Prasophyllum perangustum (Knocklofty Leek-orchid)

Advice to the Minister for the Environment and Heritage from the Threatened Species Scientific Committee (TSSC) on Amendments to the list of Threatened Species under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act)

1. Scientific name, common name (where appropriate), major taxon group

Prasophyllum perangustum (Knocklofty Leek-orchid)

2. National Context

The species is endemic to Tasmania. The species is currently listed as endangered under the EPBC Act and the Tasmanian Threatened Species Protection Act 1995.

3. How judged by TSSC in relation to the EPBC Act criteria.

TSSC judges the species to be eligible for listing as critically endangered under the EPBC Act. The justification against the criteria is as follows:

Criterion 1 - Decline in numbers

There is no quantitative data available against this criterion.

Criterion 2 - Geographic distribution

The species is known from a single population with an area of occupancy calculated to be 0.02ha and extent of occurrence calculated to be 0.0001km2. There is however, no data available indicating declines or extreme fluctuations in geographic distribution, the quality of habitat, the number of populations or number of individuals.

Therefore, the species is not eligible for listing under this criterion.

Criterion 3 - Population size and decline in numbers or distribution

The number of mature individuals is very low and the geographic distribution is precarious for the survival of the species. Dedicated field surveys having located a total of six mature individuals in a single population.

Therefore, the species is eligible for listing as critically endangered under this criterion.

Criterion 4 - Population size

The total number of mature individuals located during dedicated field surveys is six, which is considered to be extremely low. The upper limit for the population is estimated at 50 mature individuals.

Therefore, the species is eligible for listing as critically endangered under this criterion.

Criterion 5 - Probability of extinction in the wild

There is no quantitative data available against this criterion.

4. Conclusion

The species occurs in extremely low numbers of mature individuals at a single location indicating the population size and geographic distribution is precarious to its survival. The species is eligible for listing as critically endangered under criteria 3 and 4.

5. Recommendation

TSSC recommends that the list referred to in section 178 of the EPBC Act be amended by
transferring from the endangered category to the critically endangered category:

Prasophyllum perangustum (Knocklofty Leek-orchid)