foresterie, soit que la rétention des arbres vivants et morts dans les forêts aménagées devient une considération importante en aménagement forestier. Dans cet article, nous utilisons les assemblages de pics et leurs relations avec le bois mort sur pied pour statuer sur l'importance de conserver le spectre complet de stades de dégradation du bois mort dans les habitats résiduels des territoires aménagés pour maintenir les fonctions écologiques des pics, un groupe d' espèces clés dans les forêts âgées. Nous considérons l'importance de faire les liens entre les besoins d'alimentation et de reproduction des pics pour raffiner les objectifs de conservation du bois mort en forêt boréale. For personal use only.

Bird and beetle assemblages in relict beech forests of central Italy: a multi-taxa approach to assess the importance of dead wood in biodiversity conservation

“…In our analysis, dead wood of the first class decay represented by large branches on the ground or standing dead trees and stumps belonging to the third class decay affect positively the richness and abundance of xylophagous beetles that attack fresh dead wood, while standing dead trees belonging to the fourth class decay and dead trees on the ground of second class decay affect hole nesting-birds. In accordance with our results, several studies have shown that unremoved dead wood on the ground (e.g., Johansson et al 2007) or artificially created dead wood microhabitats (e.g., Lindhe and Lindelöw 2004), are used for beetle development and consequently important for hole-nesting bird foraging activity, because the number of trees required for foraging is considerably larger than the number of nest trees (Drapeau et al 2009). …”

“…decay stage, diameter, typology) rather than quantity for the maintenance of saproxylic diversity. In particular, deadwood diversity was considered as a better indicator of animal diversity than volume per se (Drapeau et al 2009, Similä et al 2003, Jacobs et al 2007, Brin et al 2009, Lassauce et al 2011, Gossner et al 2013, Lachat et al 2013). …”

Ecosystem Responses to Partial Harvesting in Eastern Boreal Mixedwood Stands

“…Coarse woody debris (CWD), snags and downed logs, is a key attribute of forest ecosystems, sustaining a myriad of species [47,48] and structural diversity [49], as well as contributing to seedling establishment [30]. One underlying objective of partial harvesting in the context of ecosystem management is to increase the recovery time of CWD dynamics following harvesting [50].…”

Do larger snags stand longer?—snag longevity in mixed conifer–hardwood forests in Hokkaido, Japan

“…The duration of time from recruitment to falling down, which is often referred to as snag longevity, not only determines snag abundance but also is closely related to the quality of the habitats provided to species associated with snags. The assemblage of species associated with snags varies by several factors, including tree species, diameter, sun exposure, burn treatment, and decay condition of snags (Drapeau et al 2009;Gibb et al 2006;Jonsell et al 1998;Saint-Germain et al 2007;Ulyshen and Hanula 2009). Snag longevity influences the succession of the species assemblages through progression of the decay stage, and the process is usually categorized into five or more stages (Stokland et al 2012).…”