Authors: Brian W van Wilgen David M Richardson
Publish Date: 2013/11/24
Volume: 16, Issue: 3, Pages: 721-734
Abstract
Over 430 alien tree species worldwide are known to be invasive and the list is growing as more tree species are moved around the world and become established in novel environments Alien trees can simultaneously bring many benefits and cause substantial environmental harm very often leading to conflicts over how they should be managed The impacts grow over time as invasions spread and societal perceptions of the value of alien trees also change as understanding grows and as values shift This leads to a dynamic environment in which tradeoffs are required to maximise benefits and minimise harm The management of alien tree populations needs to be strategic and adaptive combining all possible management interventions to promote the sustainable delivery of optimal outcomes We use examples mainly from South Africa where issues relating to invasive alien trees introduced for forestry have received most attention to argue for holistic and collaborative approaches to alien tree management Such approaches need to include bold steps such as phasing out unsustainable plantation forestry that is based on highly invasive species and in which the costs are externalised Furthermore it would be advisable to impose much stricter controls on the introduction of alien trees to new environments so that problems that would arise from subsequent invasions can be avoidedWe acknowledge support from the Working for Water programme and the DSTNRF Centre of Excellence for Invasion Biology partly though their collaborative programme on “Research for Integrated Management of Invasive Alien Species” DMR also acknowledges the National Research Foundation Grant 85417 and the Oppenheimer Memorial Trust for funding that facilitated his participation in the workshop in Bariloche in September 2012 at which a preliminary version of the paper was presented
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