Mapping is a cost effective method to identify which weed species are present, and their location. Additionally, by mapping on a number of occasions, an indication of management effectiveness can be determined. By presenting this information graphically an overview of the weed dynamics over time can also be obtained. Futher, persistent weeds and locations can be identified. By identifying persistent weeds, their modes of dispersal can inform a weed control program.
Using 5 ha quadrats (n=449) weed presence was mapped in 2002, 2009 and 2013 in the Dandenong Ranges National Park. The percentage of quadrats with weeds, both all weeds and the 20 nominated priority weeds, had significantly decreased in 2013 in comparison to 2002 in each management area; for example in Doongalla, all weeds decreased from 95.5% to 80.2% and priority weeds from 94.6% to 78.4% (P<0.001 for both). A significant decrease (P<0.001) in the mean number of species per quadrat in 2013 compared to 2002 was also demonstrated in all areas except Olinda.
In 2013, seven weed species (Blackberry, English holly, English ivy, Karamu, Sweet pittosporum, Sycamore maple and Tutsan) were considered persistent weeds in at least one management area.
Overall, these results demonstrate the effectiveness of the weed management program between 2002 and 2013.
Keatley, M.R., Yuen, K., McIntosh, T.A. and Incoll, B. (2016). Mapping the present to manage the future. Plant Protection Quarterly 31(1), 8-14.