Epacris sp. aff. virgata 'graniticola' (Mt Cameron Heath)

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

Epacris sp. aff. virgata 'graniticola' (Mt Cameron Heath)

Epacris sp. aff. virgata 'graniticola' (Mt Cameron Heath) is a new species yet to be formally described. However, the Tasmanian Herbarium has confirmed its acceptance of this species as a valid taxon. A description of Epacris sp. aff. virgata 'graniticola' (Mt Cameron Heath) has been published in the Recovery Plan for Tasmanian Forest Epacrids, which was adopted by the Commonwealth in 1998. It has also been referred to as Epacris sp. aff. exserta 'Mt Cameron', Epacris sp. aff. virgata 'graniticola', Epacris aff. virgata and Epacris graniticola.

2. Description

The Mt Cameron Heath is an upright or semi-prostrate shrub that grows to a height of 1.5m with distinctive wide-spreading branches and small lance-shaped leaves 4mm long and 3mm wide. In spring, white tubular flowers, approximately 8mm long, appear at the base of leaves near the top of branches. It grows in shallow soil on rocky outcrops in heath and dry scrub forest.

3. National Context

The Mt Cameron Heath is currently protected under Commonwealth and Tasmanian legislation as part of the species Epacris exserta (South Esk Heath) which is listed as endangered under the EPBC Act and vulnerable under the Tasmanian Threatened Species Protection Act 1995. It has also been nominated under Tasmanian legislation for separate listing as Epacris sp. aff. virgata 'graniticola' (Mt Cameron Heath).

The Mt Cameron Heath occurs at three locations among hills on the Mt Cameron Range (vacant crown land and Cameron Regional Reserve), Mt Stronach (Mt Stronach Forest Reserve) and south of Rossarden (Castle Cary Regional Reserve) in northeastern Tasmania.

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

TSSC judges Epacris sp. aff. virgata 'graniticola' (Mt Cameron Heath) to be eligible for listing as endangered under the EPBC Act. The justification against the criteria is as follows:

Criterion 1 - Decline in numbers

A decline in the number of mature plants has been recorded for the Mt Cameron Heath due to the death of old plants and limited seedling recruitment. The Mt Cameron Heath is dependent on fire for significant seedling recruitment and in the absence of fire over the past 25-30 years the population of Mt Cameron Heath has become old and begun to decline. Normally the mortality rate for established heath plants is approximately 1% per year, but for the Mt Cameron Heath it is reported to be approximately 10% per year (Keith 1998). Over a ten year period, in the absence of fire and significant recruitment, it is likely that the number of mature individuals will decline in the order of 30%.

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

Criterion 2 - Geographic distribution

The Mt Cameron Heath has a restricted and fragmented geographic distribution and occurs at three localities; on the Mt Cameron Range, Mt Stronach and south of Rossarden in northeastern Tasmania. It is restricted to skeletal soils on granite outcrops in heath and dry scrub forest with the extent of occurrence being 1195km2 and area of occupancy 36.5ha. The population is fragmented, being known from eight subpopulations at three geographically separate locations.

A decline in the number of mature plants has been recorded for the Mt Cameron Heath due to the death of old plants and limited seedling recruitment, and is likely to lead to a decline in the order of 30% over the next 10 years.

An additional threat is the infection of Tasmanian heath species by the root-rot fungal pathogen Phytophthora cinnamomi which is known to result in population declines in the order of 5-25% per year (Keith 1998). Whilst the Mt Cameron Heath has yet to be infected, it is considered to be susceptible and the pathogen is known to be in the immediate vicinity (55m) of one subpopulation. It is likely that this subpopulation will be infected and will decline within 10 years. Other subpopulations are at a lower direct risk of infection, however, they are still at risk as the pathogen is spread by running water and mud transported on footwear, vehicles and animal fur. Several subpopulations contain walking tracks or have vehicular tracks nearby that may be avenues by which Phytophthora could be spread as has occurred for other Tasmanian heath species.

Activities associated with the surface mining of alluvial tin deposits pose some threats to the Mt Cameron Heath. All subpopulations occur in a region known to contain tin deposits and on land that may be subject to mineral exploration and development, although currently there are no exploration or mining leases directly affecting them. One subpopulation, the second largest, is in close proximity (approximately 600m) to an operational tin mine with the mining lease boundary located within 300m, and a track within 100m. Mining and exploration activities may include vegetation clearing, track construction, digging of pits and trenches, and other soil disturbance. Such disturbance activities are known to encourage the spread of Phytophthora and the introduction of exotic woody weeds such as Gorse (Ulex europaeus) and Spanish Heath (Erica lusitanica). Further, the tracks and disturbed landscapes created by mining activities are known to attract recreational motor bike riders and four-wheel drive enthusiasts in the area, both of which may facilitate the spread of Phytophthora and result in physical damage to populations.

The Mt Cameron Heath has a restricted and fragmented geographic distribution. Declines in the number of mature individuals have been observed due to the death of old plants and lack of significant recruitment in the absence of fire. Further, the likely infection of at least one subpopulation by Phytophthora and the potential role of disturbance associated with nearby mining activities means that a decline in the order of 30% of the number of mature individuals can be reasonably inferred over the next 10 years.

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

Criterion 3 - Population size and decline in numbers or distribution

The total number of mature individuals is not limited, being estimated to be between 3061 and 40 313, the mean being 19 613.

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

Criterion 4 - Population size

The total number of mature individuals is not low, being estimated to be between 3061 and 40 313, the mean being 19 613.

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

Criterion 5 - Probability of extinction in the wild

There is no quantitative data available against this criterion.

5. Conclusion

The Mt Cameron Heath has a restricted geographic distribution, the extent of occurrence being 1195km2 and area of occupancy 36.5ha. The population is fragmented, being known from eight subpopulations at three geographically separate locations. It is susceptible to the root-rot fungal pathogen Phytophthora cinnamomi which is known to be in the immediate vicinity of one subpopulation. One subpopulation is adjacent to a mine and may be subject to increased threat of disturbance and weed invasion. Further, all subpopulations occur on land that is available for mineral exploration and extraction. A decline in the order of 30%, of the number of mature individuals, is inferred over the next 10 years due to the likely infection of at least one subpopulation by Phytophthora and continuing death of old plants in the absence of fire-induced recruitment. The species is eligible for listing as endangered under criterion 2.

6. Recommendation

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

Epacris sp. aff. virgata 'graniticola' (Mt Cameron Heath)

Publications used to assess the nomination:

Keith, D. (1998) Recovery Plan for Tasmanian Forest Epacrids. Tasmanian Parks and Wildlife Service. Hobart, 36pp.