Eucalyptus imlayensis - critically endangered species listing

NSW Scientific Committee - final determination

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the mallee Eucalyptus imlayensis Crisp & Brooker as a CRITICALLY ENDANGERED SPECIES in Part 1 of Schedule 1A of the Act, and as a consequence, to omit reference to Eucalyptus imlayensis Crisp & Brooker from Part 1 of Schedule 1 (Endangered species) of the Act. Listing of Critically Endangered species is provided for by Part 2 of the Act.


The Scientific Committee has found that:


1. Eucalyptus imlayensis Crisp & Brooker (family Myrtaceae) is described by Hill (2002) as a: “Mallee to 7 m high; bark smooth, grey, salmon, orange or green, shedding in long ribbons. Juvenile leaves opposite, elliptic to ovate, glossy dark green. Adult leaves disjunct, lanceolate, 10–15 cm long, 1.5–2 cm wide, green, glossy to semi-glossy, concolorous. Umbellasters 3-flowered; peduncle narrowly flattened or angular, 3–5 mm long. Buds ovoid to shortly fusiform, 6–7 mm long, 3–4 mm diam., scar present; calyptra conical to rostrate, shorter than to as long as and as wide as hypanthium. Fruit cylindrical, hemispherical or campanulate, 5–7 mm long, 6–8 mm diam.; disc raised; valves exserted.”


2. Eucalyptus imlayensis has a very highly restricted distribution at a single location, in Mt Imlay National Park, near Eden, in south-eastern NSW. Its area of occupancy is less than 4 km2, based on a 2 x 2 km grid cell, the scale recommended by IUCN (2008) for assessing areas of occupancy.


3. The known population of Eucalyptus imlayensis grows in sclerophyll woodland on skeletal soil on a steep slope (Crisp & Brooker 1980). The vegetation is dominated by Leptospermum scoparium with Boronia imlayensis, Cassytha pubescens, Derwentia perfoliata, Dianella tasmanica, Doodia media, Lomandra longifolia, Melaleuca squarrosa, Oxylobium ellipticum and Prostanthera walteri and a ground layer dominated by mosses (James & McDougall 2007).


4. Eucalyptus imlayensis has a lignotuber from which it may resprout after fire. Establishment from seed is likely to be a rare event. James & McDougall (2007) recorded no seedlings or immature plants in the population during their studies since December 1998. No fruit has been produced from flowering during the four years since 2003 (James & McDougall 2007).


5. The number of mature individuals of Eucalyptus imlayensis is estimated to be approximately 80 and there are currently no juvenile plants in the population (James & McDougall 2007).


6. Since 1998, a decline in the number and health of Eucalyptus imlayensis stems has been recorded. By March 2001, James and McDougall (2007) found that almost 10% of the total E. imlayensis stems had no foliage and more than 50% crown death was recorded in one-third of the plants in the population.


7. Causes of the decline in Eucalyptus imlayensis are currently under investigation. Recent declines may be attributable to the soil-borne pathogen Phytophthora cinnamomi, which has been identified from the roots of dying plants (Banksia cunninghamii) adjoining the E. imlayensis population (James & McDougall 2007). ‘Infection of native plants by Phytophthora cinnamomi’ is listed as a Key Threatening Process under the Threatened Species Conservation Act 1995.


8. Other possible causes of the decline include insect attack and increased frequency or severity of drought. James & McDougall (2007) twice observed leaf galls from an unknown psyllid present on most plants during autumn. Other adjacent eucalypt species did not appear to be affected. Extended dry periods, possibly associated with climate change, are also a potential threat to this species. ‘Anthropogenic Climate Change’ is listed as a Key Threatening Process under the Threatened Species Conservation Act 1995.


9. Eucalyptus imlayensis Crisp & Brooker is eligible to be listed as a Critically Endangered species as, in the opinion of the Scientific Committee, it is facing an extremely high risk of extinction in New South Wales in the immediate 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:

(a) very highly restricted


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

(i) an index of abundance appropriate to the taxon.


Clause 16

The estimated total number of mature individuals of the species is:

(a) very low


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

(i) an index of abundance appropriate to the taxon.



Dr Richard Major


Scientific Committee

Proposed Gazettal date: 11/12/09

Exhibition period: 11/12/09 – 05/02/10




Crisp M D, Brooker MIH (1980). Eucalyptus imlayensis, a new species from a mountain of south coastal New South Wales. Telopea 2, 41-47.


Hill KD (2002) Eucalyptus In ‘Flora of New South Wales Volume 2’ (Ed. GJ Harden) pp 96-164 (New South Wales University Press: Kensington)


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). (


James EA, McDougall KL (2007) Extent of clonality, genetic diversity and decline in the endangered mallee Eucalyptus imlayensis. Australian Journal of Botany 55, 548–553.


Page last updated: 28 February 2011