Larval dispersal is the primary mechanism of connectivity in marine metapopulations, impacting ecological and evolutionary processes such as population persistence, gene flow, and community dynamics. Critically, larvae dispersing in the nearshore environment are subject to temporal heterogeneity in transport and retention, but the magnitude of temporal fluctuations in patterns of connectivity is largely unknown. Though quantifying population connectivity through larval dispersal has been a major focus of marine ecology research, estimates of connectivity typically measure either dispersal in a single year or indirectly measure average connectivity averaged across many generations. Here we directly quantify the dispersal kernel across seven years in a metapopulation of yellowtail clownfish (Amphiprion clarkii) along 28 km of coastline using genetic parentage assignment with 2,984 individuals. Dispersal kernels were fit for each individual year and all years combined using maximum likelihood parameter estimation.
Results/Conclusions
Dispersal kernel fits were significantly variable between years, with mean dispersal distances ranging between 6.1-13.4 km for annual dispersal kernel estimates. However, a dispersal kernel estimated from the data of all seven years combined was distinctly different in shape from each of the annual kernels and predicted mean dispersal distance to be 2-4 times farther than annual kernels, indicating that connectivity fluctuations likely play a key role in driving rare, long-distance dispersal events and governing long-term dynamics. Given the unpredictability of dispersal observed on annual time scales, a broader understanding of the mechanisms and consequences of fluctuating dispersal in metapopulations is an important next step in metapopulation ecology and evolution.