Threatened Species Strategy – Year 3 Priority Species Scorecard (2018) Eastern Bettong Bettongia gaimardi Key Findings The mainland subspecies of Eastern Bettong was extinct by the 1920s due to predation by foxes and feral cats, habitat loss and degradation, and persecution. Tasmanian Bettongs were brought to the mainland in 2011 and 2012 to begin captive colonies in the ACT. Both populations, at Mulligans Flat and Tidbinbilla, have grown and stabilised such that growth has slowed due to space limitations, but should increase when fenced areas are expanded. Photo: Woodlands and Wetlands Trust Significant trajectory change from 2005-15 to 2015-18? Rapid increases since 2011 (the time of their re-introduction to the mainland) have slowed, population now stable. Priority future actions • Maintain and expand introduced predator-free fenced areas • Translocations to at least two islands, with suitable habitat, undertaken. • Captive colonies in Tasmania maintained Full assessment information Background information 2018 population trajectory assessment 1. Conservation status and taxonomy 8. Expert elicitation for population trends 2. Conservation history and prospects 9. Immediate priorities from 2019 3. Past and current trends 10. Contributors 4. Key threats 11. References 5. Past and current management 12. Citation 6. Support from the Australian Government 7. Measuring progress towards conservation The primary purpose of this scorecard is to assess progress against the year three targets outlined in the Australian Government’s Threatened Species Strategy, including estimating the change in population trajectory of 20 mammal species. It has been prepared by experts from the National Environmental Science Program’s Threatened Species Recovery Hub, with input from a number of taxon experts, a range of stakeholders and staff from the Office of the Threatened Species Commissioner, for the information of the Australian Government and is non-statutory. The descriptive information in the scorecard is drawn from the summaries in the Mammal Action Plan (Woinarski et al. 2014), the IUCN Red List entry (Burbidge et al. 2016), and the draft Conservation Advice for the Tasmanian subspecies of the Eastern Bettong (TSSC 2018) and references therein; unless otherwise noted by additional citations. The background information aims to provide context for estimation of progress in research and management (Section 7) and estimation of population size and trajectories (Section 8). 1 Information current to December 2018 Threatened Species Strategy – Year 3 Priority Species Scorecard (2018) 1. Conservation status and taxonomy Conservation status Bettongia gaimardi Bettongia gaimardi Bettongia gaimardi (2018) gaimardi cuniculus EPBC Extinct Not Listed Not Listed QLD Extinct in the wild NSW Extinct Extinct VIC Threatened* Threatened TAS Not listed Regionally ACT Conservation Dependent *Non-statutory Victorian listing status is Extinct (Advisory List of Threatened Vertebrate Fauna in Victoria: 2013 list). Taxonomy: Two subspecies recognised in national legislation: Bettongia g. cuniculus (Tasmania) is not listed, and B. g. gaimardi (Mainland) is extinct. However, recent work (Haouchar et al. 2016) suggests that the Eastern Bettong should be reclassified into a single species with no subspecies (Haouchar et al. 2016). 2. Conservation history and prospects The pre-European distribution of the Eastern Bettong includes the eastern two-thirds of Tasmania below 1000m, probably from the coast to adjoining tablelands, and between southeast Queensland and southeast South Australia. The species prefers open forests and woodlands with a grassy or heathy understorey. Bettongs construct daytime shelters under shrubs, grass tussocks or fallen logs, using material (twigs, bark and grasses) that they carry to their shelter with their prehensile tail. They eat tubers, seeds, bulbs and invertebrate grubs, but especially rely on underground fungi, and thus are likely to play a key role in maintaining ectomycorrhizal symbiosis in forests and woodland habitats. On the mainland, Eastern Bettongs were extirpated by the 1920s due to predation by foxes, exacerbated by habitat changes wrought by shifts in fire regime (affecting the grassy understory), land clearing, livestock grazing, the impacts of introduced herbivores especially rabbits, and predation by feral cats. Eastern Bettongs persist in Tasmania, although the species’ original distribution is now fragmented by land clearing. It is present on Bruny Island, and was introduced to Maria Island in 1971. The main threats to the Tasmanian subspecies are continued habitat loss and modification (including by changes to fire regime), and predation by feral cats; it is likely these threats interact, with predation being amplified where habitat modification is most severe. In addition, should foxes successfully colonise Tasmania, predation by foxes would be a catastrophic threat to Eastern Bettongs. 2 Information current to December 2018 Threatened Species Strategy – Year 3 Priority Species Scorecard (2018) Sixty Tasmanian Eastern Bettongs were used to re-establish the species on the mainland during 2011- 12, at two cat-and fox-free sites in the ACT. Tidbinbilla Nature Reserve is a specialist threatened species recovery centre in the ACT where bettongs are maintained as a captive colony in three free range enclosures (each 6 – 12 ha). Some natural processes such as avian predation are allowed, and bettongs are supplied with supplementary food and water to allow for higher densities without resource limitation. Bettongs are regularly rotated among enclosures to maximise the retention of genetic diversity from the original founder population, and to ensure bettongs at TNR remain suitable for translocation to wild populations. The second site, at Mulligan’s Flat Woodland Sanctuary, is a 485 ha fenced exclosure at on the edge of Canberra, where bettongs are not provided with any supplementary food or water. In 2018 an additional 11.5 km of predator-proof fencing was added to Mulligan’s Flat Woodland Sanctuary, enclosing an additional 800 ha. Eastern Bettongs may be translocated into this new area in the future. In 2015-18, 46 bettongs from Tidbinbilla and Mulligan’s Flat were released experimentally at an unfenced site on the Lower Cotter catchment in the ACT, at which intensive fox control was carried out. The intent of this trial release was to test whether Eastern Bettongs could re-establish on the mainland with intensive and sustained fox control (Portas et al. 2014; Batson et al. 2016; Portas et al. 2016). As well as the captive colony at Tidbinbilla, a small captive population of Eastern Bettongs is housed on the mainland at Moonlit Sanctuary, near Melbourne. It originated from just two founders, and has not yet been involved in any other translocations. 3. Past and current trends Spotlight surveys carried out annually by the Tasmanian government between 1985 and 2008 show a decline in abundance. However, the data fluctuates strongly between years. The population trend since 1992 indicates a 14% decline, but with such large inter-annual variability that this trend does not significantly differ from zero (i.e. no change over time) (TSSC 2018). The translocated population at Mulligans Flat has increased from the founding population of 32 adults and their associated pouch young in 2012, to a population that fluctuates between 120-180. The population is expected to grow if bettongs are released in the future into the new, additional fenced area of 800 ha. Since 2011, the population at Tidbinbilla has grown and is managed to lie between 50-85 individuals. A new 120 ha predator-free area is being constructed and may provide additional areas for Eastern Bettongs in the future. Monitoring (existing programs): In Tasmania, Eastern Bettongs have been monitored annually by the Tasmanian government using spotlight surveys since 1975; from 1985, the methods became more standardised and the survey effort increased to cover 170 different transects, each being 10 km long. Bettongs are regularly monitored at MFWS using an array of methods including capture-mark- recapture, camera trap and spotlighting. However, due to the rapidly changing nature of the Sanctuary methods are regularly revised and adjusted to maintain required confidence. 3 Information current to December 2018 Threatened Species Strategy – Year 3 Priority Species Scorecard (2018) Bettongs are regularly monitored at TNR through capture-mark-recapture in the spring and autumn. Throughout the year, bettongs are monitored with camera traps and a remote PIT tag ring scanner. Population trends: Tables 1 and 2 summarise the overall trend and status of the Eastern Bettong. The information provided in these tables is derived from the draft listing advice (TSSC 2018), with some amendments made by contributing experts based on new information. Table 1. Summary of the available information on Eastern Bettong distribution and population size, and (where possible) trend estimates between 2015 and 2018 for each parameter. Confidence in Population parameters Published baseline 2015 Estimate 2018 Estimate estimates EXCLOSURES (all Eastern Bettongs on the mainland are in exclosures) 2 2 2 Extent of Occurrence 4 km 4 km 4 km High 2 2 2 Area of Occupancy 4 km 4 km 4 km High Dates of records and Translocated to Mulligans in 2012 methods used 60 individuals 140 150 High No. mature individuals released in 2011/12 (113-179; 95% CIs) Any other measure of relative abundance (specify) No. of subpopulations