Tailing Golden Lion Tamarins
Sitting behind a desk piled with reports and paperwork is never any fun. It’s even less so when the exotic jungles of Brazil wait just outside your window. Jennifer Mickelberg, Smithsonian National Zoo research fellow with the Center for Conservation and Evolutionary Genetics, valiantly stayed indoors combing through 20 years of data this past February on an excursion to Rio de Janeiro for the greater good of the golden lion tamarin (GLT), a small monkey endemic to the Atlantic Coastal Forest.
Nearly 50 years ago, the population was estimated at only around 200 individuals due to deforestation and pet trade. Intensive conservation efforts have brought the population back from the brink of extinction to a current size of about 1,600 animals.
Part of this recovery effort was a reintroduction program started in 1984. Since then, just over 150 GLTs have been reintroduced. This program is one of the most successful reintroductions in the world; reintroduced animals and their descendants make up more than a third of the entire wild population.
Fields teams in Brazil have closely monitired the GLT population. Teams capture GLTs every six months and measure their body length, tail length, facial features, teeth lengths, and weight. Then they radio collar the animals and give each individual an identifying dye mark and tattoo, which allows them to tell which group an individual belongs to, and which individual each is. The team can then track every GLT in the forest and document changes in group composition.
Being able to monitor these endangered monkeys is critical to saving this species. Using these detailed data, Mickelberg has created a pedigree database and can evaluate the status of the GLT population. Her first task has been to study the genetics of the reintroduced population. Maintaining genetic diversity in small populations is extremely important. Small, isolated populations are particularly vulnerable to inbreeding, so it is important to maintain a population’s genetic diversity. Management strategies for doing this have been very successful in captive populations, where breeding priority is given to animals who are underrepresented in the population. This is determined by analyzing pedigrees, such the one Mickelberg has created for GLTs.
Having managed the captive population for GLTs with Zoo population geneticist Jon Ballou for the last ten years, Mickelberg uses some of the techniques she learned and applies them to the reintroduced population. This is no small task as this pedigree comprises more than 1,500 GLTs.
After spending time in Brazil working with the field team and their data to sort out any quirks, she is able to evaluate the genetic status of this population and then provide management recommendation to optimize genetic diversity. While this is frequently done with captive populations, it is rarely done with wild populations. Following this analysis, Mickelberg will be using the same database to study the movement rates of GLTs between fragmented forest patches. Understanding these movements is critical to effectively managing the population, because she needs to know which populations are entirely isolated and which are connected to other populations.
Although the population has increased, there is still significant work needed to ensure GLTs are conserved in perpetuity. Mickelberg’s research will help create a management plan for the species that optimizes genetic diversity, minimizing inbreeding and thus reducing the species’ extinction probability—it is a piece of a greater conservation effort that includes education, habitat protection, and restoration.
GLTs are a very successful model of species conservation and have become a charismatic ambassador for Atlantic coastal forest conservation, where only seven percent of the forest remains. With hardworking people such as Mickelberg fighting for their cause, we hope the effort to save the GLTs translates to saving the Atlantic coastal forest.
