Hiding in Plain Sight

Delta Science Fellow Studies the Threat from Cryptic Cordgrass Hybrids

Researcher:

Laura Feinstein
Graduate student
Department of Evolution and Ecology
UC Davis
E.: lfeinstein@ucdavis.edu
T.: (530) 204-8325

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Revised:

December 12, 2011

Hybrid exotic Spartina thriving below the lower limit of the native Spartina meadow. In time, the tidal marsh -- a prime foraging habitat for migratory birds -- could become transformed into an expanse of grass. Credit: L. Feinstein

December 12, 2011

Contact: Christina S. Johnson, csjohnson@ucsd.edu, 858-822-5334

For several years now, the state of California has been battling the spread of an exotic marsh grass in San Francisco Estuary by spraying herbicide on offending stands of the highly invasive grass.

The $20-million-plus control effort has proven successful at preventing towering tuffs of Atlantic cordgrass hybridized with the native cordgrass from attacking marshes and mudflats and destroying hemispherically important wintering and foraging habitats for migratory birds.

Cryptic hybrid Spartina. Its short stature and delicate morphology would suggest that it is native Spartina, but its genetics prove otherwise. Credit: L. Feinstein

It has also, though, artificially selected for the survival of hybrid grasses that look native but in fact contain exotic genes. The presence, and perhaps now proliferation, of these cryptic hybrids has not occurred accidentally but as a by-product of the eradication strategy. This strategy has been based around the idea that only the most threatening, biggest, tallest and thickest, red-stemmed, big-flowered hybrid cordgrass plants would be sprayed. Stands of smaller-statured, more diminutive grasses that were presumed to be primarily native Spartina cordgrass were left alone.

An ongoing project funded by the Delta Science Program is examining the prevalence of these "cryptic" hybrids in the estuary and their potential to be resurgent and stage a second wave of invasion.

Those interested in learning more about the research, which is being led by Delta Science Fellow Laura Feinstein, a graduate student in the Department of Ecology and Evolution at UC Davis, can download "Frequency, Distribution and Ecological Impact of Cryptic Hybrid Invaders: Management Tools for Eradication of Invasive Spartina." (PDF)