This situation statement, released in 2014, provides a snapshot of the opuntioid cacti in Western Australia (WA) by describing their distribution, impact and management in WA, and identifying the major stakeholders that can contribute to the active management of these species.
Opuntioid cacti already infest large areas of southern and eastern Australia. In WA the total area infested is relatively small; however, the scattered infestations are dispersed widely from the Pilbara to the south coast, and have the potential to significantly increase their abundance, particularly in the southern rangelands. Abandoned and unmanaged cactus gardens, unmanaged infestations and dumping of unwanted cacti are important sources of new infestations.
To date, infestations of 16 different species of opuntioid cacti have been recorded in WA. Their current collective impact is low, but they present potentially large impacts, especially on the agricultural activities, biodiversity and cultural values of the rangelands.
DAFWA is currently reviewing the declaration status of the opuntioid cacti. Six species of opuntioid cacti are already declared in parts of WA, but this is not sufficient to ensure the appropriate management of all opuntioid cacti in WA.
The collective knowledge of the opuntioid cacti in Australia is relatively poor, but improving, and is fragmented across State jurisdictions and between government agencies, NRM and community groups. Significant challenges exist to achieving a coordinated approach to the management of opuntioid cacti in WA. For example, the collection and identification of specimens of weedy cacti is difficult, accurate distribution maps are not available, and more work is needed on identifying suitable control techniques.
There is a need to have a nationally supported best practice management guide to bring together the management, biological and control information for this diverse group of cacti.
A large number of stakeholders with interests in and/or responsibilities for the management of naturalised opuntioid cacti are identified in WA. The diversity of stakeholders and their differing capacities to manage opuntioid cacti adds to the complexity of achieving coordinated management.
Since 2012 there has been increasing interest in the management of opuntioid cacti in WA. It is intended that this situation statement will contribute to the further development of state, regional and species-specific management and response plans for these significant weeds.