Epacris limbata (Border 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 limbata (Border Heath)

2. National Context

The Border Heath is endemic to the Eastern Tiers in Tasmania. It is currently listed as vulnerable under the EPBC Act and endangered under Tasmanian legislation.

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

The total population of mature individuals has been estimated to be approximately 72 000 with the potential range being between approximately 20 000 and 145 000. There are five subpopulations with the extent of occurrence being 10.75km2 and area of occupancy 36.87ha.

Over a five year period from 1996-2001 a 42.5% reduction in population size due to the Phytophthora cinnamomi root-rot fungus was recorded in a representative subpopulation. It is estimated that 85% of that subpopulation was infected with Phytophthora.

Phytophthora was first recorded on roads that pass through the subpopulations in 1988 (14 years ago) and it is therefore likely to have been present in parts of the overall population for at least that period of time. The most probable means of introduction was road construction. Whilst two portions of one subpopulation are free of Phytophthora these portions comprise just 1% of the total population. Phytophthora can be expected to continue to spread in the subpopulations due to its own movement, and that aided by water, wildlife and human activities. Experts also consider that fire, or frequent fires, can create conditions conducive to the increase in abundance and spread of Phytophthora. The Eastern Tiers region in which the Border Heathoccurs has a history of high intensity fires. Fire reduces the organic matter in the soil and associated soil micro-flora/fauna that can have a suppressive effect on Phytophthora. Fire also reduces the vegetation cover and allows soil temperature and water availability to rise facilitating an increase in the pathogen. The movement of firefighters and associated machinery is a secondary mechanism aiding the spread of Phytophthora.

Fire also plays an important role in regeneration of theBorder Heath.Populations regenerate from seed following fire. High frequency fire could, however, lead to exhaustion of the seed bank as plants are killed by fire and further recruitment by mature plants to the seed bank is limited.The frequency and impact of fire in conjunction with its link to periods of increased Phytophthora activity may have a significant influence on the survival of Border Heath subpopulations.

Based on the recorded reduction over the past five years and uncontrolled impact of Phytophthora in all five subpopulations, it is calculated that over 3 generations (45years) the population will decline by 84%.

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

Criterion 2 - Geographic distribution

The Border Heath has a restricted geographic distribution, the extent of occurrence being 10.75km2 and area of occupancy 36.87ha. It is known to exist at five locations and is susceptible to Phytophthora as discussed under criterion 1. The impact of Phytophthora is expected to result in ongoing declines in the extent of occurrence, area of occupancy, area, extent and/or quality of habitat, number of locations or subpopulations and the number of mature individuals. High frequency fire may also lead to depletion of the seed bank and reduced recruitment due to the death of mature individuals.

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

Criterion 3 - Population size and decline in numbers or distribution

Whilst a decline in the population size is projected (see criterion 1), the total population of mature individuals has been estimated to be approximately 72 000 with the potential range being between approximately 20 000 and 145 000.

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

Criterion 4 - Population size

The total population of mature individuals has been estimated to be approximately 72 000 with the potential range being between approximately 20 000 and 145 000.

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.

4. Conclusion

The Border Heath is susceptible to Phytophthora and the population size in a representative subpopulation is estimated to have declined by 42.5% over the five year period 1996-2001. Phytophthora is expected to continue to increase in the population and may be more prevalent following fire. Frequent fires could also lead to exhaustion of the seed bank. Based on observed declines, the rate of decline over the next three generations (45 years) is estimated to be 84%.

The species is eligible for listing as critically endangered under criterion 1.

5. Recommendation

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

Epacris limbata (Border Heath)