Strong structure among coral populations within conservation priority region, the Bird's Head Seascape (Papua, Indonesia)

While data on connectivity and genetic structure of marine populations are critical to designing appropriately sized and spaced networks of MPAs, such data are rarely available. This study examines genetic structure in reef-building corals from Papua and West Papua, one of the most biologically diverse and least disturbed coral reef regions in the world. The study focused on two common reef-building corals, Pocillopora damicornis and Seriatopora hystrix, from three regions under different management regimes: Teluk Cenderawasih, Raja Ampat, and southwest Papua. Analyses of molecular variance, assignment tests, and genetical bandwidth mapping based on microsatellite variation revealed significant genetic structure in both species, although there were no clear regional filters to gene flow among regions. Overall, P. damicornis populations were less structured (FST = 0.139, p < 0.00001) than S. hystrix (FST = 0.357, p < 0.00001). Populations of both species showed evidence of recent declines, despite occurring in one of the most pristine marine habitats in Indonesia. Furthermore, exclusion of individual populations from connectivity analyses resulted in marked increases in self-recruitment. Maintaining connectivity within and among regions of Eastern Indonesia will require coral conservation on local scales and regional networks of MPAs. The Convention on Biodiversity set a goal that at least 10% of each of the world's marine and coastal ecoregions should be set aside as MPAs by 2020. However, only ~3% of the world's marine areas are currently within MPAs (Toropova et al. 2010, IUCN 2013). Therefore, there should be significant growth in MPAs around the world, including coral reef ecosystems. Understanding connectivity, the exchange of dispersing larvae among populations that contributes to population demographics and gene flow, is critical to long-term conservation of marine ecosystems (Crowder et al. 2001, Botsford et al. 2001, Cowen et al. 2006). The Bird's Head Seascape, a region that includes the provinces of Papua and West Papua, is the most biologically diverse marine ecosystem in the world (Roberts 2002, Bellwood and Meyer 2009). It is also among the most threatened (Burke et al. 2012). A multi-institutional program, the Bird's Head Seascape Initiative, is working to confront the threats to marine habitats in this region by designing and implementing an ecosystem-based management plan, including an interconnected network of MPAs (Mangubhai et al. 2012). Understanding patterns of genetic connectivity among populations of corals and reef-associated species within this region has become a key research priority for conservation. While the presence of genetic connectivity does not ensure demographic connectivity, reduced genetic connectivity is a clear indication that demographic connectivity is extremely limited or absent (Hedgecock et al. 2007). Studies have used genetic connectivity to advance marine conservation goals from various perspectives (Palumbi 2003, Laurie et al. 2004, Kool et al. 2011, Berger et al. 2014, DeBoer et al. 2014, Serrano et al. 2014, Treml et al. 2015). The study's findings highlight the importance of understanding genetic connectivity in marine ecosystems, particularly in regions with high levels of biodiversity and conservation value. The results of this study will contribute to the development of effective conservation strategies for the Bird's Head Seascape and other marine ecosystems worldwide.