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Wildlife, Animals, and Plants |
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BOTANICAL AND ECOLOGICAL CHARACTERISTICS
GENERAL BOTANICAL CHARACTERISTICS:Foxtail chess is a cool-season [59] exotic annual grass with culms from 4 to 28 inches (10-70 cm) tall. The inflorescence is a panicle, 1 to 4 inches (3-11 cm) tall, with long awns [61]. The typical subspecies is distinguished from red brome by having relatively hairier stems and leaf sheaths, more lax panicles, and wider lemmas [1,39]. Foxtail chess is drought resistant, with high water-use efficiency [10,20].
RAUNKIAER [66] LIFE FORM:Therophyte
REGENERATION PROCESSES:Foxtail chess germinates well under the winter temperature regime of southern California [3]. Sunlight may enhance germination at higher temperatures. Freshly harvested red brome seeds are unable to germinate in the dark at temperatures above 59 degrees Fahrenheit (15 °C), but freshly harvested seeds usually germinate in the dark at temperatures between 41 and 59 degrees Fahrenheit (5-15 °C). White light inhibits germination even at low irradiance. Dry storage at 68 degrees Fahrenheit (20 °C) removes the inhibitory effects of higher temperatures ( > 68 degrees Fahrenheit (20 °C)), widening the seeds' temperature range for germination and eliminating their sensitivity to light [26]. Red brome germinates at a less exact rainfall and temperature requirement than native species [11]. In general, fall rains promote germination and establishment . In blackbrush communities of southern Nevada, Beatley [10] found red brome germination followed heavy rains (> 1 inch (3 cm)) between October and December. However, germination is not limited to fall and may occur following heavy spring rains. Laude [52] evaluated seedling emergence from freshly harvested and stored red brome seeds, which were were planted in a greenhouse setting and monitored for 28 days. Increased storage time increased percent emergence, with germinants achieving 100% emergence in October, 5 months after mid-June seed collection. High levels of cadmium and nickel impair emergence of red brome [60].
SITE CHARACTERISTICS:Foxtail chess prefers disturbed sites in Mediterranean climates [39,61]. Elevational ranges of foxtail chess are described below by state:
Regional: In California, foxtail chess prefers areas receiving less than 9.8 inches (250 mm) annual rainfall [8]. Foxtail chess is a dominant species in California valley grasslands receiving less than 7.5 inches (190 mm) rainfall [38], and is abundant in California valley grasslands receiving less than 12 inches (305 mm) annual precipitation. In areas with annual precipitation greater than 12 inches (305 m), foxtail chess is replaced by soft chess (Bromus mollis) [7,8].
Bowers [18] monitored the relative abundance of northern Mojave Desert annuals over 6 years
in relation to precipitation. Red brome density was highest during years
receiving 2.4 to 4.2 inches (63-109 mm) precipitation; results are summarized
below.
Soils: Red brome commonly occurs in small patches on shallow soils, growing best where there is little competition from other annuals [80]. In southern Nevada, red brome occupies blackbrush communities with coarse-textured soils, showing best growth under shrubs and peripheries of shrub canopies [10]. Upland clay and sandy loam ranges and rolling sandy hills receiving 8 to 12 inches (203-305 mm) precipitation promote good growth in southern Utah 60]. Red brome is often found in areas with relatively high levels of sulfur dioxide pollution [64].
SUCCESSIONAL STATUS:The presence of foxtail chess is closely related to annual precipitation. Foxtail chess is commonly an early or mid-seral species where annual precipitation is greater than 9.8 inches (250 mm) [38].
Red brome is commonly an early to mid-seral species in California chaparral. It is usually sparse in early succession
chaparral systems
of northern California but may increase rapidly in areas of low soil fertility and moisture [15].
Peak
population numbers require several years for seed dispersal into burns or buildup from on-site producers.
Continued disturbance such as grazing and repeated low-severity fires favor red brome over native
early-seral chaparral species [47].
SEASONAL DEVELOPMENT:In general, red brome initiation and establishment is a direct response to fall rains. Initial growth is relatively slow, followed by a rapid increase in vegetative growth coinciding with warming spring temperatures [8]. Flowering and fruiting generally occur in April and May [10]. Seeds are disseminated in summer [8]. No profound phenological differences are apparent between red brome individuals from the Mediterranean and California regions [43]. However, Wu and Jain [79] have observed phenological variation in seed weight, lemma length, plant height, and tiller production between populations of different environments.
Related categories for SPECIES: Bromus madritensis | Foxtail Chess |
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