Wildlife population dynamic modeling software, Vortex, is critical to assessing what is needed for a population to survive potential setbacks such as pandemics. The conservation tool is part of a set of software tools maintained and provided by the Species Conservation Toolkit Initiative (SCTI), a part of nonprofit Species360.
A story of ups and downs, Brazil’s golden lion tamarin has made a surprising comeback after yellow fever reduced populations by more than 90 percent in recent years. In fact, research published at American Journal of Primatology early last year shows a 31 percent increase in the golden lion tamarin population in Brazil’s lowland Atlantic Forest since 2014 – despite the yellow fever outbreak.
Reasons for the rebound include increased forest area, immigration from adjacent forest fragments, and a higher density of populations within survey areas. But just what is the impact of each of these variables – and what is absolutely necessary to ensure survival of these populations?
A computer modeling tool called Vortex helps scientists to project the impact when one or more variables change. Vortex was developed by population scientists of the Species Conservation Toolkit Initiative, or SCTI, which is now a part of Species360.
“The success of the golden lion tamarin research arose from lots of efforts on multiple fronts. The use of Vortex to assess conservation needs and strategies is only one piece of the story, but it is a significant part of the story. And the contributions of zoos to the conservation efforts have been overwhelmingly positive,” said SCTI co-founder Bob Lacy.
The golden lion tamarin population study was supported by Copenhagen Zoo, Disney Conservation Fund, Save the Golden Lion Tamarin, and Universidade Estadual do Norte Fluminense.
Using Vortex, researchers pinpointed the population size necessary to meet genetic and demographic goals for Brazil’s golden lion tamarin.
To understand exactly what would allow a population of golden lion tamarins to survive and thrive, researchers tested a wide range of variables ranging from population size and density to the connectivity of forested areas in which the population groups live.
Here is a recap of what they found as they ran these variables through the Vortex computer model:
“Results of the single population scenarios project that a panmictic population of 1000 golden lion tamarin will, on average, meet genetic and demographic targets given the model inputs used for yellow fever and other model assumptions. None of the iterations went extinct (PE100y = 0). Mean retention of GD (expected heterozygosity) after 100 years was only slightly reduced with yellow fever and remained >98%, although uncertainty around GD retention over time increases slightly due to stochastic processes. A population of 1200 GLTs provides higher confidence of retaining >98% GD for 100 years under yellow fever and other model assumptions (Table 3).”
In short, researchers found that an increase in forest area had proven essential to the population’s survival of the pandemic. Also key to the rebound was the density of the population groups living within the area.
>Going forward, Vortex shows, the best way to help the golden lion tamarins to survive and thrive is to increase the interconnectivity of those forested areas.
In 2023, nonprofit Species360 brought in the Species Conservation Toolkit Initiative, which embodies our dedication to providing practical solutions for conservation challenges. This community-funded initiative develops and disseminates tools, resources, and guidelines to empower conservation practitioners and institutions in their mission to protect species.
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