Saving species, slow and steady

We live on an amazing planet with an incredible diversity of natural environments. From the deepest trenches of the ocean to the highest mountains, the Earth’s natural wonders have been a source of awe and inspiration for any who are fortunate enough to behold them. Even before the days of internet searches and high-quality printed images, people have yearned to see these natural wonders for themselves, sometimes based solely on the impression these places have clearly left on those who go on to describe them to others. These “bucket list” destinations often include tropical islands like the Maldives, impressive mountain ranges like the Himalayas, and World Heritage Sites like the Galápagos Islands. 

The thing about these places, though, is that wildlife is essential to maintaining (and sometimes even creating) the landscape. We forget that sometimes. Immersed in the magnificence of the scenery, the bigger picture of interdependent relationships within the ecosystem isn’t at the front of our minds. But understanding this complex web of associations is crucial to designing and implementing effective conservation strategies to protect these places for future generations. 

Take, for example, the Galápagos Islands that I mentioned earlier. This iconic chain of islands off the coast of Ecuador in the Pacific Ocean is famous for its endemic wildlife (found nowhere else in the world), some of which inspired Charles Darwin’s theory of evolution by natural selection. Research has shown that giant tortoises play a major role in the ecosystem. As they roam around grazing on vegetation, they help maintain open areas within forests (allowing sun-loving plants to gain a foothold) and act as seed dispersers for the plants they eat. 

A lot of people don’t realize that the term “Galápagos giant tortoise” refers to 14 biologically distinct species. Due to the relatively small footprint of individual islands, most of these species had relatively small populations (in the single-digit thousands) before the Galápagos archipelago was discovered by humans ~500 years ago. Two species were already well on their way to extinction by the time Darwin arrived in 1835. The 12 extant (currently living) species are all considered threatened by the IUCN, and half of those are listed as Critically Endangered, meaning they face an extremely high risk of extinction in the wild. One species is believed to be functionally extinct in the wild – anecdotal evidence suggests that a few individuals remain, but there are not enough to rebuild the population. 

In recognition of the importance of this ecological relationship, Zoo Atlanta is supporting Iniciativa Galápagos. This joint project operated by Galápagos Conservancy, Conservando Galápagos, and the Galápagos National Park Directorate (GNPD) aims to rewild endangered species of the Galápagos and restore the ecosystems they inhabit. Giant tortoises are a priority taxon because they have faced some of the most significant declines. Part of the program involves collecting giant tortoise eggs from natural nests and raising hatchlings through the years of highest mortality before releasing them back into the wild. 

Through genetic testing, some tortoises living at the center for decades were discovered to be of hybrid ancestry. Generally, that is not ideal for conservation efforts to restore wild populations. But these individuals can still play an important role in the project. Since they’re not essential to breeding, they can be released in habitats where historic tortoise populations have gone extinct. This way, they can serve as ecosystem engineers in preparation for future generations of breeding tortoises. Like the tortoises themselves, this process will be slow. 

You may be wondering, “Won’t those hybrid individuals just breed with one another and create more hybrid tortoises?” That’s where Zoo Atlanta came into the picture! Alongside colleagues from the University of Georgia and the Houston Zoo, Zoo Atlanta’s very own Dr. Sam Rivera (Vice President of Animal Health) traveled to Galápagos to perform pre-release surgery on 30 tortoises to prevent future breeding. 

As you can imagine, performing surgery on a giant tortoise is a highly specialized skill. From understanding giant tortoise anatomy to administering anesthesia, it required knowledge and experience that only a zoo veterinarian would have (you can read more about the project and procedures in the articles linked below). It’s an excellent example of zoo animal medicine being applied to conservation projects to protect a species from extinction. I wonder where Dr. Sam will go next! 

Sarah Hamilton
Interpretive Engagement Specialist 

Sources 

Carter, A. (2023). UGA professor renowned for surgical skills assists with giant tortoise conservation in Galápagos Islands. Retrieved from https://vet.uga.edu/uga-professor-renowned-for-surgical-skills-assists-with-giant-tortoise-conservation-in-galapagos-islands/ 

Galápagos Conservancy. (n.d.). Iniciativa Galápagos: Rewilding and Restoring Galápagos. Retrieved May 1, 2024, from https://www.galapagos.org/projects/iniciativa-galapagos/ 

Knafo, S.E., Divers, S.J., Rivera, S., Cayot, L.J., Tapia-Aguilera, W., & Flanagan, J. (2011). Sterilisation of hybrid Galapagos tortoises (Geochelone nigra) for island restoration. Part 1: endoscopic oophorectomy of females under ketamine-medetomidine anaeathesia. Veterinary Record, 168(47). 10.1136/vr.c6520 

Rivera, S., Divers, S.J., Knafo, S.E., Martinez, P., Cayot, L.J., Tapia-Aguilera, W., & Flanagan, J. (2011). Sterilisation of hybrid Galapagos tortoises (Geochelone nigra) for island restoration. Part 2: phallectomy of males under intrathecal anaesthesia with lidocaine. Veterinary Record, 168(78). 10.1136/vr.c6361