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

Multiple Choice

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.
-Interpret the age structure diagram for jackals on farms compared to reserves.

A) Jackal populations on farms should expand; jackal populations in reserves should decline.
B) Jackal populations on farms should decline; jackal populations in reserves should expand.
C) Jackal populations should decline on farms and reserves.
D) Jackal populations should expand on farms and reserves.