Biodiversity response to tree retention actions at final harvest â a
The evidence-base for retention approaches in forestry Lena Gustafsson, SLU, Department of Ecology, Uppsala, Sweden Uppsala Sweden Outline • What are retention approaches in forestry? • How does biodiversity respond to retention approaches? • Are retention approaches a good conservation tool? Retention approaches in forestry – integration of conservation into production forestry Retention approaches • Focus on what is left, not what is taken out • Aim: promote biodiversity, sustain ecological functions • Mostly discussed as a modification to clearcutting • Relevant for all forestry systems • Started about 25 years ago Ecological basis: some habitats are especially important to biodiversity Application of retention approaches British Columbia, Canada Sweden Western Australia Washington state, USA Conservation or restoration – depends on landscape 1994 2014 Two main functions Lifeboating of forest species Promotion of open-habitat species Are retention approaches really good for biodiversity? A meta-analysis of studies in temperate and boreal regions Meta-analysis • ”Analysis of analyses” • 78 papers • Species number, abundance, several taxonomic groups • 30% average retention level • Sweden: 8% as average > 6,000 papers > 2,000 papers ~ 500 papers 78 papers Clearcut Harvested area with retained trees Forest species Harvested area with retained trees Forest Open-habitat species Many studies on biodiversity and retention approaches Lindenmayer et al. 2012 Conservation Letters Several large experiments Gustafsson et al. 2012 BioScience Forest species Results FOREST SPECIES Open-habitat species OPEN-HABITAT SPECIES Fedrowitz et al. 2014 Journal of Applied Ecology Results • Taxonomic groups showed largely similar responses • Response of forest species increased with retention level • Old forest was better for forest species than logged areas with retention Fedrowitz et al. 2014 Journal of Applied Ecology Conclusions • Biodiversity responses to retention approaches are overall positive • The evidence-base seems sound • Thus, this adjustment to logging can be encouraged • But: – some forest species need larger set-aside areas Fedrowitz et al. 2014 Journal of Applied Ecology Tack
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