Threatened Species Strategy Year 3 Scorecard – Central Rock-Rat

Threatened Species Strategy – Year 3 Priority Species Scorecard (2018)

Central Rock-rat Zyzomys pedunculatus

Key Findings

The Central Rock-rat has experienced extreme declines in range and population size, due to predation by feral cats and extensive fires which can remove cover and reduce food availability across the species’ entire current range. Only ~650 individuals remain and a recent analysis ranked Central Rock-rats as the mammal taxon most likely to go extinct in the next 20 years. Recovery efforts have focused on landscape-scale feral cat and has contributed to the improved population trajectory for the species since 2015. Ongoing management of feral cats and fire will be important to prevent future declines. Photo: Perth Zoo Significant change in trajectory from 2005-15 to 2015-18? Yes, decline ongoing but at a slower rate.

Priority future actions

• More intensive fire management to limit incidence of extensive fires surrounding the rock-rat refuge sites. • Ongoing cat control around Central Rock-rat sites (eg. poison-baiting), including just after high rainfall periods, when cat predation pressure may be highest. • Additional translocations to predator-free sites (islands or mainland fenced exclosures).

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. Legislative documents 5. Past and current management 12. References 6. Support from the Australian Government 13. Citation 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. It has been informed by statutory planning documents that guide recovery of the species, such as Recovery Plans and/or Conservation Advices (see Section 11).

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 Taxonomy: Conservation status 2018 No subspecies are recognised. There are EPBC Act Critically Endangered four other species of rock-rat in the NT Endangered Zyzomys genus. WA Critically Endangered

2. Conservation history and prospects The Central Rock-rat is a medium-sized rodent with a thick and furry tail. It mostly eats seeds of grasses and forbs, supplemented with leaves, stems and some invertebrates (Edwards 2013b; Nano et al. 2003). It is one of five species in the genus Zyzomys. Three of the species in the genus have experienced marked declines and are listed as nationally threatened. The Central Rock-rat is the only species confined to arid areas; all other species in the genus have distributions that are wholly or mostly tropical. The Central Rock-rat has been lost from over 95% of its pre-European distribution (McDonald et al. 2018) and its current Area of Occupancy (36 km2) is among the smallest of Australian mammals. Within its Area of Occupancy, it is found living in an area of less than 500 ha, spread across a handful of sites on the tops (>950 m) of quartzite ranges west of Alice Springs (McDonald et al. 2017b; McDonald et al. 2015b). These sites are characterised by shallow, gravelly soils and exposed, densely-creviced rocky outcrops. The vegetation is a mix of spinifex, forbs and low shrubs, with a sparse layer of taller shrubs and low trees (McDonald et al. 2015c). Although the refuge habitat is relatively narrow, Central Rock- rats are capable, at least during periods of population expansion, of living in a much broader range of habitats, from hilltops to scree-slopes and valley floors, tussock and hummock grasslands, shrublands and woodlands (Wurst 1995). Recent trends for the Central Rock-rat have been of continued decline. In the decade between the two most recent extensive rainfall events (2000-01 and 2010-11), the area occupied by the Central Rock-rat has declined by over 80% (TSSC 2018). Occupancy rates at sites monitored over the period 2015 to 2016 almost halved (McDonald et al. 2017b). A recent analysis of extinction risk across Australian mammal species ranked the Central Rock-rat as the taxon most likely to go extinct in the next 20 years (Geyle et al. 2018). A separate analysis of the conservation security of Australian mammal taxa that are susceptible to predation by cats and/or foxes concluded that the Central Rock-rat was the taxon most urgently in need of protection within a cat- and fox-free site (either an island, or a mainland fenced exclosure) (Legge et al. 2018). With support from the Australian Government, a trial of landscape-scale cat control was carried out by the Northern Territory government between 2015-18 around the refuge sites for the Central Rock-rat. Aerially-deployed Eradicat baits were effective at reducing cat density, and there was some indication of a positive response by the Central Rock-rat, although the program would need to continue for this to be confirmed (McDonald et al. 2017a). Translocation of the species to a site that is free from cats and foxes is a high priority management action. The current construction of a fenced exclosure at Newhaven Sanctuary (supported by the

2 Information current to December 2018 Threatened Species Strategy – Year 3 Priority Species Scorecard (2018)

Australian Government) may offer a translocation site; islands off the coast of Western Australia should also be considered and have previously been proposed (Burbidge 1996). Captive breeding is being considered for this species, partly as insurance against its precarious status in the wild, and also as a step towards supporting a translocation to a cat-free site. Both translocation and captive breeding entail risks, because they involve removing animals from the wild which could compromise the persistence of that small wild population. In addition, earlier attempts to maintain a captive Central Rock-rat group (1996-2007) met with mixed success, and husbandry techniques will need revision (McDonald et al. 2017b).

3. Past and current trends The Central Rock-rat has disappeared from over 95% of its pre-European distribution. Before European settlement, its distribution extended from rocky areas in central Australia (Uluru north to the Granites) to the Cape Range in Western Australia. It was one of the most abundant species in cave deposit surveys at Cape Range and featured commonly in cave deposit surveys across central Western Australia and the Northern Territory (Baynes and Baird 1992; Baynes and Jones 1993; Baynes and McDowell 2010). Living specimens of the Central Rock-rat were collected from the Granites and the Davenport Ranges in the north, to the West MacDonnell Ranges and Illamurta in the south, from the 1890s until 1960, when an individual rock-rat was “caught raiding a stockman’s tuckerbox near Mt Liebig” (Cole 1999; McDonald et al. 2017b). After 1960, the Central Rock-rat was undetected for over three decades despite extensive trapping surveys in the Northern Territory and Western Australia (Gibson and Cole 1993; McDonald et al. 2017b) and was thought to be extinct (McDonald et al. 2017b; Wurst 1990). In 1996, a population was discovered near Ormiston Gorge, in Heavitree Range, in Tjoritja (West MacDonnell) National Park, by Australian Trust for Nature Volunteers (Cole 1999; McDonald et al. 2017b). Following this discovery, the Central Rock-rat was detected at multiple sites along a 60 km section of a quartzite ridge in the West MacDonnell Ranges between 1996 and 2002 (Cole 1999). However, subsequent trapping surveys between 2002-2012 in the West MacDonnells, including around Ormiston Gorge, failed to detect the rock-rat at any of the sites where it had been captured in the previous decade. However, the rock-rat was found at two new, isolated sites at the top of Mt Sonder (to the west) and Mt Giles (on the Chewings Range) (Edwards 2013a; McDonald et al. 2013). Another isolated population was found in 2013 near Mt Edward, 70 km west of Mt Sonder (McDonald et al. 2015a). Camera trapping in 2014 detected the species again at one site on the Heavitree Range. Subsequent surveys suggest that the Mt Sonder population may have since been extirpated (McDonald et al. 2017b). Thus, the Central Rock-rat is currently known to exist only in the Chewings Range (including Mt Giles) and the Heavitree Range, both in Tjoritja (West MacDonnell) National Park, and on Mt Edward to the west, in the Haast’s Bluff Aboriginal Land Trust (McDonald et al. 2017b). Estimating population trends for the Central Rock-rat following its contraction to the West MacDonnells is difficult because of the large fluctuations in population size, changes in survey location, and the pattern of population appearance and disappearance. The recent Conservation Advice (TSSC 2018) used changes in the area of occupancy between 2000-01 and 2010-11 (the two most recent periods of extensive rainfall) to infer the rate of population decline, and estimated this as at least 81%.

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Central Rock-rat populations have sometimes increased strongly after widespread rainfall events in central Australia (e.g. in 2000), suggesting that the species expands with rainfall-driven seeding pulses. However, the abundance of Central Rock-rats did not increase after the large 2011 rainfall event. Either rainfall alone is not the key driver for changes in rock-rat abundance, or other processes are dampening the capacity of rock-rats to respond to resource pulses, or the rock-rat persists in such few refugia that the capacity for population increase is compromised. Monitoring (existing programs): The NT government has implemented an annual monitoring program for Central Rock-rats and feral cats since June 2015, using camera traps to estimate occupancy (McDonald et al. 2017b). Prior to this, surveys tended to prioritise locating the rock-rat, rather than collecting time-series data appropriate for tracking population change. Reliability of current monitoring: Medium. Recent intensive monitoring has been undertaken at some of the known sites, including an assessment of response to poison-baiting of cats. However, rock-rat populations may fluctuate in response to rainfall characteristics, making it difficult to monitor over short periods. Data availability: Trend data are available in a series of published papers and NT government reports and summarised in TSSC 2018, and McDonald et al 2017b. Population trends: The overall trend and status of the Central Rock-rat is summarised in Tables 1 and 2. Trend information is based on accounts in McDonald et al. (2017b) and TSSC (2018), supplemented by commentary provided by the contributors to this scorecard based on new information.

Table 1. Summary of the available information on Central Rock-rat distribution and population size, and (where possible) trend estimates between 2015 and 2018 for each parameter. 2015 2018 Confidence in Population parameters Published baseline Estimate Estimate estimates

Extent of Occurrence 906 km2 906 km2 906 km2 High Area of Occupancy 40 km2 36 km2 36 km2 High Dates of records and methods used Mammal Action Plan TSSC 2018 No. mature individuals <1000 770* 650 Medium Any other measure of relative 13% (in Occupancy rate 24% High abundance 2016) No. of subpopulations 4 3 3 Medium No. of locations 4 3 3 Medium Low-Medium Generation time (years) 1-2 n/a n/a (as per MAP) *Based on the estimate of 650 mature individuals in 2018 (TSSC 2018), and assuming the population remained stable between 2017 and 2018 due to cat baiting. Two years (i.e. for 2015-2017) of decline back-cast (80% over ten years) to reach 2015 estimate

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Table 2. Estimated recent (2005-2015) and current (2015-2018) population trends for each known sub-population of Central Rock-rat. Est. % of Est. % of total 2005- Confidence in Confidence in Sub- 2015-2018 total pop’n 2015 2005-2015 2015-2018 Details population trend pop’n (pre- trend trend trend (2018) 2015) Last recorded on Mt Possibly Sonder in 2012. Surveys Mt Sonder 0 Medium Medium 0 extirpated in 2014 failed to detect the species Last detected in 2002 (during a population expansion phase); Ormiston 0 High Extirpated High 0 surveys in 2003, 2004, Gorge 2005, 2006, 2009, 2010, 2011, 2012 failed to detected the species Pre 2015: No detections in most of the Chewings Range since 1999, but detected on Mt Giles Mt Giles for the first time in (Chewings 40% High Medium 40% 2011, then again 2012,

Range) 2014. Post 2015: declines in occupancy rate recorded here and at Heavitree Range Pre-2015: Detected in 2012, and 2014. Counts Point Post 2015: declines in (Heavitree 40% High Medium 40% occupancy rate range) recorded here and at Chewings Range

Mt Edward Detected in 2013, and 20% n/a Low 20% (Haast’s Bluff) ? 2017

Whole 100 High Medium 100 population

KEY: Improving Stable Deteriorating Unknown Confidence Description High Trend documented Medium Trend considered likely based on documentation

? Low Trend suspected but evidence indirect or equivocal

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4. Key threats Despite the rarity of the Central Rock-rat, a substantial research effort has described many aspects of its diet, current habitat associations, relationship to fire, and likely impacts from feral cats. This research provides strong evidence that the main threat to the species is predation by feral cats, probably exacerbated at times by large-scale fire events. The threats listed here align with the draft Recovery Plan, and the Conservation Advice, with some amendments made by contributing experts based on new information. Note that this is not a list of all plausible threats, but a subset of the threats that are likely to have the largest impact on populations. Predation by feral cats (Felis catus) Feral cats are known to prey upon the Central Rock-rat. Rock-rats’ remains have been recovered from cat scats and there is evidence that cats prefer rock-rats over alternative small mammal prey (McDonald et al. 2015b). Camera trapping data suggest that cats are resident in core refuge habitat, at a density of 0.12 cats / km2 (Legge et al. 2017; McDonald et al. 2016). The rugged and highly-creviced rocks in the Central Rock-rat’s refugial habitats may offer some protection from cats (Hohnen et al. 2016; Legge et al. 2017). Nevertheless, Central Rock-rats are highly localised and likely to have lower fecundity during non-irruptive periods, so they could be impacted even by low densities of cats. Cat densities rise following extensive rainfall events (Legge et al. 2017), and predation impacts may be acute during the post-irruptive period when prey densities are falling rapidly (Pavey et al. 2008; Short et al. 2018). Susceptibility to cat predation is also likely to increase following a wildfire event when groundcover has been eliminated or reduced (Leahy et al. 2016; McGregor et al. 2014; McGregor et al. 2015). Note that predation by red foxes is also plausible. However, foxes are generally uncommon in the central ranges, and are absent from core refuge habitat. Extensive fire events Periods of widespread and above average rainfall in central Australia are often followed by extensive wildfires, because the rain stimulates a pulse of vegetative growth, including of annual grasses which provide a wick for fire to travel between larger, discontinuous fuel patches. Extensive wildfires are likely to impact the Central Rock-rat, through the short-term removal of food, and by facilitating amplified predation (Leahy et al. 2016; McGregor et al. 2014; McGregor et al. 2015). Small-scale fires are likely to benefit rock-rats, by ensuring a range of vegetation seral communities, each favouring different plant species, and thus providing a broader range of food resources (Edwards 2013b; McDonald et al. 2016; Nano et al. 2003). Historic fire regimes in the West MacDonnell Ranges are being disturbed by the spread of the introduced buffel grass (Cenchrus ciliaris). Livestock and feral herbivores (potential threat) Feral horses (Equus caballus) thrive in rugged terrain and potentially threaten the survival of the Central Rock-rat through habitat modification and competition for food. Horses cause erosion and soil compaction, damage vegetation, and consume grasses and forbs that are also relied on by Central Rock- rats. The NT government manage horses to reduce their abundance in the West MacDonnell NP and horses are currently absent from majority of the national park. Horses reach high densities surrounding Mt Edward but have not been recorded at high elevations where the Central Rock-rats are (McDonald et al. 2017b). Horses and cattle on the low-lying areas may reduce habitat quality for dispersing rock- rats during periods when the population is expanding out of its refuge areas.

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Exotic invasive grasses (potential threat) Buffel grass is currently uncommon in the refuge habitat of the Central Rock-rat but may increase in the future. It is common in areas adjacent to the refuge populations and may reduce the potential for rock-rats to expand out of the refuges to recolonise sites that were previously occupied. Buffel grass leads to increases in fire frequency because it provides continuity of ground fuel between grass hummocks, tussocks and small shrubs, leading to shorter fire-return intervals. Higher fire frequencies will affect food resources for the Central Rock-rat, and favour further expansion of buffel grass over other native species.

The impacts of the major threats are summarised in Table 3.

Table 3. The major threats facing the Central Rock-rat, and their associated impact scores.

CURRENT THREAT IMPACT

Threat Timing Extent Severity

1. Feral cats Continuing/ongoing >90% of range 30-49%

2. Increase in fire Continuing/ongoing >90% of range 30-49% frequency/intensity

3. Feral horses Near future 50-90% of range Not negligible but <20%

4. Invasive grass Distant future 1-50% of range Causing no decline (particularly buffel grass)

5. Red foxes Distant future 1-50% of range Causing no decline

Timing: continuing/ongoing; near future: any occurrence probable within one generation (includes former threat no longer causing impact but could readily recur); distant future: any occurrence likely to be further than one generation into the future (includes former threat no longer causing impact and unlikely to recur). Extent: <1% of range; 1-50%; 50-90%; >90%. Severity: (over three generations or 10 years, whichever is longer) Causing no decline; Negligible declines (<1%); Not negligible but <20%; 20-29%; 30-49%; 50-100%; Causing/could cause order of magnitude fluctuations.

5. Past and current management The main recent and current management actions thought to be contributing to the conservation of Central Rock-rats are summarised in Table 4, with some other management actions described in Section 6. The information is a collation of material provided by contributors. A Recovery Plan (2018) and Conservation Advice (2018) are in place, guiding recovery action (see Section 11).

7 Information current to December 2018 Threatened Species Strategy – Year 3 Priority Species Scorecard (2018)

Table 4. Management actions thought to be contributing to the conservation of the Central Rock-rat.

Est. % Contributors and Action Location Timing population partners

Cat baiting trials and control using Tjoritja NP Eradicat® bait (leading to a significant Australian (West reduction in local cat numbers and 2015-2018 80% Government, NT MacDonnell increases in sites occupied by Central DENR, PWCNT Ranges) Rock-rat).

Construction of a cat-proof exclosure Fence completed Australian that could be used as a translocation Newhaven 2018; feral Government, site for Central Rock-rat (note 0 Sanctuary eradication Australian Wildlife translocation has yet to be assessed or underway Conservancy approved)

6. Actions undertaken or supported by the Australian Government resulting from inclusion in the Threatened Species Strategy Two partnership projects likely to benefit the Central Rock-rat are supported by the Australian Government: i. The “Protecting the Central Rock-rat in the West MacDonnell Ranges – NT” ($270,000 from the Australian Government, partner: NT Government) project aimed to benefit the Central Rock-rat by controlling feral cats in and around the mammal refuge areas of the West MacDonnell Ranges. As part of the project, an aerial baiting program was piloted, using Eradicat® baits dropped by helicopter. Camera traps were used to monitor the cat population and their prey, and to test the effectiveness of the baiting program. The project also collected valuable information about the location and density of other threatened species (e.g. the vulnerable black-footed rock-wallaby). A completed report on this project is available: (McDonald et al. 2017a).

ii. The “Creating one of Australia’s largest fenced feral cat and fox free areas” ($750,000 from the Australian Government, partner: Australian Wildlife Conservancy (AWC)). This project aims to benefit the Central Rock-rat by providing a safe-haven (free of introduced predators) for a translocated population. Newhaven Wildlife Sanctuary, north-west of Alice Springs, will become one of Australia's largest fenced feral cat and fox-free areas. The two-stage project will establish a 100 000 hectare enclosure to protect at least nine threatened mammals (including the Central Rock-rat), including seven to be reintroduced to the area. The project will be delivered in collaboration with traditional owners, with Indigenous rangers helping to control feral animals, manage fire and carry out biological surveys. The first fenced area of 9450 ha has been constructed, with feral eradication underway (http://www.australianwildlife.org/field- updates/2018/worlds-longest-cat-proof-fence-completed-at-newhaven.aspx).

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7. Measuring progress towards conservation Table 5. Progress towards management understanding and management implementation for each of the major threats affecting the Central Rock-rat in 2015 (i.e. timing of TSS implementation) and 2018, using the progress framework developed by Garnett et al. 2018. PROGRESS IN MANAGING THREATS

Understanding of how to Extent to which threat being Notes Threat Year manage threat managed 2.Research has provided strong 2015 0.No management direction on how to manage threat Trial control program for 1. Feral cats 4.Trial management under way but cats was effective at

2018 not yet clear evidence that it can 1.Management limited to trials reducing cat activity deliver objectives 2. Research has provided strong Trials underway to use 2. Increase in 2015 1. Management limited to trials direction on how to manage threat management burns to lessen fire frequency/ the impact of wildfire and intensity 4.Trial management under way but increase the diversity and 2018 not yet clear evidence that it can 1. Management limited to trials quantity of food plants deliver objectives 4. Solutions are enabling 2. Research has provided strong achievement but only with Horses not common in the 2015 direction on how to manage threat continued conservation refuge habitat for the intervention Central Rock-rat; horse 3. Feral horses 4. Solutions are enabling control in adjacent areas 2. Research has provided strong achievement but only with may be contributing to that 2018 direction on how to manage threat continued conservation low density intervention 1. Research being undertaken or Buffel not currently a threat 2015 completed but limited understanding 0. No management 4. Invasive grass in refugial area, but may on how to manage threat (particularly expand in the future, and 1. Research being undertaken or buffel grass) may constrain options for 2018 completed but limited understanding 0. No management translocation sites. on how to manage threat 2. Research has provided strong Foxes not currently a threat 2015 0. No management direction on how to manage threat in Central Rock-rat refugial 5. Red foxes 2. Research has provided strong area, but could be if rock- 2018 direction on how to manage 0. No management rats are translocated to threat other locations. > Green shading indicates an improvement in our understanding or management of threats between years 2015 and 2018, while red shading indicates deterioration in our understanding or management of threats.

KEY Score Understanding of how to manage threat Extent to which threat is being managed 0 No knowledge and no research No management Research being undertaken or completed but limited understanding on 1 Management limited to trials how to manage threat Work has been initiated to roll out solutions where threat applies 2 Research has provided strong direction on how to manage threat across the taxon’s range 3 Solutions being trialled but work only initiated recently Solutions have been adopted but too early to demonstrate success Trial management under way but not yet clear evidence that it can Solutions are enabling achievement but only with continued 4 deliver objectives conservation intervention Trial management is providing clear evidence that it can deliver Good evidence available that solutions are enabling achievement 5 objectives with little or no conservation intervention Research complete and being applied OR ongoing research associated 6 The threat no longer needs management with adaptive management of threat

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8. Expert elicitation for population trends An expert elicitation process was undertaken to assess population trends for the period 2005-2015 and post-2015 under the following management scenarios. Please note that differences between Management Scenarios 2 and 3 (Fig. 1) are difficult to attribute, as it can be difficult to determine whether actions undertaken after 2015 were influenced by the Threatened Species Strategy or were independent of it (see Summary Report for details of methods). Management Scenario 1 (red line): no conservation management undertaken since 2015, and no new actions implemented.

• No feral cat control, no fire management and no horse control. The pattern of pre-2015 population decline and local extirpation will continue. Management Scenario 2 (blue line): continuation of existing conservation management (i.e. actions undertaken before implementation of the Threatened Species Strategy or independent of the Threatened Species Strategy).

• Horse control effective, maintains low density near rock-rat habitat. • Limited fire management with variable success, e.g., extensive fires affected most of the area surrounding rock-rat refuge sites after the two most recent large rainfall events, in 2000-01 and 2010-11. Recent trials may lead to improvements in fire patterns. • Cat density around Central Rock-rat sites is reduced by poison-baiting. A key test will be whether the cat control can be achieved during and just after high rainfall periods, when cat predation pressure may be highest. • Translocation of Central Rock-rats to one cat- and fox-free site is undertaken in the next 10 years (e.g. Newhaven Sanctuary, or an island off the WA coast). Cat baiting stems the decline in the short term, and may allow for a population increase over ten years. The translocation causes an increase in the population, beginning from a couple of years after 2018. Overall estimated population trajectories subject to management scenarios considered The Central Rock-rat is currently operating under Scenario 3 (green line).

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Figure 1. Estimated relative percentage change in population under each of the management scenarios described above. Data derived from 7 expert assessments of Central Rock-rat expected response to management, using four-step elicitation and the IDEA protocol (Hemming et al. 2017), where experts are asked to provide best estimates, lowest and highest plausible estimates, and an associated level of confidence. The dashed line represents the baseline value (i.e. as at 2015, standardised to 100). Values above this line indicate a relative increase in population size, while values below this line indicate a relative decrease in population size. Shading indicates confidence bounds (i.e. the lowest and highest plausible estimates).

Population size projections based on expert elicitation are extended here to 2025, 2035 and 2045 (i.e. 10, 20 and 30 years after the establishment of the Threatened Species Strategy) on the grounds that some priority conservation management actions may take many years to achieve substantial conservation outcomes. However, we note also that there will be greater uncertainty around estimates of population size into the more distant future because, for example, novel threats may affect the species, managers may develop new and more efficient conservation options, and the impacts of climate change may be challenging to predict.

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Improved trajectory (Threatened Species Strategy Year 3 target): The primary purpose of this scorecard is to assess progress against achieving the year three targets outlined in the Australian Government’s Threatened Species Strategy, i.e. a demonstrated improved trajectory for at least half of the priority species (10 birds and 10 mammals). To assess this, we first use the expert-derived trend between 2005-15 (i.e. 10 years prior to implementation of the TSS) as a baseline for assessing whether there has been an improvement in trajectory in the time since implementation of the TSS (i.e. 2015-18). Table 6 below summarises this information, where negative values indicate a declining population, and positive values indicate an increasing population. We used Wilcoxon match-paired tests to compare trajectories for these two periods; a significant result (probability <0.05) indicates that there was a high concordance amongst experts that their trajectory estimates for 2005-15 were different to their estimates for 2015-18.

Table 6. A comparison of the relative annual percentage population change for the periods 2005-2015 and 2015-2018.

Pre-TSS trend Post-TSS trend Year 3 target Significant concordance (2005-2015) (2015-2018) met? amongst elicitors?

Annual Yes, elicitors had high level percentage of agreement that decline -16.2 -0.56 population  for the period 2015-18 was change less steep than for 2005-15

The Central Rock-rat is experiencing ongoing decline, however the rate of decline slowed from 2015- 18, compared to 2005-2015, as a result of targeted cat management around sites with Central Rock-rat populations. Additional actions that could improve trajectory The potential impact of carrying out specific additional conservation measures on the population trajectory of the Central Rock-rat was also evaluated through expert elicitation. Current management includes some horse control, some fire management, and cat control has been recently trialed. Additional actions that could further improve the population trajectory of the Central Rock-rat include: • More intensive fire management to limit incidence of extensive fires surrounding the rock-rat refuge sites. • Ongoing cat control around Central Rock-rat sites (eg. poison-baiting), including just after high rainfall periods, when cat predation pressure may be highest. • Additional translocations to predator-free sites (islands or mainland fenced exclosures). If these additional actions were carried out, experts considered that the trajectory of the Central Rock- rat would stabilise and then increase after about ten years, because fire, horse and cat management would stem population decline in the short term, and may allow for a small population increase. Translocations would support further increases in the population, but these increases would take time (> 5 years) to be realised.

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9. Immediate priorities from 2019 The priorities listed here are derived from the most recent Conservation Advice (TSSC 2018) and the draft Recovery Plan, with some amendments made by contributing experts based on new information. Identification of these priorities in this document is for information and is non-statutory. For statutory conservation planning documents, such as Recovery Plans or Conservation Advices, please see Section 12. Data collection: • Structured surveys to search for other refugial populations • An integrated monitoring program across all populations, focussing on:  Changed in the Central Rock-rat population, especially in response to changes in threats and threat management  The abundance of feral cats, and response to cat control and fire events • Effect of rainfall and fire on rock-rat breeding behaviour, population cycles and distribution • Impacts of fire on food resources for the Central Rock-rat, and the interactions between fire with other threats (feral cats) • Identify potential translocation sites within the historical distribution Management actions: • Reduce cat density around Central Rock-rat refuge areas (requires licencing approval from APVMA to use a range of baits). • Reduce the incidence of extensive fire events with a careful program of prescribed burning, especially after a widespread high rainfall event • Control feral horses • Establish a captive breeding population • Carry out translocations to at least one site within the historical distribution • Collaborate with relevant Indigenous groups and individuals on management and research actions.

10. Contributors Andrew Burbidge; Peter Latch (DoEE); Nicholas MacGregor (Parks Australia); Paul McDonald (NT Government), Peter Menkhorst; Simon Ward (NT Government); Sarah Legge, John Woinarski, Stephen Garnett, Hayley Geyle (NESP TSR Hub).

11. Legislative documents SPRAT profile: http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=68 McDonald, P., S. Ward, C. Nano, C. Pavey, T. Nano & P. Nunn (2018). National Recovery Plan for the Central Rock-rat, Zyzomys pedunculatus. Northern Territory Dept. of Environment and Natural Resources. Available from: http://www.environment.gov.au/biodiversity/threatened/publications/recovery/central-rock- rat-2018. In effect under the EPBC Act from 23-Feb-2019. Available from: http://www.environment.gov.au/system/files/resources/1aef5fa4-4749-45fc-b7f9- aee87cb9340a/files/draft-recovery-plan-central-rock-rat.pdf

13 Information current to December 2018 Threatened Species Strategy – Year 3 Priority Species Scorecard (2018)

Threatened Species Scientific Committee (2018). Conservation Advice Zyzomys pedunculatus Central Rock-rat. Canberra: Department of the Environment and Energy. Available from: http://www.environment.gov.au/biodiversity/threatened/species/pubs/68-conservation- advice-15022018.pdf. In effect under the EPBC Act from 15-Feb-2018. Cole, J. (1999). Recovery Plan for the Central Rock-rat Zyzomys pedunculatus. Parks and Wildlife Commission of the Northern Territory. Available from: http://www.environment.gov.au/biodiversity/threatened/recovery-plans/national-recovery-plan- central-rock-rat-zyzomys-pedunculatus. In effect under the EPBC Act from 16-Jul-2000.

12. References Baynes, A., Baird, R., 1992. The original mammal fauna and some information on the original bird fauna of Uluru National Park, Northern Territory. The Rangeland Journal 14, 92-106. Baynes, A., Jones, B., 1993. The mammals of Cape Range peninsula, north-western Australia. Records of the Western Australian Museum 45, 207-225. Baynes, A., McDowell, M.C., 2010. The original mammal fauna of the Pilbara biogeographic region of north-western Australia. Records of the Western Australian Museum 78, 285-298. Burbidge, A. (1996). Antina (Zyzomys pedunculatus) interim recovery plan 1996 to 1998. Interim Recovery Plan No. 5. Department of Conservation and Land Management, Wanneroo Cole, J., 1999. Recovery plan for the Central Rock-rat Zyzomys pedunculatus. Parks and Wildlife Commission of the Northern Territory, Alice Springs. Edwards, G., 2013a. Relative abundance of the Central Rock-rat, the desert mouse and the fat-tailed pseudantechinus at Ormiston Gorge in the West MacDonnell Ranges National Park, Northern Territory. Australian Mammalogy 35, 144-148. Edwards, G., 2013b. Temporal analysis of the diet of the Central Rock-rat. Australian Mammalogy 35, 43-48. Garnett, S.T., Butchart, S.H.M., Baker, G.B., Bayraktarov, E., Buchanan, K.L., Burbidge, A.A., Chauvenet, A.L.M., Christidis, L., Ehmke, G., Grace, M., Hoccom, D.G., Legge, S.M., Leiper, I., Lindenmayer, D.B., Loyn, R.H., Maron, M., McDonald, P., Menkhorst, P., Possingham, H.P., Radford, J., Reside, A.E., Watson, D.M., Watson, J.E.M., Wintle, B., Woinarski, J.C.Z., and Geyle, H.M. (2018) Metrics of progress in the understanding and management of threats to Australian Birds. Conservation Biology https://doi.org/10.1111/cobi.13220. Geyle, H.M., Woinarski, J.C.Z., Baker, G.B., Dickman, C.R., Dutson, G., Fisher, D.O., Ford, H., Holdsworth, M., Jones, M., Kutt, A.S., Legge, S., Leiper, I., Loyn, R., Murphy, B.P., Menkhorst, P.W., Reside, A., Ritchie, E.G., Roberts, F.E., Tingley, R., Garnett, S.T., 2018. Anticipating and predicting Australian bird and mammal extinctions. Pacific Conservation Biology 24, 157-167. Gibson, D.F., Cole, J.R., 1993. Vertebrate fauna of the West MacDonnell Ranges, Northern Territory. Conservation Commission of the Northern Territory. Hemming, V., Burgman, M.A., Hanea, A.M., McBride, M.F., and Wintle B.C. (2017) A practical guide to structured expert elicitation using the IDEA protocol. Methods in Ecology and Evolution, 9, 169-180. Hohnen, R., Tuft, K., McGregor, H., Legge, S., Radford, I., Johnson, C.N., 2016. Occupancy of the invasive feral cat varies with habitat complexity. PLoS ONE 11, (9): e0152520. doi:0152510.0151371/journal.pone.0152520.

14 Information current to December 2018 Threatened Species Strategy – Year 3 Priority Species Scorecard (2018)

Leahy, L., Legge, S.M., Tuft, K., McGregor, H.W., Barmuta, L.A., Jones, M.E., Johnson, C.N., 2016. Amplified predation after fire suppresses rodent populations in Australia’s tropical savannas. Wildlife Research 42, 705-716. Legge, S., Murphy, B., McGregor, H., Woinarski, J., Augusteyn, J., Ballard, G., Baseler, M., Buckmaster, T., Dickman, C., Doherty, T., Edwards, G., Eyre, T., Fancourt, B., Ferguson, D., Forsyth, D., Geary, W., Gentle, M., Gillespie, G., Greenwood, L., Hohnen, R., Hume, S., Johnson, C., Maxwell, M., McDonald, P., Morris, K., Moseby, K., Newsome, T., Nimmo, D., Paltridge, R., Ramsey, D., Read, J., Rendall, A., Rich, M., Ritchie, E., Rowland, J., Short, J., Stokeld, D., Sutherland, D., Wayne, A., Woodford, L., Zewe, F., 2017. Enumerating a continental-scale threat: How many feral cats are in Australia? Biological Conservation 206, 293-303. Legge, S., Woinarski, J., Burbidge, A., Palmer, R., Ringma, J., Mitchell, N., Radford, J., Bode, M., Wintle, B., Baseler, M., Bentley, J., Carter, O., Copley, P., Dexter, N., Dickman, C., Gillespie, G., Hill, B., Johnson, C., Latch, P., Letnic, M., Manning, A., Menkhorst, P., Morris, K., Moseby, K., Page, M., Pannell, D., Tuft, K., 2018. Havens for threatened Australian mammals: the contributions of fenced areas and offshore islands to protecting mammal species that are susceptible to introduced predators. Wildlife Research In press. McDonald, P., Brittingham, R., Nano, C., Paltridge, R., 2015a. A new population of the critically endangered Central Rock-rat (Zyzomys pedunculatus) discovered in the Northern Territory. Australian Mammalogy 37, 97-100. McDonald, P., Stewart, A., Tyne, J., 2017. Experimental feral cat control using the Eradicat® bait in the MacDonnell Ranges. Department of Environment & Natural Resources, NT Government, Alice Springs, NT. McDonald, P., Ward, S., Nano, C., Pavey, C., Nano, T., Nunn, P., 2018. National Recovery Plan for the Central Rock-rat, Zyzomys pedunculatus. Northern Territory Dept. of Environment and Natural Resources, Alice Springs, Northern Territory. McDonald, P.J., Brittingham, R., Nano, C., Paltridge, R., 2015b. A new population of the critically endangered Central Rock-rat (Zyzomys pedunculatus) discovered in the Northern Territory. Australian Mammalogy 37, 97-100. McDonald, P.J., Griffiths, A.D., Nano, C.E., Dickman, C.R., Ward, S.J., Luck, G.W., 2015c. Landscape-scale factors determine occupancy of the critically endangered Central Rock-rat in arid Australia: the utility of camera trapping. Biological Conservation 191, 93-100. McDonald, P.J., Pavey, C.R., Knights, K., Grantham, D., Ward, S.J., Nano, C.E., 2013. Extant population of the Critically Endangered Central Rock-rat Zyzomys pedunculatus located in the Northern Territory, Australia. Oryx 47, 303-306. McDonald, P.J., Stewart, A., Dickman, C.R., 2018. Applying the niche reduction hypothesis to modelling distributions: A case study of a critically endangered rodent. Biological Conservation 217, 207- 212. McDonald, P.J., Stewart, A., Schubert, A.T., Nano, C.E., Dickman, C.R., Luck, G.W., 2016. Fire and grass cover influence occupancy patterns of rare rodents and feral cats in a mountain refuge: implications for management. Wildlife Research 43, 121-129. McGregor, H., Legge, S., Jones, M., Johnson, C., 2014. Landscape management of fire and grazing regimes alters the fine-scale habitat utilisation by feral cats. PLoS ONE 9, e109097. McGregor, H., Legge, S., Jones, M.E., Johnson, C.N., 2015. Feral cats are better killers in open habitats, revealed by animal-borne video. PLoS ONE 10, e0133915. Nano, T.J., Smith, C.M., Jefferys, E., 2003. Investigation into the diet of the Central Rock-rat (Zyzomys pedunculatus). Wildlife Research 30, 513-518.

15 Information current to December 2018 Threatened Species Strategy – Year 3 Priority Species Scorecard (2018)

Pavey, C.R., Eldridge, S.R., Heywood, M., 2008. Population dynamics and prey selection of native and introduced predators during a rodent outbreak in arid Australia. Journal of Mammalogy 89, 674- 683. Short, J., O’Neill, S., Richards, J.D., 2018. Irruption and collapse of a population of pale field-rat (Rattus tunneyi) at Heirisson Prong, Shark Bay, Western Australia. Australian Mammalogy 40, 36-46. TSSC, 2018. Conservation Advice for Zyzomys pedunculatus Central Rock-rat. Department of the Environment and Energy, Canberra. Wurst, D., 1995. Search for the Central Rock-rat. Australian Natural History 24, 38-45. Wurst, P.D., 1990. Report on the survey for the Central Rock-rat, Zyzomys pedunculatus in the Alice Springs region. Conservation Commission of the Northern Territory.

13. Citation Please cite this document as:

National Environmental Science Program Threatened Species Research Hub (2019) Threatened Species Strategy Year 3 Scorecard – Central Rock-rat. Australian Government, Canberra. Available from: http://www.environment.gov.au/biodiversity/threatened/species/20-mammals-by- 2020/central-rock-rat

16 Information current to December 2018