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Parks Australia self-assessment for the proposed conservation introduction of the Blue-tailed skink

(Cryptoblepharus egeriae) from Taronga Conservation Society (NSW) and Christmas Island National

Park to the Cocos (Keeling) Islands (a Commonwealth area)

1.0 Purpose The purpose of this document is to assist Parks Australia (Christmas Island National Park) with advice

from the Christmas Island Reptile Advisory Panel (CIRAP) to decide whether or not a referral should be

submitted to the Commonwealth Department of the Environment and Energy for a decision by the

Commonwealth Environment Minister on whether assessment and approval under the Environment

Protection and Biodiversity Conservation Act 1999 (EPBC Act) is required for the proposed conservation

introduction of C. egeriae to the Cocos (Keeling) Islands.

2.0 Definitions

An action is defined broadly in the EPBC Act and includes: a project, a development, an undertaking, an activity or a series of activities, or an alteration of any of these things.

A significant impact is an impact which is important, notable, or of consequence, having regard to its context or intensity.

There are nine matters of national environmental significance for consideration. Our proposed action falls under the matter of “nationally threatened species and ecological communities” as C. egeriae was included in the critically endangered category of EPBC listed threatened species effective from 03/01/2014.

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 introduction 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 because C.egeriae will be moved to an area

outside of its indigenous range.

Environment’ is defined in the EPBC Act as:

a. ecosystems and their constituent parts including people and communities (‘ecosystem’ is defined in

the EPBC Act as ‘a dynamic complex of plant, animal and micro-organism communities and their non-

living environment interacting as a functioning unit’)

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b. natural and physical resources

c. qualities and characteristics of locations, places and areas

d. heritage values of places (‘heritage value’ is defined in the EPBC Act as including ‘the place’s natural

and cultural environment having aesthetic, historic, scientific or social significance, or other significance,

for current and future generations of Australians.’ ‘Indigenous heritage value’ is defined as meaning ‘a

heritage value of the place that is of significance to Indigenous persons in accordance with their

practices, observances, customs, traditions, beliefs or history’), and

e. the social, economic and cultural aspects of a thing mentioned in paragraphs a, b or c.

3.0 Self-Assessment Guidelines 1.1- Matters of National Environmental Significance This section has been prepared with reference to Matters of National Environmental Significance - Significant impact guidelines 1.1 Environment Protection and Biodiversity Conservation Act 1999

(Commonwealth of Australia 2013).

Under the EPBC Act an action will require approval from the Minister if the action has, will have, or is likely to have, a significant impact on a matter of national environmental significance.

Using the specific questions given in the guidelines, to inform as to whether or not to refer an action to the Minister, the following has been considered:

1. Are there any matters of national environmental significance located in the area of the proposed action (noting that ‘the area of the proposed action’ is broader than the immediate location where the action is undertaken; consider also whether there are any matters of national environmental significance adjacent to or downstream from the immediate location that may potentially be impacted)?

YES An EPBC Act Protected Matters generated report (2012) identifies the matters of national environmental significance in the area of the Cocos (Keeling) Islands that may occur or may relate to the Islands. These include:

Commonwealth marine areas (1) – the proposed action is unlikely to have a significant impact on this marine area as the species of concern is a terrestrial species.

EEZ and Territorial Sea: (1) – the proposed action is unlikely to have a significant impact on the EEZ and territorial sea as the species of concern is a terrestrial species.

Listed Threatened Species: (10) : see Table 1 Listed Migratory Marine Species: (19) : see Tables 2 and 3

An assessment on the likely impacts that the proposed action will have on all of the listed threatened

and migratory marine species in the destination location (i.e. Cocos (Keeling) Islands) has been

undertaken using the specific criteria in the guidelines. Tables 1 to 3 outline the outcomes of this

assessment.

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Table 1: Listed Threatened Species

Species name Status Type of presence Affected by the proposed action

Buff-banded rail E Species or species habitat likely to occur within area Unlikely

Rund Island petrel CE Species or species habitat may occur within area Unlikely

Sei Whale V Species or species habitat may occur within area No

Blue whale E Species or species habitat may occur within area No

Humpback whale V Species or species habitat may occur within area No

Loggerhead turtle E Species or species habitat likely to occur within area No

Green turtle V Breeding known to occur in the area No

Leatherback turtle E Species or species habitat may occur within area No

Hawksbill turtle V Species or species habitat may occur within area No

Flatback turtle V Species or species habitat may occur within area No

Table 2: Listed Migratory Species

Species name Status Type of presence Affected by the proposed action

Lesser Frigatebird, Least Frigatebird

M Breeding known to occur within area No

Great Frigatebird, Greater Frigatebird

M Breeding known to occur within area No

White-tailed Tropicbird M Breeding known to occur within area No

Wedge-tailed Shearwater M Breeding known to occur within area No

Masked Booby M Breeding known to occur within area No

Brown Booby M Breeding known to occur within area No

Red-footed Booby M Breeding known to occur within area No

Table 3: Listed Migratory Marine

Species name Status Type of presence Affected by the proposed action

Antarctic Minke Whale, Dark-shoulder Minke Whale

Species or species habitat may occur within area No

Sei Whale V Species or species habitat may occur within area No

Bryde's Whale Species or species habitat may occur within area No

Blue Whale E Species or species habitat may occur within area No

Loggerhead Turtle E Species or species habitat likely to occur within area

No

Green Turtle V Breeding known to occur within area No

Leatherback Turtle, Leathery Turtle,

E Species or species habitat may occur within area No

Hawksbill Turtle V Species or species habitat may occur within area No

Humpback Whale V Species or species habitat may occur within area No

Flatback Turtle V Species or species habitat may occur within area No

Killer Whale, Orca Species or species habitat may occur within area No

Sperm Whale Species or species habitat may occur within area No

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2. Considering the proposed action at its broadest scope (that is, considering all stages and components

of the action, and all related activities and infrastructure), is there potential for impacts, including indirect impacts, on matters of national environmental significance?

YES The proposed action involves the assisted movement of a Critically Endangered species (C. egeriae) to a location outside of its normal range. Potential impacts to this species may include the handling and movement of C. egeriae, impact on removal from the captive population and successful establishment of C. egeriae at the destination location. A full risk assessment of these impacts has been undertaken (see Attachment 1) and the outcomes are summarised here:

If correct handling procedures are followed and animals are in good condition before

transportation, it is unlikely that the handling and movement of the animals will negatively

impact on their health. Animals will also provide adequate ventilation and moisture and should

not impact on animal health.

A Population Viability Analysis (PVA) has been undertaken to assess the impact of removing up

to 150 animals from each of the two source populations every 1-2 years during the proposed

action, and there is no impact on each of the captive populations. The animals selected for

introduction will be surplus to the genetic management of the captive breeding program and

will have no impact in this regards.

Cryptoblepharus egeriae is considered a generalist species and is known to be adaptive to

changing environments, therefore its life history traits should not limit its success in

establishing a population within a new environment providing habitat and food availability is

adequate and all potential threats are removed. Successful establishment will only have

positive outcomes for this species.

3. Are there any proposed measures to avoid or reduce impacts on matters of national environmental significance (and if so, is the effectiveness of these measures certain enough to reduce the level of impact below the ‘significant impact’ threshold)?

YES With respect to the abovementioned impacts, the following measures are proposed to avoid or reduce impacts to C. egeriae:

All activities under the prosed action will operate under an animal ethics approval and only personnel experienced in handling C. egeriae will be involved in the movement and transport of animals.

A veterinary health check of all animals will be undertaken during the selection process of animals to ensure they are fit for relocation.

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Animal housing will meet the appropriate requirements specified in the International Air Transport Association Live Animal regulations and be similar to that used to transport C. egeriae and L. listeri to Taronga Zoo in 2011 to establish an insurance population.

As mentioned above, a PVA has been conducted and there will be no impact on removing 150 animals from the captive population every 1-2 years during the course of the proposed action.

Animals to be used for the proposed action will be surplus animals that are not part of the breeding program as per the genetic management plan.

Prior to reptile release, potential predators (rats and chickens) will be removed from the destination islands and ongoing control will be in place to maintain eradication.

Prior to reptile release, habitat restoration activities will take place on the host island(s). This will enhance the islands environment for both C. egeriae and other native species.

Post reptile release, monitoring will be undertaken to document population establishment. In addition to these measures, a number of regulatory framework exists that supports and guides our actions. This includes:

The Christmas Island National Park Management Plan 2014-2024 – provides for specific actions relating to threatened species management and recovery of Christmas Island’s species including ‘Maintaining and adaptively developing conservation programs for terrestrial reptiles under threat from extinction in the wild (Action 4.3.12)’.

A threatened species conservation advice - whilst this does not explicitly include a conservation introduction, we believe (from internal Departmental advice) that our high level management objectives are sufficient to support our action.

Other supporting documents that guide the proposed action include:

The Christmas Island Expert Working Group Report 2010 – recommendation 27 suggests that the captive breeding program continue as a high priority and that off-island populations are desirable to guard against on-island catastrophic events.

An internal habitat suitability and island assessment report for the potential conservation introduction of C. egeriae to the Cocos (Keeling) Islands.

The reptile genetic management plan

An ethical framework 4. Are any impacts of the proposed action on matters of national environmental significance likely to be

significant impacts (important, notable, or of consequence, having regard to their context or intensity)?

NO Knowing that the proposed action will impact on a matter of national significance, the checklist below provides an indication of whether the impact would be considered significant.

Impacts will need to be assessed for the actions impacting on the population of reptiles (source population i.e. the captive bred C. egeriae in CINP or Taronga) and to the environment of the destination island.

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Source populations

Using the specific criteria for critically endangered species given in the guidelines, to make a decision as

to whether or not to refer an action to the Minister, the following has been considered for the Source populations from Christmas Island and Taronga.

Criteria for whether action is likely to have a significant impact

Impact assessment

Lead to a long-term decrease in the size of a population

The conservation introduction will use C. egeriae surplus (n=150) to the CINP captive breeding population (total n=1034 as at December 2018) and surplus (n=150) to the Taronga captive breeding population (total n=403 as at May 2018). Preliminary modelling indicates if we took 150 blue tailed skinks from the CI population on just one occasion there would be 0% chance of extinction (J.P Emery pers.comm.)

Existing captive breeding facilities are now at capacity causing some mortality to captive bred reptiles (e.g. stretched resources lead to a reduced number of predator checks). If the captive breeding program becomes unsustainable due to stretched resources, then in-action will cause a long-term decrease in the population size overall

If the conservation introduction is successful, it should increase the population size of C. egeriae overall.

Reduce the area of occupancy of the species

If the conservation introduction is successful, it will increase the occupancy of C. egeriae overall. The Cocos population will be additional to the existing captive populations.

Fragment an existing population into two or more populations

The action is essentially fragmenting an existing population into two or more populations. However it is thought the newly translocated population will face less threats from invasive species (e.g. Asian wolf snake, giant centipede) than its original population. The population fragmentation will be genetically managed to increase chance of survival of any fragmented populations as per genetic management plan.

Adversely affect habitat critical to the survival of a species

It is highly unlikely the conservation introduction will affect habitat critical to the survival of a species. C. egeriae is a small, inconspicuous species thought to have a small footprint on the destination habitat, which is not known to be fragile or ecologically unique.

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Disrupt the breeding cycle of a population

C. egeriae will prey on invertebrate species for a food source. It is not known whether the translocated population will disrupt the breeding cycle of an invertebrate population to the point where the impact is significant.

Modify, destroy, remove, isolate or decrease the availability or quality of habitat to the extent that the species is likely to decline

It is unlikely the translocated population will modify, destroy, remove, isolate or decrease the availability or quality of habitat to the extent that the species is likely to decline.

Result in invasive species that are harmful to a critically endangered or endangered species becoming established in the endangered or critically endangered species’ habitat

This is highly unlikely as there are no endangered or critically endangered flora or fauna species that occur in the destination habitat.

Thought will have to be given as to whether the conservation introduction would be put on hold until rats are removed from the destination islands.

Introduce disease that may cause the species to decline

All C. egeriae translocated from CINP would come from quarantined enclosures which are routinely checked for disease. No animals showing signs of the Enterococcus disease and only animals within the healthy weight range would be translocated. Individuals translocated from Taronga have been in permanent quarantine since their arrival to Taronga in 2011 so it is highly unlikely these individuals would introduce a disease.

Interfere with the recovery of the species.

The action is designed to enhance the captive breeding program by establishing populations from captive-bred stock and to assist with the recovery of C. egeriae (as per the Conservation Advice 2013).

Recommendations in the Expert Working Group report 2010 state as a high priority to continue C. egeriae captive breeding program and that off-island populations were desirable.

Maintaining and adaptively developing conservation programs for terrestrial reptiles under threat from extinction in the wild is an action identified in the CINP Management Plan 2014-24 (Action 4.3.12)

In April 2012 the Christmas Island Reptile Advisory Panel of experts (CIRAP) made the recommendation to investigate the feasibility of introducing a

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population of C. egeriae to an uninhabited island in the southern atoll of the Cocos (Keeling) group.

In 2014 a feasibility study conducted by Parks Australia to assess the suitability of the Cocos (Keeling) Islands as a potential site for a conservation introduction of C. egeriae was done. The study showed that at least 3 islands would provide suitable habitat and other ecological requirements for C. egeriae.

The action is proposed to be done in accordance with a genetic management plan and an ethical framework.

CONCLUSIONS

Is the conservation introduction a matter of national significance?

YES both to the source population and to the destination islands.

Is the conservation introduction likely to have a significant impact?

NO to the CI source population and NO to the destination populations and habitat. (Taronga population

has not be assessed here as numbers in captivity not known). Preliminary modelling indicates if we took

150 blue tailed skinks from the CI population on just one occasion there would be 0% chance of

extinction. Overall small population size of C. egeriae may be an issue (n=1200 + Taronga), however it is

unclear what a minimum population size is to warrant having a significant impact (it was not specifically

asked in the self-assessment questions).

Caveats

One caveat is identified which relate to the source and the destination populations. 1. We must consider the principles identified by in CIRAP #13 in light of the presence of

rats on the destination islands-

No actions to be taken that does not contribute to the conservation of the species

All animals will be treated as humanely as possible

No animal will be released if they face certain death If rats are known to prey on C. egeriae or their eggs and we translocate without successful rat eradication, then our action would be significant.

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4.0 Self-Assessment Guidelines 1.2- Actions on, or impacting upon, Commonwealth

land, and actions by Commonwealth agencies This section has been prepared with reference to actions on, or impacting upon, Commonwealth land, and actions by Commonwealth agencies -Significant impact guidelines 1.2 Environment Protection and Biodiversity Conservation Act 1999 (Commonwealth of Australia 2013). Under the EPBC Act an action will require approval from the Minister if the action has, will have, or is likely to have, a significant impact on the environment.

Using the specific questions given in the guidelines, to inform as to whether or not to refer an action to the Minister, the following has been considered:

Step One: The Environmental Context

1. What are the components or features of the environment?

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).

The vegetation and environment of the Cocos (Keeling) islands has been extensively modified for

coconut (Cocos nucifera) plantations (Williams 1994) but some remnant vegetation exist. Many of the

islands have areas of vine thicket, Guettarda speciosa, Pemphis acidula, Scaevola taccada, Cordia

subcordata and Argusia argentia in addition to C. nucifera.

Pre-release assessments will be conducted on any of the potential destination islands to ensure suitable

habitat is present including abundant invertebrate communities.

2. Which components of the environment are likely to be impacted? Other species that may be susceptible to rat bait (Brodificoum) include land crabs and sea birds. However, measures successfully employed on other similar tropical island projects to prevent these impacts will be employed. The residual risk is considered low.

3. Is the environment sensitive or vulnerable to impacts? YES Crabs play an important role in the ecosystem by breaking down detritus and organic matter and returning nutrients to the soil.

4. Is the environment, or are components of it, rare, endemic, unusual, important or otherwise valuable?

NO There are no aspects of the southern atoll with Cocos (Keeling) islands that are rare, endemic, unusual, important or otherwise valuable. There are 27 coral islands in the Cocos (Keeling) group. Any of the islands selected as a destination island will be done so on their characteristics such as their accessibility, size, height above sea level, distance

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from the nearest land and habitat suitable for C. egeriae. No other particular environmental components were considered.

5. What is the history, current use and condition of the environment which is likely to be impacted by the action?

Numerous islands within the southern atoll of the Cocos (Keeling) islands have temporary infrastructure for visiting families from Home Island (locally known as Pondoks). Parks Australia will seek permission from the owners of Pondoks to release C. egeriae onto specific destination islands. The release of C. egeriae will not stop these local families from using their Pondoks where appropriate quarantine measures are taken to prevent the reinvasion of rats or other C. egeriae predator species. Parks Australia will also seek permission by Pondok owners to relocate chickens from proposed destination islands to the chicken raising area on Home Island. Step Two: Potential Impacts

1. What are the components of the action? The components of the action are: - Rat eradication using Brodifacoum rat baits and rat traps from the proposed destination islands

- Enhancement of the local habitat by removing weed species, limited Cocos nucifera removal and

potential re-vegetation with locally native (and Christmas Island native) species

- Release of C. egeriae

- Monitoring the effectiveness of the release

2. What are the predicted adverse impacts associated with the proposed action? Potential adverse impacts of the action include death or illness to non-target species after accessing the rat bait. A successfully introduced C. egeriae population would also impact on the invertebrate communities as this is the lizard’s major food source.

3. How severe are the potential impacts? Rat baiting will occur over a 28 day period and during this period the scale of the impact is potentially severe as bait stations will occur across the islands and baiting will be undertaken at high intensity.

4. What is the extent of uncertainty about potential impacts? There is little uncertainty that non-target species that consume rat bait will be adversely impacted (the level of which would depend on the dose received). It is not known what impact predation may have on the local invertebrate communities.

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Step Three: Impact avoidance, mitigation and management

The design of the rat eradication plan is based on the successful eradication of rats from Direction Island (another island in the Cocos-Keeling Islands) by the Western Australian Government and other similar tropical island rat eradications. It was prepared with significant contributions and advice from experts in invasive mammal eradications on small islands including colleagues from the Tasmanian and Western Australian governments. The baiting design has been developed to minimise non-target impacts particularly to the land crabs on the island. This includes securing baits in buckets and tunnels only accessible by rats and placing baits in trees inaccessible to crabs. Parks Australia staff will be on the island every day throughout the baiting campaign and will watch carefully for any non-target impacts.

Step Four: Conclusion-Are there any significant impacts?

Is the conservation introduction likely to have a significant impact on the environment within the Cocos (Keeling) islands?

NO

Two caveats apply:

1. That the bait devices are successful at excluding non-target species. 2. C. egeriae will predate on invertebrate species for a food source. It is not known whether the

translocated population will disrupt the breeding cycle of an invertebrate population to the

point where the impact is significant. We do know there are no known listed reptile (or even

native) species already present but we do not know the significance of the invertebrate species

and what role they may play in the overall ecosystem health.

However, the Cocos Keeling Island Terrestrial Invertebrate Survey (2005) states it was difficult to

identify which species were native and which were exotic and introduced since human habitation on

the islands. The information available makes it difficult to provide any accurate estimates, although

it can be stated that a large proportion of the invertebrates collected would be exotics. This is due to

the fact that much soil was introduced to the Cocos (Keeling) Islands, along with domestic plants and

animals. The lack of quarantine regulations in the past also saw introductions of many cosmopolitan

tramp invertebrate species that have been transported by ships across the world.

References

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.

Peter Neville, Alan Yen, Dennis O’Dowd, Melanie Archer & Kylie MacGregor (2005) COCOS (KEELING)

ISLANDS TERRESTRIAL INVERTEBRATE SURVEY. Report to Park Australia North, June 2007.

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Williams, D. G. (1994). "Vegetation and flora of the Cocos (Keeling) Islands." Atoll Research Bulletin 404: 1-29.