Mesopredator Release Hypothesis - Hypothesis

Hypothesis

Mesopredator release is a fairly new concept that is gaining approval, although it is still being debated and studied. The mesopredator release hypothesis states that if an apex predator is taken out of an ecosystem, the number of mesopredators (defined as medium-sized predators, such as raccoons, skunks, snakes, cats, and foxes) often increase in abundance when larger predators are eliminated. Mesopredator populations will surge and the predation of smaller, more vulnerable prey species will increase. As a result, the shared prey may suffer more from predation than when the apex predators (or top-predators) were controlling the mesopredators. This may lead to dramatic prey population decline, or even extinction, especially on islands. This process arises when mammalian top predators are considered to be the most influential factor on trophic structure and biodiversity in terrestrial ecosystems. Top predators may feed on herbivores and kill predators in lower trophic levels as well. Thus, reduction in the abundance of top predators may cause the medium-sized predator population to increase, therefore having a negative effect on the underlying prey community. The mesopredator release hypothesis offers an explanation for the abnormally high numbers of mesopredators and the decline in prey abundance and diversity. The hypothesis supports the argument for conservation of top predators because they protect smaller prey species that are in danger of extinction. This argument has been a subject of interest within conservation biology for years, but few studies have adequately documented the phenomenon.