National Recovery Plan for Eastern Bristlebird Dasyornis brachypterus

Small sub-populations and genetic bottlenecks

Yüklə 0,66 Mb.
ölçüsü0,66 Mb.
1   2   3   4   5   6   7   8

Small sub-populations and genetic bottlenecks

The national Eastern Bristlebird population has become severely fragmented. Fragmentation and isolation may be adversely affecting regional populations. Smith (1977) considered that the specialised habitat requirements of the Eastern Bristlebird prevented remnant populations from expanding. This is compounded by the limited amount of extant habitat available to the species. The dispersal potential and the need for dispersal corridors are unknown. Fragmented small populations are prone to deleterious genetic consequences related to their lack of genetic variability (Usher 1987). The extent of this effect on populations of the bristlebird is unknown.

The history and ecology of the species strongly suggest that as populations become small and fragmented, local extinctions ensue quickly. Some local populations are now so small in the north (only a few birds or pairs of birds in each) that young produced may not physically be able to find birds from other local populations to pair up with. Without augmentation in numbers in these locations to allow this pairing to happen, these sub-populations will not persist (D. Charley pers. comm.).
Fragmentation of habitat and isolation of populations can also occur on a smaller scale as a result of the construction or maintenance of public roads and utility corridors. Where possible further habitat loss should be avoided and regeneration of habitat on unused tracks should be undertaken.

Climate change

Climate change is one of the major threats to biodiversity on a global scale, and human-induced climate change has been listed as a key threatening process under the EPBC Act (TSSC 2001b). It is driven predominantly by the release of greenhouse gases into the atmosphere by the combustion of fossil fuels, and also from agriculture and industry.

Climate change will affect biodiversity directly and indirectly through temperature change, changes in rainfall and water quality and increases in extreme events such as fires, floods, storms, heatwaves and droughts. Ecological responses are largely driven by extreme weather events rather than by changes in mean climate (Steffen 2006), and more frequent or severe extreme events will increase the threat to species and ecosystems already under stress.
Smith (1977) suggested that remaining populations of Eastern Bristlebird are occupying marginal habitats, thus rendering them more vulnerable to small environmental changes. When climate change is superimposed on all other threats, it is expected to exacerbate their effects. As a result, current threats to Eastern Bristlebird, including fire, habitat loss, weeds and pest animals, are expected to intensify under climate change scenarios.
Individual species have two possible survival mechanisms in response to changes in climate – adaptation or migration (Hinckley and Tierney 1992). However the main threat from anthropogenic climate change is a magnitude and rate of change which exceeds the capacity of species and ecosystems to survive. Across the range of the Eastern Bristlebird, climate change impacts are likely to vary, but the fragmented nature of their habitat in some populations and their poor dispersal ability leaves few opportunities for the species to move to areas where the climate is more suitable. In populations with contiguous habitat such as in Nadgee NR, it could be argued that there is a degree of landscape resilience, although if habitat is marginal this may not help the bristlebird in the long term.

Human disturbance

The presence of humans may have an adverse impact on breeding birds and many authors have suggested closure of bristlebird areas during the nesting period (Hartley and Kikkawa 1994).

The use of call playback to detect Eastern Bristlebirds may interfere with breeding behaviour during the breeding season, potentially leading to nest abandonment.
Off-road vehicles (4WD and motor bikes) damage habitat in some areas occupied by the Eastern Bristlebird (e.g. Budderoo NP).
As a ground-dwelling species, the Eastern Bristlebird will run across busy peri-urban roads and tracks, resulting in some birds being hit by vehicles. Birds have been killed by vehicles in the Jervis Bay area but the extent of this threat to the local population is unknown. Specific Eastern Bristlebird wildlife road signage has been displayed and speed limits enforced but the extent to which this may assist in reducing the number of roadkills is unknown and roadkills are still occurring at Jervis Bay (J. Baker pers. comm.).

Recovery Information
Previous Recovery Actions
In the last 20 years, information on the occurrence, ecology and population status of the Eastern Bristlebird has increased significantly and a number of recovery actions have been implemented for its conservation. Much of the impetus for action arose from the involvement of Birdlife Australia at the Barren Grounds Bird Observatory. A variety of studies have documented these actions, and many of these are listed below, although the lists are not exhaustive. The findings and recommendations of many previous studies and outcomes of previously implemented actions have been taken into consideration in the development of proposed recovery actions in this plan.
Recovery Planning

In 1996 a recovery program for the Eastern Bristlebird commenced in NSW. The National Recovery Team was established in 1997 by the then Queensland Department of Environment and is now convened by NSW OEH. Three working groups (northern, central and southern) have also been operating for a number of years, due to the complexities of implementing recovery actions for geographically isolated populations. These working groups are represented on, and share information with, the national team.

A draft national recovery plan was prepared for the Eastern Bristlebird in 1998 (Holmes 1998). Draft national recovery plans have also been prepared for the northern population (Stewart 2001, 2006).
A draft state recovery plan has been prepared for the Eastern Bristlebird in NSW (DEC 2004) but was never exhibited publicly. The NSW TSC Act Priorities Action Statement comprises recovery actions that are consistent with this plan (DECCW 2010c). The Victorian Eastern Bristlebird Action Statement was published in 1999 (DSE 1999).
The efficacy of these plans and progress towards the implementation of recovery actions have been considered by the National Recovery Team. This recovery plan sets out the actions required to build on the successes already achieved in the recovery of this species. It builds upon the previous plans, incorporating improved knowledge of the species, and the changing priorities as objectives in earlier plans were achieved or altered.
The recovery effort has been a successful collaboration between natural resource management agencies in three states, bird research and conservation groups, DEWHA, local Government agencies, private landholders, volunteers and others. All have made significant contributions to the operation of the recovery effort. A summary of the actions that have already been undertaken is provided below.
Survey and Monitoring

The distribution and abundance of the Eastern Bristlebird have been well documented (e.g. Bramwell 2008; Clark and Bramwell 1998; Baker 1996, 1997; Baker and Whelan 1996; Holmes 1989, 1997; Sandpiper Ecological Surveys 1999, 2000b, 2002, 2003, 2008). Habitat monitoring has been undertaken in the northern population (e.g. Sandpiper Ecological Surveys 2006b). Resurveys or long-term monitoring of bird abundance have been conducted at many sites, yielding important information on population trends (e.g. Baker 1998; Bain and McPhee 2005; Holmes 1989, 1997, 2001; Sandpiper Ecological Surveys 2000b, 2002, 2003, 2006a, 2008; L. Evans pers. comm. 2010). In some cases this has been assisted by volunteer groups (e.g. Birds Queensland). Ongoing monitoring at Nadgee NR and Howe Flat have indicated stable trends for the southern population (M. Bramwell pers. comm. 2010).

A long-term vegetation and habitat monitoring program has been established for the northern population. Forty permanent survey transects have been set up in NSW and 16 in Queensland. Initial data have been analysed and findings acted upon (Sandpiper Ecological Surveys 2006b; Charley 2010). Twelve long-term vegetation monitoring plots were established at Howe Flat in 1999 (M. Bramwell pers. comm. 2010).
Habitat Mapping

The habitat of the Eastern Bristlebird has been studied and mapped to a varying degree in each population. In Jervis Bay, detailed habitat mapping was specifically conducted for development planning purposes in high urban growth areas (Bain 2001). A draft essential habitat map for Queensland has been prepared (R. Williams pers. comm. 2010). However, there is no specific niche mapping for the four populations. Currently, existing vegetation community mapping is used as a surrogate for determining potential habitat and population size. Future habitat mapping should be focused specifically on Eastern Bristlebirds, extended to cover the entire species distribution and refined using updated vegetation information (see Actions).

Research and specialist knowledge

Extensive and detailed research has been undertaken into the ecology, habitat requirements, taxonomic status and threats of the Eastern Bristlebird (e.g. Bramwell et al. 1992; Baker 1997, 1998, 2000, 2001, 2003, 2009; Baker and Clarke 1999; Gibson 1999; Schodde and Mason 1999; Gibson and Baker 2004; Bain et al. 2008), although not consistently across all populations. In particular, research into the species’ relationship with fire has been published, particularly for the central population.


Genetic analysis, however, has produced no evidence supportive of sub-speciation (Elphinstone 2008; Roberts et al. 2011) although four currently genetically isolated populations have been identified. These are: (1) the ‘northern’ population (northern NSW/southern QLD); (2) Barren Grounds (central); (3) Jervis Bay (central); and (4) the ‘southern’ population (Nadgee NR (NSW)/Croajingalong NP (Vic)) (Roberts et al. 2011). Microsatellite genetic distances among populations are correlated with geographic distance (a pattern of isolation by distance) (Roberts et al. 2011), and may have arisen over recent timeframes. The largest pool of genetic variability is in the central population, now divided into the Jervis Bay population and the Barren Grounds population.

Management and Planning

There are numerous existing plans, strategies and programs with relevance to the management of the Eastern Bristlebird and/or its habitat. Most of the known populations and habitat occur on National Parks and Nature Reserves and on Defence land. Protected area and other land management plans of interest include Plans of Management (PoM) and Fire Management Plans or Strategies (FMP or FMS) with recommendations for (or implications of) the management of Eastern Bristlebird habitat, especially in relation to fire. These plans are listed in Appendix 1.

There are numerous state, regional and local government plans and strategies that incorporate conservation requirements of the Eastern Bristlebird on private land, particularly around Jervis Bay and in northern NSW. The NSW South Coast Regional Strategy (SCRS) (DoP 2007), for example, precludes new development (i.e. rezoning) in areas of high conservation value (HCV). Conservation on private land requires ongoing cooperation between landholders, government and CMAs and NRM bodies, and linking in to programs such as the Hotspot Fire Project (NCC 2010; RFS 2010) in the northern population. Relevant plans and strategies are listed in Appendix 1.
Weed, Feral Predator and Disease Control

Feral predator baiting has been undertaken in many of the reserves occupied by Eastern Bristlebird populations to date. For example, an extensive, coordinated feral predator baiting program has been undertaken in Booderee NP since 1999 (Lindenmayer et al. 2009). The Border Ranges Biodiversity Management Plan (BMP) (DECCW 2010a) recommends undertaking coordinated and cooperative cat and fox control strategies at locally significant sites, specifically listing Eastern Bristlebird as a threatened species at risk.

Ongoing weed control is being carried out in areas occupied by Eastern Bristlebird, on public and private lands, although not at all sites. Lantana, Crofton Weed, Mistflower, Bitou Bush and Blackberry are all threats to the species and control programs being undertaken include spraying and removing by hand. In the northern population, the Border Ranges Rainforest BMP recommends identification of priority grassy wet sclerophyll areas known to contain Eastern Bristlebird and Hastings River Mouse; and development and application of appropriate fire management strategies to control weed and shrubby acacia encroachment while protecting adjacent rainforest (DECCW 2010a).
Phytophthora hygiene practices are applied in day to day management at many of the parks and reserves inhabited by Eastern Bristlebird, e.g. Beecroft Weapons Range and Nadgee NR. In the Nadgee Wilderness Area the hygiene protocol is to spray vehicles with a fungicide and use a foot-bath to remove the fungus from boots (D. Oliver pers. comm. 2010)
Grazing management and exclusion

There has been ongoing liaison between the Northern Working Group and landholders to exclude grazing on Eastern Bristlebird habitat, especially during the breeding season. Stock exclusion fencing has been constructed at two sites in northern NSW with fences yet to be erected on private land in southeastern Queensland (Charley 2010, E. Gould pers. comm.). Grazing permits have been terminated and stock removed from Border Ranges NP.

Habitat Management Burns

A number of habitat management burns have been conducted in south-eastern Qld and north-eastern NSW (Charley 2010). The Border Ranges Rainforest BMP (DECCW 2010) recommends establishment of five trial fire management sites in previously occupied Eastern Bristlebird territories at Richmond Gap in NSW.


Between 2003 and 2005, a total of 51 birds were translocated from Bherwerre Peninsula (Jervis Bay and Booderee NPs) to the nearby Beecroft Peninsula (Beecroft Weapons Range) that had been unoccupied by the species for over a century. Radio-tracking of the individuals indicated a colony was successfully established (Bain 2003a, 2003b, 2006). Surveys have shown medium-term success with high bird counts and evidence of breeding (Bain 2006; Baker 2009). Surveys in spring 2009 estimated at least 73 birds at Beecroft (M. Armstrong pers. comm. 2009).

In 2008, 50 Eastern Bristlebirds were translocated from Barren Grounds NR to the previously unoccupied Sydney Catchment Authority (SCA) Metro Special Area on the Woronora Plateau near the Cataract Reservoir (DECC 2008, Baker 2009). Follow-up monitoring showed medium-term success with evidence of breeding in the first year after release. Although a low number of birds (12) was detected 18 months after release, this may be due to access difficulties and the variable responsiveness of the birds to the call playback (Baker 2009) and potential dispersal away from survey sites.
Captive Breeding and Reintroduction

A pilot captive breeding program for the northern population commenced at David Fleay Wildlife Park in 2004 (Booth et al. 2005). Two sibling nestlings were acquired from the wild, and the evidence from five breeding seasons suggested that the species will breed readily in captivity, provided adequate numbers of founders can be acquired.

A pilot reintroduction of eight captive-bred birds from David Fleay Wildlife Park was carried out in 2008 in north-eastern NSW and south-eastern Qld. Birds were radio-tracked for four weeks post-release, with two individuals being predated in that period (R. Booth and D. Stewart pers. comm. 2009). Two of these banded captive-bred birds were observed in the wild in north-eastern NSW in 2010 (J. Young unpublished data).
Results from this study have provided information on the Eastern Bristlebird, including life history details, future captive breeding methods and optimal radio-transmitter attachment (Booth and Stewart 2007).
Community Awareness

The Eastern Bristlebird Public Contact Action Plan (York 2002) prepared in consultation with the Northern Working Group has raised the profile of the species and improved liaison with landholders and birdwatching groups. Interpretive notices, road signs and information pamphlets in central and southern population areas have increased public awareness and support.

Volunteer Involvement

Birds Queensland has been closely involved in population survey and monitoring which has involved training of skilled observers. Volunteers have assisted with survey, banding and monitoring effort at Howe Flat, Victoria. Volunteers have also been very active at many locations in the central population.

Recovery Objectives
Long-term Overall Objective

The long-term objective [by 2030] of this plan is the recovery of all populations of the Eastern Bristlebird to a position where all four populations are stable. The northern population will be enhanced to increase to a viable level. The central populations will remain stable. An additional southern population will be established in Victoria, bringing the southern population to a viable size. Viable population size will be determined by population viability analysis (PVA). Attaining this long-term objective will involve the protection and management of habitat, the management of threats and enhancement of wild populations through captive breeding, reintroduction and translocation. The objectives, criteria and actions proposed in this recovery plan work towards that objective and build on those in previous plans.

Specific Objectives [within the 5 year projected timeframe of this plan]
Objective 1: Maintain and improve the condition and extent (carrying capacity) of Eastern Bristlebird habitat and minimise known or likely threats for all populations, with particular emphasis on fire prescriptions, minimising habitat fragmentation and control of: feral predators, exotic herbivores, overgrazing and weeds.
Objective 2: Undertake survey, monitoring and mapping to improve knowledge of all Eastern Bristlebird populations. Population dynamics and habitat condition will be monitored in each population. Methods including survey effort and frequency will be reviewed and standardised and will be subject to ongoing review according to census results or special circumstances such as wildfire. Potential habitat will be surveyed to locate new colonies in the northern and southern populations, and to estimate more accurately the population size for all populations.
Objective 3: Enhance/augment northern and southern populations, building towards viable populations as determined by population viability analysis.
Objective 4: Conduct research to increase knowledge of ecology, threats and habitat management requirements of the Eastern Bristlebird.
Objective 5: Increase community awareness, understanding and involvement in the Eastern Bristlebird recovery effort, particularly on private land. Improve communication between working groups and stakeholders including Australian and State Government agencies, CMAs and other NRM bodies, the Aboriginal community, landholders, land managers, rural fire services and interest groups.
Objective 6: Effectively organise and administer the recovery effort to ensure that recovery plan objectives are met.

Recovery Actions
OBJECTIVE 1: Maintain and improve the condition and extent (carrying capacity) of Eastern Bristlebird habitat and minimise known or likely threats for all populations, with particular emphasis on fire prescriptions, minimising habitat fragmentation and control of: feral predators, exotic herbivores, overgrazing and weeds.
The recovery of the Eastern Bristlebird will depend on minimising the further loss and fragmentation of habitat and improving its condition, as well as population enhancement, security and maintenance. An increase in areas of potential habitat, appropriate fire prescriptions and control of feral pests and weeds will provide greater security to all Eastern Bristlebird populations.
Recovery criterion 1: Eastern Bristlebird populations are protected from wildfires where possible; species requirements and strategies have been incorporated into fire management strategies within occupied or potential habitat; feral predator control programs are implemented; impact of feral pigs has been investigated and control programs used where necessary; weed and Phytophthora control programs are implemented and fragmentation of habitat is minimised and the condition and extent of habitat is improved or maintained.

A: Fire prescriptions
This plan recognises that the implementation of site-specific actions for Eastern Bristlebird must occur within the context of broader fire-management issues. Clearly the requirements of all threatened species must be taken into account in the range of fire management policies and plans across the Eastern Bristlebird’s range, along with protection of human life and operational requirements. In some cases specific Eastern Bristlebird fire prescriptions may not be compatible with other management obligations. The Biodiversity Benefits section (page 45) lists other significant species within the range of Eastern Bristlebird. Some threatened species may have different habitat requirements in terms of fire frequency, e.g. New Holland Mouse.
However, where possible, fire management plans for known Eastern Bristlebird habitat and adjacent land tenures (as described in the following actions) should:

-provide for suppression of intensive and extensive wildfire (with the exception of Nadgee Wilderness);

-ensure site-appropriate burning regimes;

-contain prescriptions for habitat monitoring and habitat management;

-be updated regularly;

-provide for fire suppression using only Phytophthora-free water;

-create refugia where necessary;

-maintain fire breaks and fire management tracks; and

-maintain and update fire histories on shared computerised GIS files.
For areas adjacent to known sites, plans should also cover multi-owner areas so numerous properties can be managed together.
Action 1.1: Incorporate Eastern Bristlebird requirements and strategies into bushfire management plans where this has not occurred for all Eastern Bristlebird habitat in the northern population. Site-specific strategies will require ongoing liaison with land managers, landholders and species experts. The National Recovery Team and Northern Working Group will support the ongoing work with landholders and property-based fire planning programs of the South-eastern Queensland and Northern Rivers Fire and Biodiversity Consortiums and Hotspots Fire Project in north-eastern NSW.
Conduct habitat management burns in previously occupied territories in the northern population and ensure burns coincide with management plans for these tenures. Habitat management burns are required to maintain and rehabilitate important breeding habitat in Border Ranges NP.
Priority: Very High
Potential contributors: EHP, NPRSR, OEH, RFS and Northern Working Group

Action 1.2: Incorporate Eastern Bristlebird requirements and strategies into bushfire management plans where this has not occurred for all Eastern Bristlebird habitat in the central populations. Site-specific strategies will require ongoing liaison with land managers, landholders and species experts, but will follow principles of protection from wildfire over the five years of the plan and ensure that a high proportion of habitat remains unburnt.
At Barren Grounds NR and Budderoo NP, modify existing management tracks (principally track widening and upgrading for all weather use) and construct additional track links (to escarpment edges, etc) to provide a higher level of protection against wildfire. This will include preparation of a Review of Environmental Factors (REF) for identified works, upgrade of management tracks and amend Reserve Fire Management Strategy as required. It is important to note that lightning strikes and car arson are relatively common occurrences in the vicinity of these reserves. (The increasing incidence of car arson due to rapidly increasing residential development in nearby population centres is now a significant threat.) The frequency of these incidents, and therefore, the risk they pose is predicted to increase. The proposed works would provide a considerable fire control advantage and a very practical method of providing a higher level of security for a viable, critical population of Eastern Bristlebirds.
Priority: Very High
Potential contributors: OEH, Parks Australia, Department of Defence, Wreck Bay Community Council, RFS, National Recovery Team and Central Working Group.

Action 1.3: Incorporate Eastern Bristlebird requirements and strategies into bushfire management plans where this has not occurred for all Eastern Bristlebird habitat in the southern population. Site-specific strategies will require ongoing liaison with land managers, landholders and species experts.
Conduct an experimental burn in areas of long-unburnt (greater than 20 years) heathland north of Howe Flat. Bristlebird abundance and vegetation structure and floristics will be monitored as per Action 3.4.
Given the remoteness of the sites and lack of fire advantages, protection of refuges in Nadgee NR could only be achieved by helicopter water bucketing. Nadgee has not been burnt for 30 years but the upper biodiversity vegetation thresholds may be exceeded if it is to the advantage of the conservation of the Eastern Bristlebird population (NPWS 2003).
Priority: Very High
Potential contributors: OEH, Parks Victoria, DSE, National Recovery Team and Southern Working Group

Action 1.4: Monitor bristlebird abundance and vegetation response to fire at selected sites in each population (management dependent).
Priority: High
Potential contributors: OEH, DSE, Parks Victoria, EHP, NPRSR, BirdLife Australia/Birds Queensland, National Recovery Team and Working Groups, research organisations (e.g. ANU, UoW, UQ, Griffith University).

Yüklə 0,66 Mb.

Dostları ilə paylaş:
1   2   3   4   5   6   7   8

Verilənlər bazası müəlliflik hüququ ilə müdafiə olunur © 2020
rəhbərliyinə müraciət

    Ana səhifə