Effects of long-distance dispersal for metapopulation survival and genetic structure at ecological time and spatial scales

1 Long-distance dispersal (LDD) of seeds by wind plays an important role in population survival and structure, especially in naturally patchy or human-fragmented metapopulations. However, no study has tested its effects using a realistic dispersal kernel in a metapopulation context with explicit spatial structure and local extinctions. 2 We incorporated such kernels into a newly proposed simulation model, which combines within-patch (population) demographic processes and a simplified maternally inherited single-locus, two-allele genetic make-up of the populations. As a test case, we modelled a typical conservation scenario of Aleppo pine (Pinus halepensis) populations. 3 The effects of LDD were rather diverse and depended on initial population conditions and local extinction rates. LDD increased metapopulation survival at intermediate local-extinction probabilities. LDD helped maintain higher total genetic variability in populations that were initially drifted, but facilitated random genetic loss through drift in initially 'well mixed' populations. LDD prevented population differentiation in low extinction rates but increased it at intermediate to high extinction rates. 4 Our results suggest that LDD has broader evolutionary implications and would be selected for in populations facing intermediate local-extinction pressures. Our modelling approach provides a strong tool to test the effects of LDD on metapopulation survival and genetic variability and to identify the parameters to which such effects are most sensitive, in ecological and conservational scenarios.