Eucalyptus parvula - endangered species listing

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the tree Eucalyptus parvula L.A.S Johnson & K.D. Hill as an ENDANGERED SPECIES in Part 1 of Schedule 1 of the Act, and as a consequence omit reference to Eucalyptus parvula L. Johnson & K. Hill from Part 1 of Schedule 2 (Vulnerable) of the Act. Listing of Endangered Species is provided for by Part 2 of the Act.

NSW Scientific Committee - final determination

The Scientific Committee has found that:

1. Eucalyptus parvula L.A.S. Johnson & K.D. Hill (family Myrtaceae) (Small-leaved Gum) is described as a “tree to 15 m high; bark persistent, shedding imperfectly on lower trunk, red-brown, fibrous-flaky or platy; smooth above, grey or green, shedding in long ribbons. Juvenile leaves opposite, elliptic to obovate to broad-lanceolate, glossy green. Adult leaves disjunct or opposite, lanceolate, 4-7 cm long, 0.6-1 cm wide, green, dull, concolorous. Umbellasters 7-flowered; peduncle terete, 4-7 mm long; pedicels + absent. Buds ovoid, 3-5 mm long, 2-3 mm diam., scar present; calyptra conical, shorter than and as wide as hypanthium. Fruit cylindrical, conical or ovoid, 3-4 mm long, 3-4 mm diam.; disc raised slightly; valves enclosed or rim-level.” (Hill 2002).

2. Eucalyptus parvula was assessed as Vulnerable by Briggs & Leigh (1996) and as a consequence was placed in Part 1 of Schedule 2 as a Vulnerable species at the inception of the  Threatened Species Conservation Act 1995. Recent surveys of populations of  E. parvula (Miles 2008) have provided information for a reassessment of the species.

3. Eucalyptus parvula is a small tree or mallee, endemic to the south-eastern edge of the NSW southern tablelands (Miles 2008). It is found in the South Eastern Highlands Bioregion and may extend into the adjacent South East Corner Bioregion ( sensu. Thackway & Creswell 1995). It is currently known from Cathcart, north-east of Bombala, in the south, to the Badja River in the north, with an outlying record from Tinderry Creek,  c. 40 km south of Canberra. The geographic distribution of  E. parvula is highly restricted. Its extent of occurrence is estimated to be 2300 km². Within this range, the area of occupancy is estimated to be approximately 140 km² based on 2 x 2 km grids, the spatial scale recommended for assessing areas of occupancy by IUCN (2008).

4. Eucalyptus parvula grows mainly in grassy woodlands around the edges of broad, flat headwater valleys in frost-prone areas at altitudes of 800 – 1200 m above sea level (Hill 2002; Miles 2008). It occurs on poorly drained humic soils derived from granite or granodiorite (Miles 2008). Associated species include  E. pauciflora (Snow Gum) , E. stellulata (Black Sally) , and occasionally  E. viminalis (Ribbon Gum) , E. ovata (Swamp Gum) , and  E. rubida (Candlebark)  (Miles 2008).  E. parvula has been observed to resprout from the base after fire (Miles 2008).  Recent surveys of  E. parvula recorded approximately 4300 plants from at least 8 populations (Miles 2008), indicating that there are likely to be a moderately low number of mature individuals in the total population.

5. As populations of Eucalyptus parvula grow mainly on flats within headwater valleys separated by low ridges, its habitat is naturally patchy in the landscape (Miles 2008). However clearing of woodlands in this habitat for grazing may also have contributed to fragmentation of the populations (Prober  et al. 1990).  E. parvula has a high level of genetic variation between populations, suggesting its distribution across the landscape was once more continuous (Prober  et al. 1990). Fragmentation of the populations is likely to lead to a decline in levels of genetic diversity in the species and reduced evolutionary potential in the face of future environmental change (Prober  et al. 1990). The majority of  E. parvula populations and approximately 78% of individuals, occur on private land where cattle grazing on native pastures is the main land use (Miles 2008). Grazing and trampling by livestock may inhibit recruitment, and whilst grazing pressure can vary over time and from property to property, the smaller and more isolated populations are considered to be most threatened (Miles 2008). ‘Clearing of native vegetation’ is listed as a Key Threatening Process under the  Threatened Species Conservation Act 1995.

6. Approximately 22% of known individuals of Eucalyptus parvula occur in the following conservation reserves: South East Forest National Park, Wadbilliga National Park, Tinderry Nature Reserve, Kybeyan State Conservation Area, and possibly Deua National Park.

7. The effects of climate change may also pose a significant threat to Eucalyptus parvula (Miles 2008) and lead to future declines in the species’ populations. As the habitat of  E. parvula is located in the coldest, wettest parts of the landscape within its range, under conditions of increased average temperatures and possibly lower effective rainfall, the viability of populations could be reduced if the region becomes warmer and drier, as projected under future climate scenarios (Hennessy  et al. 2004). Invasion by seedlings of other tree species from surrounding forests and woodlands may lead to a decrease in the competitive advantage of  E.  parvula within its habitat and possibly an increase in the frequency of hybridization with related  Eucalyptus species (Miles 2008). ‘Anthropogenic Climate Change’ is listed as a Key Threatening Process under the NSW  Threatened Species Conservation Act 1995.

8. Eucalyptus parvula L.A.S Johnson & K.D. Hill is not eligible to be listed as a Critically Endangered species.

9. Eucalyptus parvula L.A.S Johnson & K.D. Hill is eligible to be listed as an Endangered species as, in the opinion of the Scientific Committee, it is facing a very high risk of extinction in New South Wales in the near future as determined in accordance with the following criteria as prescribed by the  Threatened Species Conservation Regulation 2002:

Clause 15

The geographic distribution of the species is estimated or inferred to be:

(b) highly restricted,

and:

(d) a projected or continuing decline is observed, estimated or inferred in:

(i)an index of abundance appropriate to the taxon, or

(ii) geographic distribution, habitat quality or diversity, or genetic diversity.

Dr Richard Major
Chairperson
Scientific Committee

Proposed Gazettal date: 11/12/09
Exhibition period: 11/12/09 – 05/02/10

References:

Briggs JD, Leigh JH (1996) Rare or Threatened Australian Plants, (CSIRO publishing: Melbourne).

Hennessy K, Page C, McInnes K, Jones R, Bathols J, Collins D, Jones R (2004) ‘Climate change in New South Wales. Part 1: Past climate variability and projected changes in average climate’. CSIRO Marine and Atmospheric Research, Aspendale, Victoria.

Hill KD (2002) Eucalyptus. In Flora of New South Wales Volume 2 Revised Edition. Harden GJ ed. University of NSW Press, Sydney.

IUCN (2008) ‘Guidelines for using the IUCN Red List Categories and Criteria. Version 7.0.’ (Standards and Petitions Working Group of the IUCN Species Survival Commission Biodiversity Assessments Sub-committee: Switzerland).

Miles J (2008) Conservation status of Eucalyptus parvula L. Johnson & K. Hill (Myrtaceae) in New South Wales. A report to the Scientific Committee (NSW TSC Act 1995).

Prober SM, Tompkins C, Moran GF, Bell JC (1990) The conservation genetics of Eucalyptus paliformis L. Johnson et Blaxell and  E. parvifolia Cambage, two rare species from south-eastern Australia.  Australian Journal of Botany 38, 79-95.

Thackway R, Creswell ID (1995) ‘An interim biogeographic regionalisation for Australia: a framework for setting priorities in the National Reserves System Cooperative Program’. Version 4.0. (Australian Nature Conservation Agency: Canberra)