Consequences of the Allee Effect for Behaviour, Ecology and Conservation
Defined Allee effects as positive density dependence below critical thresholds
Defines and reviews Allee effects - positive density dependence where fitness declines as population size decreases below critical thresholds, creating positive feedback toward extinction. This mechanism explains why populations can collapse rapidly once they fall below critical mass, even when absolute numbers seem adequate.
For business strategy, Allee effects explain why network-effects businesses, two-sided marketplaces, and social platforms can die from isolation while still numbering in the millions. The Allee Trap - extinction from insufficient density rather than insufficient numbers - is a critical concept for any business dependent on critical mass for value creation.
Key Findings from Stephens & Sutherland (1999)
- Defined Allee effects as positive density dependence below critical thresholds
- Documented mechanisms: mate-finding failure, reduced cooperation, predator defense collapse
- Explained positive feedback dynamics accelerating extinction
- Identified conservation implications for small populations