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US Fish & Wildlife Service FieldNotes
STOCKTON FWO: Conserving the Imperiled Howell’s Saltgrass (Puccinellia howellii) in Northern California
Region 8, February 24, 2008
Howell's saltgrass(photo courtesy Keith Paul, FWS)
Howell's saltgrass(photo courtesy Keith Paul, FWS) - Photo Credit: n/a
Monotypic stand of Howell's saltgrass(photo courtesy Keith Paul, FWS)
Monotypic stand of Howell's saltgrass(photo courtesy Keith Paul, FWS) - Photo Credit: n/a
Individual tufts of Howell's saltgrass (photo courtesy Keith Paul, FWS)
Individual tufts of Howell's saltgrass (photo courtesy Keith Paul, FWS) - Photo Credit: n/a
Construction of underdrain (photo courtesy Jennifer Gibson, NPS)
Construction of underdrain (photo courtesy Jennifer Gibson, NPS) - Photo Credit: n/a
Construction of underdrain (photo courtesy Jennifer Gibson, NPS)
Construction of underdrain (photo courtesy Jennifer Gibson, NPS) - Photo Credit: n/a
Rewatered habitat at Spring 1 (photo courtesy Jennifer Gibson, NPS)
Rewatered habitat at Spring 1 (photo courtesy Jennifer Gibson, NPS) - Photo Credit: n/a

by Keith Paul, Stockton FWO
Howell’s saltgrass is a short-lived, wetland alkali grass that is found in a complex of mineral springs along California State Highway 299 West, in Shasta County, Calif.  The plant is found on both state and federal lands and is unevenly distributed within the three mineral springs at an elevation of approximately 1,350 feet along a 1,200-foot reach of Willow Creek.  Howell’s saltgrass was recognized as a distinct species in 1990 and is known from only one population totaling approximately 1 acre.  This species has been described as one of the rarest in North America.  Despite extensive surveys of similar mineral spring habitats in Northern California, no additional Howell’s saltgrass populations have been found.

A 1992 curve realignment project eliminated 1,200 square feet of the springs and 2.9 percent of Howell’s saltgrass cover by burying a portion of the site under the road fill.  The realignment project also changed the overland flow patterns, the salinity of the water and sediment discharge in habitat formerly occupied by Howell’s saltgrass.  After the highway realignment project, large patches of Howell’s saltgrass died allowing saltgrass (Distichlis spicata) to invade.

In February 2006, a Conservation Agreement for Howell’s saltgrass was signed by the U.S. Fish and Wildlife Service, the National Park Service, the California Department of Transportation, and the California Department of Fish and Game to minimize threats to the species, restore the mineral spring habitat, and improve the status of Howell’s saltgrass through the expansion of the existing population, discovery of additional populations, and/or the establishment of new sustainable populations.  Participants were confident that implementation of the Conservation Agreement would preclude the need to list this rare plant either by the State of California or the U.S. Fish and Wildlife Service. 

With the signing of the Conservation Agreement, a research project was initiated by Colorado State University to determine the habitat requirements for Howell’s saltgrass and identify potential threats, which are primarily associated with California State Highway 299 West.  As a result, “A Restoration and Monitoring Plan for Howell’s Saltgrass, Whiskeytown National Recreation Area, California” was completed by Colorado State University in 2007.  Several recommendations for site restoration were identified by their research.  One was to re-establish saline water flow back onto part of the habitat that was de-watered during the highway realignment in 1992.  During June of 2008, a drain system was installed at the site under the roadside berm.  The underdrain successfully restored spring water flow onto the eastern half of Spring 1.  At present, individual plants are already beginning to colonize and expand into new areas.  This is a critical first step towards achieving the goals delineated in the Conservation Agreement.

Currently, stakeholders are preparing an environmental analysis and securing funding to implement other conservation actions identified by the Colorado State University research.  The recommendations include: 1) bypassing fresh water runoff around one of the springs into Willow Creek, 2) installation of a stormwater runoff catchment bypass to transport freshwater runoff and sediment to an off site location, 3) removal of a sediment fan at one of the springs formed unnaturally by an under-highway culvert, and 4) removal of sediment from a spring resulting from past road runoff and sedimentation onto the site.  Removal of existing sediment to within approximately 8 inches of bedrock will occur in selected sites to more closely match conditions of suitable Howell’s saltgrass habitat.

The three springs discharge from numerous points, producing a sheet flow over much of the site as the water moves downhill.  A narrow range of salinity, pH, inundation, and sediment depth and flux provides suitable habitat for Howell’s saltgrass.  The patch size of this plant ranges from individual tufts to monotypic stands which have a dense turf-like growth.  Howell’s saltgrass tends to occupy the central portions of the springs, often intermingled with seaside arrowgrass (Triglochin maritima) in the wetter locations.  During periods of active Howell’s saltgrass growth, the central portions of the springs remain moderately saline during the rainy season, effectively excluding plants that can only tolerate relatively low concentrations of salt.  Saltgrass is often found at the periphery or at elevated areas within the springs adjacent to the surrounding non-saline vegetation where the influence of the spring discharge is less direct.  However, where there has been a disturbance to spring flow or the introduction of above normal sedimentation, saltgrass out competes Howell’s saltgrass.

Contact Info: Keith Paul, 530-527-3043, keith_paul@fws.gov