OLM 6.2  Potential large-scale consequences of a temperature-dependent Allee-effect

Strong Allee-effect renders extinction one of the stable states of a system (Figure 6.3, p.98). This implies that colonization can be successful only if the invader population size (of individuals or propagules) exceeds the Allee threshold, i.e., population size at the unstable equilibrium (extinction threshold, Ch6.1.2, p.98). If this occurs rarely, then even non-isolated habitats providing environmental conditions within the range of the species’ ecological tolerance will remain unoccupied for long periods of time. Moreover, the dependence of growth rate on population density changes with external conditions like temperature, which may affect both the position of the unstable fixed point and the dispersal rate through multiple mechanisms in case of ectotherm organisms. This OLM presents some examples.

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