In the last Tasmanian Conservationist we reported that the eastern quoll, Dasyurus viverrinus, has been nominated for inclusion in the Tasmanian threatened species list under the Tasmanian Threatened Species Act 1995. The quoll was nominated by the Scientific Advisory Committee (SAC) established under the Act, rather than as a public nomination, although much of the scientific data was provided by Bronwyn Fancourt, who has been studying the quoll as part of her Honours and now PhD projects at the University of Tasmania. The SAC nominated the quoll for inclusion as endangered on the basis that it meets the criterion of ‘a population decline of at least 50 percent over the last ten years’. As can be seen in Figure 1, it is clear that the population of eastern quolls has declined significantly in the last ten years.
On 21st July, the Minister, Brian Wightman, decided not to accept the recommendation of the SAC to list the eastern quoll as endangered. He requested the SAC reconsider certain aspects of the data on which the nomination was based, and the Department of Primary Industry, Parks, Water & Environment’s (DPIPWE) spotlighting surveys dating back to 1975. So while his decision is extremely disappointing, especially to Bronwyn who has been living and breathing eastern quolls for a number of years, and witnessing first hand their decline, it is not the end of the story. Bronwyn is hopeful that the SAC will advise the Minister that they are still convinced that the data warrants listing the species as endangered. It is encouraging that it is open for the SAC to re-nominate the species.
Originally qualifying and working as an accountant and then as a veterinary nurse, Bronwyn’s passion for conservation of threatened species was ignited when she was studying science at the University of New England, and working with koalas in Port Macquarie. She was able to assist researchers from the University of Sydney working on Chlamydia. During university holidays she volunteered on conservation programs, including on loggerhead turtles and woylies (brush-tailed bettongs) in Western Australia and Tasmanian devils here. During Bronwyn’s fieldwork for her honours project she used the DPIPWE historic spotlighting data and compared it with historic trapping data (where available) and her own trapping surveys. Her trapping surveys show, for example, a decline at Cradoc – traditionally a stronghold for eastern quolls – of over 60 percent since trapping was last carried out in 1983-4; similarly, a comparison with historic trapping at Cradle Mountain shows a decline of over 70 percent since 1991. When selecting study sites for her PhD, Bronwyn chose two sites where numbers had been declining and two where they were relatively stable. Within 12 months, one of the non-declining sites had become a declining site, increasing the number of declining sites from two to three.
The Minister’s decision also expresses concern about the reliability of the spotlighting data, given changes in survey personnel and in procedures such as time of year when surveys were carried out. Bronwyn points out that the spotlighting data is the same data that has been used in assessing the decline of the Tasmanian devil, and also to assess changes in feral cat numbers, so this questioning of the data’s reliability in the case of the eastern quoll is rather unconvincing. Concerns over the reliability of the spotlighting data also seem less significant when data from the numerous trapping surveys reveal similar declines to those identified in the spotlighting data. Nevertheless, Bronwyn believes that the Minister’s concerns can be satisfactorily addressed. She provided all of her data to the SAC prior to the nomination, and is confident that they have all the information necessary on which to reply to the Minister that listing as endangered is warranted.
While the precise cause of the decline in eastern quolls numbers is unknown, Bronwyn posits that the decline in devil numbers, and associated rise in feral cats, is a possible cause. Coupled with the severe drought conditions prevailing during the ten years since 2000, when quoll numbers began to decline, feral cat predation and competition for prey could have placed too much pressure on the population. Bronwyn’s research on Bruny Island shows interesting results. Devils have never established there, so their population decline is not an issue. North Bruny has suitable eastern quoll habitat and has become a stronghold for them; it is one of only two surveyed sites where they have actually increased in number. Feral cats are more abundant on South Bruny; and it appears that their spread north is limited due to trapping carried out by the Parks & Wildlife Service around the Neck.
The SAC meets only quarterly, and will not consider the Minister’s eastern quoll decision until its October meeting. In the meantime, the status of this declining marsupial will be reviewed by the IUCN for its Red List, and by the federal Environment Department for listing as nationally endangered (under the Environment Protection (Biodiversity Conservation) Act 1999) over the coming year. The eastern quoll now only occurs in Tasmania, so it would be an interesting situation if the species were listed as endangered nationally without first being listed here. Bronwyn’s research will be used to provide input to the federal review.
If the Tasmanian nomination is eventually ‘successful’, the eastern quoll would be the third terrestrial mammal to be listed in Tasmania as endangered (after the New Holland mouse and the Tasmanian devil). While no-one wants any native animal to become endangered, such recognition would require the government to dedicate resources to its recovery; something which is sorely needed.