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Predator-Free Rakiura. An economic appraisal.

Foreign and Commonwealth Office

BRB

This report estimates the benefits of making Rakiura and surrounding islands predator free. The proposal is to do this in two phases, starting with the Halfmoon Bay area (denoted in this report as HMB) before progressing to the rest of the island (denoted in this report as full).

Morgan, Gareth

Simmons, Geoff

2014

Observations of a rapid decline in invasive macroalgal cover linked to green turtle grazing in Hawaiian marine reserve

BRB

Since the 1950's, 19 algal species were intentionally (e.g., aquaculture food) and/or accidentally (e.g., ballast water) introduced into Hawaii (Glenn and Doty 1990).

Bahr, Keisha D.

Balazs, George H.

Coffey, Daniel M.

Rodgers, Ku'ulei

2018

Predation pressures on sooty terns by cats, rats and common mynas on Ascension Island in the South Atlantic

Dickey, R.C.

Hughes, B.J.

Reynolds, S.J.

Despite the presence of invasive black rats (Rattus rattus), common mynas (Acridotheres tristis), and feral domestic cats (Felis catus), sooty terns (Onychoprion fuscatus) breed in large numbers on Ascension Island in the tropical South Atlantic Ocean. These introduced predators impact the terns by destroying eggs or interrupting incubation (mynas), eating eggs (mynas and rats), eating chicks (rats and cats), or eating adults (cats). Between 1990 and 2015, 26 censuses of sooty terns and five of mynas were completed and myna predation was monitored on 10 occasions. Rat relative abundance indices were determined through trapping around the tern colonies and rat predation was monitored by counting chick carcasses. Cat predation was quantified by recording freshly killed terns. Prior to their eradication in 2003, cats had the greatest impact on sooty terns and were depredating 5,800 adults and 3,600 near-fledging chicks (equivalent to the loss of 71,000 eggs) each breeding season. We estimated that 26,000 sooty tern eggs (13% of all those laid) were depredated by approximately 1,000 mynas. Rats were not known to depredate sooty terns prior to cat eradication but in 2005, 131 of 596 ringed (monitored) chicks (22%) were depredated by rats. In 2009 chick carcass density was 0.16 per m2. Predation by rats hugely increased in the absence of cats and was the equivalent of 69,000 eggs. Care is needed when applying our findings to seabirds globally. The scarcity of alternative food sources and seasonally high density of easily available prey in the sooty tern colony may have magnified predation by cats, rats and mynas.

South Africa works towards eradicating introduced house mice from sub-Antarctic Marion Island: the largest island yet attempted for mice

Beaumont, J.

Chauke, L.F.

Chown, S. L.

Cooper, J.

Devanunthan, N.

Dilley, B.J.

Dopolo, M.

Fikizolo, L.

Heine, J.

Henderson, S.

Jacobs, C.A.

Johnson, F.

Kelly, J.

Makhado, A.B.

Marais, C.

Maroga, J.

Mayekiso, M.

McClelland, G.

Mphepya, J.

Muir, D.N. Ngcaba, N. Ngcobo, J.P. Parkes, F. Paulsen, S. Schoombie, K. Springer, C. Stringer,H. Valentine, R.M. Wanless and P.G. Ryan

Preston, G.R.

House mice (Mus musculus) were introduced to South Africas sub-Antarctic Marion Island, the larger of the two Prince Edward Islands, by sealers in the early 19th century. Over the last two centuries they have greatly reduced the abundance of native invertebrates. Domestic cats (Felis catus) taken to the island in 1948 to control mice at the South African weather station soon turned feral, killing large numbers of breeding seabirds. An eradication programme finally removed cats from the island by 1991, in what is still the largest island area cleared of cats at 290 km2. Removal of the cats, coupled with the warmer and drier climate on the island over the last half century, has seen increasing densities of mice accumulating each summer. As resources run out in late summer, the mice seek alternative food sources. Marion is home to globally important seabird populations and since the early 2000s mice have resorted to attacking seabird chicks. Since 2015 c. 5% of summer-breeding albatross fledglings have been killed each year, as well as some winter-breeding petrel and albatross chicks. As a Special Nature Reserve, the Prince Edward Islands are afforded the highest degree of protection under South African environmental legislation. A recent feasibility plan suggests that mice can be eradicated using aerial baiting. The South African Department of Environmental Affairs is planning to mount an eradication attempt in the winter of 2021, following a partnership with the Royal Society for the Protection of Birds to eradicate mice on Gough Island in the winter of 2020. The eradication programme on Marion Island will be spearheaded by the South African Working for Water programme Africas biggest conservation programme focusing on the control of invasive species which is already driving eradication projects against nine other invasive species on Marion Island.

Small- and large-scale eradication of invasive ?sh and ?sh parasites in freshwater systems in Norway

Bardal, H.

In July 2016, the European Union adopted a list of invasive alien species of concern, and at present there are two freshwater ?sh species on the list. Member states are obliged to prevent further spread and to perform rapid eradication when problem species are discovered at new sites, but continental EU member states have limited experience with eradication of ?sh. Eradications are more likely to succeed if the invasive species is con?ned to insular habitats. Freshwater invasives can be regarded as island invasives, since their habitats have boundaries against shorelines, saline waters, waterfalls and dams, and these boundaries make eradications possible. CFT Legumine® containing rotenone is the only legal piscicide in the EU, and Norway has used CFT Legumine® in eradication e?orts for many years. Species that have been introduced outside their native range and have been successfully eradicated include minnow (Phoxinus phoxinus), roach (Rutilus rutilus), pike (Esox lucius), common white?sh (Coregonus lavaretus), and the salmon parasite Gyrodactylus salaris. This manuscript summarises the eradication e?orts of invasive ?sh species and ?sh parasite species during the last two decades in Norway, covering eradications from such diverse habitats as small ponds, lakes, marshlands, small streams and large rivers. An estimated £100 million has been spent in the Gyrodactylus salaris eradication programme. Costs of invasive ?sh eradications are given, ranging from less than £10,000 to more than £200,000. There are no known invasive ?sh eradication failures in Norway in the last 20 years. A summary of the e?orts in Norway can be an aid for planning control and eradication measures of invasive ?sh species in other countries.

First report of marine alien species in mainland Ecuador: threats of invasion in rocky shores

Bigatti, G.

Cornejo, M.

Coronel, J.

Cárdenas, A.

Cárdenas-Calle, M.

Keith, I.

Martinez, P.

Mora, E.

Pérez-Correa, J.

Rivera, F.

Torres, G.

Triviño, M.

Troccoli, L.

Villamar, F.

Zambrano, R.

Invasive species are of signi?cant concern, especially in mega-diverse countries, because they cause negative e?ects such as loss of native biodiversity, ecological alterations, disease spread, and impacts on economic development and human health. In mainland Ecuador, information on invasive invertebrates in marine ecosystems is scarce. The objective of this study was to describe and locate the invasive species present in the rocky shores of the intertidal and subtidal zones along 10 areas (83 sites) covering most of the Ecuadorian coast during 20152016. Benthic macroinvertebrates communities were measured over quadrats located randomly on a 50 m transect positioned parallel to the coast in the intertidal and subtidal zone, covering an area of 1,860 km2. Six invasive species were recorded: Arthropoda (Amphibalanus amphitrite), Cnidaria (Pennaria disticha, Carijoa riisei), Bryozoa (Bugula neritina), Rhodophyta (Asparagopsis taxiformis) and Chlorophyta (Caulerpa racemosa). The areas with highest abundance of invasive species were in Jama (not a protected area), Marine and Costal Wildlife Reserve Puntilla of Santa Elena and Santa Clara Island Wildlife Refuge (protected areas). The most abundant species was Carijoa riisei with a relative abundance of up to 80%. It was the most aggressive of the invasive species registered in the subtidal zone, mainly in northern centre of the Ecuadorian coast. C. riisei is growing on native coral (Pocillopora spp.) and on sessile macroinvertebrate communities (Pinctada mazatlanica, Muricea appresa and Aplysina sp.) that are being a?ected by its invasion. This study must be taken into account by local and regional government authorities to create public policy programmes of monitoring for surveillance and control of invasive species. These programmes should focus on integration of socio-economic and ecological e?ects. They should be complemented by experimental design and analysis of environmental variables to provide technical information for a baseline of bio-invasion analysis along the Ecuadorian coast and Galápagos, to avoid the expansion of invasive species negatively a?ecting the marine biodiversity of mega-diverse countries such as Ecuador and other countries of South America.

Successful eradication of signal crayfish (Pacifastacus leniusculus) using a non-specific biocide in a small isolated water body in Scotland

Ballantyne, L.

Baum, D.

Bean, C.W.

Long, J.

Whitaker, S.

The North American signal cray?sh (Pacifastacus leniusculus) has been present in Scotland since at least 1995 and the species is now known to be present in a number of catchments. Once established, few opportunities for containment exist and eradication can often be impossible to achieve. However, in small, isolated water bodies, the application of a non-cray?sh-speci?c biocide has provided the opportunity to remove this species permanently. In July 2011, signal cray?sh were discovered in a ?ooded quarry pond at Ballachulish in the Scottish Highlands. This is an isolated site located ~100 km from the nearest known population and it is likely that the population was established as the result of a deliberate release of these animals 10 years previously. Experience gained from using the eradication technique at other sites in the UK led to the site being treated with a natural pyrethrum biocide (Pyblast®) in June 2012. Post treatment monitoring from 20122017 indicates that eradication has been successful. Monitoring of native species a?ected by the biocide suggests that both invertebrates and amphibians quickly recolonised the quarry pond. Eradication of cray?sh using biocide is only feasible in water bodies where the entire population of cray?sh can be exposed to a lethal dose and the impact on non-target species can be accepted. The technique is not appropriate for large, connected water bodies, although it may be possible to treat short stretches of canals where biocide exposure can be controlled and isolated populations of cray?sh can be e?ectively treated.

Eradication of invasive alien crayfish: past experiences and further possibilities

Sandodden, R.

The EU regulation 1143/2014 On the prevention and management of the introduction and spread of invasive alien species entered into force on 1 January 2015. On 13 July 2016, the EU list of invasive alien species that require action was adopted. The list includes ?ve di?erent cray?sh species. Member states will be required to take measures for early detection and rapid eradication of these species. Except for some eradications performed in the United Kingdom and Norway, there has not been much e?ort put into eradication of invasive cray?sh species throughout Europe. The reasons for this are probably complex and di?er between member states. Are the main reasons legislative constraints, ability to eradicate or lack of knowledge and experience? Is eradication of alien cray?sh possible and desirable, and what is left to save in Europe? Focus could be put into identifying or creating island populations of special concern and preserve them for the future survival of European native cray?sh populations. Eradication measures should be considered as an option in this work. What are the experiences from completed eradication e?orts in Europe? Two cray?sh eradications have been performed in Norway, and both have been successful. The eradications were performed in locations with several ponds and small streams and performed using the synthetic pyrethroid-based pharmaceutical BETAMAX VET®. Both legislative and funding constraints seem less prominent as successful eradications have been con?rmed. Time will show if this trend will spread throughout Europe.

Archipelago-wide island restoration in the Galapagos Islands: Reducing costs of invaisve mammal eradication programs and reinvasion risk

BRB