NSW National Parks and Wildlife Service, 2002
10. Previous Actions Undertaken
- 10.1 Status of Woodhen Habitat
- 10.2 Previous Studies
- 10.3 Control of Exotic Species
- 10.4 Current Management Practices
- 10.5 Captive Breeding
- 10.6 Community Activities
Conservation measures that have been undertaken to protect the Woodhen and its habitat are described in this section.
The Lord Howe Island Group, including Lord Howe Island, Ball's Pyramid, the Admiralty Islands and the contiguous seas, was inscribed on the World Heritage List in 1982.
The LHIB is responsible for the care, control and management of the island in accordance with the LHI Act.
Approximately 75% of the land in the Island Group is included in the Lord Howe Island Permanent Park Preserve (PPP). The PPP has similar status to a national park but is managed by the Board. The remaining land area is Crown land, much of which is subject to various leases administered by the Board. A Regional Environmental Plan (REP) (1986) zones land on the island with identified permissible land uses. The REP is currently under review.
In the southern mountains, Woodhen habitat falls within the PPP. Under the REP development within the Preserve may only occur in accordance with the plan of management for the area. The plan of management restricts development to park infrastructure and no residential or commercial development is permitted.
Many local residents with Woodhens on their leases take an interest in the birds and in the outcome of breeding attempts and the fate of chicks. Many residents provide supplementary food to the Woodhens in their area. This interest has contributed to the species' rehabilitation.
In 1970, an environmental survey of the island was initiated to determine its natural values and management needs (Recher and Clark 1974). In 1972, a management plan for the island was prepared (Recher 1972). The 1970 survey led to an intensive study of the Lord Howe Woodhen on Mount Gower by the Australian Museum starting in February 1971 (Fullagar 1985). Most Woodhens were individually colour-banded and aspects of their social organisation, reproduction and feeding were documented for the first time.
In 1978, a full time study began by the LHIB and the NPWS, supported by the National Parks and Wildlife Association of NSW. The study included the evaluation of captive breeding and release site options. This study confirmed the significant role of Pigs in limiting the return of the Woodhen to the lowlands (Miller and Mullette 1985).
From 1986 to 1997, twice-yearly monitoring was undertaken by the NPWS Biodiversity Research and Management Division (NPWS BRMD). The methods and results of this program were documented in annual reports until 1998 (Harden 1986, 1987, 1990, Harden and Robertshaw 1988, 1998), and involved both census methods and maintaining a high percentage of the population individually colour-banded. A report describing the methodology and summarising results to 1997 has been produced (Harden 1998). In 1998 and 1999, annual monitoring was undertaken.
Responsibility for the surveys was transferred to the LHIB in 1999. During the 1999 November survey, Justin Billing (NPWS BRMD) trained Board staff in the survey methodology. In 2000 and 2001 the twice yearly monitoring program was reinstated. A report detailing the results from these surveys is currently in preparation (Harden in prep). An Access database has been developed for managing the monitoring data collected. The database needs to be updated to improve accuracy of data entry, reporting and to include all existing data.
In 1987, a study was undertaken to determine the occurrence of disease in the Woodhen population (see appendix to Harden and Robertshaw 1988). None was found in the birds sampled.
Like many islands in the Pacific, Lord Howe Island had a range of mammals introduced that affected the status and distribution of indigenous fauna. Table 3 summarises current knowledge of the date of introduction of exotic species and evidence for their spread on the island, as well as summarising the range of effects on the Woodhen. Information is also provided on current status and control measures.
A significant component of the Woodhen rehabilitation program and one with significant ancillary biodiversity benefits was the control of Goats and Pigs. Predation by the Ship Rat on Lord Howe Island was listed as a Key Threatening Process under the TSC Act in May 2000. A proposal to eradicate rodents from the island is being considered by the LHIB. It is likely that Woodhens would be vulnerable to the baits being laid as part of this program and birds would probably need to be removed from the wild and kept captive until the program was complete. A Risk Assessment Report is currently being prepared.
The LHIB has a 'Noxious Weed Control Procedure' under the LHI Act and the Noxious Weeds Act 1993. This procedure is being reviewed to incorporate the impact of many existing and potential environmental weed species on the island, which are not declared noxious. The new document will provide strategic direction for LHIB weed control programs.
Additionally LHIB staff carries out noxious weed inspections on all leases. These inspections allow for the identification of weed infestations and, in conjunction with the leaseholder, the development of control strategies for individual infestations.
Noxious weed species of highest priority with potential to significantly alter Woodhen habitat are:
- Bitou Bush (Chrysanthemoides monilifera subsp. rotundata)
- Ground Asparagus (Protoasparagus aethiopicus)
- Climbing Asparagus (P. plumosus)
- Bridal Veil (Myrsiphyllum asparagoides)
- Sweet Pittosporum (Pittosporum undulatum)
- Cherry Guava (Psidium catteianum var. catteianum)
- Ochna (Ochna serrulata)
- Castor Oil Plant (Ricinus communis)
In the southern mountains, Woodhen habitats fall within the Permanent Park Preserve (PPP). The Woodhens in this area are protected from the effects of developments that might occur on the island. A permit system currently operating for the track to Mount Gower requires all visitors to the Mountain to be accompanied by a guide. This enables the monitoring and control of visitor activities. The current bed limit on the island makes significant growth in visitation unlikely.
However, two indirect impacts may occur if there were increased tourism and associated development on Lord Howe Island:
- increased human visitation to key habitat areas, causing increased disturbance and possible interference with the Woodhen's usual behaviour. (Miller and Mullette (1985) warn that examination of Woodhen nests resulted in the parents destroying the eggs and the nest); and
- the requirement for the installation of additional visitor infrastructure in or near the Woodhen's key habitats.
Any proposed increase in visitor access or infrastructure would be subject to environmental impact assessment and the protection of Woodhen habitat and populations would remain a priority.
- The LHIB is funding the development of a strategic plan for the management of vegetation on the island. The Plan will provide for a weed management strategy and a re-vegetation strategy.
One of the most successful activities to promote the rehabilitation of the Lord Howe Woodhen was the captive breeding and release program between 1981 and 1983. Miller and Mullette (1985) and Lourie-Fraser (1985) provide detailed accounts of this program. The following summary is based on these accounts.
- In 1978-80, the NPWS and the Australian Museum studied the soil fauna of the island to determine possible sites for release of captive-bred birds.
- In 1980, a captive breeding facility was established at Steven's Reserve in the Settlement area and a cat-proof fence built around it.
- In June 1980, three wild, territory holding pairs were caught and transported to the facility.
- In the first season (1980-81), 13 chicks were reared. In the second season 19 chicks were reared and the breeding stock was raised to five pairs. In the third season 34 chicks were reared. In the fourth season (1983-84) 14 chicks were reared.
- Including the original wild caught birds, 82 Woodhens were released between May 1981 and March 1984 (see Table 1).
- The captive breeding and release program ceased in 1984.
- Two Woodhens were taken from the island to an enclosure at Taronga Park Zoo in 1989, however they died in 1990 without breeding. These birds were not part of a designed captive breeding proposal.
The Lord Howe Island community has taken an active interest in the protection and rehabilitation of the Woodhen since the first studies in the 1970s. This interest has included active involvement in conservation activities, including:
- participation in research and monitoring activities;
- monitoring and reporting Woodhen activities to the LHIB;
- maintaining suitable habitat for Woodhens on leases; and
- feeding Woodhens to assist their survival.
These efforts have contributed significantly to the re-establishment and survival of Woodhens in the settlement area and to rehabilitation of the species as a whole.