MEPS prepress abstract   -  DOI: https://doi.org/10.3354/meps14403

ABSTRACT: Connections among habitat patches through propagule dispersal are critical for designing effective networks of marine protected areas. To meet targets, managers need a diverse toolkit for translating patterns of connectivity to actionable metrics through specific size, spacing, and siting recommendations. Measuring ecological connectivity in the marine realm is particularly challenging because of water movement and the lack of distinct physical boundaries. Additionally, tracking most propagules is not logistically feasible. Here, we compare three approaches of increasing complexity for predicting potential ecological connectivity (measured as passive dispersal by ocean currents) of kelps and two resident invertebrates, the dominant macrograzer (Strongylocentrotus droebachiensis) and a destructive invasive epiphyte (Membranipora membranacea) among habitat patches in the NW Atlantic coast of Canada. The three approaches differ in the complexity of estimating ocean currents: current speed depth-averaged over time (1D); current velocity decomposed into along-shore and cross-shore components depth-averaged over time (2D); and spatially modelled current velocity derived from a 3D hydrodynamic model (3D). We found that the 1D approach was adequate for species with a short competent propagule duration (CPD), but that dispersal for the 2D and 3D approaches were most similar for mid-long CPD dispersers at the scale of management units, likely because they both account for the directionality of currents, whereas the 1D approach does not. This research helps bridge the gap between connectivity research and ocean management by demonstrating that the 2D approach requires lower data, time, and resources providing adequate outputs at the scale of management units.