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A Dunn and FAR Hill
Environment Australia, September 1997
Note:This publication has been superseded by the National Recovery Plan for the Abbott's Booby Papasula abbotti
To ensure progress in the Recovery Plan is reviewed regularly by a team with appropriate expertise, community standing, and concern for the conservation of the taxon.
The appropriate body to undertake reviews of the Recovery Plan is a Recovery Team drawn from representatives of funding bodies, land management agencies, the community and other people with appropriate expertise.
The Recovery Team will review the implementation of the Recovery Plan twice-yearly. Due to the expense of bringing Recovery Team members together the Recovery Team will usually communicate by telephone and email. The Recovery Team will consist of the following:
Team administration by PAN Christmas Island staff.
|Airfares and accommodation||10.0||10.0|
To develop a more cost-effective method of monitoring Abbott's Booby total population size, and methodology for comparing breeding success and proximity to forest clearings.
The current methodology to estimate total population size and breeding distribution is expensive and labour-intensive and it should be possible to reduce the survey effort required to produce acceptable estimates of total population size.
It is essential to monitor the effect of rehabilitation plantings on the breeding success of Abbott's Booby because the conservation of this species is a major justification for rehabilitation of minefields. The methodology to do this needs to be reexamined to ensure that sufficient data is collected to reveal possibly small but significant differences in breeding success and to decide, for example, whether this monitoring needs to be ongoing or repeated at intervals of a number of years.
Information on nesting distribution from previous surveys is available on Christmas Island although not all of this data may have been analysed. For example, there may be some nesting data for the northern terraces which has not been analysed (H. Yorkston personal communication). Previous workers are confident that no significant nesting areas remain undiscovered (Yorkston, H., GBRMPA, personal communication). The existing data on nest locations will be useful in designing the methodology. Estimating total population size which might involve a stratified transect design and the design for monitoring of breeding success would be nested within the overall population survey design.
A population survey probably needs to be carried out between May and November when attendance of parents at the nests is reasonably high. A survey of total population size every five years was suggested by Yorkston (1992). Methodology, plus hypothetical rates of increase of the population and the error associated with estimates of total population size are considerations in deciding the frequency of surveys. Yorkston (1992) recommended a survey interval of 5 years. The last survey was in 1991.
Re-evaluation of the survey methodology requires the expertise of population biologists as well as field biologist familiar with Abbott's Booby. PAN Christmas Island staff will compile all existing data relevant to this action and will have the lead role in this action. The budget allows for provision of expert advice to the PAN Christmas Island staff, as recommended by the participants in the forum on Abbott's Booby held in Canberra in August 1997.
To estimate the size of the breeding population, describe nesting distribution in relation to clearings, and to compare breeding success between nesting areas affected by mine clearings and other nesting areas. Some of the information gaps identified by Meek (in prep.) might be addressed in this action.
Mine clearings affect localised breeding success and result in changes in nesting distribution. Rehabilitation of mined areas has been implemented to combat these effects. The information gathered from population surveys will be used to detect changes in overall population size, distribution, and breeding success, which will aid in determining the effectiveness of the rehabilitation and may identify new priority areas for rehabilitation.
The methodology will be developed in Action 3. The costing below provides for employing a biologist for 10 months and an assistant for 7 months and is based on the methodology used by Yorkston & Green (1991). The new methodology is likely to be cheaper than this.
|Administration costs (15%)||11.5||11.5|
* based on methodology used by Yorkston & Green (1992) and is a guide only.
To prevent any further clearance or degradation of Abbott's Booby nesting habitat through negotiation with other landholders.
Extensive areas of nesting habitat of Abbott's Booby have been lost since settlement and the total breeding population size is now very small. This action aims to ensure continued protection of all known and any new nesting habitat. Some of the nesting habitat is close to areas of human use such as mining leases. It is essential that areas adjacent to nesting habitat are managed so that the breeding success of Abbott's Booby is not reduced. Clearance of forest adjoining nesting areas of Abbott's Booby have been shown to significantly reduce the breeding success of birds nesting within 300 m on the north-west side of the clearing because of increased wind turbulence. Thus clearance of vegetation within 300 m of nesting colonies, particularly on the south-east side, is highly undesirable.
Buffer areas of 300 m should be established around nesting colonies, within which any planned changes to land-use should require examination by PAN staff for impacts on Abbott's Booby. These should be mapped and made available to other agencies whose activities may impact on areas adjacent to nesting areas. PAN staff on Christmas Island (and Darwin) are routinely involved with the other stakeholders in negotiations over their activities within and adjacent to the National Park. This is ongoing.
To rehabilitate mined areas adjacent to Abbott's Booby habitat to reduce wind turbulence in the canopy downwind of these clearings. This action also includes monitoring of the impact of rehabilitation on wind turbulence within forest downwind.
Many Abbott's Booby nest sites were located in areas containing high grade phosphate which were subsequently mined. Abbott's Boobies, thus displaced, tended to move only a short distance from their last nest site. This means that a large number of nest sites are now close to the edge of clearings. Nests that are within 300m downwind of clearings have a significantly lower breeding success than nests that are upwind from clearings. One of the major reasons for this reduced breeding success appears to be wind turbulence in the canopy caused by the nearby clearing. Wind-tunnel modelling indicates that this turbulence can be ameliorated by plantings in the upwind minefields. Ultimately, the regrowth forest may provide more nesting habitat in the distant future. The effectiveness of rehabilitation plantings needs to be measured (CSIRO 1996).
The review of the CIRRP (CSIRO 1996) is likely to provide a new methodology for rehabilitating minefields. Minefields which are of a high priority for rehabilitation because of their proximity to Abbott's Booby nesting areas were provided by Carew-Reid (1987), however, the rehabilitation of these minefields is well behind schedule (Table 1; H. Yorkston personal communication, P. Meek, personal communication). In consultation with the mine an agreed and binding timetable for the rehabilitation of all priority minefields must be reached and implemented. Commencement of rehabilitation works in Field 20 is the highest priority.
The effect of rehabilitation plantings on wind turbulence must be monitored to ensure that the planting methods used do have a measurable effect. PAN Christmas Island staff are currently negotiating with a Western Australian university to carry this out. It is intended that information arising from this work could then be used in more refined wind-modelling experiments using the digital elevation model developed by the Bureau of Resource Sciences (K. Porritt, BRS, personal communication).
It is anticipated that a post-graduate student would initially undertake some modelling work to plan the experimental programme. The modelling work would attempt to model the wind flow over the island and account for the different surface roughnesses that are present. The modelling work would be used to plan an experimental programme that can validate the model. In this it would be necessary to take field measurements over different changes in surface effects. A numerical study once validated could provide a clear management tool for ascertaining what if strategies (T. Lyons, Murdoch University, personal communication).
The new mine lease provides for continued payment of the rehabilitation levy. The size of this 'Rehabilitation Levy' is not known until just prior to the commencement of that years rehabilitation work. The levy for the 1996/97 season was $756,652.
Below is a costing for monitoring the effects of rehabilitation planting on wind and on further modelling of wind effects (Murdoch University, BRS). This would involve a post-graduate student for three years. It is anticipated that this study would be partly funded by the rehabilitation levy.
To locate areas that Abbott's Booby use for feeding during the breeding season.
It is not known where Abbott's Boobies feed, however, most of their foraging appears to take place at a substantial distance from Christmas Island. Fishing pressure and other types of resource utilization of the north-west Indian ocean where the birds are likely to be feeding will inevitably increase. It is essential to know where key feeding areas are so that arguments can be made for management of them that is sympathetic with the conservation of Abbott's Booby.
Abbott's Booby are thought to forage several hundred kilometres from Christmas Island and so satellite telemetry is the only practical method of locating the birds at sea. Abbott's Boobies average about 1.4 kg in weight (Marchant & Higgins 1990) and satellite transmitters small enough for use on these birds are available
Five breeding adults, probably of the same sex, should be tracked to minimise the effects of variables such as age and time of year on results. Capturing adults is problematic and may require employment of an expert tree climbing biologist such as John Young. A tree-climber from Indonesia may be a cheaper alternative. The budget provides for this possibility.
The results of this action should be used to reexamine the findings of Reville et al. (1990a) who suggested a causal relationship between sea surface temperatures in upwellings north of Christmas Island and Abbott's Booby breeding success.
The budget provides for the analysis and write-up to be done principally by PAN Christmas Island staff (estimated 6 mos). PAN staff will probably have to come to the mainland for training on use of the transmitters.