The Weed Impact to Native Species (WINS) assessment tool - results from a trial for bridal creeper(Asparagus asparagoides (L.) Druce) and ground asparagus (Asparagus aethiopicus L.) in southern New South Wales
Paul O. Downey, Department of Environment and Conservation, PO Box 1967, Hurstville, New South Wales 2220, Australia.
The threat of plant invasions on biodiversity, while apparent, is rarely quantified in terms of the number of native species at risk, or lists of such species. While broad assumptions can be made as to what is at risk from plant invasions, the lack of specific information on individual species at risk hampers our ability to deliver weed management strategies with biodiversity conservation outcomes. A detailed examination of the biodiversity threatened by one weed, bitou bush (Chrysanthemoides monilifera subsp. rotundata (DC.) T. Norl.), in New South Wales established a process or assessment tool for identifying the native species potentially at risk from plant invasions. The Weed Impact to Native Species (WINS) assessment tool involves four stages, being: 1) a review of the literature, 2) collation and assessment of the knowledge from land managers and botanists with specific involvement, either in managing the weed species, or the native species in weed infested areas, 3) rigorous evaluation and examination of an interim list of species potentially at risk, and 4) ranking the revised list using a model.
Given the success of the WINS process in delivering a base-line of the species at risk from bitou bush, trials have been undertaken to determine if the WINS process can be adapted for other weed species. The results of one such trial, for bridal creeper (Asparagus asparagoides) and ground asparagus (Asparagus aethiopicus), conducted in southern New South Wales are presented here, based on stages 1, 2 and part of 3. The present trial suggests that the WINS assessment process or tool developed for bitou bush in New South Wales can be used/adopted more broadly for widespread established weeds.
This trial also illustrated the level of knowledge available on weed impacts to biodiversity that is not presently recorded or assessed, as well as the deficiencies in our collective understanding of weed impacts. For example, the number of plant species identified here in an interim list as potentially threatened by bridal creeper and ground asparagus was 52 and 97, respectively. The results from this trial of the WINS process significantly increased the number of species thought to be at risk from both these asparagus weeds. Such information indicates the impact asparagus weeds have on biodiversity and the need to collect, assess and disseminate such knowledge more broadly. The value of this information cannot be underestimated from a policy perspective with respect to weed and/or biodiversity conservation.
Keywords: WINS, weed impacts to native species, bridal creeper, Asparagus asparagoides, ground asparagus, Asparagus aethiopicus, biodiversity, species at risk, threat abatement plan, bitou bush.
Plant Protection Quarterly (2006) 21 (3) 109-116.