Tortoise rescue: Conservancy provides refuge for endangered turtle, tortoise species
Veterinarians, conservationists seek to protect world's most endangered species from extinction.
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A female ploughshare tortoise.
Photo by P.P. Van Dijk, PhD/Conservation International
The Behler Chelonian Center (BCC) is the Turtle Conservancy's captive breeding and management facility in Southern California, and it keeps some of the world's most endangered species of turtles and tortoises on site. Many of the world's leading authorities of chelonian species have spent time on the campus-researchers, ecologists, even filmmakers. Students from the United States and abroad are funded by the Turtle Conservancy to allow them to spend time at the center and participate in ex situ turtle and tortoise conservation. All come to the center for one reason: the conservation of some of the most endangered chelonian species on the planet.
Dr. Paul Gibbons tattoos a unique alphanumeric identification code in the abdominal scutes of a juvenile ploughshare tortoise (Astrochelys yniphora) at the Durrell Wildlife Conservation Trust's captive breeding center in Madagascar.
Photo by: Turtle Conservancy/Eric Goode
The center houses about 32 species of land-dwelling tortoises and fresh-water turtles that trace their ancestry back about 220 million years from the beginning of the age of the dinosaurs. “The center's mission is to protect the most endangered turtles and tortoises and their habitats worldwide,” says Paul M. Gibbons, DVM, MS, DABVP (avian and reptile/amphibian), the center's managing director and past president of the Association of Reptilian and Amphibian Veterinarians. “We therefore focus on conservation breeding, providing husbandry that supports and maximizes good reproduction, ensuring future options for species that currently cannot be returned to the wild.”
“Turtles are under a variety of pressures in the wild,” says Peter Paul van Dijk, PhD, who serves on the BCC Scientific Technical Advisory Committee and is co-chair of the Tortoise and Freshwater Turtle Specialist Group, a division of the International Union for the Conservation of Nature/Species Survival Commission. “They are losing their habitats-freshwater habitats from pollution, damming and other habitat changes; terrestrial habitats from deforestation and agricultural expansion; and other natural habitats from invasive species. The animals as well as their eggs also have major issues of being collected for food or for pets, or for medicinal purposes across much of their ranges.”
A ploughshare tortoise hatchling in the wild in Madagascar. The ploughshare is one of the most endangered turtle/tortoise species in the world.
Photo by P.P. Van Dijk, PhD/Conservation International
Van Dijk says the BCC and similar centers worldwide are an essential part of a broad conservation effort. “We all agree that turtle and tortoise species should be conserved as part of the habitat and ecosystem that they evolved into and are part of. In some cases, though, it's close to impossible to guarantee their survival in the wild,” he says. “Having an ‘assurance colony' like the BCC in another part of the world as insurance against extinction is a valuable part of an overall strategy. It's not the only solution, but it's a backup for when there is pressure on particular species and things go completely wrong in the wild-at least we haven't lost the species overall. And at least we can take the time and attempt to reintroduce them into the wild over time.”
Although several species of turtles and tortoises have been successfully bred at the BCC, at this time those species have still not been able to be returned to their natural habitats.
A field research team including Malagasy Forest Guardians, Madagascar National Parks staff and researchers from Durrell Wildlife Conservation Trust and the Turtle Conservancy carry out their mission to identify, mark and protect a wild adult female ploughshare tortoise in Baly Bay National Park, Madagascar.
Photo by Turtle Conservancy/Eric Goode
A self-sustaining population
“Over the last decades we've learned that some turtle and tortoise species can suffer epidemic diseases,” van Dijk says. “We've seen ‘runny-nose-syndrome' (upper respiratory tract disease) in desert tortoises, as well as a ranavirus outbreak in box turtles in the mid-Atlantic. So we're being exceedingly careful about repatriating animals back into naïve wild populations. With that said, there is movement for Burmese star tortoises to go back to Myanmar, and a number of Annam pond turtles bred in Hong Kong have returned to Vietnam with the animals currently sitting in a holding facility awaiting the securing of their habitat.”
A female ploughshare tortoise.
Photo by P.P. Van Dijk, PhD/Conservation International
A concern for disease is critical to reestablishing captive-bred animals back to the wild. “When you're working toward a release program, questions surround the ability to reintroduce a species and establish a self-sustaining population in the wild,” Gibbons says. “There are numerous facets to how various diseases interact with populations. There are many different pressures that a given population experiences to help it to balance with its natural environment. Some of those pressures include parasitic organisms-i.e., bacteria, viruses, protozoa or helminths that help control populations in the wild.”
With only a few hundred poughshare tortoises left in the wild, the Turtle Conservancy is spearheading an effort to place a unique indelible mark on every living individual in the hopes that such disfigurement might deter poaching and theft for the illegal international animal trade.
Photo by Turtle Conservancy/Paul Gibbons
Gibbons says that although there is concern about disease in general, “the real question is whether the disease will interfere with that population's ability to be self-sustaining,” he says. “It's a subtle difference but a really important one. Every species has diseases, including those captive and wild. Understanding the array of infectious diseases and how they will affect a species' ability to reestablish itself in a wild population is an important consideration.”
At Durrell Wildlife Conservation Trust's captive breeding center in Madagascar near the natural range of the ploughshare tortoise, these adult tortoises have successfully produced enough offspring to bring early success to the reintroduction program in Baly Bay National Park.
Photo by Turtle Conservancy/Paul Gibbons
Their fate
With turtles and tortoises, reproduction does not occur until 10 to 15 years of age in many species, van Dijk says. Massive numbers of eggs and juveniles are lost until eventually they reach adult size. The adults have low mortality and a significant longevity, living in many cases 50 to100 years or more, and reproduce throughout their adult lives. They have no reproductive senility; the oldest individuals may in fact be the most effective breeders.
“Once you take a species with those life characteristics and start to exploit them-take the adult animals from the wild, which is happening in many cases for the illicit trade-you bring down these native populations very rapidly,” van Dijk says. “Within a couple of years a population may collapse. It takes at least decades to recover these populations to anywhere near their former levels. And that's if all other circumstances remain unchanged-when you have pollution, fisheries bycatch or habitat degradation along with the ‘normal' challenges faced by a recovering population, it will obviously take substantially longer.”
The field research team works simultaneously on both a hatchling and an adult female ploughshare tortoise in Baly Bay National Park.
Photo by Turtle Conservancy/Maurice Rodrigues
Role for veterinarians
“I think veterinarians definitely have a role to play in the conservation of these species,” van Dijk says. “We have to have veterinary knowledge about these species because of their differences not only in habitat preferences, but also because every one of these species is different in its diseases and disease treatment, captive environmental management and nutrition. We still need to learn a lot about the husbandry and veterinary management of different turtle and tortoise species in captivity. The more we can learn, and the more we can share our expertise, even for some species that are not critically endangered right now, the more useful we can be for managing the critically threatened and spectacular species.”
A rotating bur on a battery-operated hobby tool is used to inscribe a unique alphanumeric identification code in the keratin of the vertebral scutes of a ploughshare tortoise.
Photo by Turtle Conservancy/Paul Gibbons
The key is for people around the world to be more aware of how unique turtles and tortoises are, how challenging their conservation is, and how privileged people are to share their life and environment with chelonian species, van Dijk says. “That's something we take for granted,” he says. “It's just exceptional, something really special. The more awareness and the more understanding we have-through veterinarians, through people gaining knowledge from veterinarians, from a veterinary perspective-the more progress we can make.”
A female ploughshare tortoise.
Photo by P.P. Van Dijk, PhD/Conservation International
For more information:
• Germano, JM and Bishop PJ. 2009. Suitability of amphibians and reptiles for translocation. Conservation Biology 23 (1):7.
• turtleconservancy.org The Turtle Conservancy is a 501(c)(3) non-profit organization that depends upon public support.
• arav.org
• turtlesurvival.org The Turtle Survival Alliance aims to transform passion for turtles into effective conservation action through a global network of living collections and recovery programs.
• iucn-tftsg.org The IUCN/SSC Tortoise and Freshwater Turtle Specialist Group identifies and documents threats to the survival of all species of tortoises and freshwater turtles, and helps catalyze conservation action to ensure that none become extinct and that sustainable populations of all species persist in the wild.
