Hinged Dragon Orchid (Caledenia drakeoides) Interim Recovery Plan 2003-2008

Interim recovery plan no. 141
Andrew Brown, Emma Holland and Kim Kershaw
Department of Conservation and Land Management, WA, 2003

1. Background

History

Caladenia drakeoides was first collected near Meckering in the 1960s by the late J. Tonkinson. It was then not seen again until 1984 when R. Bates (an orchidologist visiting from South Australia) found a small population near Goomalling. Subsequent surveys have located a further 17 mostly small populations with a combined total of approximately 1058 plants. During a survey for the orchid in the Merredin and Moora Districts between 1996-and 2001 no plants were found at eight populations. In recent years there has been a dramatic decline in plant numbers in many other populations. When originally gazetted as rare flora it was listed as Drakonorchis drakeoides ms but has since been placed in Caladenia (Hopper & Brown 2001).

Description

Caladenia drakeoides is an inconspicuous, erect, 20-30 cm tall tuberous herb. Usually single, or rarely two flowered, it differs from other Caladenia species in its small hanging petals and sepals (13-17 mm by 2.5-4 mm), its small hinged labellum (5-7 mm long) with two lateral slight swellings (not antenna-like as in the related C. barbarossa), and its hump like shoulder calli. The latter are 1.5-2 mm wide, golden brown with small dark red spots, with a cranial depression and two lateral anterior slight swellings. A full taxonomic description of C. drakeoides, is provided by S. D. Hopper and A.P. Brown in Nuytsia Vol. 14 1/2 2001. On rare occasions C. drakeoides hybridizes with Caladenia exilis and Caladenia longicauda, and these have been named x Caladenia ornata and x Caladenia enigma respectively.

Distribution and habitat

Caladenia drakeoides is confined to seasonally moist rises above salt lakes between Coorow, Beacon and Goomalling. Habitat is tall to medium shrubland dominated by Melaleuca and Acacia species over low shrubs and annuals. Soils are variable but consist mainly of grey sandy loam.

Biology and ecology

Caladenia drakeoides has an insect-like labellum which emits a pheromone similar to that of a female thynnid wasp. Male thynnid wasps attempt copulation with the labellum and in the process remove or deposit pollen. Like other orchids, C. drakeoides produces thousands of tiny seeds that contain little testa. These seeds rely on a symbiotic association with soil fungi for germination.

Threats

Caladenia drakeoides was declared as Rare Flora in September 1986 as Drakonorchis drakeoides ms and ranked as Critically Endangered in November 1998. It currently meets World Conservation Union Red List Category 'CR' under criteria B2a,b,(ii,iii,iv,v) due to its small area of occupancy, the populations being severely fragmented and an observed decline in area of occupancy, quality of habitat, number of subpopulations and number of mature individuals. This is due to the extremely restricted habitat of the species in a narrow ecotone on the edges of salt lakes, the wide scale clearing for agriculture in the northern and western wheatbelt and rising water tables which have caused an increase in salinity and water logging. In addition to these, current continuing threats include inappropriate fire regimes, erosion, degraded habitat, weeds, poor recruitment, grazing and trampling by sheep and goats and road maintenance. Details of continuing threats are as follows.

  • Salinisation, waterlogging and erosion are contributing to habitat degradation in populations 2, 3, 4, 5, 6, 7, 10 and 11. The rising saline water table is the greatest single threat to the species.
  • Weeds are invading the habitat of populations 1, 3, 5b, 6, 7, 9 and 10. Inappropriate fire regimes may also promote weed growth and could exacerbate the problem if not controlled.
  • Grazing and trampling by sheep has been observed in the area of populations 3, 5, 6 and 9.
  • Goats are a threat to the habitat of population 12 due to heavy grazing and trampling of plants.
  • Road maintenance may accidentally destroy Caladenia drakeoides plants and habitat.
  • Poor recruitment is a continuing threat to the species. All populations are declining with little natural recruitment observed.
Summary of population information and threats
Pop. No. & Location Land Status Year/No. plants Condition Threats
1. ENE of Gunyidi Private 1988 1000+
1998 50
Moderate Weeds, increasing salinity
2a. ENE of Gunyidi Private 1988 100+
1998 0
Moderate Rising salinity, erosion
2b. ENE of Gunyidi Private 1996 100+
1998 50
Poor Rising salinity, erosion
3. ENE of Gunyidi Nature Reserve, Class A 1988 3
1996 0
Moderate Rising salinity, weeds, grazing
4a. ESE of Pithara Private 1988 20+
1998 10
Good Grazing, rising salinity
4b. ESE of Pithara Private 1991 100+
1998 127
Good Grazing, rising salinity
5a. N of Ballidu Private 1988 15+
1996 0
Moderate Rising salinity, grazing, rabbits
5b. N of Ballidu Private 1988 15+
1998 47
Moderate Rising salinity, grazing, weeds, rabbits
6. SW of Kondut Private 1988 30+
1998 0
Poor Rising salinity, weeds, grazing by sheep, vehicles
7. W of Miling Private 1987 5
1996 0
Moderate Rubbish dumping, weeds, increasing salinity
8. ENE of Dalwallinu Shire road reserve 1991 18
1998 16
Moderate Grazing, weeds
9. NW of Goomalling Private 1984 2
1996 0
Poor Rabbits, sheep, erosion, weeds
10. WSW of Ballidu Private 1990 4
1996 0
Moderate Rising salinity, weeds, grazing
11. ENE of Gunyidi Private 1996 167
1999 75
Moderate Rising salinity, erosion, grazing
12. SW of Coorow Nature Reserve, Class C 1992 100+
1996 333+
Moderate Rising salinity, rabbits, goats
13a. N of Beacon Private 1992 8
1998 5
Not recently surveyed Rising salinity, weeds
13b. N of Beacon Shire road reserve 1992 10
1992 5
Not recently surveyed Rising salinity, weeds
14. SE of Coorow Private 1996 200+
1996 20
Good None apparent
15. W of Lake Moore Private 1999 47 Poor Rising salinity, weeds
16. W of Lake King Nature Reserve 2002 0 Poor Rising salinity, degraded habitat
17. E of Coorow Private 1999 200 Moderate Rising salinity, weeds
18a. E of Coorow Private 2001 100 Moderate Rising salinity, weeds
18b. E of Coorow Private 2001 30 Moderate Rising salinity, weeds

Critical habitat

Critical habitat is habitat identified as being critical to the survival of a listed threatened species or listed threatened ecological community. Habitat is defined as the biophysical medium or media occupied (continuously, periodically or occasionally) by an organism or group of organisms or once occupied (continuously, periodically or occasionally) by an organism, or group of organisms, and into which organisms of that kind have the potential to be reintroduced. (Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act)).

The critical habitat for Caladenia drakeoides comprises:

  • the area of occupancy of the known populations,
  • areas of similar habitat ie. Winter-moist rises above salt lakes and saline flats, within 200 metres of known populations (these provide potential habitat for natural recruitment),
  • corridors of remnant vegetation that link populations (these are necessary to allow pollinators to move between populations),
  • the local catchment which provides the correct water table for the species (the species occurs adjacent to lakes and saline flats and is dependent on maintenance of local surface hydrology),
  • additional occurrences of similar habitat that do not currently contain the species (these represents possible future translocation sites).

Habitat critical to the survival of the species, and important populations

Given that this species is listed as Critically Endangered it is considered that all known habitat is habitat critical. In addition, all populations, including translocated populations, are considered important to the survival of the species.

Benefits to other species/ecological communities

Recovery actions implemented to improve the quality or security of the habitat of Caladenia drakeoides populations will improve the status of the remnant vegetation in which the populations are located.

International Obligations

This plan is fully consistent with the aims and recommendations of the Convention on Biological Diversity, ratified by Australia in June 1993, and will assist in implementing Australia's responsibilities under that Convention. However, as Caladenia drakeoides is not listed under any international agreement, the implementation of other international environmental responsibilities is not affected by this plan.

Role and interests of indigenous people

There are no known indigenous communities interested or involved in the management of areas affected by this plan. Therefore no role has been identified for indigenous communities in the recovery of this species.

Social and economic impacts

The implementation of this recovery plan is unlikely to cause significant adverse social and economic impacts. However, as many populations occur on private land the protection of them may potentially affect farming activities. Many of these populations have now been fenced to reduce the impact on what may have otherwise been large areas that could not have been farmed.

Evaluation of the Plans Performance

The Department of Conservation and Land Management, in conjunction with the Moora, Merredin and Katanning District Threatened Flora Recovery Teams will evaluate the performance of this Interim Recovery Plan. The plan is to be reviewed within five years. Any changes to management / recovery actions will be documented accordingly.

Guide for decision-makers

Section 1 provides details of current and possible future threats. Developments in the immediate vicinity of the population or within the defined critical habitat of Caladenia drakeoides require assessment. No developments should be approved unless the proponents can demonstrate that they will not have a significant impact on the species, or its habitat or potential habitat, or the local surface and ground water hydrology

.