Sunday, October 25, 2009

Alkali grass apparently extirpated from Soda Springs, Tuolumne Meadows, Yosemite National Park

The Soda Springs at Tuolumne Meadows were first visited by botanists in 1863, when William H. Brewer and the California Geological Survey first encamped there. The springs are gas charged and mineralized [ca. 2.2 mS in August 2008]: they form a marsh dominated by halophytic vegetation characterized by arrowgrass (Triglochin coccinea and T. maritima) etc. at 8600 feet [2640 meters] An alkali grass, Puccinellia nuttalliana, has been collected twice at the Soda Springs: in 1944 by John Thomas Howell, and again in 1949 by Carl W. Sharsmith. Puccinellia nuttalliana was not relocated when comprehensive vegetation inventory of Soda Springs was conducted in 2004.

I visited the Soda Springs at Tuolumne Meadows on August 18, 2009 with the specific intent of locating Puccinellia nuttalliana. I did not relocate the occurrence. Has it become extirpated?
Presumably this halophytic grass would occur in the most saline portions of the spring outflow, where visitors do not regularly tread [being confined to the path that traverses the spring outflow]

In the 1976-1977 drought, Triglochin coccinea became extirpated in a mineralized spring in the Harvey Monroe Hall Natural Area, where it had been recorded by Clausen & Keck decades before. It is uncertain when Puccinellia nuttalliana might have disappeared at the Soda Springs, but the 1976-1977 drought would be a good first suspect.

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