Cryptic changes in the genetic structure of a highly clonal coral population and the relationship with ecological performance
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Elkhorn coral, Acropora palmata, relies heavily on clonal propagation and often displays low genotypic (clonal) diversity. Populations in the Florida Keys experienced rapid declines in tissue cover between 2004 and 2006, largely due to hurricanes and disease, but remained stable from 2006 to 2010. All elkhorn colonies in 150 m2 permanent study plots were genotyped in 2006 (n = 15 plots) and 2010 (n = 24 plots), and plots sampled in both years were examined for changes in allelic and genotypic diversity during this period of stable ecological abundance. Overall, genetic diversity of Florida plots was low and declined further over the 4-yr period; seven of the 36 original genets and two of 67 alleles (among five microsatellite loci) were lost completely from the sampled population, and an additional 15 alleles were lost from individual reefs. In 2010, Florida plots (~19 colonies) contained an average of 2.2 ± 1.38 (mean ± SD) genets with a significant negative correlation between colony abundance and genotypic diversity. When scaled to total tissue abundance, genotypic diversity is even lower, with 43 % of genets below the size of sexual maturity. We examined the hypothesized positive relationship of local genotypic diversity with ecological performance measures. In Florida plots (n = 15), genotypic diversity was not significantly correlated with tissue loss associated with chronic predation, nor with acute disease and storm-fragmentation events, though this relationship may be obscured by the low range of observed diversity and potential confounding with abundance. When more diverse plots in Curaçao (n = 9) were examined, genotypic diversity was not significantly correlated with resistance during an acute storm disturbance or rate of recovery following disturbance. Cryptic loss of genetic diversity occurred in the apparently stable Florida population and confirms that stable or even increasing abundance does not necessarily indicate genetic stability.
KeywordsMicrosatellites Genotype Disease Predation Florida Keys Acropora palmata
This work was funded by National Undersea Research Center (2004–2006), NOAA’s Coral Reef Conservation Program (2006–2010) and NOAA Fisheries’ Southeast Regional Office, Protected Resources Division, NSF grant OCE-0825979 and permitted by Florida Keys National Marine Sanctuary. M. Devlin-Durante expertly extracted and genotyped samples. Field assistance from A. Bright, C. Cameron, K. Erickson, C. Fasano, L. Johnston, K. L. Kramer, B. Mason, and R. Wilborn is gratefully acknowledged.
- Bailey JK, Schweitzer JA, Úbeda F, Koricheva J, LeRoy CJ, Madritch MD, Rehill BJ, Bangert RK, Fischer DG, Allan GJ, Whitham TG (2009) From genes to ecosystems: a synthesis of the effects of plant genetic factors across levels of organization. Phil Trans R Soc Lond 364:1607–1616CrossRefGoogle Scholar
- Baums IB, Miller MW, Szmant AM (2003) Ecology of a corallivorous gastropod, Coralliophila abbreviata, on two scleractinian hosts. I: population structure of snails and corals. Mar Biol 142:1083–1091Google Scholar
- Bruckner AW (2002) Proceedings of the Caribbean Acropora Workshop: potential application of the U.S. Endangered Species Act as a conservation strategy. NOAA Technical Memorandum NMFS-OPR-24, Silver Spring, MD, p 199Google Scholar
- Carpenter KE, Abrar M, Aeby G, Aronson RB, Banks S, Bruckner A, Chiriboga A, Cortes J, Delbeek JC, Devantier L, Edgar GJ, Edwards AJ, Fenner D, Guzman HM, Hoeksema BW, Hodgson G, Johan O, Licuanan WY, Livingstone SR, Lovell ER, Moore JA, Obura DO, Ochavillo D, Polidoro BA, Precht WF, Quibilan MC, Reboton C, Richards ZT, Rogers AD, Sanciangco J, Sheppard A, Sheppard C, Smith J, Stuart S, Turak E, Veron JE, Wallace C, Weil E, Wood E (2008) One-third of reef-building corals face elevated extinction risk from climate change and local impacts. Science 321:560–563PubMedCrossRefGoogle Scholar
- Levitan D (1995) The ecology of fertilization in free-spawning invertebrates. In: McEdward LR (ed) Ecology of Marine Invertebrate Larvae. CRC Press, Boca RatonGoogle Scholar
- McArt SH, Thaler JS (2013) Plant genotypic diversity reduces the rate of consumer resource utilization. Proc R Soc B: Biol Sci 208:20130639. doi: 10.1098/rspb.2013.0639:20130639
- NMFS (2012) Endangered and Threatened wildlife and plants: proposed listing determinations for 82 reef-building coral species; proposed reclassification of Acropora palmata and Acropora cervicornis from Threatened to Endangered. National Marine Fisheries Service, pp 73220–73262Google Scholar
- Williams SL, Heck KL (2001) Seagrass community ecology. In: Bertness MD, Gaines SD, Hay ME (eds) Marine Community Ecology. Sinauer Associates, Sunderland, MA, pp 317–338Google Scholar