Reef interconnectivity/larval dispersal

Coral reefs are naturally fragmented and the complex interactions of the reef structure and their larval behavior with the circulation at a series of spatial scales (e.g., lagoon, fringing reef, and global circulation) determine their degree of interconnectivity. Typical connectivity in marine populations ranges broadly from demographic to genetic time scales depending on the strength and frequency of larval migrations (Cowen et al., 2000, 2006). However, the spectrum of connectivity among corals is still uncertain given their longevity and complex reproductive strategies. Indeed, on one hand, a few migrants could suffice to cause demographic connectivity. Conversely, migration could play only a small role on the genetic structure of corals that are highly clonal (i.e., rely mostly on asexual propagation). An integration of numerical and empirical approaches across space and timescales offers the greatest potential for advances in understanding reef interconnectivity, requiring more interdisciplinary interaction (Levin, 2006; Werner et al., 2008). Mapping of reef interconnectivity and identifying important coral larval pathways and corridors are keys for their conservation (Treml et al., 2008). Indeed, larval connectivity helps determine the spacing and size of marine protected areas (Pelc et al., 2010), prioritize the protection of critical stepping stone reefs and nodes of populations’ networks, and maintain key linkages, enhancing reef resilience to climate change–induced stress (Mumby et al., accepted).