Ecological Pyramids

Because of the serial inefficiencies of energy transfer along food chains, there are intrinsic, energetic limits to the numbers of top carnivores that ecosystems can sustain. If top predators such as lions or killer whales are to be sustained in some minimal viable productivity and population size, there must be a suitably large productivity of animal prey that these animals can exploit. Their prey must in turn be sustained by a suitably large productivity of appropriate plant foods. Because of these ecological constraints, only very productive or extensive ecosystems can sustain top predators.

African savannas and grasslands sustain more species of higher-order carnivores than any other existing terrestrial ecosystems. The most prominent of these top predators are lion, leopard, cheetah, hyena, and wild dog. Although these various species may kill each other during some aggressive interactions (lions and hyenas are well known for their mutual enmity), they do not eat each other, and each can therefore be considered a top predator. In this unusual case, a large number of top predators can be sustained because the ecosystem is very extensive, and also rather productive of vegetation in most years. Other, very extensive but unproductive ecosystems may only support a single species of top predator, as is the case of the wolf in the arctic tundra.