Interim Recovery Plan No
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INTERIM RECOVERY PLAN NO. 121 BUSSELL’S SPIDER ORCHID (CALADENIA BUSSELLIANA) AND DUNSBOROUGH SPIDER ORCHID (CALADENIA VIRIDESCENS) INTERIM RECOVERY PLAN 2002-2007 Gillian Stack, Andrew Batty and Meredith Spencer Caladenia viridescens Caladenia busselliana Photographs: Andrew Brown December 2002 Department of Conservation and Land Management Western Australian Threatened Species and Communities Unit (WATSCU) PO Box 51, Wanneroo, WA 6946 Interim Recovery Plan for Caladenia busselliana and C. viridescens FOREWORD Interim Recovery Plans (IRPs) are developed within the framework laid down in Department of Conservation and Land Management (the Department) Policy Statements Nos. 44 and 50. IRPs outline the recovery actions that are required to urgently address those threatening processes most affecting the ongoing survival of threatened taxa or ecological communities, and begin the recovery process. The Department is committed to ensuring that Critically Endangered taxa are conserved through the preparation and implementation of Recovery Plans or Interim Recovery Plans and by ensuring that conservation action commences as soon as possible and always within one year of endorsement of that rank by the Minister. This Interim Recovery Plan will operate from December 2002 to January 2008 but will remain in force until withdrawn or replaced. It is intended that, if the taxon is still ranked Critically Endangered, this IRP will be reviewed after five years and the need for a full Recovery Plan assessed. This IRP was approved by the Director of Nature Conservation on 11 July 2003. The provision of funds identified in this Interim Recovery Plan is dependent on budgetary and other constraints affecting the Department, as well as the need to address other priorities. Information in this IRP was accurate at December 2002. 2 Interim Recovery Plan for Caladenia busselliana and C. viridescens SUMMARY Scientific Name: Caladenia busselliana Common Name: Bussell’s spider orchid Scientific Name: Caladenia viridescens Common Name: Dunsborough spider orchid Family: Orchidaceae Flowering Period: September – October Dept Region: South West Dept District: Blackwood Shire: Busselton Recovery Team: South West Region Threatened Flora Recovery Team Illustrations and/or further information: A. Brown, C. Thomson-Dans and N. Marchant (Eds) (1998) Western Australia’s Threatened Flora. Department of Conservation and Land Management, Perth; N. Hoffman and A. Brown (1992) Orchids of South-west Australia. University of Western Australia Press. Perth; S.D. Hopper and A.P. Brown (2001) Contributions to Western Australian Orchidology:2. New taxa and circumscriptions in Caladenia (Spider, Fairy and Dragon orchids of Western Australia). Nuytsia 14(1/2), 27-308; S. Elscot (2001) Carbunup Reserve Management Plan Shire of Busselton. Western Australia. Current status: Caladenia busselliana and Caladenia viridescens were declared as Rare Flora in September 1992 and ranked as Critically Endangered (CR) in September 1995. Both species currently meet World Conservation Union (IUCN, 2000) Red List Category ‘CR’ under criteria B1ab(iii,v)+2ab(iii,v) and D due to the limited distribution and severe fragmentation of populations and continuing decline in the quality of the habitat and number of mature individuals. The main ongoing threats are further habitat degradation and inappropriate fire regimes. A number of plants of both species occur adjacent to roadsides or walk trails and these are threatened by accidental destruction. Critical habitat: The critical habitat for Caladenia busselliana and C. viridescens is comprised of the area of occupancy of the known populations; similar habitat within 200 metres of known populations; corridors of remnant vegetation that link populations, additional nearby occurrences of similar habitat that do not currently contain the species but may have done so and may be used for translocations, and the local catchment for the surface water that provides the wetland habitat of the species. Habitat requirements: Caladenia busselliana is currently known from a narrow range of less than 40 linear km in the Vasse-Yallingup area. It grows in winter-wet swamps on sandy loam over clay soils in jarrah and marri woodland, with Anigozanthos viridis and C. paludosa. C. viridescens occurs over a linear range of 12 km near the northern end of the Leeuwin-Naturaliste Ridge. It grows on well-drained lateritic sandy loam soils in marri and peppermint woodlands with C. brownii or coastal heath with Calothamnus graniticus ssp. graniticus, Hakea trifurcata and many other Caladenia species, and occasionally in the same swampy areas that C. busselliana favours. Existing Recovery Actions: The following recovery actions have been or are currently being implemented – 1. Relevant land managers have been made aware of the location and threatened status of each species. 2. DRF markers have been installed at all roadside populations. 3. Habitat restoration measures including deep-ripping, rubbish removal and weed control have been undertaken at Caladenia busselliana Population 1 and C. viridescens Populations 1 and 4. 4. A track at Caladenia busselliana Population 1 and C. viridescens Population 4 has been closed. 5. Spot spraying of weeds has been carried out as appropriate for both species. 6. The habitat of Caladania busselliana Populations 1 and 2a and C. viridescens Population 4 have been fenced to exclude grazing. 7. Staff from Botanic Garden and Parks Authority (BGPA) collected seed from Caladenia busselliana Population 2 and C. viridescens Population 1 in 2001. This is stored in the BGPA’s plant science lab at –196°C. 8. BGPA staff are assessing material from Caladenia busselliana and C. viridescens to determine the genetic distinctiveness of each of the species. 9. Germination trials of Caladenia busselliana and C. viridescens are currently being carried out by BGPA staff. 10. A research burn was undertaken in December 1999 to investigate how these species respond to fire. Monitoring of this trial is ongoing. 11. A fire management plan is being developed, and will be modified as appropriate when results of fire research are known. 12. The process of changing the care, control and management of the Shire Reserve, on which Caladenia busselliana Population 1 and C. viridescens Population 4 occur, to A Class Nature Reserve vested with the Conservation Commission has commenced. 13. Staff from the Department's Blackwood District regularly monitor populations of these species. The exact location of individual plants is recorded by differential GPS when possible. 14. A new population of each species has been discovered during recent surveys. 15. Information sheets describing and illustrating each species have been produced and distributed. 3 Interim Recovery Plan for Caladenia busselliana and C. viridescens 16. These species were both promoted through threatened flora displays at local wildflower shows and Threatened Flora Field Days. Field workers from the Blackwood District have received scanned colour photographs of both species. 17. A review of historic rainfall data was undertaken in 2001 to identify any correlation between rainfall patterns and orchid flowering. 18. The South West Region Threatened Flora Recovery Team is overseeing the implementation of this IRP and will include information on progress in an annual report to the Department's Corporate Executive and funding bodies. IRP Objective: The objective of this Interim Recovery Plan is to abate identified threats and maintain or enhance in situ populations to ensure the long-term preservation of the species in the wild. Recovery criteria Criteria for success: The number of individuals within populations and/or the number of populations have increased. Criteria for failure: The number of individuals within populations and/or the number of populations have decreased. Recovery actions 1. Coordinate recovery actions 9. Monitor populations 2. Continue weed control 10. Finalise the fire management plan 3. Continue control of grazing 11. Liaise with land managers 4. Conduct further surveys 12. Seek to transfer care, control and management of habitat 5. Stimulate seed set 13. Obtain biological and ecological information 6. Collect seed and fungal material 14. Promote awareness 7. Stimulate flowering 15. Rehabilitate habitat as required 8. Undertake translocation 16. Review the need for a full Recovery Plan 4 Interim Recovery Plan for Caladenia busselliana and C. viridescens 1. BACKGROUND History The first collection of Caladenia busselliana housed at the WA Herbarium was made in 1954 from an unknown location and exhibited in a flower show. The species then escaped detection until 1990 when it was rediscovered by Busselton orchid enthusiast Mr Greg Bussell. During surveys in 1990 more than 100 plants were recorded south east of Dunsborough (Population 1). Since then the number of plants in all populations has fluctuated but shown a general decline, with only 6 plants located in Population 1 in 2001. Caladenia viridescens was first collected in 1985 in a road reserve near Dunsborough by S.D. Hopper and A.P. Brown (Population 1). They located more than 20 plants at this time. Eight plants were located in the population in 2001. There are now 6 populations, and all show a fluctuation and general decline in numbers similar to that noted for C. busselliana. Several plants were reported from Leeuwin Naturaliste National Park in 1986 (Population 5), but have not been relocated since to confirm the identification. There was