National recovery plan for the Endangered Native Jute Species, Corchorus cunninghamii F. Muell. in Queensland (2001-2006)

Marion Saunders
Rainforest Ecotone Recovery Team (RERT)
Environment Australia, 2001

1. Summary

1.1 Current species status

Corchorus cunninghamii is a herbaceous plant species with a restricted distribution occurring naturally within a 120 km region between Brisbane (Queensland) and Lismore (New South Wales). It is currently known from four locations in south-east Queensland (Brisbane Forest Park, Mt Cotton, Wongawallan and Ormeau) and two locations in northern New South Wales (Toonumbar, Bungabbee). In Queensland the species has an estimated total population size of around 6000 individuals (Parr, 2001) which is an increase from the 1032 individuals recorded the previous year (Simmonds, 2000). In New South Wales (NSW) the estimated population size is between 600-700 individuals (NSW National Parks and Wildlife Service; 1999).

Its low numbers, natural rarity and restricted distribution all contribute to C. cunninghamii being listed as Endangered under the Queensland Nature Conservation (Wildlife) Regulation, 1994 (Schedule 2, Part 2) and the New South Wales Threatened Species Conservation Act, 1995 (Schedule 1). It is also listed as Endangered by the Commonwealth under the Environmental Protection and Biodiversity Conservation Act, 1999. A recovery plan for the species in NSW. is currently being prepared by the NSW National Parks and Wildlife Service (1999).

1.2 Habitat requirements and limiting factors

C. cunninghamii occurs in the narrow ecotone between subtropical rainforest and open eucalypt forest. The species is generally located at low to mid elevations (110 - 430 metres), on upper hill-slopes or hill-crests that have a south-easterly or easterly aspect. Although it occurs primarily on upper hill-slopes the species may grow anywhere between the ridge and gully, depending on the position of the open forest-rainforest ecotone. There is no specific geology or soil type associated with the species as it occurs on both metamorphic and igneous substrates and on loam or clay soils (Halford, 1995a) and as such there does not appear to be a particular habitat that is critical to the survival of the species. In general the soils are shallow, stony and well drained and common canopy species occurring alongside C. cunninghamii include Eucalyptus propinqua (grey gum), Lophostemon confertus (brush box) and Eucalyptus siderophloia (grey ironbark). The density and composition of the understorey may be variable between sites, and introduced weed species such as Lantana camara (lantana), Rivina humilis (coral berry) and Ageratina adenophora (crofton weed) frequently occur in the shrub layer.

Whilst C. cunninghamii is a naturally rare plant species it is also directly threatened by loss of habitat due to development, genetic isolation, competition with introduced weed species, inappropriate fire and land management regimes, and forestry activities. Currently four of the ten existing populations have less than ten individuals and these are likely to disappear without effective management strategies. Other critical populations for the species include one site in Wongawallan that has more than 85 % of the total number of plants in southeast Queensland and another at Mount Cotton that is genetically distinct from those at other locations and as such may be necessary to preserve the genetic diversity of the species in the long-term.

1.3 Recovery objectives

The overall objective of this recovery plan is to protect known populations of C. cunninghamii in Queensland from further decline, and to maintain and/or enhance sustainable population levels in the wild, in the long-term with minimum management. Given current population numbers and improved management of individual populations it is foreseeable that within 10 years of implementing the current recovery plan that the conservation status of C. cunninghamii would be downlisted from 'endangered' to 'vulnerable'.

1.4 Recovery plan objectives

  • Update and improve existing knowledge of the ecology and distribution of C. cunninghamii in south-east Queensland.
  • Protect and/or enhance wild populations of C. cunninghamii and their habitat from further decline by developing management strategies for land managers.
  • Increase community awareness and involvement in maintaining and enhancing populations of C. cunninghamii.
  • Improve the conservation status of C. cunninghamii from 'endangered' to 'vulnerable' within 10 years and to double the number of plants in critical populations within 5 years.

1.5 Recovery criteria

  • Achieve an understanding of population dynamics, reproductive biology, and the role of fire and disturbance in the life history of C. cunninghamii.
  • Secure an appropriate level of protection for the habitat of existing populations of C. cunninghamii.
  • Maintain or enhance existing populations of C. cunninghamii.
  • Rehabilitate habitat where populations of C. cunninghamii currently exist.
  • Develop sustainable land management strategies for C. cunninghamii populations based on monitoring and recovery programs.
  • Increased community awareness of C. cunninghamii through the distribution of educational information on the species, through voluntary involvement in habitat recovery and monitoring programs, as well as consultation with indigenous groups regarding conservation of the species and the land on which it occurs.

1.6 Actions needed

  • Action 1: Investigate population dynamics by tagging and monitoring the life history of individual plants in existing populations of C. cunninghamii.
  • Action 2: Investigate the role of fire and weed disturbance on the ecology of individual plant populations.
  • Action 3: Implement management programs (e.g. fire and weed disturbance regimes) that improve the habitat of known populations of C. cunninghamii and increase population numbers.
  • Action 4: Consultation and involvement of indigenous groups that have an interest in land on which C. cunninghamii occurs.
  • Action 5: Preparation and distribution of educational material (bookmarks and posters) highlighting the endangered status of C. cunninghamii to conservation groups and the general public.
  • Action 6: Recruitment of community volunteers to participate in monitoring and habitat recovery programs.

1.7 Estimated costs of recovery


Table 1: Costs involved in implementing the recovery plan for Corchorus cunninghamii in Queensland.
YEAR
Action 1 Action 2 Action 3 Action 4 Action 5 Action 6 TOTAL
2001 - 2002
$ 6,940
$ 5,640
$ 7,040
unknown #
$ 5,040
$ 3,540
$ 28,200 *
2002 - 2003
$ 6,560
$ 5,410
$ 9,110
unknown #
$ 1,860
$ 3,360
$ 26,300 *
2003 - 2004
$ 5,500
$ 5,000
$ 8,700
unknown #
$ 900
$ 2,000
$ 22,100
2004 - 2005
$ 4,000
$ 4,700
$ 8,300
unknown #
$ 600
$ 1,500
$ 19,100
2005 - 2006
$ 4,000
$ 4,600
$ 7,800
unknown #
$ 600
$ 1,500
$ 18,500
TOTAL
$ 27,000
$ 25,350
$ 40,950
unknown #
$ 9,000
$11,900
$ 114,200
* The Project Co-ordinators salary and transport costs ($14,100 in 2001-2002; $14,700 in 2002-2003), which are funded through a Natural Heritage Trust (NHT) grant, have been distributed between Actions 1-5.

Other contributors (financial and in kind) to the recovery plan include Brisbane Forest Park, Gold Coast City Council, Redlands Shire Council and Brisbane City Council. This table does not include the volunteer labour contribution estimated at $17,500 for 2001-2002 and $18,900 for 2002-2003. Volunteer labour contributions would be divided between Actions 1, 2 and 3. Funding after 2003 has not been secured. The cost of implementing action 4 is unknown but is likely to be an in kind contribution provided by the Queensland Parks and Wildlife Service and Environmental Protection Agency.

1.8 Biodiversity benefits

Areas where C. cunninghamii populations occur in Queensland are of high nature conservation value as several other rare or threatened plant species are also present at these sites. These species include; Choricarpia subargentea (giant ironwood), Endiandra floydii, Macadamia integrifolia (macadamia nut), Pouteria eerwah (black plum), Sophora fraseri (brush sophora) and Randia moorei (spiny gardenia). A further benefit of implementing the recovery plan for C. cunninghamii in Queensland includes the protection and maintenance of biodiversity within the ecotonal areas that C. cunninghamii naturally occurs in. These ecotonal areas are particularly susceptible to invasion by exotic species such as Lantana camara (lantana), and a greater understanding of the role of fire and disturbance in these habitats will greatly assist in maintaining diversity of native species and controlling invasive exotic species.