You are here:
Hybridization between invasive Spartina Densiflora (Poaceae) and native S. Foliosa in San Francisco Bay, California, USA
AYRES, D. R., E. K. GROTKOPP, K. ZAREMBA, C. M. SLOOP, M. J. BLUM, J. P. BAILEY, C. K. ANTILLA, AND D. R. STRONG. Hybridization between invasive Spartina Densiflora (Poaceae) and native S. Foliosa in San Francisco Bay, California, USA. AMERICAN JOURNAL OF BOTANY. Botanical Society of America Inc., ST. Louis, MO, 95(6):713-719, (2008).
The goals of this research are to: (1) determine how landscape characteristics relate to the spread of red shiner through southeastern river systems, (2) identify behavioral and genetic mechanisms underlying interspecific hybridization, and (3) develop models to assess the vulnerability of tributary streams to invasion by red shiner.
Rapid evolution in contemporary time can result when related species, brought together through human-aided introduction, hybridize. The evolutionary consequences of post introduction hybridization range from allopolyploid speciation to extinction of species through genetic amalgamation. Both of these processes are known to occur in the perennial cordgrass genus, Spartina. Here we report the existence of a third Spartina hybridization, discovered in 2002, between introduced S. densiflora and native S. foliosa in San Francisco Bay, California. Coupling classical cytological methods with contemporary methods of flow cytometry, as well as nuclear and chloroplast DNA analysis, we found 32 F1 diploid hybrids and two triploid plants. The presence of diploid and triploid plants is important as it indicates that several avenues exist which may give rise to a new allopolyploid species, offering unique opportunities to observe the inception of a new species as evolution unfolds over decadal timescales.