Studies Examine How Prey Availability Impacts African Wild Dogs and Lions
Recent research from an ecologist at Montana State University sheds light on how the population dynamics of two prominent African carnivores relate to their prey’s availability.
“These studies are interconnected,” noted Scott Creel, the main author of a newly published paper in the Proceedings of the National Academy of Sciences, focusing on the impact of prey loss on the endangered African wild dogs, as well as the co-lead author of another study on poaching’s effects on African lion populations, which was highlighted in the January 11 issue of Conservation Science and Practice.
“The common factor is that in sub-Saharan Africa, wildlife such as wildebeest and impala are experiencing a sharp decline, primarily due to habitat destruction and meat poaching,” Creel explained. “Today, these prey species are much less abundant than they were 40 or 50 years back.”
Both studies document Creel and his students’ examination of the link between the reduction of prey and the resulting decrease in large carnivore populations. For many years, Creel, a Distinguished Professor in the Department of Ecology at MSU’s College of Letters and Science, has researched the behavior, ecology, and conservation of large mammals, focusing particularly on African carnivores.
To conduct these studies, the team observed animal groups in Zambia from 2013 to 2021, including lion prides in the vast Kafue ecosystem. This region, significantly affected by economic challenges, has seen a considerable drop in prey populations due to poaching.
“People living in villages near protected areas often resort to bushmeat poaching to find food and make a living,” Creel highlighted.
The researchers tracked the lions through visual observation and data from collars fitted to at least one lion in each group. Over the initial five years of the study, the lion population in the ecosystem decreased by 3% annually. There was some debate among ecologists regarding the possibility of reversing this trend, with some advocating for fencing to deter poachers, while others suggested alternative protection methods. Eventually, patrol efforts were ramped up in several targeted areas to combat poaching.
As a result, researchers began witnessing growth in lion populations within these monitored areas—most notably, a 29% increase in the number of cubs born.
“More prey makes it easier for female lions to nurture their cubs,” said Creel. “What used to be a litter of three is now often four, dramatically influencing the population growth rate.”
The survival rate of lions in the patrolled areas also improved by approximately 8%, partially due to fewer fatalities from snares. Additionally, a larger prey base translates to better survival chances. Most importantly, fewer of the lions’ food sources fell victim to snares. The research demonstrated that lion populations in protected areas grew roughly 8% each year, while those in unprotected areas continued to decline.
“This is encouraging news despite the challenges faced. It clearly indicates that with more investment, progress is achievable even in massive ecosystems capable of supporting large populations,” he stated. “With an annual growth rate of 8%, a lion population could double within just ten years.”
On the other hand, the findings from the wild dog study presented a different scenario, Creel explained.
African wild dogs are pack-oriented animals, generally living in groups of eight to ten adults. These creatures were categorized as endangered back in 1990, with fewer than 1,500 breeding adults left worldwide, contributing to a total population of around 6,500. They hunt collectively, targeting the same species as larger predators, but often have their kills stolen by hyenas, and their survival is threatened by lions.
“They really are caught in a tough situation,” Creel remarked. “In areas with low prey abundance, their mortality rates increase, and their reproduction rates drop. Yet, they must also evade regions with high lion populations, which pose significant dangers.”
Creel and his team analyzed the impacts of prey shortages on African wild dogs, studying two populations in distinct ecosystems where prey and competitor densities varied. One or two adult dogs from each of 16 packs were fitted with collars that tracked their energy usage, offering insights into their activities.
“We could accurately gauge when they hunted, how far they pursued their prey, and their energy expenditure,” Creel explained. “The data was unequivocal.”
Through direct observation, the findings indicated that in areas with depleted prey, wild dogs faced higher energy costs when hunting and received lower rewards for their efforts, marking a significant shift from previous studies that suggested dominant competitors primarily limited their population numbers. Creel noted, “Wild dogs have shifted from being restricted by competition at the top to being constrained by food availability at the bottom. Their struggles in such areas stem from having to venture further to hunt and typically ending up with smaller prey—leading to greater energy expenditure and lower returns.”
“The transition from being competition-limited to food-limited is alarming,” he expressed.
Both studies were conducted in collaboration with the Zambia Department of National Parks and Wildlife and the Zambian Carnivore Programme. Matthew Becker, the co-lead author of the PNAS study, is the CEO and program manager of the Zambian Carnivore Programme and has a background from MSU as an alumnus and affiliate faculty member in the Department of Ecology. Creel remarked that the support from these organizations enabled years of intensive field research, allowing scientists to gain a deep understanding of individual animal behaviors and the environmental factors influencing them.
“We’ve demonstrated that even in extensive, unfenced ecosystems already impacted by human activities, we can reverse population declines through enhanced protective measures—what we need now is the commitment to do so,” Creel asserted. “We know effective strategies, and they’re often rather straightforward.”
He expressed optimism about the Zambia Department of National Parks and Wildlife’s willingness to incorporate research and data into their decision-making processes, as well as the potential economic gains from tourism that could arise from investing in wildlife protection.
“I’m genuinely excited by the lion study; if we can apply these methods to lions, we could potentially help all wildlife,” he concluded. “Investing in protection will lift all species.”
