Distribution, habitat characteristics and conservation management of Prasophyllum stellatum (Ben lomond leek-orchid), a forest-dependent threatened species

Surveys were undertaken for Prasophyllum stellatum, a threatened forest-dependent orchid. The species occurs in the north-east (Storys Creek area on the southern foothills of Ben Lomond) and the central north (Cluan Tiers area) of Tasmania. It occurs at moderate elevations on Jurassic dolerite in a wide successional range of moist eucalypt forests dominated by Eucalyptus delegatensis. Its extent of occurrence is approximately 214 ha (Storys Creek area) and 110 ha (Cluan Tiers area) but its area of occupancy is substantially less. The species has a patchy distribution within its range and occurs in low numbers: 46 individuals were detected from 38 sites in the Storys Creek area, and 32 individuals from 13 sites in the Cluan Tiers area. P. stellatum occurs predominantly on State forest subject to forestry activities. The species was detected from a range of forest ages including relatively undisturbed mature forest through to forests regenerating from both selective logging and clearfelling in the 1970s and 1980s. The species was often recorded on old snig tracks and landings, gravel road verges, unsealed track surfaces, and in harvested forest and retained patches of mature forest within a harvested landscape. While the conservation status of endangered on the Tasmanian Threatened Species Protection Act 1995 is warranted for P. stellatum due to its restricted distribution and low population numbers, we argue that carefully managed forestry activities that exclude key sites, minimise intensive ground disturbance, and maintain some canopy and understory structure, are consistent with the conservation of this species, and may be beneficial in maintaining its habitat. The study highlighted the complex taxonomy of the genus Prasophyllum in Tasmania and the implications of this for conservation management. P. stellatum exhibits significant variation in morphological features that available descriptions and keys do not acknowledge. Further review of the Prasophyllum truncatum species-complex in Tasmania (to which P. stellatum belongs) is warranted.