Conservation Introduction Plan

Species Conservation Plan A Conservation Introduction Plan for the Christmas Island Blue-tailed skink, Cryptoblepharus egeriae From: Christmas Island and Taronga Conservation Society, Sydney To: Cocos (Keeling) Islands

1 How to cite this report

Director of National Parks 2020. A Conservation Introduction action plan for the Christmas Island Blue-tailed skink, Cryptoblepharus egeriae, from Christmas Island and Taronga Zoo to the Cocos (Keeling) Islands. Director of National Parks, Canberra.

Prepared by and CIRAP

Parks Australia Department of Agriculture, Water and the Environment GPO Box 787, Canberra 2601

With the exception of logos and cover images or where otherwise noted, this report is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

Cover photograph: Blue-tailed Skink (Cryptoblepharus egeriae), Parks Australia

2 Summary This document is a comprehensive plan for the introduction of the Christmas Island blue-tailed skink (Cryptoblepharus egeriae) to the Cocos (Keeling) islands group and has been updated following the first release on Pulu Blan in September 2019. The purpose of this reintroduction program is to establish a wild population as part of this species recovery and security. Cryptoblepharus egeriae is listed as Critically Endangered under the Environment Protection and Biodiversity Conservation Act 1999 and is endemic to Christmas Island. Historically, this species was very common across the island, however, since the 1990s their population has experienced significant declines. In 2009, 66 C. egeriae were taken into captivity to secure the species future through captive breeding. By the end of 2010 C. egeriae was presumed extinct in the wild. The cause of decline is thought to be due to the predation and competition pressures of introduced species including yellow crazy ants, cats (Felis catus), black rats (Rattus rattus), centipedes (Scolependra sp), Asian wolf snake (Lycodon capucinus), weeds, birds and geckos (Hemidactylus frenatus and Gehyra mutilata). Habitat loss and disease are also potential threatening processes.

Captive breeding has been very successful and currently about 1500 C. egeriae exist in captivity across two locations (Christmas Island and Taronga Zoo, Sydney). Threat mitigation of yellow crazy ants, cats and rats is underway and will go a long way to reducing the pressure on the reptiles if they are reintroduced back to Christmas Island. The continued presence of wolf snakes and centipedes and the inability to control or eradicate these species easily is of high concern and poses a great risk of never being able to successfully reintroduce this species back to their native habitat. Finding solutions for reintroduction beyond captive breeding is critical for avoiding extinction of both species.

This document addresses the legal, ethical, ecological and logistical issues associated with moving and introducing C. egeriae to the Cocos (Keeling) Islands as an alternative to wild release on Christmas Island.

3 Contents 1 How to cite this report ...... 2

2 Summary ...... 3

1 Project management ...... 4

1.1 Proponent ...... 4

1.2 Project Sponsor: ...... 4

1.3 Project co-ordinator: ...... 4

1.4 Project oversight ...... 4

1.5 Resourcing ...... 6

2 Project rationale ...... 7

2.1 Goal ...... 7

2.2 Objectives ...... 7

2.3 Type of conservation action ...... 7

2.4 Taxonomy of the species ...... 8

2.5 Legal Status of the species ...... 8

2.6 Documented recovery actions ...... 8

2.7 Justification for conservation action ...... 9

2.8 Consequences of not proceeding with the proposed action ...... 9

2.9 Criteria for Success ...... 9

2.10 Previous work ...... 10

2.11 Number of individuals of the species being conserved and proposed project timing ...... 11

3 Biology and ecology ...... 14

3.1 Morphology ...... 14

3.2 Reproductive cycle and timing ...... 14

3.3 Distribution and abundance ...... 14

3.4 Habitat requirements ...... 14

3.5 Nutritional requirements ...... 14

3.6 Reasons for decline and current threats ...... 14

4 Source environment, population and distribution ...... 21

4.1 Site tenure ...... 21

4.2 Source environment ...... 21

4.3 Demographics of source population ...... 21

4.4 Impact of the removal of individuals from the source population ...... 21

4.5 Methods of collection and transfer ...... 21

5 Holding site conditions ...... 23

5.1 Site tenure ...... 23

5.2 Holding site environment ...... 23

5.3 Species reproduction in captivity ...... 23

5.4 Managing known and potential threats ...... 23

6 Host environment...... 24

6.1 Site tenure and level of conservation protection ...... 24

6.2 Host environment...... 24

6.3 Is the site part of the historically known range for the species? ...... 27

6.4 Why the species cannot be conserved within its known range ...... 27

6.5 How the habitat requirements of the species will be met ...... 27

6.6 Managing known and potential threats ...... 27

6.7 Release and facilities to be used ...... 28

6.8 Consequences of the translocation on the viability of the host population ...... 28

6.9 Dispersal of individuals and the carrying capacity of the habitat ...... 28

6.10 Potential environmental impacts ...... 28

7 Monitoring and research ...... 29

7.1 Monitoring prior to release ...... 29

7.2 Monitoring in the first three months post-release ...... 30

7.3 Medium to long term monitoring ...... 31

7.4 How monitoring will inform management ...... 34

8 Risks ...... 35

8.1 Risk assessment and handling strategies ...... 35

8.2 Biosecurity ...... 35

8.3 Thresholds that determine requirement for withdrawal from the project, and exit strategy 35

9 Communications plan ...... 36

9.1 Stakeholders and public communication plan ...... 36

10 List of Appendices ...... 37

11 References ...... 38

1 Project management

1.1 Proponent

Director of National Parks

1.2 Project Sponsor:

Assistant Secretary Uluru and Island Parks Branch

1.3 Project co-ordinator:

Natural Resource Manager Christmas Island National Park 1.4 Project oversight Due to the significant decline of Christmas Island’s native reptiles and the need to access specialist advice and expertise for their conservation, in 2011 the Christmas Island Reptile Advisory Panel (CIRAP) was formed to:

1. Provide advice and direction to the Director of National Parks (DNP) and Taronga Zoo on the Christmas Island Reptile Conservation Program, in particular the captive breeding and reintroduction program.

2. Assist in the development of appropriate collaborations with other research and environmental management organisations.

Membership comprises people from various backgrounds including conservation managers, reptile/monitoring experts and a geneticist (see Table 1). Meetings are held at-least twice per year via teleconference.

While this plan prescribes envisaged actions for a 10 year period, it is recognised that there will be a need to respond to uncertainty or changing circumstances over the plan’s life. Consequently, continuing to access advice from CIRAP (and as needed other relevant experts) is considered an essential underpinning action, in order to enable an adaptive evidence based approach to the implementation of this plan. Therefore, this plan is considered a working document that may be changed over time based on new evidence and advice.

Table 2 outlines other organisations and stakeholders involved in this project.

Table 1: CIRAP membership Name Organisation Role Parks Australia Assistant Secretary, Parks and Biodiversity Science Branch Parks Australia Manager, Christmas Island and Pulu Keeling National Parks Parks Australia Natural Resource Manager Christmas Island National Park Taronga Conservation Manager Society Australia Herpetofauna Division Vacant Taronga Conservation To provide advice on genetic management Society Australia Vacant Independent expert Charles Darwin Professorial Research Fellow University Deakin University Director, Centre for Integrative Ecology Director, TechnEcology Research Network President, Ecological Society of Australia School of Life and Environmental Sciences Taronga Conservation DVM, DVSc Society Australia Australian Registry of Wildlife Health

Table 2: Internal and external stakeholders Name Organisation Role Christmas Island Independent advisory Provides advice on the captive breeding Reptile Advisory Panel panel and reintroduction of Christmas Island (CIRAP) reptiles Christmas Island Parks Australia Is responsible for the reptile captive National Park breeding program on Christmas Island, development of this plan, translocation of C. egeriae to Cocos, training of PKNP staff and initial monitoring Taronga Conservation Is responsible for the reptile captive and Taronga Zoo Society breeding program at Taronga Zoo, provides advice on genetic and husbandry management of the species and contributor to this plan Pulu Keeling National Parks Australia PKNP will assist in the pre-release Park (PKNP) assessments of the destination islands, assist with community consultations and have responsibility for long-term monitoring of the introduced population Animal Ethics Taronga Conservation Ethics approval for the project Committee Society EPBC Permits Department of Responsible for the assessment and Agriculture, Water and the approval of threatened species permits Environment Responsible for the assessment and approval of live animals imports from Christmas Island and Sydney to the Cocos (Keeling) Islands CEO and Councillors Cocos (Keeling) Shire Responsible for the management of the Council Cocos (Keeling) Islands Cocos community

1.5 Resourcing The overarching reptile conservation program is funded through the CINP operational budget. This funds one full-time reptile keeper and provides a small budget to cover operational expenses. Additional funds are received for a Memorandum of Understanding (MoU) with Taronga Conservation Society for the captive management and advice on genetic management of Christmas Island reptiles.

The proposed conservation introduction predominantly relies on staff time for maintenance of the captive colony, on-going monitoring and threat mitigation. An additional budget is required to cover short-term casual staff, operational expenses and travel. A breakdown of these costs are outlined in Table 3. Note that the bulk of staffing and fixed costs is covered by existing operational funding and has not been included here. Staffing costs included are for additional temporary staff to undertake rat eradication on the destination islands and to assist with maintaining the captive colony at the level required to support reintroduction activities (i.e. approximately 1,000 individuals per species). All costs for 2018-19 and 2019-20 are funded. Funding for all other years are not currently budgeted for.

Table 3: Estimated costs of implementing this plan Item Financial year 2018-19 2019-20 2020-21 2021-22 2022-23 2023-24 2024-25 2025-26 2026-27 Rat eradication Staffing $8,430 $8,430 (APS3 – 5 week period) Flights $570 $570 Accommodation $8,250 $8,250 Travel allowance $3,225 $3,225 Bait & equipment $3,120 $2,550 Movement of animals Flights CI to Cocos $5001 $500 $500 $500 $500 $500 Flights Sydney to $2,0002 $2,0002 $2,0002 $2,0002 $2,0002 $2,0002 Cocos Accommodation 2 x Overnight Perth $4002 $4002 $4002 $4002 $4002 $4002 Cocos (1 x Taronga) $1,0002 $1,0002 $1,0002 $1,0002 $1,0002 $1,0002 Cocos (1 x CINP) $2,5003 $2,5003 $2,5003 $2,5003 $2,5003 $2,5003 Travel allowance $1,2903 $1,2903 $1,2903 $1,2903 $1,2903 $1,2903 Monitoring $5,0004 $5,0004 $5,0004 $5,0004 $5,0004 $5,0004 $5,0004 $5,0004 Captive breeding Staffing (0.8 x APS2) $32,8075 $65,6135 TOTAL UNFUNDED $64,092 $101,898 $12,690 $5,000 $12,690 $5,000 $12,690 $5,000 $12,690

1 Release of animals to the first destination island was actually in September 2019-20 and the second release is planned for March 2020. Subsequent releases to both islands will be concurrent and only require 1 trip. 2 Possibly covered by Taronga MoU payment but have been included here to reflect total cost. Accommodation budget is for 1 person for 4 nights. 3 Accommodation for CINP staff is for 10 nights and may not be required if shared staff accommodation is available at no cost. Travel allowance is based on $129/day. 4 Monitoring costs include additional boating costs that will be incurred by PKNP to monitor introduced populations. 5 Staffing costs for 2018-19 is for 0.8 APS2 for 6 months including on-costs. 2019-20 budget is for 0.8 APS2 for 12 months including on-costs.

2 Project rationale

2.1 Goal • Introduce a number of self-sustaining wild populations of C. egeriae to the Cocos (Keeling) island group by 2020 to secure the future of the species outside of captivity. This will include an initial release of up to 300 individuals on each destination island in 2019 and 2020 and may involve subsequent releases every two years until 2027 (pending genetic advice). This will be the first wild release of C. egeriae outside of Christmas Island.

2.2 Objectives • Continue captive breeding programs on Christmas Island and at Taronga Zoo to secure a source population for introduction and subsequent releases until 2027. • Gain necessary approvals, permits and community support for the project. • Achieve chicken removal and rat eradication on the destination islands prior to any proposed releases, see Appendix D for details on the planned rat eradication. • Select a genetically diverse founder population from the Christmas Island and Taronga Zoo captive populations for release by February 2019. • Transport and release up to 300 animals to the first destination island in September 2019. • Transport and release up to 300 animals to other destination islands in 2020 pending chicken and rat removal. • Monitor the introduced populations post-release to record successful establishment.

2.3 Type of conservation action Under the revised IUCN reintroduction guidelines a conservation introduction is defined as the intentional movement and release of an organism outside its indigenous range. Two types of conservation introductions are recognised: a. Assisted colonisation is the intentional movement and release of an organism outside its indigenous range to avoid extinction of populations of the focal species.

This is carried out primarily where protection from current or likely future threats in current range is deemed less feasible than at alternative sites. b. Ecological replacement is the intentional movement and release of an organism outside its indigenous range to perform a specific ecological function.

This is used to re-establish an ecological function lost through extinction, and will often involve the most suitable existing sub-species, or a close relative of the extinct species within the same genus.

The proposed action is classed as an assisted colonisation as C. egeriae will be moved to an area outside of its indigenous range to help avoid potential extinction.

It is not intended for any C. egeriae released on Cocos during the Conservation Introduction or their offspring to return to Christmas Island or be moved to any other location. It is considered a ‘one way ticket’. At a later date, consideration may be given for the movement of C. egeriae from Cocos to another location, e.g. failure of the Christmas Island captive colony. However, this is not covered in

this plan and would require a new Species Conservation Plan, associated risk assessment and other documentation.

2.4 Taxonomy of the species The species is conventionally accepted as Cryptoblepharus egeriae (Boulenger, 1889). Cryptoblepharus egeriae is in the Family Scincidae. This species is endemic to Christmas Island.

2.5 Legal Status of the species Cryptoblepharus egeriae is listed as Critically Endangered under the Environment Protection and Biodiversity Conservation Act 1999. A Conservation Advice exists for this species effective from 3/1/2014. Priority research actions include:

 Investigate options for establishing additional populations from captive-bred stock;  Undertake adaptive release trials, such as through the use of enclosures, to trial the reintroduction of captive-bred individuals into the wild; and  Monitor the status of introduced individuals.

Internationally C. egeriae is listed on the IUCN Red List of Threatened Species as Extinct in the Wild (IUCN, 2018). Conservation actions for C. egeriae include:

 The release of captive animals into outdoor enclosures protected from predators; and  Release to the Cocos (Keeling) Islands. 2.6 Documented recovery actions Table 4: Summary of recovery actions and their status as per the Conservation Advices

Blue-tailed skink, Cryptoblepharus egeriae Recovery actions Source Status Monitor areas where the C. egeriae was last known to Monitoring undertaken until occur to help identify key threats and determine the 2012 relative impacts of potential threats. Ensure there is no disturbance in areas where the C. Achieved egeriae was last known to occur, excluding necessary actions to manage the conservation of the species. Effectively manage any known, potential or emerging YCA biological control threats to the C. egeriae, such as introduced predators implemented, cat eradication and diseases, particularly in areas where the species was occurring, targeted centipede last known to occur/potential habitat. and wolf snake control possible at a local scale -but impossible Conservation island-wide), disease being Advice investigated Control and reduce the impacts of introduced pests As above including the feral cat, rat, yellow crazy ant, Asian wolf snake and giant centipede on Christmas Island, particularly at sites where C. egeriaeis known to have previously occurred, by developing or implementing existing management plans to control these species. Monitor the effectiveness of management programs to Control programs independently control population numbers of feral animals. reviewed periodically Improve biosecurity on Christmas Island to maintain Biosecurity alerts distributed for effective quarantine against the introduction of diseases, potential new introductions parasites, pathogens and invasive species. If a disease, fungi and/or parasite is found to be impacting Disease currently being upon, or may potentially impact upon C. egeriae, investigated

implement appropriate management actions to minimise the adverse impacts of such threats. Continue to support and enhance the captive breeding Ongoing program for the species with the aim of breeding enough genetically diverse individuals to enable future re- establishment of wild populations. Develop educational and awareness raising programs Ongoing regarding C. egeriae status, threats and recovery activities.

2.7 Justification for conservation action The Director of National Parks Corporate Plan 2018-2022 supports the finalisation of the feasibility study (Appendix E) for the introduction of C. egeriae to the Cocos (Keeling) Islands which in broad terms includes a trial release. The Christmas Island National Park Management Plan 2014-2024 also seeks to maintain and adaptively develop conservation programs for terrestrial reptiles under threat from extinction in the wild (Action 4.3.12). The objective of the CINP Reptile Conservation Program is to conserve and restore populations of native reptile species on Christmas Island, with all extant species persisting in the wild. This includes a subsidiary objective to successfully reintroduce C. egeriae back into the wild.

There is a high chance that successful reintroduction of C. egeriae is not possible on Christmas Island due to the ongoing pressures of the Asian wolf snake and giant centipede. Looking at alternative options for reintroduction is crucial for managing this species into the future.

The reptile conservation work associated with this Plan will help enhance the recovery of C. egeriae by establishing a wild population in a location where its main threats are absent. The action is not likely to have any negative impacts to the native flora and fauna at the release location and the pre-release works of rat eradication and chicken removal will only seek to enhance the local environment.

The destination islands will be assessed on their suitability to support a population of skinks with a particular focus on their accessibility, abundant invertebrate population and suitable habitat. 2.8 Consequences of not proceeding with the proposed action If suitable options for reintroduction are not found on Christmas Island and the proposed conservation introduction is not trialled, then there is a real chance that C. egeriae will remain in captivity indefinitely.

2.9 Criteria for Success To provide standards for the evaluation of the project’s success, the following criteria will be used: Short-term (six months):  Eradication of rats from the destination islands  Removal of chickens  Successful transfer of up to 300 animals from captivity to the release site  Signs of mating and reproduction (e.g. bite marks or gravid females)  >50% survivorship of animals six months post-release on one or two of the release islands (to be informed by soft-release on Christmas Island) Medium-term (one year):  Absence of introduced predators  Stable population of at least 50% of the release population on at least one of the release islands  Successful transfer of additional animals from captivity to the release site  Successful recruitment (persistence of newly recruited animals to at least 6 months of age) on at least one of the release islands Long-term (> two years):  Absence of introduced predators

 Stable/organically growing population* on at least one of the release islands  Successful recruitment (persistence of recruited animals to adult age) on at least one of the release islands  Successful transfer of additional animals from captivity to the release site (dependent on success achieved in criteria above)

* Actual target population size is highly speculative and dependent on a number of variables including habitat preference, food availability, carrying capacity and complete transfer numbers. Through monitoring, carrying capacity of the island(s) may be identified. 2.10 Previous work By 2009 it was recognised that the wild population of C. egeriae was rapidly declining and, over the course of 2009 and early 2010, a total of 66 individuals were collected from the wild to establish a captive colony on Christmas Island.

Prior to genetic management advice, captured animals were intermittently moved between enclosures (approximately every 6 months), whilst avoiding the possibility that mature offspring would be housed with either their siblings or parents. All captured animals and their offspring were given an identifying toe-clip at this time. In May 2011, eight C. egeriae captive populations were established. Animals were grouped according to their capture location and genetic heritage following genetic management advice from Taronga Zoo Threat mitigation.

By the end of 2011, the captive population size of C. egeriae had almost doubled. These populations were split into two colonies with one colony remaining on Christmas Island and the other transported to Taronga Zoo, Sydney. In three shipments, a total of 83 C. egeriae were transferred to Taronga Zoo to establish a second insurance population.

Since the establishment of a captive colony, the population has significantly increased and as of June 2018, 1629 individuals exist in captivity.

In 2017, an attempt was made to reintroduce 139 C. egeriae into a soft-release site on Christmas Island. The attempt was unsuccessful and the site was reconstructed in 2018 following significant improvement works and predator removal. In August 2018, 170 C. egeriae were released and as of April 2019, all criteria for success have so far been met with the population growing from the released number.

NESP PhD research

Whilst the first trial reintroduction of C. egeriae into the soft-release site on Christmas Island was unsuccessful in 2017, we learnt a number of valuable things including; (1) food availability appeared sufficient as all animals recaptured maintained body condition, and (2) lizards were observed still maintaining antipredator behaviour towards avian predators. Unfortunately, the primary reason was not identified, however a few hypotheses were developed which include (1) did introduced giant centipedes play a significant role in the demise of this population, (2) was the habitat suitable to maintain a population of C. egeriae and (3) did natural avian predators predate heavily on C. egeriae. Points two and three are being investigated in much more detail currently in the second release that occurred in August 2018. Before this release, CINP staff significantly increased the complexity, connectivity and amount of habitat available, and we are stringently monitoring what habitat they favour and to assess whether there is enough. To do this we will use selectivity indices. This is a method to see whether a species are disproportionately favouring a specific habitat type, and if they are, is there a sufficient amount of it and if there isn’t, can we increase this habitat to make the site more suitable for them. 10

Furthermore, we are currently undertaking an experiment to elucidate relationships between C. egeriae and giant centipedes (Scolependra subspinipes) to investigate whether they may have played a potential role in the decline of the reintroduced population of C. egeriae. Whilst we undertook removal of centipedes from the soft release site, we underestimated the densities of centipedes in the site. To do this, we have set up six 25m2 mesocosm exclosures with two different centipede densities to assess survival over 12 weeks. Preliminary analysis is starting to indicate an effect after 7 weeks at high (6 centipedes over 10cm) centipede densities, however there is no such effect yet at small centipede densities (2 centipedes over 10cm). Irrespective of the result, centipedes have been eradicated from the soft release site before C. egeriae were re-released in August 2018, however this experiment will be incredibly important for two reasons; (1) were they responsible for the decline of that population and (2) if they were, does density play a role and how much management needs to be done to keep the site centipede free?

Finally, the only predators believed to be able to access the site are avian threats, primarily the Christmas Island thrush and Christmas Island Goshawk. We will spend time monitoring interactions between these birds and C. egeriae. Once C. egeriae has become established in area, we will set up a number of remote triggered motion cameras to see whether and how often these possible predators are spending trying to consume skinks.

2.11 Number of individuals of the species being conserved and proposed project timing This project proposes to harvest up to 150 individual C. egeriae from each of the two captive populations (i.e. Christmas Island and Taronga Zoo) on eight to ten separate occasions from 2019 to 2027 (i.e. 150 x 2 x 10 = a total of 3,000 C. egeriae over 8 years). The number of animals harvested on each occasion will depend on how many excess animals are available from the captive colonies. The number of animals harvested from both colonies will always be equal to support genetic management goals. On the final year, up to 500 C. egeriae will be swapped between the two destination islands to enhance genetic diversity. The harvested C. egeriae will comprise a mixed cohort (including juveniles, sub adults and adults) containing both sexes, harvested equally from both remaining captive populations. The number and age class of animals to be used in this project was determined in consultation with Taronga Zoo to ensure that genetic diversity is maintain and that the introduced population has the best chance of successful establishment. Whilst tables 5 to 9 outline the steps for the initial release in 2019, the tasks in tables 7-9 are still applicable for all subsequent releases and monitoring. Due dates for activities 2020 onwards will be planned annually.

Table 5: Planning phase Item Description of Major Tasks Due Date

1 Seek Executive Board approval November 2018

2 Seek approval from the Shire of Cocos (Keeling) Islands September 2018

Apply for import approval through the Department of Agriculture and Water Before June 3 Resources 2019

4 Apply for animal ethics approval through Taronga Conservation Society September 2018

5 Apply for EPBC Part 13 permit November 2018

6 Undertake an environmental referral self-assessment July 2018

7 Circulate all documents through CIRAP November 2018

8 CIRAP meeting #14 February 2019

9 Reapply for EPBC Part 13 permit to include all Cocos (Keeling) Islands February 2020

Table 6: Preparation and extraction Due date for Item Description of Major Tasks Destination Island #1

1 Rat eradication from destination island one January 2019

2 Removal of introduced geckos pre-release if necessary (see section 6.6) January 2019

Habitat improvement; Provide canopy openings (fell coconut), weeding, tree 3 January 2019 planting if necessary

4 Chicken relocation (if applicable) January 2019

5 Preparation of animal transport containers as per ethics approval August 2019

Capture and health assessment of captive animals for release including weight, 6 September 2019 morphometric measurements and toe-clips

Table 7: Treatment while in captivity Item Description of Major Tasks Due Date

Standard Christmas Island Reptile Captive Breeding program animal management as per the ‘Christmas Island National Park Reptile Conservation 1 Ongoing Plan 2014-2024’ and ‘Christmas Island Terrestrial Reptile Captive Breeding Program Manual’

Completion of Reptile census, exclosures cleaned, animal health checks, Every 6 months 2 identification of release numbers and age cohort (February/July)

Table 8: Species first release (subsequent release due dates will be planned annually) Due Date for Item Description of Major Tasks Destination Island #1

Package animals for transport from Sydney to Cocos and Christmas Island to 1 September 2019 Cocos

Quick health assessments on arrival to Cocos as per guidelines outlined in the 2 September 2019 animal ethics application

Depending on flight times/delays and weather conditions, animals may be 3 September 2019 immediately released or held for 1-3 nights before release to destination island

Animals will be released late afternoon to strategic areas within the site that 4 September 2019 contain a significant amount of refugia

Table 9: Post-release monitoring and reporting following first release (subsequent post-release monitoring and reporting will be planned annually) Due Date for Item Description of Major Tasks Destination Island #1

1 Weekly monitoring for one month October 2019

2 Monthly monitoring from 2-6 months February 2020

3 CIRAP #15 (report on release one) October 2019

4 CIRAP #16 (progress report on C. egeriae survivorship and monitoring) May 2020

5 Monthly Project Status Report monitoring Ongoing

3 Biology and ecology

3.1 Morphology

3.2 Reproductive cycle and timing Cryptoblepharus egeriae is oviparous and can lay multiple clutches of one-two eggs per breeding season. In captivity, the breeding season is from October to April. Eggs are generally laid in moist areas under leaf litter or bark and take approximately two months to incubate. 3.3 Distribution and abundance Formally, C. egeriae was widely distributed across Christmas Island. However they are no longer found in the wild and exist only in captivity at two locations, Christmas Island and Taronga Zoo, Sydney. 3.4 Habitat requirements Cryptoblepharus egeriae favoured a wide variety of habitats on Christmas Island including; primary rainforest, thickets, coastal areas and disturbed/modified habitat. In 1979, it was reported as abundant in household gardens, brick walls and roadside vegetation but less common in primary rainforest where it was found in clearings (Cogger, Sadlier et al. 1983). 3.5 Nutritional requirements Cryptoblepharus egeriae feeds on a variety of small invertebrates including crickets, grasshoppers, termites, spiders and moths. These invertebrates naturally occur within the host environment. 3.6 Reasons for decline and current threats No single known causal factor has been identified as being responsible for the decline of the CI native reptile fauna. It is likely a combination of factors has contributed to their decline. Table 10 identifies a number of possible threats present on Christmas Island that have been implicated in the decline of the CI reptile fauna, the history of their introduction, an overview on their likely impact (Smith et al., 2012) and how they are currently being managed.

A number of these threats were considered by the Christmas Island Reptile Advisory Panel (CIRAP), which was established by the DNP in 2011 to inform the conservation of Christmas Island’s reptiles. At the first CIRAP meeting on 5 August 2011 (and based on expert opinion), threats were prioritised on the extent of their likely detrimental impact, the level of current management response as well as the likelihood of reptiles persisting with or without the presence of these pressures. The presumed threats that remain uncontrolled and/or do not have resources currently allocated for investigating techniques for their control were prioritised. This information is also included in Table 10.

It was however recognised that there is little, and insufficient, empirical basis for evaluating the relative impacts of these factors, and a key priority is to undertake research that can better resolve the threat context. Current PhD research by will help to address this issue.

Table 10: Possible threats to Christmas Island native reptiles

Threat History Role in reptile declines Management

Yellow Crazy Ants Early 1900s – introduced Unknown but has most 1999 – Crazy Ant Steering Committee established (now CASAP) accidentally via shipping likely indirectly impacted on 2000 – hand and aerial baiting program commenced. Hand baiting has been food resources by reducing 1990s – discovery of undertaken when needed invertebrate diversity and destructive supercolonies abundance and habitat 2001 – the first biennial island-wide survey was conducted and has been Distribution of supercolonies quality undertaken every two years since has changed overtime with 2002 – first aerial baiting campaign. Over 2500ha baited control efforts Impact on reptiles 2005 – YCAs listed as Key Threatening Process to the Biodiversity on CI YCAs have affected about under the EPBC Act 39% of the island in total MODERATE 2006 – YCA identified as a priority species in the Threat Abatement Plan to In 2012, supercolonies Reduce the Impacts of Tramps Ants on Biodiversity in Australia and its spread across about 8% of Impact on reptiles with Territories the island management intervention 2009 – second aerial baiting campaign. Approximately 500ha baited. LOW Commencement of three year research into YCA biological control 2012 – third aerial baiting campaign. Approximately 1067ha baited 2013 to 2015 – hand baiting and implementation of YCA biological control 2016 to 2018 – rearing and island-wide release CIRAP acknowledged that the control of Yellow Crazy Ants is a priority for broader biodiversity conservation on the island and a management plan exists which guides a well-established control program. Although an important issue, CIRAP considered that it did not need to be addressed separately for the purposes of reptile conservation as it was already being addressed and advised by the Crazy Ant Scientific Advisory Panel (CASAP).

(Table 10 continued)

Threat History Role in reptile declines Management

Competition with Introduced accidentally Unknown but is most likely No current management in place non-native reptiles probably via shipping. Initially impacting indirectly through CIRAP considered this threat as a lower priority at the time with respect to restricted to disturbed areas competition for resources other pressures highlighted, however, introduced geckos have been and habitat as well as the 1947 – H. frenatus (Gibson- implicated in native gecko declines in the Pacific Islands and warrants further spread of disease/parasites Hill, 1947) investigation on Christmas Island. (see disease/parasites) 1979 – G. mutilata (Cogger

et al., 1983) Impact on reptiles 1979 – L. bowringii (Cogger et al., 1983) MODERATE 1987 – L. capucinus (Smith Impact on reptiles with 1988) management intervention 1980s – observations of MODERATE (no introduced reptiles beginning management) to spread into undisturbed

areas (Cogger et al., 1983)

Habitat disturbance 1898 – phosphate mining Generally loss of habitat 1980 – the south western corner of the island is protected under the National and fragmentation commenced and has been although some species Parks and Wildlife Conservation Act 1975 and Christmas Island National Park almost continuous since were common in settled is declared areas and old mine sites 1989 – no further clearing of 1986 – Christmas Island National Park was extended in two stages primary rainforest allowed Impact on reptiles 1989 – A further addition to Christmas Island National Park including wetland LOW and marine areas and much of the island’s remaining undisturbed rainforest Impact on reptiles with Future clearing is subject to assessments under the Environmental Protection management intervention Act 1986 (WA)(CI). MINOR

Climate Change Unknown Unknown but changing No current management in place temperatures and periods CIRAP considered this as a lower priority at the time with respect to other of wet and dry may impact pressures highlighted. on reproductive success

(Table 10 continued)

Threat History Role in reptile declines Management

Cats 1888 - introduced by early Predation of native reptiles 1981 – survey of feral cat distribution (Yorkston, 1981) settlers 1989 – Survey of terrestrial mammals (Tidemann, 1989) Initially cats were Impact on reptiles 1994 – Cat dietary studies confirming native reptile predation (Tidemann et concentrated around al., 1994) settlement and mining areas LOW to MODERATE but with the movement of 1997 – Cat dietary studies confirming continued predation on native reptiles Impact on reptiles with black rats across the island, (van der Lee, 1997) management intervention feral cats become more 2002 – Cat dietary studies inferred by scats showed a shift in diet to widespread and are now NIL predominantly birds and insects (Corbett et al., 2003) found island-wide 2005, 2008 – survey of feral cat distribution and abundance and diet in 2005 (Algar and Brazell, 2005, 2008) 2010 – a threat abatement plan implemented for cats and black rats. Introduction of council cat by-laws. Domestic cat registration and de-sexing. 2011-2012 – annual domestic cat survey and de-sexing. Control of stray and feral cats in residential and industrial areas and along major road ways (2012 only) 2013 - annual domestic cat survey. Control of stray and feral cats in residential and industrial areas and along major road ways. Approximately 502-595 feral cats removed to date 2014 – maintain current control efforts until further funding is secured for island-wide eradication 2015 – commence island-wide eradication CIRAP considered the control/eradication of cats a priority for broader biodiversity conservation on the island and noted that a threat abatement plan exists. There was agreement that cat control did not need to be addressed separately for the purposes of reptile conservation.

(Table 10 continued)

Threat History Role in reptile declines Management

Centipedes Introduced accidentally via Unknown but predation No current broad-scale management in place shipping in the early 1900’s and/or competition for Targeted control at a soft-release site and thought to have habitat or food may have significantly increased in been a contributing factor CIRAP noted that little is known about the effects of centipedes on reptile abundance by the 1990’s survivorship, therefore investigating the impacts of centipedes was

considered one of the most immediate issues for successful reintroduction of Impact on reptiles reptiles back into the wild. MODERATE-HIGH Impact on reptiles with management intervention MODERATE-HIGH (no management)

Wolf snakes Thought to have been Likely to play a significant 1992 – survey into the distribution, population, structure and ecological introduced accidentally via role in the disappearance of behaviour of the wolf snake including diet analysis (Rumpff 1992) shipping around 1987 native reptile species 1999 – wolf snakes included in a terrestrial reptile survey (Cogger and Sadlier through predation. 1999) Impact on reptiles 2004-2006 – wolf snake study included in the Christmas Island Biodiversity HIGH Monitoring Program including 200 dissections and nocturnal surveys (James 2007) Impact on reptiles with management intervention 2008 - wolf snakes included in a terrestrial reptile survey (Schulz and Heywood Barker 2008) HIGH (no management) 2008-present – Opportunistic and targeted wolf snake monitoring/gut contents analysis conducted by DNP 2016 – wolf snake Master’s research undertaken 2018 – Targeted control at a soft-release site CIRAP noted that wolf snakes have been implicated in the decline of native reptiles through their dietary preferences. The pattern of decline or the native reptile species has closely matched the spread of the wolf snake from East to West across the island. Furthermore, native reptiles were frequently detected

in the stomach contents of dissected wolf snakes. Investigating techniques for wolf snake control was considered one of the most immediate issues for successful reintroduction of reptiles back into the wild.

(Table 10 continued)

Threat History Role in reptile declines Management

Rats 1899 – introduced Unknown but predation on 2010 – a threat abatement plan implemented for cats and black rats accidentally via shipping reptiles and/or eggs may be 2012 to 2014 – settlement foreshore baiting a likely contributing factor Rats brought a disease 2014 onwards – community rat baiting parasite, murid trypanosome, which was transmitted by 2016 – PhD project focusing on meso-predator relationships and impact of Impact on reptiles fleas to native rats rats post cat removal LOW Within less than 10 years from the time of introduction Impact on reptiles with native rats became extinct management intervention LOW

Red Jungle Fowl Introduced during settlement Unknown but predation on No current management in place reptiles may have been a Abundant in settled and contributing factor disturbed areas

Impact on reptiles LOW Impact on reptiles with management intervention LOW (no management)

Disease/parasites Unknown Unlikely to have played a 2010 – The Director of National Parks commissioned a study to assess role in decline however the whether parasites, disease and/or heavy metals were key contributing factors discovery of enterococcus in the reptile declines. This study was undertaken by the Australian Registry of Wildlife Health (Taronga Conservation Society Australia)

in 2014 may impact on 2011 – Hall et al. (2011) reported on this study. They found no evidence that reintroduction disease, pathogens or heavy metals were contributing factor to the declines 2014 – Discovery of a new disease in geckos which was later confirmed as a new enterococcus bacteria Impact on reptiles 2017 – PhD research commenced to investigate a novel enterococcus MEDIUM bacteria found in geckos Impact on reptiles with There has been no further management response management intervention MEDIUM (no management)

4 Source environment, population and distribution

4.1 Site tenure Animals will be sourced from the Christmas Island National Park reptile captive breeding program located at the Pink House within the National Park and Taronga Zoo, Sydney.

4.2 Source environment Captive.

4.3 Demographics of source population The captive population supports individuals within all size and age classes and has a sex ratio of approximately 1:1 for both species.

4.4 Impact of the removal of individuals from the source population Ensuring the viability of the captive populations of C. egeriae and L. listeri whilst reintroductions attempts are occurring is critically important. One commonly used conservation tool to help with this form of decision making are Population Viability Analyses (PVA’s). PVA’s are a tool that allow wildlife and conservation managers to simulate extinction processes using computer simulation models to predict the viability of populations under different management options using demographic and stochastic parameters specified by the user (Possingham et al. 1993). A PVA was undertaken to assist guiding suitable decisions regarding the harvesting of C. egeriae from Christmas Island unpublished data 2018). Using a conservative total of harvesting 200 animals (100 juveniles and 100 adults using an estimated 50/50 ratio) from a population with 1000 individuals (approximate current population) on a single occasion suggests there is a 0% risk of extinction to the Christmas Island populations over a 10 year time frame. These models will be continuingly refined over time to ensure the most up to date data is being incorporated into the future management of these species. Overall, the risk to the source population is negligible for a one off harvest, however the risks of multiple harvests over a sustained time period would be considerably different and will be assessed separately.

4.5 Methods of collection and transfer Cryptoblepharus egeriae will be held in a captive environment until they are ready for relocation. During this time they will be fed invertebrates three times per week (Monday, Wednesday, and Friday) and water will be checked daily as per the husbandry requirements of the captive population.

On Christmas Island, four enclosures, each containing up to 30 individuals (120 total) are currently being filled with newly recruited animals. It is anticipated that by the release date (Jan-June 2019) these animals will be 1-18 months age. The remaining 30 animals will be harvested from young ‘overflow’ enclosures. Each enclosure will be checked for disease one, six and twelve weeks before departure. If disease is detected in any enclosure within 12 weeks prior to departure, it will not be included.

At Taronga Zoo, up to 30 individuals will be held in 6 enclosures in a quarantined room in preparation for release. These will contain mostly juvenile to sub-adult individuals that have been harvested from across the breeding colony to capture maximal genetic diversity. Each enclosure will be under health surveillance, with physical examinations and disease checks to be undertaken

by zoo veterinarians and skilled and trained keeping staff in the months prior to release, with a thorough examination within two weeks of departure.

Up to 150 C. egeriae will be selected from the Christmas Island captive population and the Taronga Zoo captive population for introduction to the Cocos (Keeling) Islands (total of up to 300 animals). Prior to transport all animals will be individually toe-clipped using approved procedures consistent with the Australian Society of Herpetologists (Appendix C).

On the day of departure C. egeriae will be transferred to Sistema 400 ml hard plastic ‘Click-Clack’ boxes (with air holes) (Figure 1), containing slightly moistened tissues, up to 2 lizards per box. These plastic boxes will be inside a large box insulated from temperature changes and sharp movements to maintain the temperature if travelling in air conditioning.

Figure 1: Sistema transport box

From Sydney to Perth (a Thursday flight), Perth to Cocos (a Friday flight) – C. egeriae will be transported to the airport by road accompanied by Taronga staff member. Estimated time in a vehicle is up to 1 hour to Sydney airport. Flight time is approximately 5 hours. Animals will be held overnight in Perth and the containers unopened. The following morning, animals will be transported back to Perth airport by vehicle (10 minutes). There is a risk that the flight from Perth to Cocos will be delayed by more than 24 hrs. If this eventuates the animals will be transported to Perth Zoo, housed in a quarantine facility in large containers, fed and given water.

From Christmas Island to Cocos (a Tuesday flight) - C. egeriae will be transported to the airport by road accompanied by CINP staff. Estimated time in vehicle is 10 minutes. There is a risk that the flight from Christmas Island to Cocos will be delayed by more than 8 hrs. If this eventuates the animals will be returned to their original enclosure until a recovery flight is scheduled.

Both transfers will occur on the same week. Animals will be transported by aircraft as cargo in a pressurised hold. A CINP or Taronga staff member will travel on the respective flights with the animals. Estimated time on the aircraft is 2 hours Christmas Island to Cocos (CINP) or up to 6 Perth to Cocos (Taronga).

5 Holding site conditions

5.1 Site tenure The staging area will be located at the Pulu Keeling National Park (PKNP) office on West Island under the direction of CINP and PKNP staff and Taronga staff.

5.2 Holding site environment On arrival to the Cocos (Keeling) Islands, C. egeriae will be transferred from the airport to the PKNP office where they will be given a visual health check by experience Taronga and/or CINP staff. Animals from Christmas Island (Tuesday) will be moved into larger holding tubs in groups of up to 20 with a small amount of habitat, provided with water and food and held overnight (Figure 2). In the larger holding tubs, C. egeriae will be transported by small boat to the destination island. Animals from Taronga will be transported in their original holding containers directly to the destination island by boat. Estimated time on the boat is 30 mins.

Figure 2: Large holding tub 5.3 Species reproduction in captivity Captive breeding of C. egeriae will only be undertaken as part of the existing captive breeding program on Christmas Island and at Taronga Zoo as per the genetic management plan. Animals will not be bred in captivity at the holding site.

5.4 Managing known and potential threats N/A in the holding site.

6 Host environment

6.1 Site tenure and level of conservation protection The islands within the southern atoll of the Cocos (Keeling) islands is Commonwealth land managed in trust by the Cocos (Keeling) Shire Council (CKSC). Land ownership will not change with the introduction of C. egeriae and the responsibility for future land management will remain with CKSC. It is possible that long-term invasive species control may be transferred to Parks Australia depending on discussions with CKSC. An agreement with CKSC may be developed to outline each party’s responsibility.

6.2 Host environment The Cocos (Keeling) Islands are located 900km west of Christmas Island (Woodroffe & Berry 1994) as is shown in Figure 3. They are marginally further south and have a very similar climate profile to Christmas Island with the major difference being that Cocos tends to have slightly less distinct wet- dry seasons with a peak of 250mm in April and minimum of 82mm in October, while Christmas Island (airport) has a peak of 343mm in February and minimum of 42.2 in August.

Figure 3: Location of Christmas Island and the Cocos (Keeling) islands Source: (WA now and then, 2019)

Table 11: Christmas Island/Cocos climate comparisons

Location Annual mean Annual mean Annual mean Years active Elevation above rainfall (mm) maximum (°C) minimum (°C) sea level (m) CI Airport 2199.4 27.4 22.6 1972-2018 261 CI Rocky point 1923.6 30.2 24.3 1901-1973 17 Cocos West Island 1983.1 29.1 24.6 1901-2018 3

Mean rainfall (mm) 400 350 300 250 200 150 100 50 0

CI Rocky Point Christmas Island Airport Cocos West Island

Figure 4: Monthly mean rainfall (mm) for comparison sites

Mean maximum temperature (°C) 32 31 30 29 28 27 26 25 24 23 22

CI Rocky Point Christmas Island Airport Cocos West Island

Figure 5: Monthly mean maximum temperature (°C) for comparison sites

Mean minimum temperature (°C) 30 29 28 27 26 25 24 23 22 21 20

CI Rocky Point Christmas Island Airport Cocos West Island

Figure 6: Monthly mean minimum temperature (°C) for comparison sites The vegetation and environment of the 21 vegetated Cocos (Keeling) islands (Figure 7) been extensively modified for coconut (Cocos nucifera) plantations (Williams 1994) however some remnant vegetation does exist. In a 2014 feasibility study (Director of National Parks 2014), Appendix E to this plan, a number of islands were assessed as being suitable based on their habitat complexity, height above sea level, isolation and invertebrate abundance. Not all islands were surveyed extensively to assess their suitability so were ruled out for the first release. However further assessments may deem them suitable for future releases.

Figure 7: Map of the Cocos (Keeling) islands

C. egeriae is a highly adaptable and generalist species capable of flourishing in highly modified environments including urban landscapes and cleared mine sites (Cogger, Sadlier et al. 1983).

Furthermore, the plant species including Cocos nucifera, Guettarda speciosa, Pemphis acidula, Scaevola taccada, Cordia subcordata and Argusia argentia are all found on Christmas Island and C. egeriae were readily encountered in habitats containing these species.

6.3 Is the site part of the historically known range for the species? No.

6.4 Why the species cannot be conserved within its known range There is a high chance that successful reintroduction of C. egeriae will not be possible on Christmas Island due to the ongoing pressures of the Asian wolf snake and giant centipede, among other known threats. Soft-release of C. egeriae is currently being trialled on Christmas Island however we are yet to determine if this will be a successful long-term option for reintroduction.

6.5 How the habitat requirements of the species will be met Ensuring suitable habitat at the reintroduction site is considered one of the most important components of maximising the likelihood of success of any reintroduction (Seddon et al. 2007). The removal of predators such as rats and chickens, and control of potential competitors such as introduced geckos, will be undertaken prior to the introduction of C. egeriae to enhance the quality of the habitat. Some habitat improvement will be performed on the islands including; providing canopy openings (fell coconuts), weeding and tree planting and post-release monitoring will help determine whether the site is providing adequate habitat requirements for these species.

6.6 Managing known and potential threats Release on the Cocos (Keeling) islands is possible as most of the known threats that extirpated them from the wild on Christmas Island (see table 10) are either not present (wolf snakes), possible to eradicate/manage at a local scale (rats, cats, red jungle fowl), not detected on the release islands (centipedes), or not considered crucial to the survival of the released C. egeriae if the other threats are managed (yellow-crazy ants, competition with non-native reptiles, habitat disturbance and fragmentation, climate change). The 2014 feasibility assessment (Appendix E) identified a number of potential threats including rats, chickens, fires and introduced geckos.

As outlined in section 2.10, rat eradication and the removal/relocation of chickens is planned prior to any planned release. Rat eradication will be achieved following the Rat Eradication Plan outlined in Appendix D. Any resident chickens are the property of Pondok owners and any necessary removal/relocation will be done with consent and in collaboration with Pondok owners. If this is not achieved then the release will be delayed or reconsidered.

Culling of introduced geckos Hemidactylus frenatus, Gehyra mutilata and Lepidodactylus lugubris will also be undertaken prior to release to reduce competition pressure on food resources. Ink card monitoring will establish a baseline of gecko abundance pre-gecko control. Should gecko numbers increase post-release, coupled with trigger points 2 and 7 in Table 17, additional introduced gecko management will occur.

Seabirds are present throughout the Cocos (Keeling) Islands but do not pose a threat as their diet does not include land vertebrates. Other birds such as the Nankeen night heron, reef egret, white- breasted waterhen and the Cocos buff-banded rail may be a potential threat however no control will

be undertaken on these species. Possible mitigation measures may include bird deterrents if necessary as outlined in the risk assessment.

Through community education, the community will be encouraged not to burn rubbish or light camp fires on the destination islands following release of C. egeriae.

6.7 Release and facilities to be used C. egeriae appear to be social as reports by Cogger et al. (1983) and James (2007) often noted multiple animals interacting with each other in a small area, and therefore we believe that releasing animals that have already been housed together in the enclosures will help in the establishment phase post release due to familiarity. Release time is dependent on tidal movements, but will take place during the day with enough time for individuals to seek refuge before nightfall.

No CIRAP members (other than local staff) will be on-site for the release. However, CINP and Taronga staff members (CIRAP observers) will be present.

6.8 Consequences of the translocation on the viability of the host population N/A

6.9 Dispersal of individuals and the carrying capacity of the habitat If conditions are optimal we estimate the carrying capacity on any of the potential destination islands to be over 1000. This is a best guess estimate and based on captive densities as we have no information on densities in the wild. Cogger et al. 1983 observed that C. egeriae were hyper- abundant in the 1980’s in the settlement area, but actual densities in a given area are unknown. Additionally, the likely carrying capacity of each of the islands will fluctuate between wet and dry seasons, however we do anticipate the two sites to eventually reach an equilibrium. Monitoring will help to identify carrying capacities of the islands. There is no data on the dispersal rates of C. egeriae, however dispersal across the release sites is likely to be significantly higher immediately post release as animals seek suitable habitat. Once animals become established in an area, it is likely that dispersal will be very small. The monitoring program has been designed to gather information on home range and dispersal rates post release.

6.10 Potential environmental impacts We do not foresee any adverse environmental impacts to the site. The introduction will enhance the ecosystem at this location by removing invasive species and revegetating parts of the island if necessary. There are no native reptiles on Cocos (Keeling) Islands so the introduction of Christmas Island reptiles will not have any negative impact on any native reptile species. No other species including land crabs or other invertebrates, native or non-native are expected to be affected. An environmental referral self-assessment has been undertaken to assess impacts on matters of National Environmental Significance (NES) and has identified that the planned conservation introduction will not significantly impact on matters of NES and only seeks to enhance the recovery of a Critically Endangered species (Appendix F).

7 Monitoring and research

7.1 Monitoring prior to release

Table 12: Monitoring requirements prior to release Key Outcomes: Eradication of rats from the destination islands Identification of potential predators Establish baseline of relative abundance of potential predators Technique Target information Frequency / Timing Resources / Responsibility Priority personnel Active nocturnal Rats presence, introduced geckos Once 2 people x 5hrs per Cocos, Christmas staff, Medium presence and density visit for 5 days MSc student Passive camera Rat and Predator (bird) Ongoing, checked during active Up to 28 cameras Cocos, Christmas staff Medium presence/interactions prior to monitoring per island release of animals Passive ink card Rat and Predator (bird) presence Ongoing, checked during active Min 8 cards per Cocos, Christmas staff Medium prior to release of animals monitoring island Goodnaturetm rat trap Rat presence Ongoing, checked during active 4 traps per island Cocos staff Medium monitoring

7.2 Monitoring in the first three months post-release

Table 13: Monitoring requirements 0 – 3 months Key Outcomes: Eradication of rats from the destination islands Removal of chickens Successful transfer of up to 300 animals from captivity to the release site >50% survivorship of animals three months post-release on at least one of the release islands > estimated density of invasive geckos on release island Identification of habitat preference Identification of potential predators Preliminary information survival differences between CI and Taronga animals Technique Target information Frequency / Timing Resources / Responsibility Priority personnel Active diurnal transect Occupancy, behaviour, species Weekly 2 people x 5hrs per MSc student, Cocos, High and point counts (predator) interactions, relative visit Christmas staff abundance trends and habitat use Active nocturnal Rats presence, introduced geckos Once 2 people x 5hrs per Cocos, Christmas staff, Medium presence and density visit for 5 days MSc student Active distance Population estimate Once 2 people x 5hrs per MSc student, Cocos, Medium sampling visit for 5 days Christmas staff Mark recapture Population estimate, Once 2 people x 5 days MSc student, Cocos, High Vital rates estimates Christmas staff Transect ink card Occupancy, habitat use Once every 6 weeks One-person x 4hrs MSc student Low per visit Passive camera Rat and Predator (bird) Ongoing, checked during active Up to 28 cameras Cocos staff Medium presence/interactions monitoring cameras per island Passive ink card Rat presence Ongoing, checked during active Min 8 cards per Cocos staff Medium monitoring island Goodnaturetm rat trap Rat presence Ongoing, checked during active 4 traps per island Cocos staff Medium monitoring

7.3 Medium to long term monitoring

Table 14: Monitoring requirements 3 - 6 months Key Outcomes: Eradication of rats from the destination islands Removal of chickens >50% survivorship of animals six months post-release on at least one of the release islands Evidence of attempted breeding Successful recruitment of island born juveniles into the population Technique Target information Frequency / Timing Resources / Responsibility Priority personnel Active diurnal transect Occupancy, behaviour, species Once every 2 weeks 2 people x 5hrs per MSc student, Cocos, High and point counts (predator) interactions, population visit Christmas staff trend and habitat use Active nocturnal Rats presence, introduced geckos Once 2 people x 5hrs per MSc student, Cocos, Medium presence and density visit for 5 days Christmas staff Active distance Population estimate Once 2 people x 5hrs per MSc student, Cocos, Medium sampling visit for 5 days Christmas staff Mark recapture Population estimate Once 2 people x 5 days MSc student, Cocos, High Vital rate information (mortality) Christmas staff Transect ink card Occupancy, habitat use Once every 6 weeks One-person x 4hrs MSc student Low per visit Passive camera Rat and Predator Ongoing, checked during active 2 cameras per island Cocos staff Low presence/interactions monitoring Passive ink card Rat presence Ongoing, checked during active Min 8 cards per Cocos staff Medium monitoring island Goodnaturetm rat trap Rat presence Ongoing, checked during active 4 traps per island Cocos staff Medium monitoring

Table 15: Monitoring requirements 6 - 12 months Key Outcomes: Eradication of rats from the destination islands Removal of chickens Successful transfer of up to 300 animals from captivity to the release site >50% survivorship of founder animals 6-12months post-release on at least one of the release islands Identification of preferred habitat Successful recruitment of island born animals into the population Technique Target information Frequency / Timing Resources / Responsibility Priority personnel Active diurnal transect Occupancy, behaviour, species Once every 2-4 weeks 2 people x 5hrs per MSc student, Cocos High and point counts (predator) interactions, population visit staff trend and habitat use Active nocturnal Rats presence, introduced geckos Once every 3 months 2 people x 5hrs per MSc student, Cocos Medium presence and density visit for 5 days staff Active distance Population estimate Once every 3 months 2 people x 5hrs for 4- MSc student, Cocos, Medium sampling 5 days Christmas staff Mark recapture Population estimate, estimates of Once 2 people x 5 days MSc student, Cocos, High vital rates Christmas staff Transect ink card Occupancy, habitat use Once every 3 months One person x 4hrs MSc student Low per visit Passive camera Rat and Predator Ongoing, checked during active 2 cameras per island Cocos staff Low presence/interactions monitoring Passive ink card Rat presence Ongoing, checked during active Min 8 cards per Cocos staff Medium monitoring island Goodnaturetm rat trap Rat presence Ongoing, checked during active 4 traps per island Cocos staff Medium monitoring

Table 16: Monitoring requirements >12 months Key Outcomes: Eradication of rats from the destination islands Removal of chickens Successful transfer of up to 300 animals from captivity to the release site >50% survivorship of animals six months post-release on at least one of the release islands Technique Target information Frequency / Timing Resources / Responsibility Priority personnel Active diurnal transect Occupancy, behaviour, species Once every 1-3 months 2 people x 5hrs per Cocos staff High and point counts (predator) interactions, population visit trend and habitat use Active nocturnal Rats presence, introduced geckos Once every 3 months 2 people x 5hrs per Cocos staff Medium visit Active distance Population estimate Once every 3-6 months 2 people x 5hrs for 5 Cocos, Christmas staff Medium sampling days Mark recapture Population estimate Once every 6-12 months (cease 2 people x 5 days Cocos, Christmas staff High 24 months after release) Passive camera Rat and Predator Ongoing, checked during active 2 cameras per island Cocos staff Low presence/interactions monitoring Passive ink card Rat presence Ongoing, checked during active Min 8 cards per Cocos staff Low monitoring island Goodnaturetm rat trap Rat presence Ongoing, checked during active 4 traps per island Cocos staff Medium monitoring

7.4 How monitoring will inform management Ongoing monitoring will allow for adaptive risk management, i.e. research will identify possible management improvements, and ultimately inform as to whether the introduction of C. egeriae is a long-term solution for species recovery in the wild. It will also help to establish whether it is feasible to consider introduction to other, larger islands in the Cocos (Keeling) Islands southern atoll.

Table 17: Information gathered/benefits from monitoring techniques

Technique Information gathered/benefit Passive camera  Predator presence  C. egeriae activity, abundance, distribution, individual identification (possible) Passive ink card  C. egeriae activity, abundance, distribution  Rat presence Active nocturnal  Centipede/introduced gecko/rat/cat presence and removal  Invertebrate (food) abundance Weekly population  Population estimates counts, capture-  Body condition recapture, distance  Survival, reproduction, capture probabilities sampling  Distribution and abundance  Habitat and resource preference  Predation (avian threats and other threats)

8 Risks

8.1 Risk assessment and handling strategies A risk assessment and handling strategies is included in Appendix A. 8.2 Biosecurity General, pre-release biosecurity strategies to reduce the level of biosecurity risks were identified and addressed in the habitat suitability and island assessment conducted in 2014 (DNP, 2014), which is Appendix E to the Conservation Introduction Plan. These included the following;

1. Distance to nearest land – is the island relatively geographically isolated from the main inhabited islands or other more frequently visited islands?

2. Tenure – are there permanent or semi-permanent inhabited dwellings? Is the island frequently visited (e.g. Direction Island)? Or does it have cultural significance or other local islander use (e.g. farming)?

3. Height above sea level – Does the island contain significant elevated land (masl), minimising the risk of animals being washed off the island?

Several post-release biosecurity measures have been considered to protect the Cocos (Keeling) Islands and released population of C. egeriae. Biosecurity risks include the following;

A. The introduction of a reptile pathogen(s) to the Cocos Islands, or to the introduced C. egeriae – To address the significant threat to both the host environment and released C. egeriae, a Biosecurity Action Plan has been developed, Appendix G to this plan. B. Reintroduction of rats to the destination island – A rat eradication plan that is applicable to all destination islands has been developed and contains biosecurity measures and a checklist to minimise the risk of rat reintroduction. Points 4 and 10 in Table 18 below identify management actions for this eventuality and if eradication fails in the first place. Escape of C. egeriae to neighbouring islands – Other than the general biosecurity measures identified and addressed in Appendix E, the habitat suitability and island assessment conducted in 2014 (DNP, 2014), no additional post-release biosecurity strategies will be implemented to prevent the spread of C. egeriae to neighbouring islands. As is outlined by point 9 in Table 18 below a monitoring program will be developed to record any movement of C. egeriae through the atoll.

8.3 Thresholds that determine requirement for withdrawal from the project, and exit strategy A number of triggers may initiate some management action on the islands, or discontinue future translocations to the Cocos (Keeling) islands. However, no attempts will be made to remove the released animals from the Cocos (Keeling) Islands. Table 18 lists the management actions for each trigger point.

Table 18: Trigger points for management intervention

Trigger Point Action 1 Identified decline in numbers (<60%  If on one island; Attempt to identify and fix the cause. survivorship of animals six months post- If cause is un-treatable or not identified attempt to release. Population less than 60% of the translocate animals to other island*. Abandon future release population 1 year post release. releases to the island. Population not stable or organically  If on multiple islands; Attempt to identify and fix the growing, 2 years post release) cause. If cause is un-treatable or not identified abandon future releases to the islands 2 Loss in animal body  Consider site rehabilitation condition/weight  Delay future releases to the island(s). If animal condition does not improve, abandon future releases to the island(s) 3 Recruitment not observed  Attempt to identify and fix the cause. If cause is un- treatable or not identified, abandon future releases to the island(s) 4 Rats detected  Increase rat eradication activities on the island(s)  Delay further releases if impacts on C. egeriae population observed  Advice will be sought from CIRAP on if/how to proceed with the conservation introduction of C. egeriae to the host island(s) 5 Predation from bird species  No action, unless trigger point one realised. If so, observed investigate bird deterrents 6 Chickens detected  Remove chickens 7 Disease detected in released  Remove and euthanise affected animals to reduce animals spread. Try and catch as many lizards/gecko's as possible to understand if more animals are showing clinical signs, (particularly if it is the enterococcus disease). 8 Inappropriate use of host island (e.g.  Careful consultation with the Cocos community with fire, significant infrastructure the aim of avoiding the activity development, clearing, massive increase in visitation) 9 Animal escape to neighbouring  Monitor only islands 10 Inability to eradicate rats within  Delay release and seek expert advice on whether to re- specified time and budget attempt eradication or proceed with release  Review methods of eradication 11 Centipedes detected and become  Consider trapping, baiting and poison sprays abundant (meso-predator release  Delay further releases if impacts on C. egeriae following rat removal) population observed  Advice will be sought from CIRAP on if/how to proceed with the conservation introduction of C. egeriae to the host island(s) *depending on available resources and suitability assessment

9 Communications plan

9.1 Stakeholders and public communication plan Appendix B outlines the Communications Plan for this project.

10 List of Appendices Appendix A: Risk Analysis

Appendix B: Reptile reintroduction Communication plan

Appendix C: Australian Society of Herpetologists Toe-clipping SOP

Appendix D: Rat eradication plan

Appendix E: Feasibility results

Appendix F: Environmental Referral Self-assessment

Appendix G: Biosecurity Action Plan

11 References Algar, D. & Brazell, R.I (2005). Efficacy of a baiting technique to control feral cats on Christmas Island. Unpublished Report to Christmas Island Phosphates.

Algar, D. & Brazell, R.I. (2008). A bait-suspension device for the control of feral cats. Wildlife Research 35, 471-476.

Boulenger, G. A. (1889). On the reptiles of Christmas Island. Proceedings of the zoological society of London 1888:534-536.

Cogger, H.G. Sadlier, R. and Cameron, E. (1983). The terrestrial reptiles of Australia’s island territories. Canberra, Australia, Australian National Parks and Wildlife Service.

Cogger, H.G. & Sadlier, R.A. (1999). The terrestrial reptiles of Christmas Island – a reappraisal of their status. Australian Museum. Sydney: Australian Museum.

Corbett, L., Crome, F. & Richards, G. (2003). Fauna survey of mine lease applications and national park reference areas, Christmas Island, August 2002. Appendix G. In: CIP (ed) Draft Environmental Impact Statement for the proposed Christmas Island phosphate mines (9 sites). Christmas Island Phosphates, Perth.

Director of National Parks (2014). Habitat suitability and island assessment for the potential translocation of Blue-tailes skinks (Cryptoblepharus egeriae) to the Cocos (Keeling) Islands. Christmas Island National Park Natural Resource Management Program: report to the Department of the Environment. Christmas Island, Christmas Island National Park

(2018). Unpublished data on Population Viability Analysis of Christmas Island blue-tailed skinks.

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