Mangrove propagules are limited in their capacity to disperse across long distances

Mangroves are subject to rapid and large-scale habitat changes which threaten their unique genetic diversity and provision of critically important ecosystem services. Habitat fragmentation reduces connectivity which can impair dispersal and lead to genetic isolation. However, it is unclear whether fragmentation could impact mangrove genetic isolation, as mangrove propagules can disperse long distances. Here, we conducted a meta-analysis of studies reporting a correlation between geographic distance and genetic distance in mangrove plants. From the 22 studies that met the inclusion criteria, we found a significant isolation-by-distance effect; geographic distance was significantly associated with Neis genetic distance and FST. Our results show that mangrove propagules may be limited in their capacity to disperse across long distances, which highlights the importance of maintaining close proximity between habitat patches and reducing habitat fragmentation.