Metapopulation Dynamics Metapopulation structure: Demes linked via dispersal Local scale: colonization, extinction Regional scale: Occupation frequency global extinction
University of Kentucky
Extinction, Re-colonization Dynamics
University of Idaho
Spotted Owl: Lahaye et al., 1994, Oikos 63:775
Metapopulation
Colonization balances Extinction
Metapopulation Dynamics p(t): proportion patches occupied, time t Spatially implicit (ignore spatial structure): All patches equally linked
Metapopulation Dynamics Predict: p*, equilibrium occupation frequency Equilibrium: colonization = extinction Closed metapopulation (internal colonization) Open metapopulation (island-mainland)
Closed Metapopulation
Open Metapoulation Colonization: propagule rain from mainland x frequency of open sites Extinction: linear in occupied-site frequency
Open Metapoulation
Metapopulation Dynamics Assume: Patches identical: colonization, extinction Each patch direct link to all others c, m, e constants Total number of patches large
Patch Size, Inter-Patch Distance
Migration: Mass, Temperature
Metapopulation Extinction Local extinction versus global extinction Consider spatial synchrony across demes Local densities correlate positively Moran effect Dispersal and “simpler” dynamics
Metapopulation Extinction High synchrony Global extinction Asynchrony Regional persistence Chaos: “nearby trajectories diverge” Can increase local extinction; reduce global extinction
Global Synchrony