Collecting history and distribution of the potentially invasive Disa bracteata (South African orchid) in Tasmania

Abstract

The collecting history of Disa bracteata Sw. (South African orchid) in Tasmania (Australia), the state's only naturalised member of the Orchidaceae family, is presented. Details of its distribution in Tasmania, since it was first discovered in 2005, are included and discussed with information on habitat, abundance and management. The species is primarily distributed across the north coast (Smithton to Musselroe) with an outlier in Huonville in the state's south. Most sites are from verges along public roads and highways, but the species has also been detected on several private properties and other less disturbed habitats. Many sites with the species have been actively managed with the objective of eradication, although some sites are now well-established so eradication will require concerted effort. It is recommended that the species be added to the Tasmanian Weed Management Act 1999 as a declared species with the primary objective of eradication.

Climate change will likely facilitate invasion of Asian orchid Eulophia graminea into new areas

“…Two other common, non-indigenous orchids on the island also serve as hosts, Arundina graminifolia and Dendrobium crumenatum, and may elevate weevil populations as well, with possible impacts on native species (Foster and Ackerman 2021). The other orchid which is considered by local authorities to constitute a threat to native plants is Disa bracteata which invaded Australia in 1944 (Wapstra et al 2020). However, in this case there is no evidence of negative effects on the Australian flora.…”