Did you ever wonder, as most children inevitably do, why your favorite animated movie was called “The Lion King” instead of “The Endangered African Wild Dog King”? Wonder no more, the answer is here. Dr. Rosemary Groom of the African Wildlife Conservation Fund and her colleagues address this (slightly paraphrased) question in their new article, “The impact of lions on the demography and ecology of endangered African wild dogs” from Animal Conservation. The plight of declining mesopredators – species that both predate and are preyed upon – such as this study’s Lycaon pictus is a global phenomenon, yet not common knowledge. Fortunately, Groom and her team confirmed aspects of the relationship between lions and the dogs and have come to several conclusions that, applied on a broader scale, could drastically improve the situation of many other endangered mesopredators.
Human habitation as well as competition and predation by the wild dog’s apex predator, the African lion, has driven Africa’s most threatened large carnivore species to a severely diminished population and a mere 9.4% of all its previous lands. This study shows that increasing the density of lions in a territory alters the demographics and behavior of wild dogs, in ways that force them to stint their own population growth. They make dens in rugged and unpopulated areas, decrease pack sizes, lose more of the pup population to lion predation, and disperse less to compensate for the lack of increase in litter size.
After coming across a unique, rarely-seen area in Zimbabwe’s Save Valley Conservancy where the wild dogs actually outnumbered the lions, the researchers used the opportunity to set up two four-year time blocks. In the first, they studied the behavior and makeup of the pack as it was. Before the second, they introduced more lions to the area to increase lion density. This allowed them to prove that the changes in behavior they witnessed were caused by the lion population.
These results imply that lion density gave rise to a spatial avoidance strategy for the dogs, in which they sacrifice availability of prey and maneuverability of terrain to protect their pups during vulnerable periods (mating and denning). Their instincts are generally to avoid lions at all costs – but those costs often include their breeding rate and survival of their young. This is a very drastic response, and the explanation lies not in the natural world of competition between two predators, but in human impact.
Human conservation efforts focused on lions often allow their density to increase unchecked, which alters the natural balance and puts the wild dog population at further risk. And because lion conservation gets more visibility than that of wild dogs (maybe a new animated movie would help?), the lack of information makes it difficult to implement proper protections. That’s why Groom’s work is so noteworthy. According to wild dog expert Dr. Ange Baker of Humboldt State University, “Papers like this one are quite significant because they provide even more specific information on this topic that aids those in the field that are using these techniques to protect and manage wild dog populations.” And the article’s directive is clear: to help both species, conservation should protect areas that include refuge locations of lower lion densities for the dogs, and should promote adult longevity over juvenile survival.
In terms of limitations, the experiment lacks a control due to environmental constrictions, and an absence of familiarity with lions may have caused an otherwise unrealistic population crash in the second time period. Additionally, critics may argue that this paper’s relevance ends at mammalian carnivores. However, the obvious results and implied causations of the study apply to many mesopredators worldwide, especially in indicating the significance of group size in these populations.
Accordingly, in the crucial discipline of predator conservation studies that gets so little well-deserved attention from the scientific world, Groom’s study provides definitive answers in a way most natural experiments are incapable of. With these conclusions, the situation of the African wild dog can be used to draw deductions about mesopredators all over the globe and beyond the mammalian carnivore sect. The result? Not an animated movie, but even better: more well-informed conservation efforts, and hopefully an ultimate increase in mesopredator populations.
R. J. Groom, K. Lannas & C. R. Jackson, (2017). “The impact of lions on the demography and ecology of endangered African wild dogs”, Animal Conservation, Volume 20, Issue 4, Pages 382-390