Golden frogs are extinct in the wild, but in addition to two Panamanian facilities, about 50 zoos and aquariums in the USA participate in a Species Survival Program led by the Maryland Zoo to help breed and conserve these precious animals. Investigate TV interviews Matt Evans at the Smithsonian’s National Zoo and Conservation Biology Institute about his work with this species.
In August 2022 a diverse team of researchers, conservationists, artists, representatives of local and Indigenous communities and park rangers met at Estación Experimental San Lorenzo in the Sierra Nevada de Santa Marta in Colombia with one common objective in mind: studying and preserving Harlequin Toads (genus Atelopus). The meeting was part of the project “The last refuge of Harlequin Toads: working together to save the jewels of the forest”, funded by the National Geographic Society.
The project involves a large group of people and organizations, including several Amphibian Survival Alliance (ASA) partners, ASA Future Leaders of Amphibian Conservation and members of the Atelopus Survival Initiative (ASI). The partnership between scientists, conservationists, artists, and educators resulted in the creation of scientific protocols for research and monitoring of Atelopus and the publication of a children’s book and songs about Harlequin Toads. The continued persistence of the frogs was no mystery to local members of the Arhuaco community who said the reason they disappeared everywhere else is because in other places the harmony between the earth and its people had been disrupted, but here was special because the people respect their environment and its inhabitants. As researchers discussed the possibilities that may allow the frogs to persist here in this unique place and how unlocking the mysteries may help recover harlequin frogs elsewhere.
The team was led by Lina Valencia, coordinator of the IUCN SSC Amphibian Specialist Group Atelopus Task Force, and Luis F. Marin da Fonte, coordinator of the ASI and Director of Partnerships & Communications at the Amphibian Survival Alliance. Other team members were Jeferson Villalba, José Luis Peres, and Sintana Rojas (ASA partner Fundación Atelopus), Brian Gratwicke (ASA partner Smithsonian Conservation Biology Institute), Pedro Peloso (ASA Future Leader of Amphibian Conservation), Juan Manuel Guayasamin (Jambato Alliance), Janni Benavides, Julia Alvarez and Andrés Alvarez (Jacana Jacana), Delia Basanta (University of Nevada), Mirna Garcia-Castillo (Universidad Nacional Autónoma de México), Ruperto Chaparro and Rufino Arroyo (Arhuaco Indigenous community), Sara Ramírez (Selva Selvita), Timothé Le Pape (Cerato, Association Herpétologique de Guyane), and Lilia Mejia, Anibal Benitez, Jorge Meza, Elmer Ortega and Angela Arias (Parques Nacionales Naturales de Colombia). Additional team members that were not able to join the fieldwork activities include Luke Linhoff (Smithsonian Conservation Biology Institute) and Jamie Voyles (University of Nevada).
Our planet is home to almost 9,000 amphibian species. For more than 100 years, these animals have dramatically suffered the consequences of deforestation, agriculture, wetland drainage, agrochemicals and other pollutants. In recent times, new threats have emerged making 40% of all amphibian species threatened with extinction under “Red List” released by the International Union for the Conservation of Nature (IUCN), which was recently updated. New threats include climate change and emerging infectious diseases. Among them, amphibian chytrid fungi causing skin infections play a key role. These fungi have been spread all over the world by humans and induce the disease chytridiomycosis in amphibians, leading to population declines and even extinctions.
Already 30 years ago, researchers, conservationists and other stakeholders have realized the crisis the amphibians are in. Various initiatives, at the global, regional and local scales have been founded to safeguard amphibian diversity including numerous management and action plans. Due to these activities, we massively augmented our knowledge about where declines happen, as well as the mechanisms behind these and how threats interact. This goes hand in hand with enormous engagement for protecting natural habitats and accompanying captive breeding in conservation facilities. Also, diseases and their agents are much better understood. There have been many stories of success and without all the investment, work and passion of dedicated actors many amphibian species would have become extinct by now!
However, it is difficult to appreciate where we stand in overcoming the amphibian crisis. Threats and the vulnerability to them are not equally distributed over all species. Certain amphibians are more susceptible and suffer more. They represent ‘worst-case scenarios’ of the amphibian crisis. For many of them, we lack sufficient information to access their current status. Not so for harlequin toads, genus Atelopus, from Central and South America. These are small, often colourful and day-active animals that inhabit lowland rainforests to high Andean moorlands (páramos) above tree line.
More than 130 Atelopus species are known and – being highly sensitive to threats – many of them have declined and are even feared extinct. Harlequin toads are the poster child of the amphibian crisis, and due to their iconic appearance, scientists have studied population status data since the early 1990s. In a recent study published in Communications Earth and Environment, Lötters and 99 colleagues, mostly conservationists and researchers from countries where harlequin toads naturally occur, compared population status data as of 2004 and of 2022 to examine species-specific trends over the last two decades.
Data from the authors confirm that massive conservation efforts from many scientists, conservationists and local communities have revealed that more than 30 Atelopus species that in part were feared to have vanished are still there! However, evidence suggests that at the same time all species remain threatened and their conservation status has not improved. Factors threatening the remaining harlequin toads remain unchanged and include habitat change and chytrid fungus spread. In addition, the authors demonstrated that in the future harlequin toads suffer from climate change.
Authors conclude that other worst-case amphibians continue to be imperilled demonstrating that the amphibian crisis is still an emergency. Thanks to the tremendous strength put into conservation, by collaborative networks like the recently launched Atelopus Survival Initiative under the umbrella of the Atelopus Task Force of the IUCN Amphibian Specialist Group, these amphibians have not yet vanished. It is now more than ever critical to continue and increase efforts to escape the emergency the amphibian crisis still is.
Lötters, S., A. Plewnia, A. Catenazzi, K. Neam, A.R. Acosta-Galvis, Y. Alarcon Vela, J.P. Allen, J.O. Alfaro Segundo, A. de Lourdes Almendáriz Cabezas, G. Alvarado Barboza, K.R. Alves-Silva, M. Anganoy-Criollo, E. Arbeláez Ortiz, J.D. Arpi L., A. Arteaga, O. Ballestas, D. Barrera Moscoso, J.D. Barros-Castañeda, A. Batista, M.H. Bernal, E. Betancourt, Y.O. da Cunha Bitar, P. Böning, L. Bravo-Valencia, J.F. Cáceres Andrade, D. Cadenas, J.C. Chaparro Auza, G.A. Chaves-Portilla, G. Chávez, L.A. Coloma, C.F. Cortez-Fernandez, E.A. Courtois, J. Culebras, I. De la Riva, V. Diaz, L.C. Elizondo Lara, R. Ernst, S.V. Flechas, T. Foch, A. Fouquet, C.Z. García Méndez, J. E. García-Pérez, D.A. Gómez-Hoyos, S.C. Gomides, J. Guerrel, B. Gratwicke, J.M. Guayasamin, E. Griffith, V. Herrera-Alva, R. Ibáñez, C.I. Idrovo, A. Jiménez Monge, R.F. Jorge, A. Jung, B. Klocke, M. Lampo, E. Lehr, C.H.R. Lewis, E.D. Lindquist, Y.R. López-Perilla, G. Mazepa, G.F. Medina-Rangel, A. Merino Viteri, K. Mulder, M. Pacheco-Suarez, A. Pereira-Muñoz, J.L. Pérez-González, M.A. Pinto Erazo, A.G. Pisso Florez, M. Ponce, V. Poole, A.B. Quezada Riera, A.J. Quiroz, M. Quiroz-Espinoza, A. Ramírez Guerra, J.P. Ramírez, S. Reichle, H. Reizine, M. Rivera-Correa, B. Roca-Rey Ross, A. Rocha-Usuga, M.T. Rodrigues, S. Rojas Montaño, D.C. Rößler, L.A. Rueda Solano, C. Señaris, A. Shepack, F.R. Siavichay Pesántez, A. Sorokin, A. Terán-Valdez, G. Torres-Ccasani, P.C. Tovar-Siso, L.M. Valencia, D.A. Velásquez-Trujillo, M. Veith, P.J. Venegas, J. Villalba-Fuentes, R. von May, J.F. Webster Bernal & E. La Marca (2023): Ongoing harlequin toad declines suggest the amphibian extinction crisis is still an emergency. — Communications Earth and Environment, 4, 412. https://www.nature.com/articles/s43247-023-01069-w
Habitat destruction and disease are both well-documented causes of the decline of amphibians—among the most threatened animals on the planet—but a new paper analyzing two decades’ worth of data from around the world has found that climate change is emerging as one of the biggest threats to frogs, salamanders, and caecilians. The study was published today, Oct. 4, in the scientific journal Nature.
The study, “Ongoing declines for the world’s amphibians in the face of emerging threats,” is based on the second global amphibian assessment, coordinated by the Amphibian Red List Authority, which is a branch of the International Union for Conservation of Nature’s Species Survival Commission’s Amphibian Specialist Group, hosted and managed by Re:wild.
The assessment evaluated the extinction risk of more than 8,000 amphibian species from all over the world, including 2,286 species evaluated for the first time. More than 1,000 experts across the globe contributed their data and expertise, which found that two out of every five amphibians are threatened with extinction. These data will be published on the IUCN Red List of Threatened Species™.
Between 2004 and 2022, a few critical threats have pushed more than 300 amphibians closer to extinction, according to the study. Climate change was the primary threat for 39% of these species. This number is expected to rise as better data and projections on species’ responses to climate change become available. Climate change is especially concerning for amphibians in large part because they are particularly sensitive to changes in their environment.
“As humans drive changes in the climate and to habitats, amphibians are becoming climate captives, unable to move very far to escape the climate change-induced increase in frequency and intensity of extreme heat, wildfires, drought and hurricanes,” said Jennifer Luedtke Swandby, Re:wild manager of species partnerships, Red List Authority coordinator of the IUCN SSC Amphibian Specialist Group, and one of the lead authors of the study. “Our study shows that we cannot continue to underestimate this threat. Protecting and restoring forests is critical not only to safeguarding biodiversity, but also to tackling climate change.”
Habitat destruction and degradation as the result of agriculture (including crops, livestock like cattle and livestock grazing, and silviculture), infrastructure development and other industries is still the most common threat, according to the paper. Habitat destruction and degradation affect 93% of all threatened amphibian species. Expanded habitat and corridor protection in the places most important for biodiversity is going to continue to be critical.
Disease caused by the chytrid fungus–which has decimated amphibian species in Latin America, Australia and the United States–and overexploitation also continue to cause amphibian declines. Habitat destruction and degradation, disease, and overexploitation are all threats that are exacerbated by the effects of climate change.
The study also found that three out of every five salamander species are threatened with extinction primarily as the result of habitat destruction and climate change, making salamanders the world’s most threatened group of amphibians. North America is home to the most biodiverse community of salamanders in the world, including a group of lungless salamanders abundant in the Appalachian Mountains of the eastern United States. Because of this, conservationists are concerned about a deadly salamander fungus that has been found in Asia and Europe, called Batrachochytrium salamandrivorans (Bsal), entering the Americas.
“Bsal has not yet been detected in the United States, but because humans and other animals can introduce the fungus to new places, it may only be a matter of time before we see the second global amphibian disease pandemic,” said Dede Olson, a research ecologist with the USDA Forest Service, member of the IUCN SSC Amphibian Specialist Group, and co-author on the paper. “It is critical that we continue to implement proactive conservation actions to prevent the spread of Bsal into the United States, including effective biosecurity practices for wild and captive amphibians, and rapid detection and response measures. The North American Bsal Task Force includes a multi-pronged strategic plan that includes: a continental surveillance and monitoring network; research studies identifying high-risk geographies and species; and collaborative partnerships across public, private, and governmental sectors.”
The Nature paper provides an update to the 2004 landmark paper that was based on the first global amphibian assessment for the IUCN Red List, which revealed the unfolding amphibian crisis for the first time and established a baseline for monitoring trends and measuring conservation impact. According to this new study, nearly 41% of all amphibian species that have been assessed are currently globally threatened, considered critically endangered, endangered or vulnerable. This is compared to 26.5% of mammals, 21.4% of reptiles and 12.9% of birds.
Four amphibian species were documented as having gone extinct since 2004—the Chiriquí harlequin toad (Atelopus chiriquiensis) from Costa Rica, the sharp snouted day frog (Taudactylus acutirostris) from Australia, Craugastor myllomyllon and the Jalpa false brook salamander (Pseudoeurycea exspectata), both from Guatemala. Twenty-seven additional critically endangered species are now considered possibly extinct, bringing the total to more than 160 critically endangered amphibians that are considered possibly extinct. The assessment also found that 120 species improved their Red List status since 1980. Of the 63 species that improved as the direct result of conservation action, most improved due to habitat protection and management.
“The history of amphibian conservation itself proves how vital this information is,” said Adam Sweidan, chair and co-founder of Synchronicity Earth. “If the IUCN Red List had been updated on a similar scale in the 1970s that it is today, we could have traced the sweeping amphibian disease pandemic 20 years before it devastated amphibian populations. It isn’t too late–we have this wealth of information, we have the Amphibian Conservation Action Plan, but plans and information are not enough. We need to act. We need to act fast.”
Conservationists will use the information from this study to help inform a global conservation action plan, to prioritize conservation actions at the global level, to seek additional resources, and to influence policy that can help reverse the negative trend for amphibians.
Citation: J.A. Luedtke, J. Chanson, K. Neam, L. Hobin et. al. 2023. Ongoing declines for the world’s amphibians in the face of emerging threats. Nature. https://doi.org/10.1038/s41586-023-06578-4
This video celebrates Atelopus manauense, a small recently described harlequin toad species from Manaus in central Amazonia, Brazil. The music video was made by JacanaJacana as part of a National Geographic grant to foster interdisciplinary conservation collaboration.
With the formation of the Atelopus Survival Initiative (ASI)–a new alliance of more than 40 organizations from 13 countries–comes a new day for harlequin toads, the jewels of South and Central America’s forests and creeks and a group of amphibians hardest hit by the deadly chytrid fungus Batrachochytrium dendrobatidis (Bd).
While amphibian researchers and conservationists have worked for many years to save harlequin toads (which make up the Atelopus genus) and groups of species in individual countries, the ASI is bringing them together for the first time to pool the resources, decades of experience and knowledge necessary to prevent the extinction of the entire genus of harlequin toads across the region where these species still survive.
“As an incredibly diverse group of amphibians facing a number of threats, harlequin toads require innovative solutions coming from a diverse group of individuals and organizations with different expertise, knowledge and capacities,” said Lina Valencia, ASI founder, co-coordinator of the IUCN SSC Amphibian Specialist Group Atelopus Task Force and Andean countries coordinator for Re:wild, one of the primary ASI conveners. “More than ever before, we need a constellation of champions working together to bring harlequin toads back from the brink of extinction. The ASI underscores the vital need to implement on-the-ground conservation actions that will mitigate the main threats to this beautiful group of amphibians.”
Over the past few decades, many harlequin toad species have suffered severe population declines and extinctions throughout their range. Today, of the 94 harlequin toad species that have been assessed by the IUCN, 83 percent are threatened with extinction, while about 40% of Atelopus species have disappeared from their known homes and have not been seen since the early 2000s, despite great efforts to find them. Four harlequin toad species are already classified as extinct, according to the IUCN Red List of Threatened Species, but this number is likely higher.
The fungus Batrachochytrium dendrobatidis (Bd) causes the lethal disease chytridiomycosis, which has resulted in amphibian declines all around the world, including in South and Central America, Australia and the western United States. Although Bd may likely be the primary driver of these declines, a number of other threats are exacerbating the precipitous drops in population numbers. This includes habit destruction and degradation (as the result of animal agriculture, logging, mining and infrastructure development), the introduction of invasive species such as the rainbow trout that prey on harlequin toad tadpoles, pollution, illegal collection for the pet trade, and the effects of climate change.
The ASI and its members, including governments, local communities and Indigenous peoples, will collaboratively address each of these threats–and new ones as they arise–across the genus’s full range, taking into account the social, political and cultural realities of each of the 11 countries where harlequin toads are found.
“With their beautiful songs and unique lifestyles, amphibians are among the most extraordinary animals on Earth, and among them, harlequin toads stand out for their amazing colors,” said Luis Fernando Marin da Fonte, coordinator of the ASI and director of partnerships and communications for the Amphibian Survival Alliance. “But these colorful and delicate jewels are becoming increasingly rarer. Harlequin toads must be protected not only because of their beauty and uniqueness, but also because of their intrinsic value and biological, ecological and even cultural importance.”
The initiative’s newly developed Harlequin Toad (Atelopus) Conservation Action Plan (HarleCAP) provides the roadmap for conserving and restoring harlequin toads as a genus and their habitat. The action plan’s goals, which ASI aims to achieve by 2041 (the 200th anniversary of the description of the genus Atelopus), include:
- developing and implementing innovative methods to mitigate chytrid’s impacts on harlequin toad populations and better understanding why some species are less susceptible to the effects of chytrid;
- protecting and restoring harlequin toads’ forests and watersheds;
- creating and maintaining conservation breeding programs;
- searching for species that are lost to science and filling in other gaps in scientific knowledge about harlequin toads;
- sharing stories that will transform harlequin toads into symbols of hope for the region and the world and a flagship for conservation success, and demonstrate a commitment to the conservation of harlequin toads;
- ensuring the Atelopus conservation network has the technical, logistical, and financial support to secure the long-term conservation of harlequin toads
“The establishment of collaborative initiatives at the international and regional level is essential to coordinate efforts and obtain tangible results that have an efficient and real impact on the conservation of an endangered species,” said Gina Della Togna of the Universidad Interamericana de Panamá, Panamá. “The Atelopus Survival Initiative is a concrete example, which not only aims to conserve one species, but an entire genus, perhaps the most threatened by the global amphibian extinction crisis.”
Harlequin toads are found from Costa Rica in the north to Bolivia in the south, and Ecuador in the west and French Guiana to the east. They are known as the jewels of South and Central America in part because of their beautiful and varied colors, which range from orange, green, yellow, brown, black, red, and sometimes even purple. They are celebrated in a number of Latin American cultures, including Indigenous cultures, and across entire countries, like in Panama, where the national animal is the Panamanian golden toad.
Like other amphibians, harlequin toads support healthy ecosystems. Their tadpoles depend on clean water and, because of this, the presence of harlequin toads indicates better quality water in an ecosystem, while their decline or absence is often the first sign of an ecosystem in trouble.
“Protecting and restoring harlequin toads and their habitats will also benefit the species that share the ecosystems in which they live and that provide water to tens of millions of people, and ultimately all life on Earth,” Valencia said. “And we’re hoping that the ASI will be a successful model that conservationists can emulate for other groups of threatened species.”
The Atelopus Survival Initiative includes national and international conservation groups, zoos, captive breeding centers, academic institutions, governments and local communities. Its current members represent the following organizations: Amphibian Ark, Amphibian Survival Alliance, Asociación Pro Fauna Silvestre – Ayacucho, Bioparque Municipal Vesty Pakos, Bolivian Amphibian Initiative, Centre National de la Recherche Scientifique, Centro de Conservación de Anfibios AMARU, Centro Jambatu de Investigación y Conservación de Anfibios/Fundación Jambatu, CORBIDI, DoTS, El Valle Amphibian Conservation Center Foundation, Facultad Latinoamericana de Ciencias Sociales, Florida International University, Fort Worth Zoo, Fundación Atelopus, Fundación Zoológica de Cali, Universidad del Tolima (GHEE), Grupo de Trabajo Atelopus Venezuela, Image Conservation, Instituto Nacional de Pesquisas da Amazônia, Instituto Venezolano de, Investigaciones Científicas, Ministerio del Ambiente de Perú, MUBI (Museo de Biodiversidad del Perú), Parque Explora, Parque Nacional Natural Puracé, Photo Wildlife Tours, Pontificia Universidad Católica del Ecuador, Pontificia Universidad Javeriana, Re:wild, San Diego State University, Smithsonian Tropical Research Institute, Trier University, Universidad de Antioquia, Universidad de Costa Rica, Universidad de los Andes, Universidad del Tolima, Universidad del Magdalena, Universidade Federal do Pará, Universidad Nacional, Universidad Interamericana de Panamá, Universidad Nacional de Colombia, Universidad San Francisco de Quito, Universidade Estadual de Campinas, Universidade Federal do Oeste do Pará, University of Nevada, Reno, University of Notre Dame, University of Pittsburgh, WCS (Wildlife Conservation Society), WCS Colombia, Zoológico Cuenca Bioparque Amaru
Recorded talk by Dr. Angie Estrada, Director of the Summit Municipal Gardens as part of the virtual Golden Frog Festival for 2020.
The Panama Amphibian Rescue and Conservation Project was created in 2009 as a partnership between Zoo New England, Cheyenne Mountain Zoo, Houston Zoo, Smithsonian National Zoo, Smithsonian Tropical Research Institute and Defenders of Wildlife to build captive populations of species at risk of extinction from the deadly amphibian chytrid fungus. Together we have built significant capacity for amphibian conservation in Pamama by contributing financial resources, involving zoo staff in field work to collect and care for endangered amphibians, training our Panamanian colleagues in state-of-the art animal care, veterinary care, pedigree management and record-keeping.
Since the project was established, Zoos have provided approximately $300K per year with a total investment of $2.7m in the project that leveraged additional support of $3.9m in grants from Miambiente, First Quantum Minerals (Cobre Panama), USAID, the National Science Foundation, SENACYT, National Geographic, US Fish and Wildlife Service, Mohamed bin Zayed Species Conservation Fund, the Morris Animal foundation and other private donors. First Quantum Minerals (Cobre Panama) has been our largest corporate contributor, providing approximately $450K per year with a total investment of $2.3m in the project.
Established founding populations of 12 species of Panama’s most endangered frogs, including Panama’s iconic Panamanian Golden Frog. Reproduced all 12 species in captivity most of them bred in captivity for the first-time ever by project staff.
Constructed the Gamboa Amphibian Rescue and Conservation Center which is now the largest amphibian conservation breeding center in the world and trained a professional cadre of conservation staff to care for the animals.
Established a world-class research program investigating the frog-killing chytrid fugus and searching for a cure for the disease. Conducting hormone stimulation research to improve captive reproduction. Continued publications of veterinary care, nutrition and husbandry of amphibians to improve knowledge to sustain captive amphibians.
Conducted the first-ever reintroduction trials of amphibians to learn about the limiting factors how captive frogs transition back into the wild. This data will be used to inform future release strategies using adaptive management principles.
Annual coordination of ‘Festival la Rana Dorada’ activities in Panama City, continued operation of fabulous frogs of Panama exhibition and the integrated informal schools’ curriculum.
Vision for the future
We need to continue to grow the captive amphibian populations to about 300 animals per species with even representation of founder animal genes as the primary assurance colony. This core captive population will safeguard against species’ extinction, and biological banking of gametes will help to ensure against unintended genetic bottlenecks in captivity. Surplus-bred animals will be used for further basic reintroduction research, breeding for disease-resistance, finding a cure for the amphibian chytrid fungus, and basic research that will ultimately be used to reestablish viable wild populations of these species.
Many infectious diseases can fade away after initial outbreaks. Bubonic plague, cholera, and influenza are examples from recent human history. The same phenomenon occurs for wildlife diseases as well. How does this happen? One popular explanation is that the pathogen evolves to become less deadly, so that it doesn’t completely wipe out its hosts, ensuring pathogen survival. While this scenario does sometimes play out, we know that there are other reasons why the severity of diseases can change over time.
For amphibians, we’ve known about a highly lethal disease called “chytridiomycosis” since the 1990s. This disease was especially devastating in Central America, where it may have wiped out entire species. In this study, we made the exciting discovery that some amphibian species – frogs that were thought to be extinct – are persisting, and even recovering, after lethal disease outbreaks. We wanted to understand how it was happening. Was it a change in the pathogen, the frogs, or both?
To answer these questions, we did two things. To begin with, we surveyed frogs in Panama before and after the disease outbreak. In addition, we collected samples of the pathogen at multiple time points: during initial outbreaks and ~10 years later. We found that nearly a decade after the outbreak, the pathogen was just as deadly. However, the frogs are surviving and have better defenses against it. Panama’s frogs are fighting back! Understanding how amphibian communities are recovering after this disease outbreak is important multiple reasons. First, resolving how this works will help us develop more informed conservation strategies to protect amphibians from disease-induced extinctions. Second, clarifying how disease outbreaks subside will help us predict, and respond to, other emerging pathogens in plants, wildlife, and in humans. These goals are increasingly important in a time when rapid globalization has increased the introduction of pathogens to naïve host populations.
by Jamie Voyles and Cori Richards-Zawacki
Read the paper: Shifts in disease dynamics in a tropical amphibian assemblage are not due to pathogen attenuation BY JAMIE VOYLES, DOUGLAS C. WOODHAMS, VERONICA SAENZ, ALLISON Q. BYRNE, RACHEL PEREZ, GABRIELA RIOS-SOTELO, MASON J. RYAN, MOLLY C. BLETZ, FLORENCE ANN SOBELL, SHAWNA MCLETCHIE, LAURA REINERT, ERICA BREE ROSENBLUM, LOUISE A. ROLLINS-SMITH, ROBERTO IBÁÑEZ, JULIE M. RAY, EDGARDO J. GRIFFITH, HEIDI ROSS, CORINNE L. RICHARDS-ZAWACKI SCIENCE 30 MAR 2018 : 1517-1519