Proceedings of the Third International Conference on Invasive ...

<strong>Proceedings</strong> <strong>of</strong> <strong>the</strong> <strong>Third</strong> <strong>International</strong> <strong>Conference</strong> on Invasive SpartinaChapter 2: Spartina Distribution and SpreadSpartina hybrid seedling occurrence is highest atinvaded mudflat sites. While recruitment is mainly local,seed exportation on <strong>the</strong> tide will likely intensify aspopulations grow and expand. We predict that transgressivehybrid plants, with <strong>the</strong> greatest reproductive fitness willdrive <strong>the</strong> spread, colonizing new open mudflat sites allaround SFB at an ever-increasing rate. This will not onlyfur<strong>the</strong>r threaten <strong>the</strong> persistence <strong>of</strong> <strong>the</strong> native Californiacordgrass S. foliosa (Ayres et al. 2003), but will likelyirreversibly change <strong>the</strong> character <strong>of</strong> <strong>the</strong> SFB ecosystem.Open mudflats will turn into hybrid Spartina meadows,which over time, after <strong>the</strong> accretion <strong>of</strong> sediment, will changefrom intertidal to terrestrial systems.ACKNOWLEDGMENTSWe would like to thank Team Spartina at UC Davis, andacknowledge <strong>the</strong> financial support from <strong>the</strong> CaliforniaCoastal Conservancy (CalFed grant #99_110), CaliforniaSea Grant #27CN to DRS, and NSF Biocomplexity DEB0083583 to A. Hastings and D.R. Strong.REFERENCESAyres, D.R., D.R. Strong, and P. Baye. 2003. Spartina foliosa(Poaceae): A common species on <strong>the</strong> road to rarity? Madrono.50:209-213.Ayres, D.R., D.L. Smith, K. Zaremba, S. Klohr, and D.R. Strong.2004. Spread <strong>of</strong> Exotic Cordgrasses and Hybrids (Spartina sp.)in <strong>the</strong> Tidal Marshes <strong>of</strong> San Francisco Bay, California, USA.Biological Invasions 6:221-231.Ayres, D.R., K. Zaremba, C.M. Sloop, D.R. and Strong. 2008.Sexual reproduction <strong>of</strong> cordgrass hybrids (Spartina foliosa x alterniflora)invading tidal marshes in San Francisco Bay. Diversityand Distributions 14:187-195.Blum, M.J., C.M. Sloop, D.R. Ayres, and D.R. Strong. 2004. Characterization<strong>of</strong> microsatellite loci in Spartina species (Poaceae).Molecular Ecology Notes 4:39-42.Gerber, S., P. Chabrier, and A. Kremer. 2003. Famoz: a s<strong>of</strong>twarefor parentage analysis using dominant, codominant and uniparentallyinherited markers. Molecular Ecology Notes 3: 479-481.Sloop, C.M, H.G. McGray, M.J. Blum and D.R. Strong. 2005.Characterization <strong>of</strong> 24 additional microsatellite loci in Spartinaspecies (Poaceae). Conservation Genetics 6:1049–1052.Sloop, C.M., D.R. Ayres, D.R. Strong. 2009. The rapid evolution <strong>of</strong>self-fertility in Spartina hybrids (S. alterniflora x foliosa) invadingSan Francisco Bay, CA. Biological Invasions 11:1131-1144.-97-