Case study — example of trends in species and communities — victoria and south australia

South-eastern red-tailed black-cockatoo Calyptorhynchus banksii graptogyne

Description

The south-eastern red-tailed black-cockatoo Calyptorhynchus banksii graptogyne, is the smallest of five subspecies of the red-tailed black-cockatoo. Male red-tails have glossy black plumage with stunning, bright red tail panels. Females are quite different but equally spectacular – they are one of the most brightly marked subspecies of red-tail.

The south-eastern red-tailed black-cockatoo occurs as a single population in far south-western Victoria and the south-east of South Australia. The cockatoo is widespread but rare within a range of approximately 18000 km². Annual organised counts indicate a total population of about 1000 birds, including 600-700 breeding adults.

Red-tailed black-cockatoos are specialist feeders, relying almost entirely on the seeds of brown and desert stringybark (Eucalyptus baxteri and E. arenacea) and buloke trees (Allocasuarina luehmannii). The cockatoos feed almost entirely on the stringybark species that has fruited most recently and there are marked periods of food shortage between new crops. For a period of 2-3 months in late summer and autumn the seeds of buloke can be a very important source of food in years when it has seeded prolifically.

Red-tailed black-cockatoos require very old, large, hollow eucalypts for nesting. To be successful, a nest needs to be within about 5 km of stringybark woodland of at least 5 ha with a seed crop. A nest tree can be a single isolated paddock tree or within a forest block.

Breeding seems to occur in loose colonies – frequently, several nests are found within about one km2. Some breeding areas are used in most years, whereas others appear to be used less regularly.

Significance

The south-eastern red-tailed black-cockatoo has been classified as threatened due to having a small population size (<1000 individuals) in a single population, together with the loss of breeding and feeding habitat across the species range. It is listed as Endangered under the Environment Protection and Biodiversity Conservation (EPBC) Act 1999. In Victoria it is listed as threatened in Schedule 2 of the Flora and Fauna Guarantee (FFG) Act 1988, and classified as Endangered on the Advisory List of Threatened Vertebrate Fauna in Victoria – 2007 (DSE 2007). It is listed as Endangered in South Australia (National Parks and Wildlife Act 1972). The south-eastern red-tailed black-cockatoo is also listed under the Japan-Australia Migratory Bird Agreement (due to being a threatened Australian species), and the Convention on International Trade in Endangered Species.

The south-eastern red-tailed black-cockatoo’s habit is also classified as threatened under a number of legislative frameworks. ‘Buloke Woodlands of the Riverina and Murray-

Darling Depression Bioregions’ is a Threatened Ecological Community listed under the EPBC Act 1999. In Victoria ‘Grey Box Buloke Grassy Woodlands Community’ is listed as threatened in Schedule 2 of the FFG Act 1988. ‘Loss of hollow-bearing trees from Victorian native forests and woodlands’ is also listed as a Potentially Threatening Process under the FFG Act 1988, with a corresponding Action Statement (Garnett, Loyn & Lowe, 2003).

Data and information

The main source of population data comes from coordinated annual counts by volunteers. Flock count data collected in the weeks following the annual count are used to estimate the percentage of males in the population. As females and birds up to 3 years of age are indistinguishable in flocks, the proportion of males is used to indirectly measure breeding success. Sightings are also reported to the Recovery Team via mail, email, and a freecall telephone service. However, estimating population size and trends in population size is made difficult by the cockatoo’s mobility, low visibility when feeding, and difficulties of access to some stringybark woodlands.

A number of research projects have contributed significant knowledge of benefit for the recovery effort. Key recent research includes: research on breeding success, habitat use and ranging behaviour (Hill 2000); factors limiting food supply in stringybark (Koch 2003) and buloke (Maron 2000, Maron and Lill 2004); on nest predators (Jarmyn 2000); on farming impacts on Buloke tree loss and recruitment (Maron 2005a and 2005b); and modeling of habitat status and future scenarios (Maron et al, 2007). A survey of 500 landholder’s understanding of and attitudes towards the conservation of the south-eastern red-tailed black-cockatoo was undertaken by the Recovery Team (Beumer 2003).

A recent exercise identified large unprotected areas of feeding habitat in the South Australian portion of the subspecies’ range (Herpich 2007). This exercise identified comparatively ‘large’ patches supporting Eucalyptus arenacea/ E. baxteri which are currently unprotected, i.e. not within the State’s reserve system, under Heritage Agreement or some other form of conservation covenant or management agreement.

There is a lack of information on the location of some red-tailed black-cockatoo nest colonies, and little information on refuge areas. Similarly, there is a lack of detailed information on the whereabouts of key blocks of private land for which managers may need financial and management assistance. The relative importance of buloke woodland to red-tailed black-cockatoos could be confirmed by collecting time budget data on birds foraging in buloke and comparing these with data from stringybark woodlands in years of adequate and poor seed availability. The flock count data and growth rate data for chicks need further analysis if they are to inform managers and there is a need to increase the number of flock counts to strengthen the predictive power of this key monitoring tool.

Management requirements and issues

Food shortages are the main threat to the long-term survival of the south-eastern red-tailed black-cockatoo, with the availability of food of sufficient quality thought to be the primary factor limiting population size (Hill & Burnard, 2001). Some food shortages are natural: Desert stringybark fruit on a three year cycle and brown stringybark on a 2-4 year cycle. Past fire management practices (pre 1990) are believed to have significantly reduced food availability in stringybark woodlands. This is because most fire, whether wildfire or deliberate fire for fuel-reduction or ecological purposes, scorches or removes some or all of the stringybark canopy, producing a significant reduction in fruit production for 9-11 years after the fire (Koch 2003). Buloke, thought to be of particular importance to newly fledged birds (Maron & Lill, 2004), has irregular seasonal fruiting with the cockatoos preferring to feed from very old trees. The impact of natural shortages is exacerbated by the historical removal of feeding habitat: about half of all suitable habitat has been cleared within the bird's current range, with feeding habitat much more fragmented in South Australia (87 per cent cleared) than in Victoria (42 per cent cleared). Only 3 per cent of buloke is estimated to remain across the Cockatoo’s range. Buloke occurs on heavier, more fertile soils better suited to agriculture than the sandy soils that support stringybark. Food shortages are also influenced by land management activities such as the further clearing of habitat, scattered tree removal, tree decline and death due to damage from domestic animals, and inappropriate fire management. Research undertaken by Maron et al (2007) has shown that the annual percentage loss of paddock buloke trees was higher during the period 1997-2004 than it was when calculated for the period 1963-2004.

Breeding habitat loss is also a significant threat to the cockatoo. The most serious medium to long term threats include: the loss of dead hollow-bearing trees, lack of regeneration of future hollow-forming trees on private land, deliberate removal of paddock trees and the continuing decline in the health of living trees on farmland.

Other threats include the further fragmentation of foraging habitat, weed invasion of foraging habitat, the impact of firewood harvesting on feeding and nesting habitat, and interference with nests from nest predators and humans.

Management actions and responses

Conservation attention has been focused on the south-eastern red-tailed black-cockatoo since the early 1980s. In 1993 a Victorian Flora and Fauna Guarantee Action Statement provided a focused list of management actions. In 1996 the first Recovery Plan was produced using funds from the Natural Heritage Trust, with the Red-tailed Black-cockatoo Recovery Team formed to facilitate implementation of the recovery plan. These plans focused on protecting critical habitat, restricting permits to clear native forests, encouraging land holders to protect nesting trees, and modifying fuel reduction burning to maintain seed availability in stringybark forests. Survey work, monitoring and research were also emphasized, as well as the need to engage in public education programs to highlight the issues concerning the species. A breakdown of the recovery actions undertaken in Victoria is shown in Figure 1.

Figure 1: red-tailed Black Cockatoo recovery actions in Victoria 2004-7 (Source: ABC 2007)

The recovery effort has led to a number of significant outcomes over recent years:

·  Mapping of existing and potential feeding habitat, published in the National Recovery Plan (Commonwealth of Australia 2007)

·  Habitat Tender (2006): A tender-based conservation program that provides financial support to landholders who agree to manage red-tailed black-cockatoo habitat. The Australian Government’s Natural Heritage Trust provided $1.3m to fund this project across south-east South Australia and south-west Victoria. The project is administered by the Wimmera Catchment Management Authority with key partners the South East Natural Resource Management Board and Glenelg Hopkins Catchment Management Authority. Through this process 3000 ha of Stringybark and 140 ha of bloke have been protected within the South Australian and Victorian range

·  Non-government conservation groups have increasingly supported efforts to protect habitat through a range of actions including property purchase, registration of conservation covenants on title, lobbying of all tiers of Government and public education. E.g. Trust for Nature purchase of buloke woodland property (c. 250ha) in southern Wimmera (2006/7). The Judith Eardley Save Wildlife Association raised funds for land purchase of stringybark property in Glenelg Hopkins CMA. Matching funds were provided by Birds Australia (see below)

·  In 2006 $64000 was provided for land purchases to the Trust for Nature through the Commonwealth Games Karak program. $180000 was raised through the sale of Karak number plates and distributed to Australian Bush Heritage, Birds Australia and Trust for Nature to contribute to red-tailed black-cockatoo conservation. Funds have been used to establish a revolving fund for land purchase in the cockatoo’s range in Victoria.

·  Habitat restoration: Replanting feeding habitat: Eg. 9 ha Karak site near Casterton planted with stringybark through a Commonwealth Games Environment Program initiative coordinated by the Victorian Department of Sustainability and Environment (DSE) and Greening Australia in 2005 and 2006.

·  Integration with Habitat 141, a large landscape project aiming to build resilience in existing ecosystems to accommodate climate change and other environmental pressures over the long term.

·  Fire management: The Portland Fire Protection Plan (DSE 2004) and Horsham Fire Protection Plan (2004) provide for managing fire at the landscape level. The plans aim to meet objectives for fuel management whilst maintaining adequate food resources for the red-tailed black-cockatoo by undertaking cool burns which minimize canopy scorch.

·  Strengthening of Local Government planning overlays: to protect dead, hollow bearing eucalypts across the breeding range in Victoria. A draft overlay is to provide stronger protection for all potential red-tailed black-cockatoo habitats on private land.

·  Advocacy by the Recovery Team has helped with the protection of habitat under South Australia’s Native Vegetation Act 1991, by emphasising protection of feed trees and potential nesting trees (living or dead) within the subspecies' range in South Australia.

·  Community engagement over 10 years of recovery has contributed to a high level of awareness of red-tailed black-cockatoos reflected in the high level of ongoing volunteer involvement in activities such as the annual count.

Outcomes

Habitat protection measures have substantially reduced the rate of loss of foraging and nesting habitat, and in so doing we can infer a reduced rate of decline in the cockatoo population. While annual count figures have shown some trend to higher numbers, with 1078 red-tailed black-cockatoos counted during the 2006 annual count, this has been attributed to better on-ground coverage and location of birds rather than an increase in population. This is supported by the decrease in numbers counted during 2007 (801), attributed to the birds not being found rather than the results of a population decrease. Flock count data which measures recruitment from the previous breeding season also supports this as, despite high numbers of birds being counted in 2006, recruitment levels reflected in the percentage of males in the population were down on the previous year. Lower nesting success is consistent with predictions based on the availability of young (< 12 month) stringybark seed crops. The highest nesting success occurs when both species of stringybark have young seed crops. This occurred in 1999 and 2005 and is not predicted to occur again until 2010.

The research project Habitat status and future scenarios (Maron et al 2007) provides an assessment of change in status of habitat since 1940 including a measure of the rate of habitat loss. This project models habitat loss and various scenarios of habitat restoration to help set overall protection and restoration targets, by recommending levels of restorative work and protection required in order to achieve target habitat levels (eg. pre 1997, pre 1963 etc.). This research is pivotal in setting the future direction of the recovery effort.

Future scenario

Current recovery plans in effect are the National Recovery Plan (Commonwealth of Australia 2007) under the EPBC Act 1999, and the Victorian FFG Action Statement No 37 (Menkhorst et al 2006) under the FFG Act 1988.

The National Recovery Plan aims to demonstrate within five years a reversal of recent population declines, and to initiate longer-term measures designed to ensure the persistence of a viable breeding population. The FFG Action Statement aims to shift the status of the South-eastern red-tailed black-cockatoo from endangered to vulnerable within 20 years. This will require the population to increase to greater than 1000 mature individuals with no evidence of an on-going decline in numbers.

The focus of these management plans is on continuing the protection and restoration of feeding habitat, maintaining the current availability of nesting habitat, and minimising the impact of nest predators. There is also strong emphasis on further monitoring of distribution, abundance and population trends, and increased community awareness and involvement in conservation of the south-eastern red-tailed black-cockatoo. Key features of these plans include: