Sunday 2 March 2014

Animal Aggregations

Ed Ricketts attended the University of Chicago in the 1920's. One of the tutors he came into contact with was Warder Clyde Allee - a zoologist and ecologist who had a profound influence on Ricketts' approach to marine biology and ecology. Allee was the first to describe what has become known as the Allee Effect, defined as "the positive correlation between population density and individual fitness". 

In 2008 Franck Courchamp, Ludek Berec, and Joanna Gascoigne published a 270 page  monograph dedicated to the Allee Effect in Ecology and Conservation. In the preface they define the effect informally as the idea that "the more individuals there are (up to a point), the better they fare" and explain;

The Allee effect is an ecological concept with roots that go back at least to the 1920s, and fifty years have elapsed since the last edition of a book by W.C. Allee, the “father” of this process. Throughout this period, hardly a single mention of this process could be found in ecological textbooks. The concept lurked on the margin of ecological theory, overshadowed by the idea of negative density dependence and competition. The situation has appeared to change dramatically in the last decade or so, however, and we now find an ever-increasing number of studies from an ever-increasing range of disciplines devoted to or at least considering the Allee effect.
Warder Clyde Allee's classic from 1931 - Animal Aggregations. A study in General Sociology was published by the University of Chicago Press and is available to download in its entirety HERE.