this case, the species receives none of the benefits of a small sub-population (loss of the sub-population is not catastrophic to the species as a whole) and all of the disadvantages (inbreeding depression, loss of genetic diversity and increased vulnerability to environmental instability) and the population would survive better unfragmented. Allee principles of aggregation Clumping results due to individuals aggregating in response to: local habitat or landscape differences, daily and seasonal weather changes, reproductive processes, or as the result of social attractions. References Further reading External links Berryman, AA (1997). Underpopulation (Allee) effects, Entomology Department, Washington State University. Retrieved 19 May 2008. Allee effect, Warner College of Natural Resources, Colorado State University. Retrieved 19 May 2008. Stephens, PA, Sutherland, WJ and Freckleton, RP (1999). "What is the Allee effect?" (summary), Oikos, 87, 185-90, at Evolutionary Biology Group, Department of Zoology, University of Oxford. Updated 22 November 2005. Retrieved 19 May 2008 Classics: the Allee effect Biology terminology Ethology Mathematical and theoretical biology