Density dependence of seed dispersal and fecundity profoundly alters the spread dynamics of plant populations

Plant population spread has fundamental ecological and evolutionary importance. Both determinants of plant spread, fecundity dispersal, can be density-dependent, which should cause feedback between densities dynamics. Yet it is poorly understood how density-dependence affects key characteristics spread: rate at the location furthest forward individual moves, edge depth (the geographical area over individuals contribute to spread) continuity (occupancy spreading population). We present a general modelling framework for analysing effects density-dependent dispersal on parameterize this with experimental data from common-garden experiment using five wind-dispersed species grown different densities. Our model shows that strongly affect all three both exponential lognormal kernels. Spread are correlated but show weaker correlations continuity. Positive increases characteristics. Increasingly positive generally decreases Density-dependent largely additive in their effect For continuity, joint somewhat contingent kernel. The experimentally parameterized mechanistic revealed across study species. All exhibited negatively fecundity, they differed qualitatively distance probability long-distance dispersal. negative found reinforced each other reducing depth. positively two markedly increased Population was hardly affected by density except Crepis sancta reduced fecundity. Synthesis. seed profoundly alter spread. In particular, promote genetic diversity populations migrating under climate change also complicate control invasive