Dirk Hartog Island National Park Ecological Restoration Project
Return to 1616
The Return to 1616 project aims to restore Dirk Hartog Island National Park’s habitats and native animal populations so that they are similar to what Dirk Hartog would have seen when he landed there in 1616.
The primary goal of the project is to re-establish at least 10 terrestrial native mammal species on the island, and establish at least another two native mammal species that may have previously occurred there, along with healthy vegetation and ecosystem processes to sustain the island’s biodiversity.
The GBI-NCB Fund has financed most of the first stage of the project, over the seven years to 30 June 2018. The first stage of the project is focused on the removal of pest animals including feral cats, goats and sheep from the island allowing for the second stage of native fauna translocations.
Integral to the success of the project is the implementation of biosecurity protocols to prevent the introduction or reintroduction of high risk pest species. These biosecurity protocols are being implemented by Parks and Wildlife, and their adoption by visitors to the island and other stakeholders is encouraged.
Other aspects of the project include weed management, surveys for the introduced black rat, monitoring of the threatened bird and reptile species on the island and vegetation monitoring. The project will help secure a future for several animals that are threatened or extinct on mainland Australia, and these ecosystem engineers will play an important role in restoring the Dirk Hartog Island ecosystems.
Achievements to date
Significant progress has been achieved since the project commenced in February 2012.
A cat barrier fence has been installed across the island, separating the island into two management sections to assist the staged cat eradication program. Two aerial cat baiting operations were completed in May 2014 (entire island) and May 2015 (north of the cat fence). An intensive cat monitoring and trapping program commenced south of the cat fence in July 2014, with only one feral cat photographed on the monitoring cameras since the last known cats were removed in October 2014.
The intensive cat monitoring program north of the cat fence commenced in June 2015, with trapping of the remaining cats well underway. The project is on track to complete on-ground cat eradication work by 30 June 2016, with monitoring and surveillance programs to continue until the end of 2018 to confirm eradication success.
Since 2010, aerial shooting operations have removed a total of 6,981 goats and 124 sheep; in addition no sheep have been observed for the seventh consecutive aerial operation since the last two were shot in February 2013.
Fifteen aerial goat shoot/monitoring operations have recorded a decreasing trend in the number of goats shot, from 2,519 in February 2010 to zero in February 2016. Further aerial monitoring will continue until eradication is confirmed. The project is on track to confirm sheep eradication by 30 June 2016 and goat eradication by 30 June 2018.
A biosecurity implementation plan was developed with input from island stakeholders to guide biosecurity actions by Parks and Wildlife, and to encourage voluntary cooperation by visitors and other stakeholders. Keeping weeds, pest animals and diseases off the island is crucial to the success of the project.
A weed management and action plan is guiding the management of invasive plant species on the island through to 2018.
Three surveys for the introduced black rat conducted in 2011, 2013 and 2014, have so far failed to detect the rat on the island or in the communities of Denham, Useless Loop and Monkey Mia.
Baseline distribution maps are being produced for three threatened bird subspecies endemic to the island: the rufous field wren, southern emu-wren, white-winged fairy wren and one threatened reptile: the western spiny-tailed skink. Additionally, genetic work is being carried out to determine if the rufous field wren and the southern-emu wren are genetically distinct from the mainland populations.
A study evaluating vegetation recovery since destocking sheep in 2008 and ongoing goat removal suggests that between 2008 and 2015, 28% of the island experienced a significant increase in vegetation cover, this is up from 20% in 2014.
With the sheep believed removed and the goats and cats nearly gone, habitats are recovering and the natural processes are starting to return. Once the island is declared free of cats and goats the project will be ready to implement stage two of the project, with the return of at least 10 mammal species that became extinct on the island along with the additional two species for conservation purposes, which may have lived there.
Prior to this a significant amount of planning will be undertaken to identify suitable locations in which to introduce animals, identify appropriate source populations to supply animals for introduction to Dirk Hartog Island and develop monitoring protocols to ensure successful establishment of new populations.