Does global change increase the success of biological invaders?
Cunningham, D. C., Barry, S. C., Woldendorp, G., & Burgess, M. B. (2004). A framework for prioritizing sleeper weeds for eradication. Weed technology, 18(sp1), 1189-1193. PDF.
Summary
Cunningham et al. (2004) develop some recommendations for prioritizing the eradication of ‘sleeper weeds’. Sleeper weeds are non-native plants that have established populations within a region, but whose populations have not yet increased exponentially. The authors give the examples of Mimosa pigra and Cortaderia selloana in Australia, both species that were established for decades before becoming weeds of national concern. But, not all non-native species are sleeper weeds (in fact, only a small proportion could likely achieve ‘invasive’ status). The expansion and invasion of sleeper weeds are potentially limited by several factors, including low genetic diversity, absence of mutualists, and limited suitable habitat. The extents of suitable habitat could expand as potential ranges shift with climate change. Therefore, Cunningham et al. (2004) recommend prioritizing sleeper weeds based on their potential impact, and then refining this list to identify target species for treatment based on the likelihood of eradication and proximity to high value land resources.
Take home points
A sleeper weed is a species that could become invasive in a region, but is currently limited from population expansion – potentially due to unsuitable climate.
Although some naturalized species could be sleeper weeds, most are likely to remain at small population sizes and never have major impacts on ecosystems or economies
Therefore, prioritizing eradication efforts should focus on impacts if the species becomes invasive, likelihood of eradication, and value of surrounding land resources.
Management implications
Cunningham et al. (2004) recommend prioritizing sleeper weeds for eradication based on 1) Some sort of risk assessment based on the non-native species’ potential impact, 2) Valuation of land nearby the population of the sleeper weed (e.g., conservation priorities), and 3) An estimate of potential for successful eradication based on area of infestation, number of infestations, ease of access, and seedbank longevity. The authors present an equation to calculate eradication costs based on these criteria.
Keywords
Shifting Seasons; Climate Extremes; Review; Invasive Plant; Risk Assessment