Caribbean island launches plan to remove invasive rats and goats

Mongabay: Redonda’s invasive black rats and long-horned goats have transformed the once-forested island into a ‘moonscape’, conservationists say

Shreya Dasgupta for Mongabay, part of the Guardian Environment Network

Monday 1 August 201616.51 BST

The remote Caribbean island of Redonda, part of Antigua and Barbuda, is home to numerous species of plants and animals found nowhere else on earth. It is also home to invasive black rats and non-native goats that are wiping out the island’s native, rare wildlife, conservationists say.

To help the island’s flora and fauna, the Government of Antigua and Barbuda is now initiating a plan to remove all goats and rats from the island. The Redonda Restoration Program program has been formed by the Antigua & Barbuda Government and the Environmental Awareness Group (EAG) in collaboration with organizations like Fauna & Flora International, British Mountaineering Council, Island Conservation and Wildlife Management International Ltd.

“This work will dramatically transform an entire island ecosystem,” Sophia Steele of Fauna & Flora International told Mongabay. “It will save a number of rare endemic species from otherwise almost certain extinction, such as the Critically Endangered Redonda tree lizard, which currently finds itself living on an island almost devoid of trees.”

The island currently has a population of over 5,000 invasive black rats that prey on the island’s native species. The rugged island is also home to around 60 long-horned goats that humans brought to Redonda more than a century ago. The rats and goats are believed to have been introduced into the island by a guano mining community, which was disbanded after World War I.

Read on … 

Black rats rainforest invasion 'speeded by deforestation'

By Matt McGrathEnvironment correspondent

Cutting down trees in rainforests facilitates the spread of invasive black rats, a study suggests.

The rodents normally avoid mature forests with large trees as they provide little in the way of cover.

But researchers, writing in Biotropica, say that logging makes rainforests more attractive for rats as fallen wood contains more insects which they eat.

Scientists are concerned that the invading black rats will be bad news for native mammals.

Sometimes called the ship rat, these rodents have spread around the world over the past 400 years, often causing the extinctions of native species and spreading disease.
Noisy trails

Much of their notoriety rests on the idea that black rats were the origin of bubonic plague, although recent research casts doubt on that notion.

Black rats have usually avoided older forests as they contain large trees which do not provide much in the way of ground level protection. They also tend to have leafy forest floors which are noisy for rats to run through, as they attract predators.

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Campaign to rid Galapagos of 180,000,000 rats is launched

Black rats have prevented tortoises from breeding

November 2012. Galapagos National Park Service (GNPS) rangers and partners from Island Conservation have begun to spread rat bait on South Plaza Island and Pinzón Island.

No tortoises have bred in the wild for 150 on Pinzon
Introduced black rats have prevented the giant tortoises on Pinzón Island from successfully reproducing in the wild for nearly 150 years, due to their predation on tortoise eggs and hatchlings. For the past 45 years, the GNPS and Charles Darwin Foundation have collected eggs, and artificially incubated, hatched, and raised the young in captivity. At four years of age, the young are considered "resistant" to attack by rodents and can be returned to their natural habitat. Since the first reintroduction of 20 young Pinzón tortoises in 1970, more than 550 juvenile tortoises have been released on the island. The rodent bait used in the project does not pose a risk to the tortoises.

The Galapagos National Park Director, Edwin Naula, said, "Invasive species are recognized as a major threat to the biodiversity of Galapagos, so the National Park Service and its partners are using new techniques to remove these threats and to prevent the extinction of species not found anywhere else in the world, such as the giant tortoise of Pinzón."

Lava lizards
Invasive rats also have had negative effects on the endemic Pinzon lava lizard, resulting in the decline of this unique species. On South Plaza Island, invasive rats destroy the root systems of the Opuntia cacti, a favorite food of Galapagos land iguanas and other endemic species such as the cactus finch.

Are rodenticides safe?
The GNPS has received many inquiries regarding the risks of using anticoagulant rodenticides in protected areas. Before implementing eradication programs, the Park and its partners conduct thorough toxicity studies involving the species found on each of the islands where baits are to be applied in order to determine which species are at high, medium, or low risk. Mitigation plans have been implemented for such species as the Galapagos hawk, which are being kept in captivity for as long as the bait is considered toxic in order to protect them from primary exposure (by eating the bait) or secondary exposure (indirect contact from eating dead or live animals that have been poisoned).

Read on:  http://www.wildlifeextra.com/go/news/galapagos-rat.html

Puerto Rican island to be cleared of rats to save rare wildlife

Desecheo Island rat clearance
August 2012. The U.S. Fish and Wildlife Service and Island Conservation have announced that efforts to restore Desecheo Island's native species and their habitat by removing non-native, invasive black rats from Desecheo Island have been completed safely and successfully. The removal of invasive rats will allow the native forest to recover and will promote the recolonization of the island by several seabird species that historically nested there.

Poison bait
Beginning March 13, 2012, the Service and Island Conservation successfully carried out the first aerial application of rodent bait in the Caribbean to remove destructive rats from the island and surrounding islets, while minimizing threats from the bait to other animals. Intensive monitoring took place prior to and after the bait application, from February to April to assess the effectiveness of the operations. Two years of additional monitoring will take place before the island can be officially declared free of destructive invasive rats.

"I would like to thank all of the dedicated and hardworking professionals involved in each aspect of the Desecheo National Wildlife Refuge (NWR) restoration project" said Susan Silander, Project Leader of the Caribbean Islands National Wildlife Refuge Complex. "Logistically, this project was no easy task. However, with the expertise and dedication of each of these individuals the operations were carried out safely and efficiently. In collaboration with Island Conservation and Puerto Rican government agencies, we have begun saving our extraordinary species, and we are anxiously waiting to document and monitor the positive changes that we anticipate will occur on the Desecheo National Wildlife Refuge."

According to Brad Keitt, Island Conservation's Director of Conservation, "Desecheo is an absolute jewel of an island, but its birds have been missing for many years. That is about to change - using techniques that have been successful in removing rats from hundreds of islands around the world, we have begun the process of recovery. Desecheo Island's future is now one of native species thriving and abundant seabirds."

Continued:  http://www.wildlifeextra.com/go/news/Desecheo-Island.html