Winning the Battle Against Invasive Species

Galapagos’ Greatest Threat

Introduced plants, animals and insects represent the single greatest threat to the native and endemic species of Galapagos. Many alien species were brought to Galapagos intentionally by humans—goats, cats, vegetables, and fruit plants to name a few—while others, such as insects and weedy plants, have been carried to the islands accidentally. While 95% of the archipelago’s native species still remain intact today, due in large part to the islands’ remoteness and relatively recent discovery and settlement by humans, the islands’ native plants and animals are vulnerable to new arrivals. Today, invasive species in Galapagos include:

• At least 526 alien invertebrates, or 1/4 of the total invertebrate fauna. Among the most serious threats to Galapagos biota are two fire ant species (which have a severe impact on native invertebrates, as well as the young of reptiles and birds), two wasp species (which prey on native invertebrates and compete for food with finches), and an ectoparasitic fly (which feeds on and harms many bird species).
• More than 750 introduced plants, 90% of which were brought deliberately by humans for agricultural and ornamental purposes, as well as many aggressive invasive weeds.
• 29 species of vertebrates, including goats, rats, cats, pigs, dogs, horses, cattle, donkeys, geckos and mice. Six species of birds have been introduced, including chickens and ducks, as well as semi-domestic Rock Pigeons. During the wet El Niño year of 1997-1998, the first recorded amphibian—the tree frog Scinax quinquefasciata arrived in cargo. New vertebrates are arriving continuously. Tilapia, a fresh water fish, was discovered on San Cristobal in 2006. Other recent captures or sightings include two green iguanas, a boa constrictor, a tree snake, a monkey and two species of turtle.

The Battle to Date

Important steps have already been taken in battling invasive species. In 1999, the Charles Darwin Research Station played a lead role in establishing the Galapagos Quarantine and Inspection System (SICGAL) which inspects cargo from ships and planes, as well as the bags and luggage of tourists. Important community education programs have been implemented in schools and Environmental Education Centers on Santa Cruz and Isabela, and strategies to increase community awareness and involvement in identifying and responding to emerging threats of invasive species are being implemented.

Biological control—the use of natural enemies to reduce the damage caused by pest populations—has shown promise for controlling invasive species. In 2002, following six years of thorough impact studies, the Australian ladybug, Rodolia cardinalis, was liberated to control the cottony cushion scale which was threatening 62 native and endemic plant species. This was the first intentional introduction of an insect to Galapagos and it has proven effective at reducing the population of this scale insect to manageable levels.

Other successes include the eradication of fire ants from Marchena Island, feral pigeons—dangerous disease carriers—from San Cristobal and two species of blackberries from Santa Cruz. But the most dramatic success related to invasive species was achieved in March 2006, when Project Isabela—an unprecedented island restoration program in terms of size and scope—was completed with the successful eradication of feral goats from northern Isabela Island and goats and pigs from Santiago Island.

Expanding on Successes and Lessons Learned

As the level of human activity continues to rise in Galapagos, so does the threat of new introductions of potentially dangerous species. Over the next five years, the Charles Darwin Research Station, the Galapagos National Park Service, and other organizations in Galapagos require funding for:

Prevention and Awareness

• Strengthen the inspection capabilities of the Galapagos Quarantine System through improved training and equipment
• Expand Community Monitoring Projects (CMPs) to achieve greater involvement of the local population in identifying and responding to new threats of invasive species
• Strengthen education programs in schools and Environmental Education Centers

Introduced Large Mammals

• Apply methodologies developed in Project Isabela to Floreana and San Cristobal with the goal of making these islands goat-free by December 2008
• Initiate goat and donkey eradication work on Santa Cruz beginning
  in 2009
• Ensure ongoing monitoring for re-introductions on Santiago, Isabela, and
  other islands

Introduced Small Mammals

• Involve international experts on rodent eradication to develop an effective plan for rodent eradication in Galapagos
• Eliminate rodents on small and medium-sized islands that are least likely
  to be re-invaded, and develop the capacity to begin eradication techniques on large islands
• Initiate removal or sterilization projects of rodent and feral cat populations on Floreana and other large islands in 2009
• Support ongoing cat and dog sterilization programs on inhabited islands

Introduced Invertebrates

• Complete the inventory of introduced invertebrates present in urban and agricultural areas and prioritize species that require management action
• Conduct feasibility studies for biological control options for ants and invasive wasps
• Determine the feasibility for eradicating the mosquito Culex quinquefasciatus, a potential vector of West Nile Virus
• Research short-term and long-term techniques for controlling parasitic
   flies and protecting their endangered host birds, such as the mangrove finch
• Attempt further eradications of fire ants on priority small islands and smaller infestations of larger islands

Introduced Plants

• Prioritize problems and initiate control programs for the worst invasives on Isabela, Floreana and Santiago island, using a suite of tools already developed
• Eliminate 30 invasive plant species before they become a problem, in the next two years
• Prepare a comprehensive management plan with an eradication emphasis for the highly invasive Quinine tree and implement the tree’s large-scale eradication
• Conduct feasibility studies of biological control options for the Lantana shrub, Mysore Raspberry, Quinine tree, and Guava shrub
  
  

Join the Battle

The Charles Darwin Research Station, the Galapagos National Park Service and others in Galapagos join us in thanking you for your partnership in these important efforts. We always welcome your ideas and feedback.

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