Sagina diemensis (Pearlwort)

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

Sagina diemensis (Pearlwort)

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 geographic distribution of the species is precarious for the survival of the species and is very restricted. The species has not been seen since field surveys conducted in 1990. The prior area of occupancy was 0.1ha. The species was known from a single population. Continuing decline in the area, extent and quality of habitat, is projected due to ongoing habitat destruction caused by human trampling.

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

Criterion 3 - Population size and decline in numbers or distribution

The total number of mature individuals is very low, the species not being recorded in field surveys since 1990. As continuing decline in the area, extent and quality of habitat, is projected due to ongoing habitat destruction caused by human trampling, the population size and geographic distribution is precarious for the survival of the species.

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

Criterion 4 - Population size

The number of mature individuals is extremely low with the total population recorded to number 12 in 1990 and no plants being recorded since.

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 exists in extremely low numbers, last reported to number 12 in 1990 and no plants being recorded since. The geographic distribution, area of occupancy in 1990 being 0.1ha, is precarious for the survival of the species in the face of ongoing habitat destruction due to human trampling. The species is eligible for listing as critically endangered under criteria 2, 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:

Sagina diemensis (Pearlwort)