In southern Africa, jackals are major predators of livestock on farms. As a control measure, farmers often kill jackals they find on their farms. Scientists Liaan Minnie and colleagues predicted that increased mortality of jackals would result in altered life history traits of this carnivore species. To test their predictions, they compared the number of pregnant female jackals in different age classes in populations that were hunted (on farms) to those that were not hunted (in conservation reserves). The resulting pattern shown in the first graph is the proportion of females that are pregnant in each age class. The scientists also collected demographic data to construct age structure diagrams (second graph) of jackals in (a) hunted populations (farms) and (b) populations that were not hunted (reserves). In the age structure diagram, males are plotted on the left, females are plotted on the right, and the median age class is denoted with hatched bars.
Source: Minnie, L., Gaylard, A., & Kerley, G. I. (2016). Compensatory life‐history responses of a mesopredator may undermine carnivore management efforts. Journal of Applied Ecology, 53(2), 379-387.
-What are the management implications of this study?

Question

In southern Africa, jackals are major predators of livestock on farms. As a control measure, farmers often kill jackals they find on their farms. Scientists Liaan Minnie and colleagues predicted that increased mortality of jackals would result in altered life history traits of this carnivore species. To test their predictions, they compared the number of pregnant female jackals in different age classes in populations that were hunted (on farms) to those that were not hunted (in conservation reserves). The resulting pattern shown in the first graph is the proportion of females that are pregnant in each age class. The scientists also collected demographic data to construct age structure diagrams (second graph) of jackals in (a) hunted populations (farms) and (b) populations that were not hunted (reserves). In the age structure diagram, males are plotted on the left, females are plotted on the right, and the median age class is denoted with hatched bars.
  Source: Minnie, L., Gaylard, A., & Kerley, G. I. (2016). Compensatory life‐history responses of a mesopredator may undermine carnivore management efforts. Journal of Applied Ecology, 53(2), 379-387.
-What are the management implications of this study?

Quizplus · Accepted Answer

The study suggests that hunting jackals on farms may actually lead to increased population growth and exacerbate the problem of predation on livestock. This is because the hunting releases the jackal populations from density-dependent limits on reproduction, leading to compensatory responses such as increased pregnancy rates and earlier age at first reproduction. Therefore, the management implications of this study are that hunting jackals may not be an effective solution to reducing predation on farms and may actually make the problem worse.

In Southern Africa, Jackals Are Major Predators of Livestock on Farms