Tuesday, March 14, 2017

The Galapagos Tortoise: A conservation success story

It would seem that the Galapagos tortoise has been officially declared a conservation success. This is lovely news- in the first decade of the 20th century, there were few tortoises left on the islands and researchers could find no active nests. In effect, the tortoises that existed on the islands when Darwin visited on his Beagle voyage had stopped breeding or being able to bring clutches to fruition. This population decimation came from two major pressures- the Pacific whaling community had been using the Galapagos as a convenient stop for fresh water as they roamed further and further from shore for longer voyages. When they were stopped for water, the sailors supplemented their diet of hard tack and dried beef with fresh turtle soup. This effectively lowered the number of breeding tortoises, but it wasn’t the only cause of their demise. In addition to eating the tortoises, the whalers introduced pests, such as goats. They were introduced to the islands to serve as supplemental meat for future voyages and they overgrazed the islands, leaving no food for the tortoises.  These pressures effectively destroyed the population and habitat of the species, pushing them to the brink of extinction. But, now these tortoises on making a comeback!

In recent years, Galapagos tortoises have returned to the islands through a combined effort. The largest effort, and the one written about in the most recent news releases about this success, involves the eradication of goats and the restoration of vegetation on the affected islands. In an article on The Conversation, James Gibbs states that "the tortoise dynasty is on the road to recovery, thanks to work by the Galapagos National Park Directorate, with critical support from nonprofits like the Galapagos Conservancy and advice from an international team of conservation scientists."  Gibbs highlights the work done to restore the ecosystem and to breed the species in captivity on the islands.  Other news outlets have trumpeted the breeding capacity of individual (male) tortoises. Diego, a Hood Island tortoise, is being hailed as a lascivious sex-machine who has bred his species back from near extinction. The NYTimes says that he’s "an ancient male" tortoise returned to the Galapagos from the San Diego Zoo in 1977. What is most interesting to me about these articles is not that they aren't fascinating and completely correct, but that they are so short-sighted in their conception of the conservation effort to save these tortoises. 

Also, someone please tell me why everyone is so freaking interested in male tortoises and how they have sex. The continued obsession with Lonesome George is confusing to me. I can name at least 6 male Galapagos tortoises but there aren't any famous females. Why? Why are science journalist obsessed with the virility of male tortoises?!  (go ahead and google diego the tortoise and you'll find these headlines: "How one highly fuckable tortoise saved his whole species from extinction" and "Fuck Tortoise saves his entire species from extinction by having sex all the time" and my personal favorite "A bro tortoise had so much damn sex on the Galapagos that he's been credited with single handedly saving his species." The NYTimes article is only one step away from these bro tortoise articles and seriously, all of these sound really like this Onion article.   Apparently no one cares that male tortoises gotta have some receptive ladies. But I think you should know about these amazing ladies. So here's a famous lady- Nigrita is a tortoise at the Zurich Zoo doing some great work laying clutches and bringing baby tortoises into the world with her mate Jumbo. Check her out!

In fact, Diego is part of a group of tortoises taken from the Galapagos in 1927 as a last ditch effort to save the species and learn to breed them in captivity.  These tortoises ended up at zoos and aquariums throughout the southern hemisphere in the hopes that breeding pairs would produce offspring in captivity. And they did. The first Galapagos tortoise was born in captivity in 1945 and today, many of those pairs have been returned to the Galapagos to continue breeding.  This historical narrative is extremely important because it is a (tentative) success- we have so few of these that watching something work should be cause for analyzing why and how it has worked. Of particular interest in this story is the combination of ark breeding--that is breeding a population of endangered or extant in the wild organisms in captivity to create a reserve population meant to eventually be released-- with ecosystem restoration. This is, for all intents and purposes, the gold standard in conservation- the meeting point of two types of conservation to produce a revived population.  It is important that we tell the century-long conservation story of these tortoises (not only the recent narrative) to fully understand the time required to actually produce results with ark breeding and ecosystem recovery. Townsend removed these tortoises from a dying ecosystem in 1927 and it is only 90 years later that we are seeing a recovery and tentative success story emerge. Much of this comes from the nature of Galapagos turtle breeding but we can think about the long road of conservation with this particular story. 

In the early 20th century, Charles Haskin Townsend worked for the US Bureau of Fisheries. Townsend, along with David Starr Jordan, were asked to look into the conservation of the United States’ fur seal herd in the Bering Strait. Jordan, Townsend’s superior, suggested that Townsend speak with Japanese and Russian officials to get their whaling and sealing records to see how many seals these men were taking each year. While Townsend was pouring over the whaling and sealing records, he noticed something else startling: whalers were reporting fewer and fewer tortoises on the Galapagos every time they stopped. By looking through the logs, Townsend could tell that the population was completely decimated. Townsend visited the islands himself and confirmed this suspicion. And for his own reasons (he was not particularly moved by all species so it is unclear why he was so moved by the tortoises), Townsend set out to save this species. He did this is two ways: he urged the New York Zoological Society (who ran the Bronx Zoo and NY Aquarium) to lobby to Ecuadorian government to protect the islands and label them a national park. In addition, he sought permission to bring as many Galapagos tortoises as could be found on the islands to the United States to figure out how to breed them in captivity.

This is an image of Townsend and his men collecting tortoises for export off of the island chain. Wildlife Conservation Society Archives, Bronx Zoo (Townsend Collection) 
In 1927, Charles H. Townsend, then the director of the New York Aquarium, transported as many Galapagos tortoises as could be found from the islands to a group of botanical gardens, zoos, and aquariums throughout the US, the Caribbean and Australia. Townsend didn’t just give the tortoises to these places and walk away- he wanted to actively breed these animals. He asked the zoos to keep track of each animal, keep records of weight, age, and any ailments and to send those reports to Townsend. He used these reports to track the health of the animals and to gain knowledge of what they ate, common ailments, and the possibility of breeding behavior.

The Hawaii zoo sent this diagram of a tortoise's shell after a necropsy. Townsend hoped a better understanding of the morphology and behavior of the animals would help in breeding efforts. Townsend papers, Wildlife Conservation Society Archives, Bronx Zoo, New York

A list of the many places Townsend sent tortoises. This note in 1930 shows all the deaths of individuals based on location and, if a large amount, what had caused those deaths. By 1935, Townsend shifted most of the tortoises to warmer climates where it was believed they would be healthier and more likely to breed. Townsend papers, Wildlife Conservation Society Archives. 

An image of Townsend measuring a juvenile tortoise taken from the Galapagos. This might possibly be the infamous #120, a very small tortoise stolen from the exhibit at the Bronx Zoo in 1930. I like to think that some family in the Bronx still has #120 hiding somewhere (they'd be almost 500 pounds now) and is just co existing with him or her. 

In the earliest years, he found that the tortoises did not do well in colder climates. To decrease mortalities and save the animals, he sent them from New York to Arizona. He also suspected that the tortoises preferred certain rocky enclosures without deep sand and urged a similar habitat for all the tortoises across institutions.  While many tortoises were lost (including the youngest and smallest- #120- stolen from the Bronx zoo exhibit) the tortoises did eventually breed. The year after Townsend died (1944), the first Galapagos tortoise born in captivity hatched at the Bermuda zoo and aquarium, run by a former co-director of the New York Aquarium under Townsend.

Diego is a Townsend tortoise and to date, he has fathered over 350 tortoises. Other Townsend tortoises have been shipped to the Galapagos, as well as throughout the world to breed in zoo programs. Read this story about Ralph, a 100 year old tortoise just shipped to Texas to be a companion to Mr. Potato Head (another old tortoise).

There are two really important sides to the Galapagos tortoise success story. The first is the repair of an imbalanced ecosystem no longer able to support the tortoises. The removal of goats and the regrowth of native flora were both extremely important. But the other half was the removal of organisms to be bred in zoos. This type of breeding is known as ark breeding- named after the Judeo-Christian tale of Noah who saved animals on the ark until they could be returned to dry land. Ark breeding creates captive stocks (reserve stocks) that can, hopefully, be returned to their habitat once it has been restored. The Galapagos tortoise success can be added to others, including the black footed ferret, the California condor, the American bison (also a Bronx Zoo early 20th century story) and others that have been deemed relatively successful. 

Saving the Galapagos tortoise took over 90 years and the (initial and continued) collaboration of individuals, scientific institutions, and governments from all over the world. We should celebrate this tentative success, but also make sure we understand and properly tell the historical pieces of the puzzle. We cannot fully apply the lessons learned from this story unless we tell the whole thing- it is long and it involves a lot of trial and error. And oddly enough, a weird bro culture surrounding tortoises. Let's understand what we did to hopefully apply these lessons to other endangered ecosystems and species.