Zambia Lion Populations Intermingle On Land Believed To Be Uninhabitable

DNA evidence suggests that modern lions, as a species, originated in the Republic of Zambia, a u-shaped country in southern Africa known for its rugged terrain and diverse wildlife.

Today, Zambia has one of the largest lion populations. With more than 77,000 square miles of protected land, the population is approximately 1,200 strong.

Modern lion inhabitants live in what has been thought to be two isolated, genetically distinct subpopulations divided by an area that includes Zambia’s capital and largest city Lusaka, as well as a lot of rural communities and farming and grazing land.

This “middle ground” has always been considered uninhabitable by lions; however, researchers at the Texas A&M University College of Veterinary Medicine & Biomedical Sciences (CVM) havefound that small numbers of lions in Zambia are, in fact, moving across this previously believed uninhabitable land.

Map of lion populations in Zambia
Researchers found genetic similarities between lion subpopulations, showing that lions were crossing lands that had been considered “uninhabitable” for the species.

Texas A&M CVM

In their genetic analysis of these lions, recently published in the journal PLoS One, CVM doctoral student Caitlin Curry and professor in the CVM’s department of Veterinary Pathobiology (VTPB) Dr. James Derr found through examining the nuclear and mitochondrial genes of lions on both sides of the divide that there were high levels of genetic diversity within the entire lion population.

“The nuclear DNA is inherited by both parents, so you get an idea of diversity in the entire population, whereas the mitochondrial DNA is only inherited through the mother,” Curry said. “By examining both, you’re getting two different views of inheritance through the populations.”

Working in collaboration with Dr. Paula White, of the Zambia Lion Project, the pair analyzed the genes of 409 lions using DNA extracted from material collected in cooperation with the Zambian Wildlife Authority.

By focusing on the nuclear DNA, the researchers saw movement, or similarities, between the two subpopulations. They attribute this to what is called male-mediated gene flow.

“In the lion mating system, the females stay in or don’t move very far away from their natal prides, but males move all over trying to find new prides. Once they get old enough, males are kicked out of the pride and they either find a new pride or make a new pride,” Curry said. “So, males are the ones bringing the genes to new locations.”

This gene flow increases genetic diversity by introducing new genes to a new area.

“A benefit of having higher genetic diversity is a greater chance for adaptation to a changing environment,” Curry said. “Both the eastern and western subpopulations have high levels of genetic diversity, but they are still staying genetically distinct enough to remain two sub-populations.”

The study also determined where the lions are moving based on which lions are more genetically similar to each other.

“Lions in the North and South Luangwa National Parks, part of the eastern sub-population, appear completely separated from the western sub-population,” Curry said. “Gene flow also is occurring through the southern regions of the eastern sub-population, with lions moving between the Lower Zambezi National Park and eastern corridor to the Kafue National Park.”

These findings will be used to help with lion conservation and wildlife management in and around Zambia.

“Lions are a flagship species, meaning that as a large, charismatic carnivore their research and conservation influences many other species that share its habitat,” Curry said. “Knowing where lions are moving will help in making decisions on where and how to manage lions and other wildlife populations.

“This shows them they need to open corridors to make movement across that land easier and safer for lions and also to reduce human-wildlife conflict,” Curry said. “That’s probably why they’re having that conflict in the first place, because they’re not taking into consideration that lions actually are moving across it.”

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