By Ben J. Novak
On September 3, and 4, 2016, Revive & Restore participated in the IUCN World Conservation Congress. Revive & Restore cofounder Ryan Phelan convened two sessions on the potential role biotechnology could play in conservation. The 2016 congress was the largest in the 68-year history of the International Union for the Conservation of Nature, with nearly 10,000 registered participants. It was also the first held in the United States. The setting was Hawaii, sometimes labeled “the extinction capital of the world.” Few places have more urgency to introduce new tools for saving species and ecosystems.
The goal of Revive & Restore’s sessions at the congress was to lead the conversation: how might conservation use new genetic tools to save endangered species? Ryan Phelan noted, “Many Hawaiian species are on the verge of extinction, and there may be a way to save them. It is entirely up to the local community to decide whether these tools might be appropriate, but it’s important to remember the consequences of doing nothing.”
Revive & Restore’s two sessions were sponsored by the National Geographic Society and the National Park Service. Representation and logistical support also came from the American Bird Conservancy, San Diego Zoo Global, the National Tropical Botanical Garden, and the U.S. Fish & Wildlife Service.
The September 3 public event was titled, “Stamping Out Mosquitoes in Hawaii: Can new technology stop avian malaria from driving Hawaii’s native birds to extinction?” It drew a jam-packed audience, with the crowd bleeding into the aisles of the main exhibition floor.
Sam ‘Ohukani’ōhi‘a Gon, III, Senior Scientists and Cultural Advisor at The Nature Conservancy, began the session with the creation chant of Hawaiʻi, followed by a poignant call to save the sacred birds of Hawaii .
Avian malaria and pox, introduced by invasive mosquitoes brought to Hawaii less than 200 hundred years ago, have caused the extinction of 34 Hawaiian bird species to date. Currently, just 30% of Hawaii’s native birds remain, and the majority of these species are threatened with extinction as mosquitoes continue to spread.
The topic of mosquitoes in Hawaii is literally heating up. Because of climate change, disease-carrying mosquitoes are expanding their range to higher elevations each year, encroaching upon the last safe refuge of Hawaii’s native birds.
The session’s speakers outlined the urgency and the facts:
- Hawaii’s birds, particularly the unique honeycreepers, will go extinct within a matter of years because of mosquito-borne diseases, unless backup populations are established in captivity.
- The only way to ensure the survival, or reintroduction, of wild birds is to eradicate mosquitoes and their lethal pathogens. The use of pesticides will be difficult to cover the entire landscape, and will kill millions of endemic insects in the process.
- Mosquitoes are 100% invasive to Hawaii, meaning no species existed on the islands until brought by whaling ships in the 1800s. They do not play an important role in the ecosystem: they are not preferred by native insectivores nor are they significant pollinators for the island’s endemic flowers. Therefore, eradicating mosquitoes will not have negative impacts.
- There are several approaches that can be used to eliminate mosquitoes: Oxitec discussed a self-limiting solution, in which the mosquitoes are engineered to contain a gene that makes their offspring reproductively inviable, while Anthony James discussed engineering the mosquitoes so they no longer carry the pathogen. In addition, gene drives tailored to Hawaii’s needs, could offer a means of eradicating mosquitoes with the ability to scale up to whole landscapes with no collateral damage.
Gene drives are not without risks, and speakers were keen to advise caution about identifying dangers and designing mitigation strategies. However, the stakes are clear: without eradicating mosquitoes, the extinction of Hawaii’s endemic birds is inevitable.
The September 4 workshop, “Genetic Rescue: Can new genomic tools solve conservation problems such as exotic wildlife diseases and destructive invasive species?” delved beyond on the topic of mosquito-borne diseases and birds to encompass other pressing problems for Hawaii’s native ecosystems and potential genomic solutions. These solutions could apply to environments facing similar problems around the world.
Once again, it was standing room only as Sam ‘Ohukani’ōhi‘a Gon, III opened with a chant to Kū, the Hawaiian god of governance and beautifully illustrated the significance of the ʻōhiʻa tree, known as ʻōhiʻa lehua, to the indigenous people of Hawaii. The ʻōhiʻa is a keystone species to Hawaii’s forests – the first colonizer of new lava flows and the dominant tree from lowlands to high peaks, ranging in size from a hundred feet high to just six inches tall in the wettest bogs. The ʻōhiʻa has coevolved with Hawaii’s honeycreepers, and like the honeycreepers it now faces extinction due to disease: an invasive fungal blight.
The fungus (known as Rapid Ohi’a Death) has killed hundreds of thousands of trees since 2012. On Hawaii Island, 47,000 acres, representing 9% of its surveyed forest, are infected – an increase from 38,000 acres in February 2016. The loss of this tree would mean the collapse of Hawaii’s native forests. Given the significant impact of this disease, all conservation tools need to be explored. With the use of state-of-the-art genomics, there may be hope to better diagnose and maybe save the trees. One powerful option is to use genomic analysis to identify whether any trees have developed resistance to the disease. If so, it might provide insights for a potential cure.
Like the ʻōhiʻa tree, the American chestnut tree suffered from an invasive fungal blight, causing its virtual extinction, But researchers at the State University of New York’s College of Environmental Science and Forestry have engineered the chestnut to combat the fungus using a single wheat gene. Andy Newhouse, of the American Chestnut Research and Restoration project, shared how the engineered chestnut trees are now able to produce an enzyme that neutralizes the effects of the blight – resulting in trees that are 100% immune to the disease. Because of this effort, eastern America’s once most abundant tree is poised to make a comeback, a hundred years after their obliteration from the landscape. Could a similar method help save the ʻōhiʻa tree?
The workshop concluded with the most notorious villain of all islands – invasive rodents. Island Conservation scientist Karl Campbell outlined the need for eradicating invasive species on islands: 40% of the world’s endangered species live on islands all threatened by invasive species, especially rodents. Ecosystems have shown extraordinary resilience once invasive species are removed. On Pinzon Island in the Galapagos, the resident giant tortoise species successfully hatched offspring for the first time in over a century, just 6 months after invasive rats were removed from the landscape. That success took years of planning and execution, with much labor devoted to mitigating the risk posed by the agent of rodent eradication: brodifacoum toxicants.
Rodenticides are the only efficient tool that conservationists have to eliminate rodents on islands, but collateral damage to native wildlife and potential lingering toxicity in the environment are the side effects of its use. It is also a limited tool for scaling up to the large landscapes of many islands in dire need of rodent removal.
For this reason, Island Conservation is developing gene drive techniques to employ on islands in the future, which will skew sex ratios of the invasive rodent population. The basic concept is that when engineered male rodents are introduced to an island their sex-determining genes will spread each generation, turning the entire population male and creating a final generation. There are no toxic side effects to native wildlife in the process and it is a system that can scale up to large landscapes.
Kevin Esvelt, of MIT, presented his laboratory research for self-limited gene drives, which he hopes to eventually deploy with New England white-footed mice to stop the spread of Lyme disease.