Conservation Genetics

, Volume 5, Issue 5, pp 661–671 | Cite as

Relationships between bed age, bed size, and genetic structure in Chesapeake Bay (Virginia, USA) eelgrass (Zostera marina L.)

  • Jennifer M. Rhode
  • J. Emmett Duffy
Article

Abstract

Genetic structure and diversity can reveal the demographic and selective forces to which populations have been exposed, elucidate genetic connections among populations, and inform conservation strategies. Beds of the clonal marine angiosperm Zostera marinaL. (eelgrass) in Chesapeake Bay (Virginia, USA) display significant morphological and genetic variation; abundance has fluctuated widely in recent decades, and eelgrass conservation is a major concern, raising questions about how genetic diversity is distributed and structured within this metapopulation. This study examined the influence of bed age (<65years versus<6years) and size (>100ha versus<10ha) on morphological and genetic (allozyme) structure and diversity within Chesapeake Bay eelgrass beds. Although both morphology and genetic diversity varied significantly among individual beds (FST=0.198), neither varied consistently with bed age or size. The Chesapeake eelgrass beds studied were significantly inbred (mean FIS=0.680 over all beds), with inbreeding in old, small beds significantly lower than in other bed types. Genetic and geographic distances within and among beds were uncorrelated, providing no clear evidence of isolation by distance at the scale of 10's of km. These results suggest that local environmental conditions have a greater influence on plant morphology than do bed age or size. They support the hypotheses that eelgrass beds are established by multiple founder genotypes but experience little gene flow thereafter, and that beds are maintained with little loss of genetic diversity for up to 65 years. Since phenotypic and genotypic variation is partitioned among beds of multiple ages and sizes, eelgrass conservation efforts should maximize preservation of diversity by minimizing losses of all beds.

age FST Nei's genetic distance size Zostera marina 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Agrawal AA (2001)Phenotypic plasticity in the interactions and evolution of species. Science, 294 (5541), 321–326.Google Scholar
  2. Alberte RS, Suba GK, Procaccini G, Zimmerman RC, Fain SR (1994). Assessment of genetic diversity of seagrass populations using DNA fingerprinting:implications for population stability and management. Proc. of the Nat. Academy of Sci., 91, 1049–1053.Google Scholar
  3. ArcView GIS [GIS software ](2001)Version 3. 2. Environmental Systems Research Institute, Inc, Redlands, CA.Google Scholar
  4. Backman TWH (1991)Genotypic and phenotypic variability of Zostera marina on the west coast of North America. Canad. J. Bot., 69 (6), 1361–1371.Google Scholar
  5. Beardmore JA (1983)Extinction, Survival, and Genetic Variation. In:Genetics and Conservation:A Reference for Managing Wild Animal and Plant Populations. (eds. Schonewald-Cox, CM, SM Chambers, B MacBryde, and WL Thomas), 722 pp. The Benjamin/Cummings Publishing Co., Inc, Menlo Park, CA.Google Scholar
  6. Blank S, Seiter C, Bruce P (1999)Resampling stats in Excel. Version 1. 1. Resampling Stats, Inc, Arlington, VA.Google Scholar
  7. Caswell H (2000)Matrix Population Models. 2nd edn. Sinaeur Associates, Sunderland, MA.Google Scholar
  8. Cerco CF and Moore K (2001)System-wide submerged aquatic vegetation model for Chesapeake Bay. Estuaries, 24 (4), 522–534.Google Scholar
  9. Churchill AC (1983)Field studies on seed germination and seedling development in Zostera marina L. Aquat. Bot. 16, 21–29.Google Scholar
  10. Cheplick GP (1991)A conceptual framework for the analysis of phenotypic plasticity and genetic constraints in plants. Oikos 62, 283–291.Google Scholar
  11. Costanza R, d'Arge R, de Groot R, Farber S, Grasso M, Hannon B, Limburg K, Naeem S, O'Neill RV, Pareulo J, Raskin RG, Sutton P, van den Belt M (1997)The value of the world 's ecosystem services and natural capital. Nature, 387, 253–260.Google Scholar
  12. Cox PA, Laushman RH, Ruckelshaus M (1992)Surface and submarine pollination in the seagrass Zostera marina L. Bot. JL Soc., 109, 281–291.Google Scholar
  13. de Cock AWAM (1980)Flowering, pollination, and fruiting in Zostera marina L. Aquat. Bot., 9, 202–220.Google Scholar
  14. den Hartog C (1970)Seagrasses of the World. North-Holland, Amsterdam, The Netherlands.Google Scholar
  15. Endler JA (1986)Natural Selection in the Wild. Princeton University Press, Princeton, NJ. 336 pp.Google Scholar
  16. Eriksson O (1993)Dynamics of genets in clonal plants. Trends Ecol. Evol. 8 (9), 313–316.Google Scholar
  17. Ewanchuk PJ (1995)Population Growth of Eelgrass (Zostera marina L. ):The Relative Importance of Sexual vs. Asexual Reproduction. 93 pp. San Diego State University Thesis.Google Scholar
  18. Ewanchuk PJ, Williams SL (1996)Survival and re-establishment of vegetative fragments of eelgrass, Zostera marina. Canad. Jo. Bot., 74, 1584–1590.Google Scholar
  19. Fain SR, DeTomaso A, Alberte RS (1992)Characterization of disjunct populations of Zostera marina (eelgrass)from California:genetic differences resolved by restriction-length polymorphisms. Marine Biol., 112, 683–689.Google Scholar
  20. Francisco-Ortega J, Santos-Guerra A, Kim SC, Crawford DJ (2000)Plant genetic diversity in the Canary Islands:a conservation perspective. Am. Jo. Bot., 87 (7), 909–919.Google Scholar
  21. Gagnon PS, Vadas RL, Burdick DB, May B (1980)Genetic identity of annual and perennial forms of Zostera marina L. Aquat. Bot., 8, 157–162.Google Scholar
  22. Hammerli A, Reusch TBH (2001)Inbreeding depression influences genet size distribution in a marine angiosperm. Mol. Ecol., 12, 619–629.Google Scholar
  23. Hamrick JL (1983)The distribution of genetic variation within and among natural plant populations. In:Genetics and Conservation:A Reference for Managing wild Animal and Plant populations., pp. 335–348. Biological Conservation Series, NY.Google Scholar
  24. Harada Y, Iwasa Y (1996)Analyses of spatial patterns and population processes of clonal plants. Res. Popul. Ecol., 32 (2), 153–164.Google Scholar
  25. Harada Y, Kawano S, Iwasa Y (1997)Probability of clonal identity:Inferring the relative success of sexual versus clonal reproduction from spatial genetic patterns. J. Ecol., 85 (5), 591–600.Google Scholar
  26. Harwell MC (2000)Ecological Dispersal Mechanisms, Reproductive Ecology, and the Importance of Scale in Zostera marina in Chesapeake Bay. Ph. D. Thesis, Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, VA. 230 pp.Google Scholar
  27. Harwell MC, Orth RJ (2002a)Long-distance dispersal potential in a marine macrophyte. Ecol., 83 (12), 3319–3330.Google Scholar
  28. Harwell MC, Orth RJ (2002b)Seed bank patterns in Chesapeake Bay eelgrass (Zostera marina L. ):a bay-wide perspective. Estuaries, 25 (6A)1196–1204.Google Scholar
  29. Heij H, Nienhuis P (1992)Intraspecific variation in isozyme patterns of phenotypically separated populations of Zostera marina L. in the south-western Netherlands. Jo. Exp. Marine Biol. and Ecol., 161, 1–14.Google Scholar
  30. Hootsmans MJM, Vermaat JE, Van Vierssen W (1987)Seed-bank development, germination, and early seedling survival of two seagrass species from the Netherlands:Zostera marina L. and Zostera noltii Hornem. Aquat. Bot., 28, 275–285.Google Scholar
  31. Jelinski DE (1997)On genes and geography:a landscape perspective on genetic variation in natural plant populations. Landscape Urban Plan. 39 (1), 11–23.Google Scholar
  32. Joshi JB, Schmid JB, Schmid B, Caldeira MC, Dimitrakopoulos Pg, Good J, Harris R, Hector A, Huss-Danell K, Jumpponen A, Minns A, Mulder CP, Pereira JS, Prinz A, Scherer-Lorenzi M, Siamantziouras AD, Terry AC, Troumbis AY, Lawton JH (2001)Local adaptation enhances performance of common plant species. Ecol. Lett., 4 (6), 536–544.Google Scholar
  33. Jover MA, del Castillo-Agudo L, Garcia-Carrascosa M, Segura J (2003)Random amplified polymorphic DNA assessment of diversity in western Mediterranean populations of the seagrass Posidonia oceanica. Am. J. Bot., 90 (3), 364–369.Google Scholar
  34. Laska G (2001)The disturbance and vegetation dynamics:a review and an alternative Framework. Plant Ecol., 157 (1), 77–99.Google Scholar
  35. Laushman RH (1993)Population genetics of hydrophilous angiosperms. Aquat. Bot., 44, 147–158.Google Scholar
  36. Leberg PL (1992)Effects of population bottlenecks on genetic diversity as measured by allozyme electrophoresis. Evolution 46 (2), 477–494.Google Scholar
  37. Linhart YB, Grant MC (1996)Evolutionary significance of local genetic differentiation in plants. Ann. Rev. Ecol. System., 27, 237–277.Google Scholar
  38. McCauley DE, Raveill J, Antonovics J (1995)Local founding events as determinants of genetic structure in a plant metapopulation. J. Heredity, 75 (6), 630–636.Google Scholar
  39. McMillan C (1982)Isozymes in seagrasses. Aquat. Bot., 14, 231–243.Google Scholar
  40. McNeilly T (1967)Evolution in closely adjacent plant populations. III. Agrostis tenuis on a small copper mine. Heredity, 23, 99–108.Google Scholar
  41. McRoy CP (1996)The global seagrass initiative continues. In (eds. Kuo J, Phillips RC, Walker DI, Kirkman H. )Seagrass Biology:Proceedings of an International Workshop. 385 pp. University of Western Australia, Nedlands.Google Scholar
  42. McRoy CP, Helfferich C, eds (1977)Seagrass Ecosystems:a scientific perspective. Marcel Dekker, Inc., New York.Google Scholar
  43. Murphy RW, Sites JW, Jr, Buth DG, Haufler CH (1996)Proteins:Isozyme Electrophoresis. In:(eds. Hillis DM, Moritz C., Mable BK)Molecular Systematics, 2nd ed. 655 pp. Sinauer Associates, Inc., Sunderland, MA.Google Scholar
  44. Nei M (1972)Genetic distance between populations. Am. Naturalist, 106, 283–292.Google Scholar
  45. Oostermeijer JGB, Van Eijck MW, Den Nijs JCM (1994)Offspring fitness in relation to population size and genetic variation in the rare perennial plant species Gentiana pneumonanthe (Gentianaceae). Oecologia, 97 (3), 289–296.Google Scholar
  46. Orth RJ, Harwell MC, Fishman JR (1999)A rapid and simple method for transplanting eelgrass using single, unanchored shoots. Aquat. Bot., 64, 77–85.Google Scholar
  47. Orth RJ, Luckenbach M, Moore KA (1994)Seed dispersal in a marine macrophyte:implications for colonization and restoration. Ecology 75(7), 1927–1939.Google Scholar
  48. Orth RJ, Nowak JF, Wilcox DJ, Whiting JR, Nagey LS (1998) Distribution of Submerged Aquatic Vegetation in Chesapeake Bay and Tributaries and Chincoteague Bay-US EPA Report, Grant CB993267–03-1, 165 pp. Chesapeake Bay Foundation, Annapolis.Google Scholar
  49. Orth RJ, Moore KA (1983)Chesapeake Bay:an unprecedented decline in submerged aquatic vegetation. Science, 222, 51–53.Google Scholar
  50. Orth RJ, Moore KA (1986)Seasonal and year-to-year variations in the growth of Zostera marina L. (eelgrass)in the lower Chesapeake Bay. Aquat. Bot. 24, 335–341.Google Scholar
  51. Orth RJ, Wilcox DJ, Nagey LS, Tillman AL, Whiting JR (2002) 2001 Distribution of Submerged Aquatic Vegetation in the Chesapeake Bay and Coastal Bays. VIMS Special Scientific Report Number 143. Final report to U. S. EPA, Chesapeake Bay Program, Annapolis, MD. Grant No. CB993777–04-0, http://www. vims. edu/bio/sav/sav01Google Scholar
  52. Phillips RC, Grant WS, McRoy CP (1983)Reproductive strategies of eelgrass (Zostera marina L. ). Aquat. Bot. 16, 1–20.Google Scholar
  53. Procaccini G, Piazzi L (2001)Genetic polymorphism and transplantation success in the Mediterranean seagrass Posidonia oceanica. Restor. Ecol., 9 (3), 332–338.Google Scholar
  54. Rasmussen E (1977)The wasting disease of eelgrass (Zostera marina )and its effects on environmental factors and fauna. pp. 1–51 In:(eds. McRoy CP and Helfferich C. Seagrass Ecosystems:a scientific perspective. Marcel Dekker, New York.Google Scholar
  55. Reusch TBH, Stam WT, Olsen JL (1999a)Microsatellite loci in eelgrass Zostera marin a reveal marked polymorphism within and among populations. Mole. Ecol., 8, 317–321.Google Scholar
  56. Reusch TBH, Stam WT, Olsen JL (1999b)Size and estimated age of genets in eelgrass, Zostera marina, assessed with microsatellite markers. Marine Biol., 133 (3), 519–525.Google Scholar
  57. Reusch TBH, Hukriede W, Stam WT, Olsen JL (1999c)Differentiating between clonal growth and limited gene flow using spatial autocorrelation of microsatellites. Heredity, 83 (2), 120–127.Google Scholar
  58. Reusch TBH, Stam WT, Olsen JL (2000)A microsatellite-based estimation of clonal diversity and population subdivision in Zostera marina, a marine flowering plant. Mol. Ecol., 9, 127–140.Google Scholar
  59. Reusch TBH (2001)Fitness-consequences of geitonogamous selfing in a clonal marine angiosperm (Zostera marina ). J. Evol. Biol., 14, 129–138.Google Scholar
  60. Reusch TBH (2002a)Local adaptation and transplant dominance in genets of the marine clonal plant Zostera marina. Marine Ecol. Progress Ser. 242, 111–118.Google Scholar
  61. Reusch TBH (2002b)Microsatellites reveal high population connectivity in eelgrass in two contrasting coastal areas. Limnol. and Oceanogr., 47, 78–86.Google Scholar
  62. Rhode JM (2002)Microevolution in Chesapeake Bay Populations of Eelgrass (Zostera marina L). Ph. D. Thesis, Virginia Institute of Marine Science, College of William and Mary, Gloucester Point, VA.Google Scholar
  63. Rhode JM, Duffy JE (2004)Seed production from the mixed mating system of Chesapeake Bay (USA)eelgrass (Zostera marina L;Zosteraceae). Am. J. Bot., 91 (2), 192–197.Google Scholar
  64. Richardson BJ, Baverstock PR, Adams M (1986)Allozyme Electrophoresis:a Handbook for Animal Systematics and Population Studies. 410 pp. Academic Press, Orlando.Google Scholar
  65. Ruckelshaus M (1994)Ecological and Genetic Factors Affecting Population Structure in the Marine Angiosperm Zostera marina L. Ph. D. Thesis. 207 pp. University of Washington.Google Scholar
  66. Ruckelshaus M (1996)Estimation of genetic neighborhood parameters from pollen and seed dispersal in the marine angiosperm Zostera marina (L. )Evolution, 50 (2), 856–864.Google Scholar
  67. Ruckelshaus MH (1998)Spatial scale of genetic structure and an indirect estimate of gene flow in eelgrass, Zostera marina. Evolution, 52 (2), 330–343.Google Scholar
  68. SAS (Statistical Analysis Software), Version 8. 0. (1999). SAS Institute Inc., Cary, NC, USA.Google Scholar
  69. Schneider S, Roessli D, Excoffier L (2000)Arlequin:A Software for Population Genetics Data Analysis. Ver 2000. Genetics and Biometry Lab, Dept. of Anthropology, University of Geneva.Google Scholar
  70. Setchell WA (1929)Morphological and phenological notes on Zostera marina L. Univ. California Publi Bot., 14 (19), 389–452.Google Scholar
  71. Short FT, Muehlstein LK, Porter D (1987)Eelgrass wasting disease:cause and recurrence of a marine epidemic. Biol. Bull., 173, 557–562.Google Scholar
  72. Soltis D, Haufler C, Darrow D, Gastony G (1983)Starch gel electrophoresis of ferns:a compilation of grinding buffers, gel and electrode buffers, and staining schedules. Am. Fern Jo., 73, 9–27.Google Scholar
  73. Sultan SE (2000)Phenotypic plasticity for plant development, function, and life history. Trends Plant Sci., 5 (12), 537–542.Google Scholar
  74. van der Bank H, van der Bank M, Van Wyk BE (2001)A review of the use of allozyme electrophoresis in plant systematics. Biochem. Syst. and Ecol., 29 (5), 469–483.Google Scholar
  75. Van Dijk H (1987)A method for the estimation of gene flow parameters from a population structure caused by restricted gene flow and genetic drift. Theor. Appl. Genet., 73 (5), 724–736.Google Scholar
  76. Weidema IR, Siegismund HR, Phillip M (1996)Distribution of genetic variation within and among Danish populations of Armeria maritima, with special reference to the effects of population size. Hereditas, 124 (2), 121–129.Google Scholar
  77. Williams SL (2001)Reduced genetic diversity in eelgrass transplantations affects both population growth and individual fitness. Ecol. Appl., 11 (5), 1472–1488.Google Scholar
  78. Williams SL, Davis CA (1996)Population genetic analysis of transplanted eelgrass (Zostera marina )beds reveal reduced genetic diversity in Southern California. Restor. Ecol. 4 (2), 163–180.Google Scholar
  79. Williams SL, Orth RJ (1998)Genetic diversity and structure of natural and transplanted eelgrass populations in the Chesapeake Bay. Estuaries, 21 (1), 118–128.Google Scholar
  80. Wright S (1978)Evolution and the Genetics of Populations. Vol. 4. Variability Within and Among Natural Populations. University of Chicago Press, Chicago, IL.Google Scholar
  81. Zar JH (1998)Biostatistical Analysis. 4th edn. 929 pp. Prentice Hall, NY.Google Scholar

Copyright information

© Kluwer Academic Publishers 2004

Authors and Affiliations

  • Jennifer M. Rhode
    • 1
  • J. Emmett Duffy
    • 1
  1. 1.School of Marine ScienceCollege of William and Mary, Virginia Institute of Marine ScienceUSA

Personalised recommendations