Connecting Palau’s marine protected areas: a population genetic approach to conservation
Bleaching events are becoming more frequent and are projected to become annual in Micronesia by 2040. To prepare for this threat, the Government of Palau is reviewing its marine protected area network to increase the resilience of the reefs by integrating connectivity into the network design. To support their effort, we used high-throughput sequencing of microsatellites to create genotypes of colonies of the coral Acropora hyacinthus to characterize population genetic structure and dispersal patterns that led to the recovery of Palau’s reefs from a 1998 bleaching event. We found no evidence of a founder effect or refugium where colonies may have survived to recolonize the reef. Instead, we found significant pairwise F′ st values, indicating population structure and low connectivity among most of the 25 sites around Palau. We used kinship to measure genetic differences at the individual level among sites and found that differences were best explained by the degree of exposure to the ocean [F 1,20 = 3.015, Pr(>F) = 0.01], but with little of the total variation explained. A permutation test of the pairwise kinship coefficients revealed that there was self-seeding within sites. Overall, the data point to the population of A. hyacinthus in Palau recovering from a handful of surviving colonies with population growth primarily from self-seeding and little exchange among sites. This finding has significant implications for the management strategies for the reefs of Palau, and we recommend increasing the number and distribution of management areas around Palau to capture the genetic architecture and increase the chances of protecting potential refuges in the future.
KeywordsMicrosatellites Connectivity Oceanographic modeling Genetic architecture
We are grateful to M Belcaid and Y Cros for assistance with raw data processing and to the following University of Hawai‘i undergraduates for help in the laboratory: I Buffenstein, G Ciszek, B Haun, K Kaneshiro, M Keliipuleole, H Lim, K Niimoto, A Sifrit and T Whitman. We also thank M Iacchei for help with the manuscript and K Edwards for help with the analysis. Special thanks to The Nature Conservancy and Palau International Coral Reef Center for enabling the fieldwork and shipping permits. All collections were done under CITES permit PW 12-091 and a Palau Marine Research Permit RE-12-27. Funding was provided to A Cros and SA Karl by the Disney Wildlife Conservation Fund, to A Cros by the Graduate Women in Science Adel Lewis Grant Fellowship, the Founder Region Fellowship, the Ecology Evolution Conservation Biology Watson T. Yoshimoto grant and the Colonel Willys E. Lord Scholarship Award and the National Science Foundation grant OCE 12-60169 to RJ Toonen. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript. We also thank the HIMB NSF-EPSCoR Core Genetics Lab Facility (NSF, EPS-0903833). This is the Hawai‘i Institute of Marine Biology contribution # 1677 and the School for Ocean and Earth Science and Technology contribution # 9906.
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