M.G. Richardson and J.P. Croxall Richardson, M.G. and J.P. Croxall. Achieving post-eradication biosecurity on South Georgia
Achieving post-eradication biosecurity on South Georgia
M.G. Richardson and J.P. Croxall
South Georgia Heritage Trust, Verdant Works, West Henderson’s Wynd, Dundee, DD1 5BT, UK.
Abstract The world’s largest island rodent eradication programme to date was carried out on South Georgia between 2009 and 2018 (baiting on island in 2011, 2013 and 2015) by the South Georgia Heritage Trust (SGHT). A comprehensive survey in 2017/18 found no signs of rodents. Although SGHT planned and executed this eradication under permits issued by (and with collaboration from) the Government of South Georgia and the South Sandwich Islands (GSGSSI), the scale and complexity of the multi-year project was not conducive to prior agreement on post-eradication biosecurity to prevent rodent re-invasion. Thus by 2013, two years after initial baiting, biosecurity measures for rodents remained inadequate, relying mainly on rodent detection boxes on vessels and at the island’s main point of entry. The more substantive post- eradication biosecurity measures implemented by other administrations were absent. In late 2014, after more than three years with no rodent sign, there was unambiguous evidence of a rat within the island’s settlement. This coincided with a vessel berthed alongside a nearby jetty. Between 2015 and 2017, SGHT formally submitted recommendations to the GSGSSI on enhanced biosecurity provisions. Some of these recommendations have been implemented but arguably the most important, relating to vessel berthing and secure handling of imported cargo, remain to be addressed effectively. We summarise what remains to be done, recognising the logistic and financial challenges involved, but conscious that, until all measures are in place, there is significant risk of re-infestation of South Georgia by invasive rodents, compromising a decade of work (and funding) by multiple stakeholders.
Keywords: baiting, poison, rodents, sub-Antarctic
INTRODUCTION Tentative plans for the possible eradication of rodents In the 2017/18 austral summer, a comprehensive from the sub-Antarctic island of South Georgia date monitoring survey, organised and led by SGHT in back to 2000 (S. Poncet, pers. comm.). The subsequent collaboration with GSGSSI, was undertaken to determine success of the eradication programme on Campbell Island the results of the eradication project. The five-month survey (McClelland & Tyree, 2002; Towns & Broome, 2003) deployed over 1,500 inert devices (chew-sticks, tunnel and encouraged the Government of South Georgia and the camera traps and analogous devices) and, augmented by South Sandwich Islands (GSGSSI) to undertake a feasibility trained rodent-detection dogs (which travelled 2,420 km), study of the practicalities of a large-scale (island-wide) covered a minimum of 8,600 ha across 120 sites. No signs eradication of rats and mice on South Georgia (Christie & of rodents were detected, allowing the conclusion that the Brown, 2007). However, due to resource limitations at the eradication phases had been successful. time, the Government opted not to proceed. This paper aims to review the rodent-related biosecurity Nevertheless, the small UK charity (NGO) South status of South Georgia before and during the eradication Georgia Heritage Trust (SGHT) agreed to take up the project and to summarise proposals to enhance this in the challenge and started to develop fundraising and project light of events during the project, and after its successful management structures and initiatives to address this. conclusion. It highlights the remaining measures to be GSGSSI accepted the involvement and lead role of SGHT implemented to minimise the risk of inadvertent re- in principle and practice, subject to the project conforming introduction of rodents. to the relevant legislation and permitting processes. In 2009, SGHT established a Steering Committee (SC) RODENT BIOSECURITY AT SOUTH GEORGIA to oversee the management of the whole operation. The SC PRIOR TO 2014 comprised Trustees from SGHT and the Friends of South The need for biosecurity measures to be integral to any Georgia Island (FOSGI), key GSGSSI officials (Chief eradication efforts on South Georgia was recognised back Executive and Environmental Officer), representatives of in 2007, with a governmental report stating then that: 'First British Antarctic Survey (BAS), and the SGHT Project and foremost, an effective and robust biosecurity regime Director (Prof. Tony Martin of the University of Dundee). needs to be in place on South Georgia before eradication The SC met quarterly from 2010 to 2015 and its main is attempted' (Christie & Brown, 2007). roles were to ensure the effective execution of the plans for the acquisition and shipment of equipment, vessels, Although SGHT submitted Biosecurity Plans to helicopters and staff, and that all documentation required GSGSSI for each of the three phases of baiting, those plans by the regulatory authorities (mainly GSGSSI but also dealt with biosecurity solely in relation to the operational the UK's Civil Aviation Authority (CAA)) was submitted requirements of the project itself – for example, the on time. A list of all such documentation can be found at importation into South Georgia of materials needed for the
In: C.R. Veitch, M.N. Clout, A.R. Martin, J.C. Russell and C.J. West (eds.) (2019). Island invasives: scaling 489 up to meet the challenge, pp. 489–493. Occasional Paper SSC no. 62. Gland, Switzerland: IUCN. Island invasives: scaling up to meet the challenge. Ch 3A Strategy: Biosecurity with what was clearly going to be a multi-year, complex was mid-2015, following completion of the last phase of operation it would have been difficult in the initial 'proof-of baiting, that the Government requested SGHT input to concept' stages of the project to have developed a realistic an apparent major review of South Georgia's biosecurity and pragmatic prescription for post-eradication biosecurity. arrangements. The SGHT response, submitted in late July, In consequence, biosecurity arrangements were held, at was a series of 10 recommendations to enhance island- least in respect of rodents, under relatively rudimentary wide biosecurity (Table 1). provisions. For example, the governmental Biosecurity Protocols of 2013 and 2014 (GSGSSI, pers. comm. 2013 These recommendations were based on the fact that, and 2014) did little more than stipulate the need for rat with aircraft unable to operate into South Georgia, the guards on vessels, the deployment of rodent bait boxes (a re-introduction of rodents to South Georgia could only requirement for yachts only), and the requirement that all come about via shipping. That is: by shipwrecks on the vessels be inspected for the presence of rodents. coast, or by animals swimming ashore from a vessel; gaining access along mooring warps or down gangplanks; Despite what, in retrospect, was a deficiency in project or coming ashore in cargo or luggage. Although none of planning, the HR Project progressed well. By mid-2014 these potential introduction pathways can be ruled out, the (more than three years after the initial baiting) the Phase greatest risk of a rodent re-introduction to South Georgia 1 area (c. 14,000 ha) had been tentatively declared free of is most likely to be via one or other of the last two routes. rodents, and a relatively extensive survey in March of that year by SGHT detected no signs of rodents in the 60,000 SGHT's recommendations included the requirement ha. of the more extensive Phase 2 area. to maintain an adequate supply (at least three tonnes) of in-date brodifacoum bait at KEP, the need for a series of Deficiencies in the biosecurity provisions became pre-baited box traps (which would be inspected frequently) evident on 23 October 2014 when the unambiguous signs of around the base area, and the deployment of effective rat- a rat were seen in newly fallen snow at King Edward Point guards on vessels moored alongside. (KEP) – the administrative centre of the island in the heart of the Phase 1 area. The Government rapidly set in train its The Trust's four main recommendations are shown in contingency plan for just such an incident. Brodifacoum bold in Table 1. These were: the use of rodent-detection bait was spread by hand out to an arc perimeter of 1.5 km dogs at ports in the Falkland Islands and on vessels destined from the sighting and many more rat traps were placed for South Georgia; prohibiting the mooring alongside of around the KEP base area. In the event, no more sign of vessels except for tightly prescribed activities; the erection this animal was seen; nor was a corpse found. This was of rodent-proof fences around offloading jetties in South unfortunate since, through DNA analysis, the origin of this Georgia; and the construction of rodent-proof containment lone animal could have been determined (see Piertney, et areas at KEP within which shipping containers and other al., 2016). The presumption was that the rat succumbed to large-scale cargo could be held, and unpacked, in a the poison bait. biosecure manner. The origins of this one known rat could only be Totally eliminating the risk of a rodent reintroduction speculated on. It could have been a survivor (or offspring of to South Georgia cannot be guaranteed. However, SGHT a survivor) from the 2011 baiting phase. However, this is was of the view that comprehensive implementation of unlikely in the most inhabited part of South Georgia where its recommendations would very substantially reduce the there had been no rodent signs in the preceding 3.5 years risk of rodents either getting to South Georgia in the first since baiting. Alternatively, it could have been imported place or, if that failed, at least preventing their escape in one of the small vessels based at KEP from another part from the immediate surroundings of the cargo unloading/ of the island yet to be baited or swam ashore from a vessel handling areas at KEP/Grytviken. The recommendations anchored offshore. The latter scenarios are not impossible were considered by SGHT to be necessary, realistic, but seem implausible. Given the coincidental timing, the practical, cost-effective (especially in terms of the cost of most probable source for this rat was from one or other of mounting a subsequent eradication operation) and based two vessels that had recently tied-up alongside the nearby on international best practice. KEP jetty. Records showed that one vessel had visited a The presumption was that these proposed provisions number of times between 5–22 October whilst another would be included within a new, strengthened vessel had arrived on 22 October and was still moored governmental Biosecurity Plan. Instead, the Biosecurity alongside the jetty the following day at the time of the Handbook, published in December 2015 (GSGSSI, 2015) incident (GSGSSI, in litt. to SGHT). simply re-stated the existing provisions. It took no account The general conclusion was that this latter vessel was of the SGHT recommendations. This caused SGHT to the most likely source of this incursion. The Government re-state its case to GSGSSI in January 2016 and again in concurred through a statement that "the rat was most February 2017 (SGHT, 2016; 2017 in litt. to GSGSSI). likely to have originated from a ship tied up at KEP in Unfortunately, we are unaware of any substantive change in the previous days, though it was impossible to prove this" biosecurity practices at South Georgia, with one important (GSGSSI, 2015 in litt. to SGHT). exception, relating to the trial use of rodent-detection dogs (see below). Whatever the means of introduction, this rat had managed to evade all prevention and detection measures IMPLEMENTATION OF BEST PRACTICE in place at the time – bait boxes and traps deployed both BIOSECURITY AT SOUTH GEORGIA on the vessels and extensively around the base area. Its presence was only detected due to recent snow cover. GSGSSI's policy, in principle, over biosecurity is rightly predicated (as is best practice) on the concept that: RODENT BIOSECURITY AT SOUTH GEORGIA "The most effective way of dealing with biosecurity is to SINCE 2014 have pre-border measures in place...the aim is to prevent an alien reaching the island, not try and deal with it on Although this incident apparently involved only a single arrival" (Christie & Brown, 2007). Furthermore, in its animal, SGHT assumed that it would rapidly trigger a major five-year Strategy Paper (GSGSSI, 2016) the Government Government-led review of biosecurity arrangements, in advocated that "Biosecurity protocols should be reviewed order to implement more robust measures. However, it on a regular basis and best practice adopted"
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Table 1 Biosecurity recommendations* submitted to South Georgia Government (GSGSSI) – 2015/16 and 2017.
Recommendation Implementation Vessels/cargo checked by rodent-detection dogs (in Falklands) then during transit Trial underway in 2018 to, and on arrival at, South Georgia. Vessels (other than yachts) must be prohibited from mooring alongside except Only partial when unloading/loading cargo or other strictly prescribed activities; then for minimum time only. In all other circumstances vessels must either anchor off or moor to buoy. When moored alongside, or to the shore, all mooring warps must have effective rat Yes, though design of guards guards fitted. needs further attention When moored alongside, gangway ashore must only be in place when necessary, and ? for minimum time. Rodent-proof fence must be constructed around every dock area (KEP/ None Grytviken) No loose cargo (other than personal effects) must be offloaded. All cargo must be Only partial carried in sealed shipping containers which must be (a) fumigated, and (b) contain rodent bait stations. A rodent-proof containment area suitable for shipping containers must be Under consideration. constructed at KEP. Containers must only be opened and unpacked within the Construction potentially containment area. starting 2019; completion 2021? In the event of known or suspected rodent incursion, pre-planned response action must Yes be activated immediately. Must include setting of traps and spreading poison out to stipulated radius from incursion. A network of pre-baited trap boxes must be installed permanently around any dock Yes area and checked frequently (daily when vessel moored alongside). Suitable quantity (minimum 3 tonnes) in-date brodifacoum bait must be held at KEP Yes, but whether in date is as contingency. Such bait must be replenished as appropriate. unknown * Recommendations in bold are the most substantive ones.
In relation to the recommendations of SGHT (Table 1) b) Vessel mooring and practices prevailing at the closest analogue operation, that following the comprehensive and successful At Macquarie Island, the risk of further rodent eradication programme on Macquarie Island (Springer, invasion is reduced still further by there being no harbour 2016), we review the current situation at South Georgia or jetty facilities on the island. This means that, unlike below: South Georgia, all cargo transfers from ship to shore are performed either by helicopters or amphibious lighters, enabling more stringent biosecurity checks to be made. a) Pre-border measures: cargo checking on Vessels anchoring well offshore, beyond the swimming embarkation and in transit distance of rats, reduce the risk that any shipborne rodents In its most recent policy statement (GSGSSI, 2017), may gain direct access to the island through their ability pre-border biosecurity measures in relation to rodents rely (documented in both the UK and Falklands) to swim up principally on the use of rat-guards on vessels, requiring to 1–2 km between, or out to, islands. The Macquarie rodent detection boxes to be carried onboard vessels and situation has the added advantage that ship movements the use of bait stations within cargo shipping containers. are confined largely to transits between Tasmania and the However, even taken together, we contend that these island. This again enables far greater biosecurity control. measures are unlikely to be effective. For example, despite At South Georgia, in contrast, whilst ships depart GSGSSI having trialled a number of rat-guard designs, to South Georgia from a variety of locations (e.g. South none to date has proved capable of coping with the harsh American ports), those that are currently allowed to tie- weather conditions prevailing in South Georgia. up alongside at KEP are invariably governmental vessels At Macquarie Island, the deployment of rodent- arriving from the Falklands, where the embarkation detection dogs is now routine. Dogs check all cargo twice ports are known to be infested with rats and lack fully before it departs Australia and then again during passage appropriate facilities for biosecure handling of cargo. to, and on arrival, at Macquarie where the environs of the SGHT has recommended that the practice of mooring research station are then also subject to survey by dogs. alongside, the most likely route for a rodent incursion, With financial assistance from SGHT, GSGSSI embarked should be prohibited, except for cargo handling and in early 2018 on a trial deploying rodent-detection dogs other closely prescribed activities (such as undertaking at embarkation points in the Falkland Islands and on necessary mechanical repairs to a vessel or for safety). ships destined for South Georgia. This is a very welcome The current criteria allowing alongside mooring include initiative which, it is hoped, will be converted into a activities such as the "transfer of personnel, or "allowing permanent procedure. for crew rest periods". Given the biosecurity risks that alongside mooring poses, convenience per se should not be Nevertheless, the most likely pathway for a rodent a valid justification for continuation of this practice. This to gain access to South Georgia is from vessels moored is particularly so given that the many thousands of tourists alongside a jetty at KEP/Grytviken either via offloaded who visit South Georgia (and KEP/Grytviken) annually do cargo or by simply "jumping ship". so from vessels anchored offshore.
491 Island invasives: scaling up to meet the challenge. Ch 3A Strategy: Biosecurity c) Cargo-handling ashore the increase in the numbers and distribution of some Biosecurity handling facilities at KEP are currently breeding birds (including endemic species) since baiting, restricted to a single shed where small-scale cargo can be has already been dramatic. unpacked and checked within a confined space. There are no facilities, in the form of a rodent-proof fenced area, Notwithstanding that result, two major lessons can within which large-scale cargo (i.e. shipping containers) be taken from this important project; one highly positive, can be stored and then opened securely. Such a facility, the other less so. On the former, large scale eradications coupled with rodent-proof fencing around the jetty areas at (e.g. Campbell Island (McClelland & Tyree, 2002) and KEP/Grytviken, would provide some measure of constraint Macquarie Island (Springer, 2016)) have usually relied for any rodent that either managed to escape from a vessel on the extensive resources of governments. In contrast, or survived inside a shipping container. the South Georgia project has demonstrated that, through extensive fundraising and competent project planning and It is evident that the rodent incursion of October 2014 implementation, even relatively modest or small-sized was of an animal that had apparently circumvented both NGOs can take on the challenge of large-scale eradications. shipboard measures and the numerous traps and bait boxes around KEP. Those measures, at least then, had proved The downside of the South Georgia operation has wanting. been the lack of a close synergy between eradication and biosecurity. Again, previous large eradications have had the benefit of intra-governmental co-ordination with BIOSECURITY COSTS AND RISKS often the same governmental agency (e.g. New Zealand's It is important to contrast the respective costs of Department of Conservation or the Tasmanian Parks eradication and biosecurity. Investment in the eradication and Wildlife Service) having responsibility for both project by SGHT has been considerable, with direct costs elements. The problems in the case of South Georgia were of around £7.5 million, rising to c. £10 million when complicated by the fact that two organisations, of highly indirect costs are included. Over 80% of the project contrasting status, undertook or were responsible for the costs have been raised through charitable donations and eradication and biosecurity elements. sponsorship; although GSGSSI provided extensive staff To ensure that these two equally important aspects are and logistic assistance throughout the project it made no taken forward in close harmony, we make the following other contribution to direct costs. In contrast, we estimate recommendations for future rodent eradication projects. that the capital costs of the additional recommended That: biosecurity measures are unlikely to exceed £0.5 million. In December 2016, SGHT offered to fundraise to help pay ●● adequate biosecurity measures must be in place for those capital costs. before, during and after eradication; SGHT recognises that implementation of the more ●● in those instances where responsibilities for substantive measures would come with additional costs eradication and biosecurity may reside with (including ongoing maintenance costs), alternative risks, different organisations, agreement must be reached and the need for specific design considerations to meet in advance between those entities; and that: South Georgia's harsh conditions. For example, any rodent- ●● such agreements should set out the respective proof structure on the island must be able to withstand responsibilities, objectives and timetables for both extremely high wind loadings, ice and snow accumulation parties before eradication is allowed to commence. as well as the attention of other wildlife such as southern elephant seals (Mirounga leonina). Experience from South Georgia has shown that in the absence of any such prior agreements, eradication and Even significantly reducing the practice of alongside biosecurity may get out of step either in their timing or mooring would not entirely eliminate risk. The alternatives effectiveness – or both. Such a situation creates a potential are either anchoring offshore or mooring to a suitable risk that the considerable investment in eradication and its buoy. Large vessel buoyage is no longer available at South corresponding environmental benefits may be jeopardised Georgia and its provision and maintenance would be both subsequently by inadequate biosecurity provisions. expensive and not without liability for the regulatory authority (GSGSSI). Vessels at anchor can also be at risk. Weather conditions at South Georgia can change at short ACKNOWLEDGEMENTS notice and be severe. In March 2000, three long-lining As Chair of the SC, MGR would like to thank all fishing vessels were driven ashore one night in Cumberland members of that Committee, not least the Project Director, Bay in extreme weather conditions. One managed to Prof. Tony Martin of Dundee University. We would also pay re-float; the other two were completely wrecked onan tribute to the Island Foundation, Prof. Frederick Paulsen inshore reef. Whether there were rodents on either of those and the Paulsen Foundation, without whose massive vessels, and whether they escaped ashore is not known generosity, particularly in start-up costs, the whole project but the incident emphasises that some risks of rodent re- could never have commenced. Fundraising also relied in introduction will always remain. This makes it even more a large part on FOSGI (the US counterpart of SGHT). imperative to address those risks which can be mitigated Our thanks go also to all staff involved throughout the or eliminated. near-decade of the project and to the hundreds of donors, large and small, individuals, trusts and foundations, who CONCLUSIONS have helped bring this eradication project to a successful conclusion. The South Georgia Habitat Restoration Project has been the largest island rodent eradication yet undertaken. The overall effectiveness of the three seasons of baiting REFERENCES over five years with brodifacoum has recently been Christie, D. and Brown, D. (2007). Recommendations and Concerns confirmed following a comprehensive monitoring survey Regarding Proposed South Georgia Rat Eradication. Stanley, Falkland in the 2017/18 season. This found no signs of rodents in Islands: Report prepared for the Government of South Georgia and the South Sandwich Islands.
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GSGSSI. (2015). Biosecurity Handbook. Stanley, Falkland Islands Government of South Georgia and the South Sandwich Islands.
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