Recovery Plan for Three Orchid Species in South Australia and Victoria

Catherine Dickson, Ross Anderson, Anna Murphy, Andrew Pritchard and Anne Craig, 2012

Caladenia richardsiorum (Little Dip Spider-orchid), Caladenia calcicola (Limestone Spider-orchid) and Pterostylis tenuissima (Swamp Greenhood)

About the document

This recovery plan covers three nationally threatened terrestrial orchids endemic to mainland south-eastern Australia (Table 1). The nationally Endangered Caladenia richardsiorum (Little Dip Spider-orchid), and nationally Vulnerable Caladenia calcicola (Limestone Spider-orchid) and Pterostylis tenuissima (Swamp Greenhood) are small terrestrial orchids, which have highly fragmented and isolated sub-populations. Caladenia richardsiorum is endemic to the coastal vegetation of the South East Natural Resource Management Region of South Australia, with an approximate population of 11,000 individuals occurring across 46 sub-populations. Caladenia calcicola consists of only 277 recorded individuals across eight sub-populations, which occur predominantly near Portland and Nelson, Victoria. In contrast, P. tenuissima has a relatively wide distribution, occurring in Silky Tea-tree (Leptospermum lanigerum) Scrub from near Robe in south-east South Australia, through to Wilson’s Promontory National Park in eastern Victoria. There are approximately 17,700 individuals of P. tenuissima distributed across 57 sub-populations. Although there are a high number of sub-populations of both C. richardsiorum and P. tenuissima, only 11 and 12 sub-populations respectively, occur on land reserved for conservation. Current threats to the remaining sub-populations include vegetation clearance, isolation and hence limited opportunity for genetic exchange, grazing, weed invasion, disturbance and destruction of plants from recreational activities.

This national recovery plan is the first for these species and details their taxonomy, ecology, distribution, current and potential threatening processes, as well as the existing and intended management actions required to prevent the further decline of the species.