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Small Islands, Big Impact The Consequences of Tackling Invasive Alien Species in the

Innovative conservation since 1903 Our mission To act to conserve threatened species

science and take into account human needs.

International (FFI): Supports local, national and regional agencies to conserve their

Seeks to improve the livelihoods of local people. Is lean and cost effective.

1 Small Islands, Big Impact The Consequences of Tackling Invasive Alien Species in the Caribbean Jenny Daltry PhD FRGS, Senior Conservation Biologist 22 March 2016 Innovative conservation since 1903 Our mission To act to conserve threatened species and ecosystems worldwide, choosing solutions that are sustainable, based on sound science and take into account human needs. Innovative conservation since 1903 Who We Are Founded in 1903, Fauna & Flora International (FFI): Supports local, national and regional agencies to conserve their biodiversity. Is innovative and entrepreneurial. Seeks to improve the livelihoods of local people. Is lean and cost effective. Works with all interested parties, from local communities to multinational corporations. Co created WWF, IUCN, TRAFFIC The Caribbean Islands How most people see the Caribbean Islands The Caribbean Islands The Caribbean Islands 0.15 % of the Earth s land area How biologists see the Caribbean Islands: One of the world s most species-rich regions. J.C. Daltry 1

2 The Caribbean Islands The Caribbean Islands 10 % of the world s bird extinctions since % of the world s mammal extinctions since 1500 The Caribbean Islands The Caribbean Islands >65 % of the world s reptile extinctions since 1500 >65 % of extinctions caused by invasive alien species Invasive Alien Species Invasive Alien Species Non-native species plague almost every Caribbean island. A wide range of organisations are controlling and eradicating alien species with remarkable results. J.C. Daltry 2

3 Antiguan Racer (Alsophis antiguae) Critically Endangered and non-venomous Antigua s Offshore Islands Antigua Eradicating rats Innovative conservation since 1903 In 1995, the Antiguan racer was the World s rarest snake. Antigua Antigua 5 km Antiguan racers used to be abundant on Antigua (with other endemic reptiles, birds and mammals) 5 km Rats arrived in the 1800s. Antigua 5 km 5 km In the 1890s, the British plantation owners released mongooses to control the rats. Antiguan racers survived only on one offshore island. FFI was asked to investigate. J.C. Daltry 3

Tail and reproductive organs bitten off by

of Antiguan racers Rats removed So we cleared

4 Tail and reproductive organs bitten off by rats Great Bird Island (8 hectares) was home to the last 50 Antiguan racers. Only 50 Antiguan racers remained. All were being attacked by rats. We placed rat bait (Klerat, brodifacoum) every 10m across the island. All rats were dead within two weeks. The Antiguan racer population quickly increased to 113, but lacked room to continue growing. Red = rats eradicated Results Total population of Antiguan racers Rats removed So we cleared rats from 15 islands around Antigua, and we have reintroduced racers to three. Antiguan racers have increased by more than 20-fold on rat-free islands. J.C. Daltry 4

Results Birds on Great Bird and Galley Islands

removed Rats removed Birds have also increased by

have also increased by 5-fold to 20-fold on islands

population Number of nesting females Rats removed

West Indian whistling duck Dendrocygna arborea -

should come as no surprise Results Results Redonda

The impact of rats on birds and reptiles should come

5 Results Birds on Great Bird and Galley Islands Results Birds on Rabbit and Redhead islands Rats removed Rats removed Birds have also increased by 5-fold to 20-fold on islands cleared of rats Birds have also increased by 5-fold to 20-fold on islands cleared of rats Results Results Hawksbill turtle population Number of nesting females Rats removed Levasseur & Tilley 2011 Antigua s hawksbill turtles have increased three-fold. (Probably due to a combination of factors). West Indian whistling duck Dendrocygna arborea - Vulnerable The impact of rats on birds and reptiles should come as no surprise Results Results Redonda ground lizard Ameiva atrata - Critically Endangered The impact of rats on birds and reptiles should come as no surprise Brown booby Sula leucogaster The impact of rats on birds and reptiles should come as no surprise J.C. Daltry 5

Results Results Items in the stomachs of adult Rattus rattus on Redonda

Rats consume plants and invertebrates in vast quantities too.

Point Photographs) Results Results Antigua s offshore islands have been

Area. Snails and other invertebrates appear considerably more abundant on

What is happening on islands that still have rats?

June 2011 We compared: 6,000 5,000 Ameiva griswoldi Anolis leachii Anolis

Number per hectare 4,000 3,000 2,000 1,000 0 Exchange Major Galley Major

Pelican Whelk Rock Point Count surveys were conducted to compare the

6 Results Results Items in the stomachs of adult Rattus rattus on Redonda Island (Bell & Daltry, 2012) 1995: Rats present 2015: No rats for 20 years Rats consume plants and invertebrates in vast quantities too. Vegetation biomass has also increased on rat-free islands (seen from Fixed Point Photographs) Results Results Antigua s offshore islands have been designated an Important Bird Area and a Global Priority Key Biodiversity Area. Snails and other invertebrates appear considerably more abundant on rat-free islands Could these increases be due to other factors? What is happening on islands that still have rats? Results Lizard density Antigua's on offshore Offshore islands, Islands June 2011 We compared: 6,000 5,000 Ameiva griswoldi Anolis leachii Anolis wattsi RATS PRESENT 5 islands with rats. 9 islands without rats. Number per hectare 4,000 3,000 2,000 1,000 0 Exchange Major Galley Major Great Bird Green Hawes Lobster Rabbit Redhead York Codrington Crump Guiana Pelican Whelk Rock Point Count surveys were conducted to compare the density of lizards on islands with and without rats. We found lizards were typically three times more abundant on islands without rats J.C. Daltry 6

Results Breeding pairs of seabirds on Antigua s offshore islands, June 2010 We compared: 600 500 Red billed Tropicbird Sooty Tern RATS PRESENT 6 islands with rats.

Rabbit Redhead York Hell's Gate Bird Exchange Maj. Exchange Min.

We found seabirds breeding only on islands without rats Results We compared: 6 islands with rats. 17 islands without rats.

7 Results Breeding pairs of seabirds on Antigua s offshore islands, June 2010 We compared: Red billed Tropicbird Sooty Tern RATS PRESENT 6 islands with rats. 400 Royal Tern Roseate Tern Bridled Tern 17 islands without rats 300 Caribbean Brown Pelican Brown Noddy Laughing Gull Galley Major Galley Minor Great Bird Green Lobster Lobster Ext. Rabbit Redhead York Hell's Gate Bird Exchange Maj. Exchange Min. Jenny Pitchy Rock Unnamed Whelk Rock Pelican Crump Guiana Codrington Guardhouse A survey compared the number of seabirds on islands with and without rats. We found seabirds breeding only on islands without rats Results We compared: 6 islands with rats. 17 islands without rats. Results Land Bird Species Richness Variable r s Probability RAT-FREE: Number of years without rats SIZE: Area of island, measured using GIS < VEGETATION: Presence or absence PROXIMITY: Distance from mainland Antigua MONGOOSE: Presence or absence Diversity measured as the mean number of species per point count on every island Point Count surveys were conducted to compare the density of land birds on islands with and without rats. A significant positive correlation between bird diversity and how long the island had been rat-free. Results Land Bird Species Abundance Variable r s Probability RAT-FREE: Number of years without rats Rat Eradications Database of Island Invasive Species Eradications SIZE: Area of island (measured using GIS) < VEGETATION: Presence or absence PROXIMITY: Distance from mainland Antigua MONGOOSE: Presence or absence Abundance measured as mean number of individuals per point count on every island A significant positive correlation between bird abundance and how long the island had been rat-free. Since 1994, rat eradications have been carried out on more than 40 Caribbean Islands J.C. Daltry 7

White Cay = 15 hectares White Cay, Bahamas White Cay, Bahamas

since 1903 In 1998, fewer than 150 White Cay iguanas remained on

White Cay, Bahamas White Cay, Bahamas White Cay iguana Cyclura rileyi

and young The raccoon was caught and the rats poisoned (bait put in

University Thanks to removing rats and raccoons in the late 1990s

8 White Cay = 15 hectares White Cay, Bahamas White Cay, Bahamas Consequences of eradicating rats and raccoons Innovative conservation since 1903 In 1998, fewer than 150 White Cay iguanas remained on White Cay. White Cay, Bahamas White Cay, Bahamas White Cay iguana Cyclura rileyi cristata Invasive black rats and a raccoon preyed on the iguanas eggs and young The raccoon was caught and the rats poisoned (bait put in iguana-proof tubes) White Cay, Bahamas Dr Bill Hayes, Loma Linda University Thanks to removing rats and raccoons in the late 1990s there are now over 2,000 iguanas on White Cay. A closer look at the consequences of eradicating rats Innovative conservation since 1903 J.C. Daltry 8

rats (Rattus rattus) in 2012 The largest

surprising increase in Turk s cap cacti.

2014 and 2016, and show continued growth

9 Rat eradication by numbers 207 hectares 44 km of trails cut 1,714 bait stations 1.5 tonnes rat bait 10,000 rats culled >50 personnel >17,000 person-hours US$ 350,000 Dog Island Anguilla (UK) Dog Island was cleared of invasive black rats (Rattus rattus) in 2012 The largest Caribbean island to be successfully cleared of rats, entirely by hand. Spring 2012 March 2012 March 2016 Spring 2014 Only 2 years after eradicating rats, the birds, reptiles, insects and plants had increased. Fixed point photos also reveal a surprising increase in Turk s cap cacti. Bird density before and after Changes in lizard Anolis density gingivinus since rat eradication 1,600 Mean number per hectare 1,400 1,200 1, Rats eradicated Anolis gingivinus Only 2 years after eradicating rats, the birds, reptiles, insects and plants had increased Lizard populations were re-surveyed in 2012, 2014 and 2016, and show continued growth J.C. Daltry 9

Changes in lizard Ameiva density pleei since

600 500 400 300 200 Rats eradicated Ameiva

were re-surveyed in 2012, 2014 and 2016, and

Offshore Islands as Havens Dog Island was

because aliens can be removed and excluded

Offshore Islands as Havens Saint Lucia s

cane toads, goats, sheep, opossums Endangered

10 Changes in lizard Ameiva density pleei since rat eradication 700 Mean number per hectare Rats eradicated Ameiva pleei Lizard populations were re-surveyed in 2012, 2014 and 2016, and show continued growth Over 320,000 seabirds nested on Dog Island in Immigration or reproduction? Offshore Islands as Havens Dog Island was quickly recolonised by Audubon s shearwaters and least terns once the rats had gone. Offshore islands like Dog Island are important because aliens can be removed and excluded more effectively. Offshore Islands as Havens Saint Lucia s Offshore Islands Eradicating rats, mongooses, cane toads, goats, sheep, opossums Endangered Iguana delicatissima are now being moved to offshore cays to avoid alien Iguana iguana. Innovative conservation since 1903 J.C. Daltry 10

Maria Islands Saint Lucia whiptail lizards lived

lizards survived only on the Maria Islands,

Rat Island Rat Island Dennery Island Praslin

Three offshore islands Praslin, Rat and Dennery

Praslin, Rat and Dennery Islands were cleared of

Saint Lucia s Offshore Islands Saint Lucia s

had goats, sheep and cane toads; all of them

11 Maria Islands Saint Lucia whiptail lizards lived on Saint Lucia until mongooses were introduced The lizards survived only on the Maria Islands, without rats or other aliens. Rat Island Rat Island Dennery Island Praslin Island Dennery Island Praslin Island Maria Islands Three offshore islands Praslin, Rat and Dennery were chosen to become additional sanctuaries. Praslin, Rat and Dennery Islands were cleared of rats to allow the lizards to be re-introduced Saint Lucia s Offshore Islands Saint Lucia s Offshore Islands October 2012 Dennery Island also had goats, sheep and cane toads; all of them removed by hand in October 2013 Vegetation and birds are recovering on Dennery Island J.C. Daltry 11

Saint Lucia s Offshore Islands New trees appearing within 12 months

Island: Natural reforestation taking place.

Mongoose invaded 1995 Mongoose removed 1995 Opossum invaded Opossum

Rats eradicated 2011 Unfortunately, islands can be invaded again

Mongoose invaded 1995 Mainland Mongoose removed 1995 Saint Lucia

Rats eradicated 2000 Rats invaded 2011 Rats eradicated 2011

Saint Lucia Saint Lucia has many endangered endemic species and

What is being done to stop aliens spreading?

12 Saint Lucia s Offshore Islands New trees appearing within 12 months of removing goats and sheep Wildlife are recovering on Dennery Island: Natural reforestation taking place. Saint Lucia s Offshore Islands Praslin Island Rats eradicated 1993 Mongoose invaded 1995 Mongoose removed 1995 Opossum invaded Opossum removed Rats invaded 2000 Rats eradicated 2000 Rats invaded 2011 Rats eradicated 2011 Unfortunately, islands can be invaded again and again by different aliens. Saint Lucia s Offshore Islands Praslin Island Rats eradicated 1993 Mongoose invaded 1995 Mainland Mongoose removed 1995 Saint Lucia Opossum invaded Opossum removed Praslin Island Rats invaded 2000 Rats eradicated 2000 Rats invaded 2011 Rats eradicated 2011 Especially if they are close to other areas with aliens. Saint Lucia Saint Lucia has many endangered endemic species and over 350 invasive alien species. What is being done to stop aliens spreading? Innovative conservation since 1903 Many Caribbean countries are developing strategies to prevent aliens from arriving and spreading J.C. Daltry 12

1) Identify the Risk Species Which aliens pose a threat?

site? 3) Take action against the Risk Species: Prevention Make it harder for the

Worse impact Incursion Response Remove the species before it becomes fully

The main components of a Biosecurity Strategy Risk Species identified for Saint

the Incursion Response Remove the species before it becomes fully The main

boats (fishers, visitors, researchers ) In bags and gear for fishing, picnics,

mainland Risk Species Mongoose, cane toad, goat, sheep, pig, cat, dog, opossum,

plants/seeds Rats, mouse, reptiles, cane toad, ants, snails, plants/seeds Rats,

sparrow, ants Rats, mongoose, green iguana Examples of the Pathways by which harmful

2) Identify the Pathways How could the Risk Species reach components of a

13 1) Identify the Risk Species Which aliens pose a threat? More likely to invade 2) Identify the Pathways How could the Risk Species reach the site? 3) Take action against the Risk Species: Prevention Make it harder for the species to reach the site. Surveillance Detect the invading species promptly. Worse impact Incursion Response Remove the species before it becomes fully established. The main components of a Biosecurity Strategy Risk Species identified for Saint Lucia s offshore islands 1) Identify the Risk Species Which aliens pose a threat? 2) Identify the Pathways How could the Risk Species reach the site? 3) Take action against the Risk Species: Prevention Make it harder for the species to reach the site. Surveillance Detect the invading species promptly. Incursion Response Remove the species before it becomes fully established. The main components of a Biosecurity Strategy Pathway Deliberate release by the public On boats (fishers, visitors, researchers ) In bags and gear for fishing, picnics, camping Storm dispersal from mainland (rafting, wind) Fly from mainland Swim from mainland Risk Species Mongoose, cane toad, goat, sheep, pig, cat, dog, opossum, monkey, chicken, pet birds, plants Rats, mouse, reptiles, cane toad, ants, snails, plants/seeds Rats, mouse, reptiles, cane toad, ants, snails, plants/seeds Rats, mouse, reptiles, cane toad, ants, snails, plants/seeds Doves, pet birds, house sparrow, ants Rats, mongoose, green iguana Examples of the Pathways by which harmful animals and plants may reach islands. 1) Identify the Risk Species Which aliens pose a threat? 2) Identify the Pathways How could the Risk Species reach the site? 3) Take action against the Risk Species: Prevention Make it harder for the species to reach the site. Surveillance Detect the invading species promptly. Incursion Response Remove the species before it becomes fully established. The main components of a Biosecurity Strategy e.g. Educate international travellers not to transport aliens J.C. Daltry 13

Housing development in the core habitat of the

Tackle dumping of garbage that can harbour or support

Minimise construction work in or near areas of high

1) Identify the Risk Species Which aliens pose a

2) Identify the Pathways How could the Risk Species

3) Take action against the Risk Species: Prevention

Surveillance Detect the invading species promptly.

need to cooperate to prevent the spread of aliens.

14 Housing development in the core habitat of the Endangered Barbados leaf-toed gecko e.g. Tackle dumping of garbage that can harbour or support ants, rats and other invaders. e.g. Minimise construction work in or near areas of high conservation importance. 1) Identify the Risk Species Which aliens pose a threat? 2) Identify the Pathways How could the Risk Species reach the site? 3) Take action against the Risk Species: Prevention Make it harder for the species to reach the site. Surveillance Detect the invading species promptly. Incursion Response Remove the species before it becomes fully established. As trade and traffic increase, Caribbean countries need to cooperate to prevent the spread of aliens. The main components of a Biosecurity Strategy Use commercial bait stations for rats. Raise stations 15 cm above the ground. Contain rodenticide (e.g. Klerat TM 0.005% brodifacoum Stations checked regularly. Jenny Daltry, FFI Even with preventative measures established, sites should be checked regularly for alien species. Permanent bait stations can help detect rodents. J.C. Daltry 14

15 Bait station at 50-metre intervals e.g. (207 hectares), has 170 permanent bait stations around the coastline. Other materials can be used to detect rodents: e.g. Chocolate wax, candles, sticks soaked in edible oil Rat Mongoose Feral pig Sandy beaches and muddy areas can be inspected for animal tracks. Jenny Daltry, FFI Devon Carter, ANGUILLA Saphira Hunt, SAINT LUCIA Tahambay Smith, ANTIGUA Surveillance needs skilled field personnel who know the sites well and can recognise native and alien species. 1) Identify the Risk Species Which aliens pose a threat? 2) Identify the Pathways How could the Risk Species reach the site? 3) Take action against the Risk Species: Prevention Make it harder for the species to reach the site. Surveillance Detect the invading species promptly. Incursion Response Remove the species before it becomes fully established. The main components of a Biosecurity Strategy Jenny Daltry, FFI Neem tree (Azadirachta indica) Opossum (Didelphis marsupialis) If an alien incursion is detected early, They can be culled before they multiply. J.C. Daltry 15

Offshore Islands, Antigua Costs over US$ 30,000 and 100

prevention is costly: How do we demonstrate the impact of this?

1903 Eradicating Aliens From More Sites Eradicating Aliens

Globally important population of Saint Lucia whiptail lizards.

biodiversity responds rapidly to aliens being removed.

islands wherever possible (e.g. Redonda).

More Sites Barbados leaf-toed gecko Phyllodactylus pulcher:

Tacking aliens on large, complex areas may be technically

16 Offshore Islands, Antigua Costs over US$ 30,000 and 100 person-hours every year to prevent invasions by rats Even prevention is costly: How do we demonstrate the impact of this? Conclusions and Recommendations Innovative conservation since 1903 Eradicating Aliens From More Sites Eradicating Aliens From More Sites Praslin Island 2 hectares. Globally important population of Saint Lucia whiptail lizards. Redonda Even small areas can make a big difference: Island biodiversity responds rapidly to aliens being removed. We should continue removing invasive alien species from islands wherever possible (e.g. Redonda). Eradicating Aliens From More Sites Eradicating Aliens From More Sites Barbados leaf-toed gecko Phyllodactylus pulcher: Endangered African house gecko Hemidactylus mabouia Invasive Tacking aliens on large, complex areas may be technically difficult and prohibitively expensive. It is especially difficult to eradicate certain aliens without harming similar native counterparts. J.C. Daltry 16

17 Suppression Eradicating Aliens From More Sites Feral fallow deer (Dama dama) are controlled on Barbuda by hunters When eradication isn t possible (or socially acceptable) reducing their numbers appears the next best option. Mainland Islands could be a solution for some countries: Priority areas enclosed by a high-tech pest-proof fence. Mainland Islands Over 50 mainland islands Largest is over 3,300 ha Most less than 200 ha Already constructed in: New Zealand Australia Hawaii Azores Mauritius Feasibility studies for mainland islands are underway in several Caribbean countries. Building Capacity to Tackle Aliens There is a need for more training, exchange visits and mentoring for professionals and volunteers. Research to Inform Management More people need more tools (like this) and expertise to identify invasive alien species There is a great need for more research in this complex and rapidly-growing field J.C. Daltry 17

18 Research to Inform Management Research to Inform Management For example, research on how aliens interact with native wildlife and their ecosystems and research into more effective control methods Research to Inform Management Research to Inform Management Changes in lizard Anolis density gingivinus since rat eradication 1,600 Mean number per hectare 1,400 1,200 1, Rats eradicated Anolis gingivinus and more detailed monitoring of the results of tackling aliens, both short term and long term. All of this is necessary to help NGOs, governments and funders decide how and where to invest their resources. Preventing Extinctions Thank You! To You, Caribaea Initiative, Our Partners, and Our Supporters We can and must strive to avoid further extinctions. Innovative conservation since 1903 J.C. Daltry 18

Iguana Technical Assistance Workshop. Presented by: Florida Fish and Wildlife Conservation Commission

Iguana Technical Assistance Workshop Presented by: Florida Fish and Wildlife Conservation Commission 1 Florida Fish and Wildlife Conservation Commission Protects and manages 575 species of wildlife 700