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United States Department of Agriculture

Agricultural Research Service

Title: Taxonomic Confusion Permits the Unchecked Invasion of Vernal Pools in California by Glyceria declinata

Authors
item Gerlach, J - TECHNOLOGY ASSOCIATES
item Bushman, Shaun
item Mckay, J - COLORADO STATE UNIV.
item Meimberg, H - COLORADO STATE UNIV.

Submitted to: Invasive Plant Science and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 12, 2008
Publication Date: January 1, 2009
Citation: Gerlach, J.D., Bushman, B.S., Mckay, J.K., Meimberg, H. 2009. Taxonomic Confusion Permits the Unchecked Invasion of Vernal Pools in California by Low Mannagrass (Glyceria declinata). Journal of Invasive Plant Science and Management 2:92-97.

Interpretive Summary: Chloroplast DNA molecular markers and recently established morphological characters were used to confirm the widespread invasion of California's vernal pools by European low Glyceria (Glyceria declinata). Morphological similarities between low Glyceria and western mannagrass (Glyceria occidentalis) have led to different taxonomic treatments depending on the geographical extent of a particular flora. When California's flora was last revised, the two species were combined as western mannagrass which was then considered to be a native species. Unfortunately, the revised flora was published just as low Glyceria began to rapidly expand its range within the state and, because it was considered to be a native species in the new flora, no actions were initiated to limit the invasion. Our data show that low Glyceria was present at all localities in the Central Valley of California that were investigated, indicating a widespread and undetected invasion. The invasion has led to a serious degradation of the vernal pool ecosystems, which are the habitat of many federal and state protected endangered and threatened species.

Technical Abstract: Chloroplast DNA molecular markers and recently established morphological characters were used to confirm the widespread invasion of California's vernal pools by European low Glyceria (Glyceria declinata). Morphological similarities between low Glyceria and western mannagrass (Glyceria occidentalis) have led to different taxonomic treatments depending on the geographical extent of a particular flora. When California's flora was last revised, the two species were combined as western mannagrass which was then considered to be a native species. Unfortunately, the revised flora was published just as low Glyceria began to rapidly expand its range within the state and, because it was considered to be a native species in the new flora, no actions were initiated to limit the invasion. Our data show that low Glyceria was present at all localities in the Central Valley of California that were investigated, indicating a widespread and undetected invasion. The invasion has led to a serious degradation of the vernal pool ecosystems, which are the habitat of many federal and state protected endangered and threatened species.

Last Modified: 12/27/2014
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