There are many challenges associated with managing wild populations within fenced areas. One of the major challenges associated with lion management is population control. Compared to more open systems such as Kruger National Park (NP) and Serengeti NP, lion populations on small reserves reproduce more rapidly. Specifically, age of first reproduction for lionesses is lower, inter-birth intervals are shorter and litter sizes are larger compared to more open systems. This results in population growth rates that are faster than those in more open systems. Combine this with high survival rates and lion populations can rapidly get out of control if no steps are taken.
To address population growth rates, there are three obvious parameters to target: age of first reproduction, inter-birth interval and litter size. If one or more of these parameters can be manipulated to mimic more open systems, growth rates can be reduced to more appropriate levels. Two approaches are currently in use on small reserves in South Africa: slow-release Deslorelin implants and unilateral hysterectomy surgery. In the study below (see link) Deslorelin treatment was more effective in reducing the reproductive output of managed wild lionesses than unilateral hysterectomy surgery.
McEvoy et al. 2019, Wildlife Research: 46(5) 398-408