CPC National Collection Plant Profile
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Puccinellia howellii
Family: |
Poaceae |
Common Name: |
Howell's alkali grass |
Author: |
Davis |
Growth Habit: |
Perennial |
CPC
Number: |
13543 |
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Primary
custodian for this plant in the CPC National Collection of Endangered
Plants is: |
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Edward Guerrant, Ph.D. contributed to this Plant Profile. |
Puccinellia howellii
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A small cluster of mineral springs in Shasta County, California is the only place that the perennial bunchgrass Puccinellia howellii has ever been found. The total spring area is only 1.2 acres (about 52,000-sq. ft.), and the limited habitat makes this species particularly vulnerable to catastrophic events. This very specific habitat for Howell's alkaligrass is unfortunately located directly adjacent to a state highway and has been subjected to disturbances and destruction from garbage dumping, vehicle parking, accidents, road construction, road maintenance, and pollution. In the mid-90's, the California Department of Transportation (CalTrans) re-aligned the road resulting in the loss of 1,200 square ft. of habitat from one spring. To offset this destruction, CalTrans workers restored a section of another spring that had been disturbed by bridge construction and covered with fill in the 1950's. Transplantation of P. howellii into the restored area was initially successful, but as of 2001 competition from saltgrass (Distichlis spicata), a native but invasive and aggressive grass, is threatening the success of the restoration. The original disturbance in the 1950's allowed D. spicata to gain a foothold in the springs.
Protection of the site from further disturbance will be critical to the continued survival of Howell's alkaligrass. Although saltgrass has already invaded the disturbed areas, effective methods of control have been developed. Efforts must be made to ensure that further habitat disturbances do not give saltgrass additional opportunities to colonize. In this instance, it is abundantly clear that human caused disturbance has been the instrument of destruction. Protection of the springs will not only benefit this species and other native plants, but wildlife as well, as the springs are an important source of salt for local wildlife, especially the black-tailed deer (think salt licks) and the band-tailed pigeon. (Fulgham et al. 1997).
Distribution
& Occurrence |
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State Range
Habitat
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Found in a specific cluster of three high salt content mineral spring and seeps at approximately 1640 ft. (500m) elevation. Associated species include Juncus bufonius, Spergularia marina, Triglochin maritima, Distichlis spicata (saltgrass) and Polypogon monspeliensi. |
Distribution
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CA: Klamath Range (Shasta Co.) |
Number Left
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One Site/ One population/ three sub-populations, one at each spring. Total population estimated at several thousand in 1990 (S. Morey field survey in CA Natural Diversity Database).
The total spring area is only 52,000 square ft, or about 1.2 acres. Spring #1 is (estimated) ~0.613 acre, spring #2 is ~0.526 and spring #3 is ~0.074 acre (Fulgham et al. 1997). |
State/Area
Protection
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State/Area |
Rank |
Status |
Date |
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Conservation,
Ecology & Research |
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Ecological
Relationships
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Most members of the genus Puccinellia are endemic to highly saline or mineralized soils, with all members being found on some saturated, saline, or alkaline substrate. Puccinellia howellii is the dominant vegetation found in this specific series of mineral seeps. They have Cl- (Chloride) concentrations up to 10.8 g/l, and high Na+ (Sodium) concentrations. (Davis 1990).
High levels of soil salinity impose extreme stresses on plants by lowering water availability in the soil. The accumulation of toxic ions such as sodium, chloride, and magnesium can disrupt plant metabolism. Saline soils often have low fertility, due to limited nitrogen. Research has shown that many halophytes (plants that grow in saline conditions) are able to grow on non-saline media, but under natural conditions they are restricted to high saline areas due to an inability to compete with other species (Bacca 1995).
Howell's alkaligrass reproduces only by seed (Bacca, 1995). The plants must grow for two years before they are able to flower and produce seed. Seed can be dispersed both by water flow and by animals such as the black-tailed deer and the band-tailed pigeon (Fulgham et al. 1997). After flowering, the plants gradually die back (Stacey 2001).
After the fall rains begin, the water in the springs is diluted and germination is possible. Vegetative growth occurs primarily in the fall, winter, and spring (Oct.-May) when temperatures are cool and salt concentrations are moderate. The plants go though a period of relative dormancy and/or senescence during the hottest summer months (June-Sept.) when evaporation leads to high salt concentrations (Fulgham et al. 1997).
Howell's alkaligrass grows best (as large, monotypic stands) in developed soil with a permanent supply of mineralized water. In less developed soils they occur in smaller clumps or as scattered individuals. They have even been observed growing in vertical rock walls where water seeps occur.
Distichlis spicata (saltgrass) also grows in the salt spring area. It is native to California, but can be very invasive. It is an aggressive, warm-season grass that spreads via rhizomes and can rapidly colonize an area. Saltgrass is able to grow in high salt concentrations because its roots and leaves are able to extrude salts and its roots can selectively take up ions. In addition, its rhizomes can spread great distances both vertically and horizontally, allowing it to take resources from a large area (Bacca 1995). There is concern that this species may eventually out-compete and exclude P. howellii from the area (Bacca 1995). Additionally, saltgrass is considered poor forage, and may not be as palatable for deer as Puccinellia howellii (USDA 2001). Saltgrass is found at all three springs, but it is only considered invasive in the disturbed portions of the spring (Stacey 2001). D. spicata is not as tolerant of inundation as P. howellii is, indicating that it may be possible to control invasion by lowering the grade of the area so that spring seepage would occur year-round (Fulgham et al. 1997). |
Threats
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The only known population is located along a state highway.
Small population size makes it susceptible to extinction due to random events.
Invasion and exclusion by Saltgrass (Distichlis spicata) (Bacca 1995). Saltgrass is present at all springs, but only invasive in disturbed areas of the springs (Stacey 2001).
Off-Road-Vehicle use
Pollutant spills and physical damage due to vehicle accidents
Garbage dumping
Changes in hydrology of area |
Current Research Summary
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Extensive inventories of mineral springs in the region have yielded no other populations. Fifteen springs in the nearby area have been searched with negative results (Villa and Martz 1991).
Genetic (isozyme) studies of P. howellii show a high degree of genetic diversity among individuals and that P. howellii is genetically distinct from other Puccinellia species in the region (Davis 1993).
Investigation of control methods for saltgrass (Distichlis spicata), a potentially invasive species. Prescribed burning, clipping, and herbicide application (a glyphosate-based product, RODEO, the commercial version of ROUNDUP) were studied. For burn treatments, the entire plot was burned. For clip and herbicide treatments, only the area of the plot dominated by D. spicata was treated. Only application of RODEO was found to be effective. All other methods encouraged regrowth of the saltgrass. Several herbicide applications directly to the saltgrass may be necessary for effective treatment (Bacca 1995).
Greenhouse tests of germination and growth at different salinity levels demonstrated that germination is greatest in fresh water and is delayed as salinity increases (this reinforces observations that seeds germinate after fall rains when spring water is diluted). Growth is greatest at a moderate salinity level (Fulgham et al. 1997).
Determination of habitat requirements revealed that low magnesium, high winter salinity, and inundation by water characterizes the microhabitat of the species (Fulgham et al. 1997).
Demographic studies: Reproductive output, seedling recruitment, seedling survival (Fulgham et al. 1997).
Germination tests at the Berry Botanic Garden revealed high germination percentages under a variety of conditions. Seeds were either cold stratified for eight weeks or not stratified. They were then placed in either constant 68°F (20°C) or alternating 50°/68°F (10°/20°C) growth chambers. The only treatment not to show 100% germination was the "no cold stratification followed by alternating temperatures," which yielded 83% germination (BBG File).
Management Summary:
The California Department of Transportation (CalTrans) re-aligned the road running by the springs to increase safety. Work involved widening and straightening the road and the installation of guardrails. Retaining walls were erected to keep fill material from impacting much of the springs, but 1,200-sq. ft. of spring habitat was covered. Although the road re-alignment was not undertaken to benefit P. howellii, a decrease in the number of accidents and pollution and the elimination of vehicle access to the springs will benefit the species (Villa and Martz 1991).
Restoration of 1,200-sq. ft. of a nearby spring to mitigate for area lost during road re-alignment (Fulgham et al. 1997). Puccinellia howellii seedlings and transplants grew well for the first two years. Saltgrass eventually invaded the disturbed areas and out competed the P. howellii (Stacey 2001).
Spraying and removal of invading saltgrass. The area naturally re-seeded with P. howellii, and after one year, the area was nearly covered. Observations will be made on any subsequent invasion of saltgrass (Stacey 2001).
Fences erected around clumps of P. howellii. Though only erected for a brief period of time, results showed that the grass is heavily impacted by grazing, presumably by deer (Fulgham et al. 1997)
Seeds collected from each of three springs is stored at The Berry Botanic Garden. |
Current Management Summary
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The California Department of Transportation (CalTrans) re-aligned the road running by the springs to increase safety. Work involved widening and straightening the road and the installation of guardrails. Retaining walls were erected to keep fill material from impacting much of the springs, but 1,200-sq. ft. of spring habitat was covered. Although the road re-alignment was not undertaken to benefit P. howellii, a decrease in the number of accidents and pollution and the elimination of vehicle access to the springs will benefit the species (Villa and Martz 1991).
Restoration of 1,200-sq. ft. of a nearby spring to mitigate for area lost during road re-alignment (Fulgham et al. 1997). Puccinellia howellii seedlings and transplants grew well for the first two years. Saltgrass eventually invaded the disturbed areas and out competed the P. howellii (Stacey 2001).
Spraying and removal of invading saltgrass. The area naturally re-seeded with P. howellii, and after one year, the area was nearly covered. Observations will be made on any subsequent invasion of saltgrass (Stacey 2001).
Fences erected around clumps of P. howellii. Though only erected for a brief period of time, results showed that the grass is heavily impacted by grazing, presumably by deer (Fulgham et al. 1997)
Seeds collected from each of three springs is stored at The Berry Botanic Garden. |
Research Management Needs
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Removal of Distichlis spicata (saltgrass), followed by re-seeding or transplanting of Puccinellia howellii (Bacca 1995).
Study effect of flooding and inundation on D. spicata (Fulgham et al. 1997).
Continued protection of site from disturbances. D. spicata is only invasive in areas of the spring that have been disturbed to some extent.
Limit roadside application of herbicides |
Ex Situ Needs
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Determine long term viability of seeds and recollect as necessary. The last seed collection stored at The Berry Botanic Garden is from 1992. All collections are bulk; there is no separation of maternal lines. (1 accession bulk from all 3 springs, 3 accessions-1 from each spring).
Long term seed storage. |
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Books (Single Authors)
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Nakamura, Gary; Kierstead Nelson, J. 2001. Illustrated Field Guide to Selected Rare Plants of Northern California. University of California, Agriculture and Natural Resources. Publication 3395. 370p.
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Books (Edited Volumes)
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James C. Hickman, Editor. 1993 The Jepson manual: Higher plants of California. Berkeley: University of California Press. 1400p.
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Electronic Sources
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CDFG. (2001). Special Vascular Plants, Bryophytes, and Lichens List. Biannual Publication, Mimeo. 141 pp. California Department of Fish and Game, Natural Diversity Database. Accessed: 2001.
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CNDDB. (2000). Calfornia Natural Diversity Data Base (CNDDB). Version 2.1.2. California Natural Diversity Database. Accessed: California Department of Fish and Game, Sacramento.
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USFS. (2002). Sensitive and Endemic plant species known or suspected to occur on the Shasta-Trinity National Forest. Shasta-Trinity National Forest. http://www.r5.fs.fed.us/shastatrinity/manage/wildlife/plants/. Accessed: 2002.
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Journal Articles
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Davis, J.I. 1990. Puccinellia howellii (Poaceae), a new species from California. Madroρo. 37, 1: 55-58.
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Davis, J.I. 1993. Puccinellia howellii (Poaceae) is genetically distinct. Madroρo. 40, 4: 202-208.
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Levine, L.; Bacca, M.; Fulgham, K. O. 2002. Plant zonation in a Shasta County salt spring supporting the only known population of Puccinellia howellii (Poaceae). 49: 178-185.
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Personal Communications
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Stacey, S. 2001. E-mail communication to Rebecca Weaver dated Aug. 13, 2001. Sharon Stacey, California Department of Transportation, District 2, Redding, CA. On file at The Berry Botanic Garden.
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Reports
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Fulgham, K.O.; Levine, L.; Bacca, M. 1997. Autecological study of Puccinellia howellii (Howell's Alkaligrass) located in three mineralized springs found within CALTRANS right-of-way in Shasta County, CA. CALTRANS Project Final Report on Contract No. 02E326. p.90.
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Villa, S.L.; Martz, C.P. 1991. Mitigation and Monitoring Plan for 1.3 miles of realignment of Rout 299, in Shasta County from 1.4 miles west of Trinity Mountain Road to 0.2 mile west of clear Creek Bridge (Crystal Creek Curves Project). Department of Transportation, District 2 and Office of Environmental Analysis. p.15+.
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Theses
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Bacca, M.A. 1995. Control Strategies to Inhibit Saltgrass (Distlichlis spicata) Encroachment upon Howell's Alkali Grass (Puccinellia howellii) at an Inland Mineralized Spring Area in Shasta County, California. [Masters Thesis]: Humboldt State University. Arcata, California. 110p.
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This
profile was updated on 3/4/2010 |
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