The Keystone Species Concept in Ecology

The keystone species concept revolutionized the way naturalists and ecologists looked at the study of ecology. Ecology has been defined as the study of organisms in relation to one another and the environment.

One of the key ecology mechanisms revolved around the axiom of stability in an ecological community. “Stability increases as the number of links increases” (MacArthur) or “rich fauna and flora…tend to be very stable because of the multiplicity of ecological checks and balances” (Watt). This axiom of stability was used in ecology for years but did not have a true definition, because of this Paine sought to define these difficulties by using events that occurred in the marine littoral zone, which showed food web complexity in a community. Paine experimented in the rocky intertidal zone that spans from Alaska to Baja California, where he removed a dominant carnivore, the starfish Pinaster Ochraceus (Paine 1969.). Paine observed that by the removal of the starfish the species composition of the intertidal zone changed dramatically. He originally defined keystone species as “a species on which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically.” Even though, Paine coined the term “keystone species” using a carnivorous predator, a keystone can be a carnivore, herbivore, predator, prey or mutualist. For example, elephants are a keystone species in the African Savannahs and Serengeti Plains by controlling the tree population.

An example of a keystone mutualist would be pollinators that impact the entire ecosystem by geneflow and dispersal. Since the introduction of the keystone species concept, research involving keystone species has revolved around ways of identifying keystone species and the role they play in their ecosystem, in order to apply the keystone concept to various aspects of ecosystem management. Ecologists have studied ways of applying this concept not only to a species but also community’s and ecosystems.

Mouquet, illustrated the keystone concept on ecosystems by links and networks, which lead to the idea that certain ecosystems could be more important to a region than others. By applying this concept to community and ecosystems, ecologist want to make better management and conservation decisions for disturbed landscapes. For conservationists and naturalists, the keystone concept singled out keystone species for protection with the mindset, protect keystones, maintain the ecosystem.

Although the keystone species concept, changed the way ecologists looked at ecosystem interactions, it is also very controversial. Some believe that those who advocate for the labeling of keystone species fail to advance the study of interaction strengths in communities and protect the biodiversity. Instead studies should be more focused on the complexity of interactions in natural systems (Mills).