Alkali Meadow
Alkali meadow communities: Alkali meadows occur in areas where the water table is shallow (one to three meters deep), and soils are alkaline. They are probably the most distinctive native plant communities in Owens Valley. In California, outside the Eastern Sierra alkali meadows remain only in small fragments in the southern Central Valley, and on the Modoc Plateau (Davis 1998), and are classified as “very threatened” by the California Natural Diversity Database (Sawyer and Keeler-Wolf 1995). In the Great Basin, alkali meadow is not even recognized as a major plant community (Cronquist 1986, Barbour and Billings 1988). In 1864, however, William Brewer estimated meadows to cover up to 10% of the entire Owens Valley (Farquahr 1974), while DWP estimated that meadows occupied about 25% of its Owens Valley holdings in 1984.
Owens Valley meadows are distinctive due to their topographic positions as well as their extent. While meadows typically occur throughout the Great Basin in narrow flood plains along rivers and streams, alkali meadows in Owens Valley also occurred in a broad zone at the toe slopes of the giant alluvial fans coming down the west side of Owens Valley from the Sierra. According to Lee (1912):
The grass or meadow lands...extend well out into the level valley. The growth is most luxuriant in the spring zone, which is about a quarter of a mile wide and is situated at the upper edge [i.e. the upslope edge on the west side] of the valley floor. Here are numerous small flowing springs ... which start the meadow grass early in the season and keep it green until late in autumn. Farther out in the valley [i.e. to the east, approaching Owens River] the salt grass makes a green carpet from May until late July... In the salt grass land there is always a deposit of alkali around the plant roots, and the soil surface is crusted. The spring zone, however, is free from alkali.
Two native grasses are characteristic of Owens Valley alkali meadows: Sporobolus airoides (sacaton) and Distichlis spicata (saltgrass). The meadows are home to several endangered species such as state-listed Sidalcea covillei (Coville’s checkerbloom) and CNPS-listed Calochortus excavatus (Inyo County star tulip), Crepis runcinata ssp. hallii (Hall’s meadow hawksbeard), and Spartina gracilis (alkali cordgrass). Other common common graminoids are Leymus triticoides (beardless wildrye) and Juncus balticus (Baltic rush), while Glycyrrhiza lepidota (American licorice) and Haplopappus racemosus are some of the more common perennial herbs (Manning 1997). Total grass cover in relatively unimpacted meadows ranges from as low as 15% to as high as 100%. In many meadows, however, the shrub species Chrysothamnus nauseosus (rabbitbrush) and Atriplex lentiformis ssp. torreyi (Nevada saltbush) are present and increasing in abundance over time. Evidence suggests that when meadows are subject to pumping-induced water table drawdowns, they are vulnerable to conversion to alkali scrub communities (Manning 1999). While some shrubs were undoubtedly present in meadows at the time of European settlement, it is interesting to note that none of the early observers of the valley noted their presence in meadows.
Alkali meadows provide valuable forage for livestock and without proper management may suffer grazing impacts. They are also reliable indicators of shallow water tables and thus are the sites of many of Los Angeles's groundwater pumps. Given the biological value of meadows and the potential for both grazing and pumping impacts, their condition in Owens Valley is one of the key indicators by which the effectiveness of management under the Inyo-LA Water Agreement can be measured. To date, results show pumping management is failing in many parcels (Manning 2002).
