Basin wildrye grows on sites subject to environmental extremes: freezing and thawing as well a saturated soils in spring followed by hot, desiccated soils in summer [6,27,72].
Elevation: The general elevation range of basin wildrye is 1,970 to 9,840 feet (600-3,000 m) [27,66]. It grows at 1,000 to 2,000 feet (300-600 m) in drainage basins and up to almost 10,000 feet (3,000 m) in mountains [66,129,132]. The elevation distribution of basin wildrye is presented by state in the following table:
State Elevation References California <9,840 (3,000 m) [66] Idaho 4,920 feet (1,500 m) [6] Montana 3,500-7,500 feet (1,060-2,300 m) [113] Nevada 5,200-8,400 feet (1,600-2,600 m) [21,22,91] New Mexico 5,000-8,000 feet (1,500-2,400 m) [84] Utah 2,590-9,515 feet (790-2,900 m) [12,132] Wyoming 3,000-6,770 feet (915-2,060 m) [15,120,126]
Climate: Basin wildrye generally requires at least 8 inches (200 mm) of precipitation per year [35], but may be adapted to sites receiving 5 to 20 inches (130-500 mm) [16,27,116]. A breakdown of annual average precipitation by state is found below:
State Average Annual Precipitation References Idaho 8.8 inches (224 mm), 36% during April-June [6] Montana <13 inches (330) [69] Nevada 11.4 inches (290 mm) [21,22] Utah 9 to 17 inches (230-430 mm) [12,121] Wyoming 5 to 19 inches (130-220 mm) [15]
Basin wildrye grows at locations experiencing 3 to 4 frost-free months [6,12,15].
Topography: Basin wildrye is found on dry to moist sites [132], often occurring on bottomlands and uplands where lateral drainage and soil water are high [4,33,69,92,113,116,129]. Basin wildrye is commonly found on floodplains [25,82], prairies and foothills [27,132] with gentle to moderate slopes [127], and along streams, gullies, and roadsides [17,27,32,66,68,92,113,132].
Soils: Basin wildrye is commonly found on low lying areas with deep [1,6,27,30,113,127], well-drained soil [27,82,127], though it may also grow on poorly drained soil [120]. Basin wildrye may be intolerant of shallow soils and does not perform well on deep, coarse soils, though it is adapted to a wide range of other soil types [33,116]. It is found on fine-textured [82,129], calcareous clay soils with claypan layers around 17 inches (43 cm) deep [12], and on sandy to gravelly soils [16,17,25,68,129]. It experiences optimal growth on silty and clayey soils [129]. Soil depths on basin wildrye sites range from 12.5 to 27.5 inches (32-70 cm) [25]. Basin wildrye generally prefers deeper soils with higher effective rooting depth and/or greater effective moisture content than adjacent areas [33]. A field study in Colorado found that basin wildrye produces more biomass on sites with topsoil depth of 24 inches (60 cm) than on soil depths of 6, 12, or 18 inches (15,30, 45 cm) [102].
Basin wildrye's size and annual production suggest high seasonal water use [1,6]. However, basin wildrye has high water-use efficiency, making it tolerant of water stress [5,27]. Basin wildrye maintains its growth into the dry summer months as long as moisture remains available [5], actively photosynthesizing and transpiring after seed ripening [6]. Established stands of basin wildrye can survive long periods of summer drought [56]. Bain wildrye is also tolerant of acidity, alkalinity, and salinity [16,25,27,56,69,82,89,92,113,116,120,129]. Though well adapted to saline, arid soils, basin wildrye may require supplemental irrigation to establish from seed [108]. In laboratory experiments, basin wildrye was less tolerant of salinity at germination than at the seedling stage of development, provided salinization was gradual. Abrupt increases in salinity may result in death regardless of developmental stage [28]. Though plants survived soil osmotic potential down to -3.5 mP, the 'Magnar' cultivar of basin wildrye grown in salinized greenhouse cultures demonstrated reduced root and shoot growth and grew very little at soil osmotic potential below -1 mP [107].
Basin wildrye may also be abundant on sites with high potassium concentrations [127].