Managing Alien Plants for Biodiversity Outcomes—the Need for Triage

Abstract

Recognition that alien plants pose a significant threat to biodiversity has not always translated into effective management strategies, policy reforms, and systems to establish priorities. Thus, many alien plant management decisions for the protection of biodiversity occur with limited knowledge of what needs to be protected (other than biodiversity in a generalized sense) or the urgency of actions. To rectify this, we have developed a triage system that enables alien plant management decisions to be made based on (1) the urgency of control relative to the degree of threat posed to biodiversity, compared with (2) the likelihood of achieving a successful conservation outcome as a result of alien plant control. This triage system is underpinned by a two-step approach, which identifies the biodiversity at risk and assesses sites to determine priorities for control. This triage system was initially developed to manage the threat posed by bitou bush to native species in New South Wales (NSW), Australia. It has subsequently been improved with the national assessment of lantana in Australia, and the adaptation from a single to multiple alien plant species approach on a regional scale. This triage system identifies nine levels of priority for alien plant management aimed at biodiversity conservation, ranging from immediate, targeted action to limited or no action. The development of this approach has enabled long-term management priorities to be set for widespread alien plants that are unlikely to be eradicated. It also enables control to occur in a coordinated manner for biodiversity conservation at a landscape scale, rather than as a series of individual unconnected short-term actions.

Management of invasive Phragmites australis in the Adirondacks: a cautionary tale about prospects of eradication

“…However, deciding which plant species to target for control is difficult, especially when multiple species co-occur and each is associated with or facilitated by other biotic or abiotic stressors (Simberloff and Von Holle 1999;Bertness et al 2002;Minchinton and Bertness 2003;Nuzzo et al 2009;Fisichelli et al 2013;Kuebbing et al 2013;Dávalos et al 2014Dávalos et al , 2015Craven et al 2016). An abundance of prioritization schemes exist, largely developed by scientists, to help land managers make better informed decisions that focus control efforts (Robertson et al 2003;Fox and Gordon 2009;Downey et al 2010;Esler et al 2010b;Darin et al 2011;Barney et al 2013;Abella et al 2015;Adams and Setterfield 2015;Lindenmayer et al 2015). Depending on a particular scheme's focus, species, habitats, ecosystem services, control strategies, probability of achieving success, expected impacts, and costs may be evaluated.…”

Managing for biodiversity: impact and action thresholds for invasive plants in natural ecosystems

“…When considering the management of widespread serious weeds on a larger scale there is a need for an understanding of the biodiversity values of different assets, as well as the urgency of control (see Hiebert 1997) relative to the degree of threat posed to biodiversity (Downey et al 2010). The need for further research is manifold.…”

The grass may not always be greener: projected reductions in climatic suitability for exotic grasses under future climates in Australia

“…propagule pressure, human usage, physical disturbance), incorporating modelled projections of climatically suitable habitat into prioritisation systems would provide a useful indicator of future threats, and help identify which regions may become hotspots for invasion under future climates (O'Donnell et al 2011). In addition, the predicted distributions under climate change of the native species at risk from specific alien plants could be matched to those for alien plants to determine future impacts, because the degree of distributional overlap is a critical factor in determining the threat (Downey et al 2010c).…”