Many of us have heard of invasive species. We may even know a few species that are wreaking havoc in your local area. You have heard the doom and gloom of extinct species and ecosystem collapse. However, have your heard the success stories? How people have successfully managed to reclaim native landscapes and return species from the brink of extinction? Well, this is the good news story for you! We talk invasive species eradication on islands, and what we can learn from it.
Episode highlight
In this episode, Wes Jolley and Dena Spatz talk about invasive species eradication to restore native species populations on islands.
Resources
The global contribution of invasive vertebrate eradication as a key island restoration tool
The Biogeography of Globally Threatened Seabirds and Island Conservation Opportunities
Estimating Burdens of Neglected Tropical Zoonotic Diseases on Islands with Introduced Mammals
International Union for Conservation of Nature
Database of Island Invasive Species Eradications
Invasive mammal eradication on islands results in substantial conservation gains
Sponsors
Quotes
19.54 - 20.04: “Most people know that we are losing biodiversity… across our planet at unprecedented rates but what is… maybe not as well known is that that is… happening faster on islands than anywhere else.”
46.02 - 46.12: “Eradications are not just done by one group of people; it is an incredibly collaborative effort that really comes from the people that live on the islands first.”
Takeaways
Diving into research waters (4.24)
Dena is a Senior Conservation Scientist at Pacific Rim Conservation whose mission is to restore bird populations in the Hawaiian islands and across the Pacific through the removal or control of invasive species on those islands. In the senior year of her environmental studies-anthropology degree, she took a class on birds, which ignited her passion. Her professor invited her to a free research internship in the San Juan Islands, where she learned about the near-shore marine ecosystem.
Seabirds (07.04)
Observing seabirds during her internship made Dena fall in love with them. She later took jobs in seabird fieldwork and realized that they are the most threatened bird group on the planet. She went to grad school to become a seabird conservation scientist with the people who founded Island Conservation, who introduced her to the issues of invasive species on islands, where seabirds breed. She took up a volunteer opportunity to study seabirds and focussed her grad work on preventing extinctions and Island Conservation, even working with them later.
The island life (10.20)
Wes is the Head of Operations for the United States Program at Island Conservation whose mission is to prevent extinctions by removing invasive species from islands. Over his 13 years with the organization, he has developed expertise in project management. He studied wildlife biology and took up a summer position trapping raccoons and studying the impact of predator species on the Barrier Islands in Virginia. He worked for the Forest Service on islands too, and later found an opportunity working on invasive species removal efforts on other islands, realizing how vulnerable islands can be when an invasive species is introduced.
“Biodiversity is concentrated on islands” (18.55)
Dena differentiates between non-native species, a species that has been introduced outside of its native range, and invasive species, a non-native species that causes harm to that ecosystem. She notes, “About 20% of all known species are from islands and islands only represent about 5% of [the] global landmass so there is a disproportionate amount of species richness already on islands”. She explains how different island types came about and that it takes effort for anything to establish itself on islands due to its remoteness (and invasive species have jumped that hurdle because they are brought by people)
Island species (22.25)
Dena highlights that since predation is not common on islands, island species lose their defences, and gives a few examples of such species. Islands are hotspots for endemism (being the only place where certain species are found), which makes them epicentres for extinction. The primary driver of this threat is invasive species, making the damage on islands quicker since native species can’t compete. However, since islands are insular places, there is also a huge opportunity to remove invasive species.
The human element (27.14)
Dena explains island species' behaviour using the example of the Galápagos Islands, where many invasive species like goats and rats, who prey on tortoise hatchlings, were introduced. A lot of work is being done to reverse the damage done by invasive species on the islands. She recalls why goats were introduced to different islands by hunters as a food source. Wes points out the human element in their work - as carriers of invasive species but also as inhabitants of the island and creators of its culture and the victims of damage by invasive species.
Invasive species cost over a trillion dollars (32.00)
Wes talks about different approaches to removing invasive species - a one-time action and then opportunities for human-assisted recovery, creating a long-term sense of biosecurity through financial and conservation investments. Biosecurity is “the prevention of species you removed from coming back but also the prevention of other new species being introduced”, he explains. Dena found there to be an 80% success rate in removing invasive species, an effort which prevents biodiversity loss and protects economic interests on islands large and small.
Nuanced conservation (41.15)
Wes acknowledges that different people value different aspects of conservation efforts. He shares the different considerations in the efforts to remove the coconut monoculture on Palmyra Atoll to bring back the native forest and the seabirds, and take the coconut monoculture to an island which relies on coconut farming. This value-based approach considers the broader benefits of biodiversity restoration, like increasing productivity in surrounding areas. He believes there is a need to incorporate different values into the definition of invasive species.
Collaborative and holistic efforts (45.57)
Dena highlights the importance of recognizing the values and needs of the community where eradication efforts take place. She commends Mexico for its outstanding eradication efforts in collaboration with the local NGOs, government agencies and the local community. After the one-time effort of eradication, it is the local community that is mindful of preventing invasive species from coming to their islands. She recounts how seedlings of native trees reappeared after the eradication of rats from the Palmyra Islands, which eventually turned into forests.
Considerations in conservation efforts (52.11)
Wes talks about the connectedness of conservation efforts using the example of Laysan and black-footed albatrosses and the removal of mice. Dena also speaks about the collaboration between Pacific Rim Conservation and Island Conservation. Together, they are creating ways to ensure restoration after the eradication of invasive species and build predator-proof fencing to prevent further invasions. This creates new colonies of species where invasive species can’t be removed and regenerates the forest. Wes discusses the project management considerations in conservation efforts - eradication principles, risks and decision-making.
Global conservation efforts (1.04.29)
Dena talks about the development of DIISE, the Database of Island Invasive Species Eradications to bring to light all the invasive species eradications and conservation efforts around the world over time, capturing 100 years of 1500+ efforts on 1000 different islands with 88% success rates. She explains how New Zealand, as an island nation, is a world leader in eradicating invasive species, and its goal is to be predator-free by 2050. Recently, she has observed more countries taking on these efforts and creating targeted methodologies.
“We can only do what we have the tech to be able to do” (1.10.42)
Dena laments that there are some communities who do not accept the removal of invasive species. She is now focusing on the reintroduction of seabird species after eradication, taking inspiration from success stories in other restoration sites. Wes celebrates the potential of these success stories in creating hope for more such efforts to take place. Dena knows there is a lot more work to be done but that there are tools and information available to make it possible. The cost of harm by invasive species is a big driver for change.
It’s raining iguanas! (1.18.30)
Dena shares some examples of translocating native species to restoration sites instead of completely eradicating invasive species, sharing some techniques used and the behaviour pattern of the seabirds involved. Seabirds are valuable to the islands in every way, and recovering their population shows changes in plant recovery too. Wes shares two anecdotes of tortoise and iguana restoration.
Taking a leaf from the island book (1.27.17)
Dena highlights that islands are insular systems due to their geographic separation by water, but the lessons from island conservation efforts can be applied to other insular areas like mountaintops. People today are becoming more aware of the harm by invasive species, and she encourages everyone to learn more about the same to communities resilient to invasions. Wes believes it is important to set expectations when managing invasive species on a larger scale, which requires more investment and tools.
Proactive control (1.32.53)
Dena acknowledges that a globalized economy with its import-export trade and travel brings with it invasive species. There are political controls in place to ensure biosecurity and protect agriculture and the economy. She hopes that people will speak to their political representatives to improve the controls in their area.
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