Intermediate Disturbance Hypothesis

The intermediate disturbance hypothesis (IDH) traces its roots back to the island biogeography studies of the 1940s but it wasn’t until the 1970’s that it became a commonly accepted ecological theory. The base of the theory is that ecosystems are never in a state of equilibrium and species existence in a site in not solely dependent on adaptation. IDH depends on the notion that disturbance intensity brings the stand back to a previous state and the rate of disturbance also plays a role in what state a stand is in. In IDH the prevailing thought is that biodiversity is highest at a level of disturbance that is neither to frequent or intense. However, if disturbance is too infrequent or not intense enough then long lived species will come to dominate the landscape. In order for maximum biodiversity the disturbance must be such that allows all levels of competitors a chance to colonize a landscape.

IDH is related to invasive species because the earliest stages of succession are often where a plant invasion occurs because of reduced resource competition. Human disturbances are more intense and more frequent then the ones seen in nature, this is also coupled with the issue that many nonnative invasive are in the colonizing early successional niche of their novel ecosystem. Due to this when invasive are present (as they are virtually everywhere) the maximum level of biodiversity is actually seen in the early stages, however this is due to the nonnative species. The invading species can also alter the introduced ecosystem in ways that favor there survival. This trend can result in lower native biodiversity as the time progress after a disturbance event.

1.)           Wilkinson, David M. "The disturbing history of intermediate disturbance." Oikos (1999): 145-147.

2.)           Catford, Jane A., et al. "The intermediate disturbance hypothesis and plant invasions: Implications for species richness and management." Perspectives in Plant Ecology, Evolution and Systematics 14.3 (2012): 231-241.

3.)           MICHAEL ALLABY. "intermediate disturbance hypothesis." A Dictionary of Ecology. 2004. Retrieved April 13, 2015 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O14-intermediatdstrbnchypthss.html

4.)           "The Intermediate Disturbance Hypothesis and Plant Invasions: Implications for Species Richness and Management." The Quantitative Applied Ecology Group. N.p., 12 Jan. 2012. Web. 13 Apr. 2015.