The emergent geography of biophysical dispersal barriers across the Indo‐West Pacific

Abstract

AbstractAimTo discover and evaluate potential dispersal barriers across the Indo‐West Pacific Ocean and to develop spatially explicit hypotheses regarding the location of barriers and their capacity to filter taxa. Additionally, to compare model predictions with previously described barriers and build a more thorough understanding of the region's biogeographic patterns.LocationThe reefs of the Indo‐West Pacific Ocean, from 100 to 170°E and from 30°N to 30°S.MethodsA biophysical larval dispersal model was used to quantify over 800,000 dispersal kernels by simulating 99 model taxa. Spatial analysis was used to map emergent patterns of potential multispecies population connectivity and predict geographic locations and strength of concordant dispersal barriers across the seascape.ResultsAlthough individual taxa varied in their predicted fine‐scale population connectivity, there was consistency in the location of dispersal barriers. Across all trait combinations, reproductive output (fecundity and density of reproductive adults), reproductive strategy (spawning phenology) and the length of the larval dispersal phase determined the strength of barriers across the seascape. More than 80% of the previously described marine boundaries in the region were predicted to restrict the dispersal of at least 10% of the simulated taxa. The location and strength of many additional multitaxa barriers were described at scales <200 km.Main conclusionsThe geographic structure of many previously described multispecies barriers across the Indo‐West Pacific were predicted with the biophysical dispersal model and spatial analysis. The permeability of individual dispersal barriers was primarily determined by reproductive output, spawning phenology and the length of the pelagic larval stage. Across all dispersal barriers analysed, Euclidean distance explained up to 49% of the variation in barrier strength.