Establishing the Honduran Amphibian Rescue and Conservation Center
One of the first programmes to protect amphibian populations from extinction in the wild caused by disease is being set up in Honduras. The new rescue facility will treat infected tadpoles and froglets, raise them to adulthood, and then reintroduce the healthy adults back into their environment.
The endangered amphibians of Honduras are experiencing a storm of assaults from habitat destruction, climate change, and emerging infectious diseases. A growing number of species face an uncertain future unless ex situ management efforts are soon implemented to ensure long-term survival.
Since 2004, Operation Wallacea has been studying the amphibians of Cusuco National Park, Honduras (CNP), a small cloudforest where 16 endangered and critically endangered amphibian species can be found.
In recent years, Opwall surveys have indicated an overall decline in the presence of stream-associated amphibians and concurrent disease surveys reveal that many of these species carry a high level of infection with amphibian chytrid fungus. Chytrid fungus causes chytridiomycosis, an emerging disease bringing about global amphibian declines and extinctions and jeopardizing ecosystem stability.
Amphibian chytrid fungus has proven to be especially devastating to amphibian populations in Latin America, but the amphibians of Honduras have received little applied conservation attention.
Rescue and conservation
In response, plans are now underway to establish the Honduran Amphibian Rescue and Conservation Center. This facility and long-term programme is designed to ensure the survival of three Critically Endangered species in CNP: Plectrohyla dasypus, Plectrohyla exquisita, and Duellmanohyla soralia. Already threatened by illegal deforestation, amphibian chytrid fungus is further impacting each of these species by shrinking populations and pushing them closer towards extinction.
The foundation of this rescue effort is to annually supplement wild adult populations by collecting tadpoles and froglets from CNP, treating them for chytrid infection and raising them in a protected biosecure environment, and then reintroducing healthy adults back into CNP.
Long-term data previously collected in CNP suggests that the adult frogs possess a stronger resistance to chytrid than their younger counterparts and are more likely to survive infection in the wild. By increasing the number of breeding adults present in the wild, we will also promote an increase the volume of offspring produced. Although these offspring will still be vulnerable to chytrid, the sheer increase in volume is expected to result in the survival of a greater number of offspring in their natural habitats. This is because despite the high chytrid infection prevalence at metamorphosis, a small portion of the population appears to consistently escape the disease and has an opportunity to become future breeding adults. Simply raising the number of frogs in the overall population should proportionally increase the number of frogs in the group of “lucky” survivors and eventually, may reach self-sustaining levels that can reverse population declines on their own.
Meanwhile, a small number of adults will be retained to establish captive breeding populations to ensure the long-term survival of these three species in the event of sudden population crashes or extinctions, which remain highly likely at present. The proposed research centre will be located at Lancetilla Botanical Garden and Research Institute, in Tela, Honduras, where biosecure Isolated Amphibian Rooms will be constructed to maintain up to 600 amphibians in a chytrid-free environment.
This programme will provide one of the first examples whereby amphibian populations are protected from disease-driven extinction in the wild caused by chytrid fungus, and not just protected in captivity. This is a critical aspect often overlooked; maintaining captive breeding programmes can prevent complete extinction of a species, but without active reintroduction efforts, individuals become permanently absent from natural habitats where they played important ecological roles.
The adult frogs are less affected by chytrid than their younger counterparts and can survive infection in the wild
Adult and larval amphibians provide a significant source of prey for other wildlife species in tropical ecosystems. In CNP, a number of snake species feed on amphibians, most notably the Palm viper (Bothriechis marchi) which has a specialised diet of frogs. This species is now believed to be in decline in response to the lower abundance of amphibian prey. The activity and feeding behaviour of larval amphibians has also been shown to affect aquatic ecosystem structure; their disappearance is likely to promote algal blooms, reduce aquatic invertebrate diversity, and reduce water quality. Therefore, this conservation programme also aims to publicise the need to protect not only the amphibians, but also the ecosystem services and balance they provide.
This programme is made possible by an international collaboration I have orchestrated between Jonathan Kolby and Operation Wallacea, Lancetilla Botanical Garden in Honduras, the Henry Doorly Zoo, Expediciones y Servicios Ambientales de Cusuco (ESAC) and Departamento de Vida Silvestre del Instituto Nacional de Conservacion y Desarollo Forestal Areas protegidas y Vida Silvestre (ICF). In 2013, activities will include construction of the biosecure amphibian husbandry rooms at Lancetilla, promotion of local capacity-building and training local Honduran staff, and the continuation of disease surveillance and population surveys in CNP.
Long-term funding to operate this research centre is actively being pursued so that the first collection of wild amphibians can occur in June 2014 with reintroduction targeted for the following year. For more information about this programme or for future opportunities to become involved in this project, please contact Jonathan Kolby (Jonathan.Kolby@my.jcu.edu.au).