Testing the utility of novel, pre-emptive surveillance techniques to achieve earlier detection of five high-risk weeds.

Abstract

Early detection is a critical pre-cursor to successful eradication of potentially serious weed species. Rather than relying only on traditional passive forms of surveillance, such as public awareness campaigns, a targeted, pre-emptive approach is currently being explored to achieve earlier detection of five high-risk weed species currently absent or rare in south-east Queensland, namely: Tropical soda apple (Solanum viarum), Miconia (Miconia calvescens), Cecropia (Cecropia peltata/palmata complex), Karroo thorn (Vachellia karroo) and Siam weed (Chromolaena odorata). Pathways analysis was used to understand dispersal vectors and to predict places where target species are perhaps most likely to be found. Since flying foxes are known to be a primary dispersal vector for Cecropia (and to a lesser degree Miconia), three flying fox camps on the Gold Coast were selected as ‘sentinel sites’ and the understorey beneath the bats will be searched for these species each winter. Similarly, since cattle are the primary dispersal vector of Tropical soda apple and Karroo thorn, a sentinel site used to dump the stomach contents of millions of cattle from across Queensland is being searched each year. Sentinel sites associated with movement of military equipment will be searched for Siam Weed. A network of volunteer weedspotters, numbering over 1100 people, is being utilised to reinforce this pre-emptive surveillance capacity. There is also future scope to explore emerging eDNA technology to detect the pollen of high-risk weed species. If the concept is successful, it will be applied elsewhere in the State.