More info for the terms: association, cover, density, mesic, phase, shrub, warm-season, xeric
Granite prickly-phlox occurs on dry, open, often sandy or rocky places from deserts and plains to alpine sites. Apparently granite prickly-phlox prefers full sun, medium to coarse soil textures, soil pH from moderately acid to moderately alkaline, and shallow to moderate soil depths [121].
Soils: Granite prickly-phlox occurs typically on coarse, shallow, skeletal, well-drained, nutrient-poor soils (e.g., [50,57,58,61,64,67,72,85,93,105]).
Order: Granite prickly-phlox grows on mollisols [13,148], aridisols [13,148], and entisols [148].
Texture: Most soils supporting granite prickly-phlox are coarse [1,15,45,46,59,63,124,134,136,139] and commonly rocky, gravelly, or cobbly (e.g., [1,4,77,82,105,119,120,126,142,148]). However, granite prickly-phlox also grows in very fine [13] and fine [15,44,45,86] soil textures. Granite prickly-phlox occurs in sand [15,134], loamy sand [40,40,45,59,63,99,134], loam [13,15,45,99,139], and sandy loam [46,59,86,99]. In old-growth western juniper woodlands of central Oregon, granite prickly-phlox increased with increased sand content at 7 sites [135]. Granite prickly-phlox occurred in Rocky Mountain juniper/antelope bitterbrush woodlands where coarse fragments constituted 33% to 45% of the soil profile and in Rocky Mountain juniper/big sagebrush woodlands where coarse fragments constituted 45% to 55% of the soil profile [59]. In the Cheyenne River Basin, it occurred in skunkbush sumac (Rhus trilobata)/bluebunch wheatgrass shrublands where coarse fragments of all sizes covered the ground surface and were abundant throughout the soil profile [124]. Less commonly, granite prickly-phlox is found in clay soils [13,45,63], although clay soils supporting granite prickly-phlox often have coarse fragments [63].
Depth: Soils supporting granite prickly-phlox are shallow [1,59,81,115,126,136,148] to moderately deep [124,126,136,146]. On No Man's Land Mesa in Utah, granite prickly-phlox occurred on upland sites in Colorado pinyon-Utah juniper woodlands but did not occur in Colorado pinyon-Utah juniper woodlands on upland shallow breaks, a result attributed to the "distinctly different" soils. The upland soils were deep (2-3 feet (0.6-0.9 m)), well-drained, loamy fine sands, whereas the shallow breaks soils were shallow, well-drained, very fine sandy loams [86]. On the Fremont National Forest, granite prickly-phlox occurred where total soil depth was 16 to 36 inches (41-91 cm); it was most common in soils <24 inches (61 cm) deep [63]. In Rocky Mountain juniper/antelope bitterbrush woodlands, granite prickly-phlox occurred in soils 2 to 9 inches (6-22 cm) deep. In Rocky Mountain juniper/big sagebrush woodlands, it occurred in soils 2 to 8 inches (4-20 cm) deep [59]. Granite prickly-phlox also occurred with trace cover in needle-and-thread grass/mountain muhly grasslands, where soils ranged from 17 to 26 inches (43-66 cm) deep [136]. In the Upper Rio Puerco watershed, New Mexico, granite prickly-phlox occurred in soils that were >60 inches (152 cm) deep with A horizons <10 inches (25 cm) deep [45].
Soils supporting granite prickly-phlox are often poorly developed, overlying bedrock [46,68] or claypan [40,148]. Near timberline in the central Sierra Nevada, granite prickly-phlox occurred in soils that were described as a "thin veneer of weathered rock with only a modicum of soil development" [68]. At the US Sheep Experiment Station, granite prickly-phlox occurred in threetip sagebrush-bluebunch wheatgrass shrublands where soils were 20 to 39 inches (50-100 cm) deep and underlain by basaltic bedrock [98]. Granite prickly-phlox often occurs in areas of exposed rock such as on rocky outcrops, benches, and ledges [9,59,115,117]. In many communities in which granite prickly-phlox occurs, such as black sagebrush communities, a dense claypan occurs close to the soil surface [148]. Soil depth to hardpan was 24 inches (61 cm) in big sagebrush/Idaho fescue shrublands in eastern Oregon [40].
pH and parent materials: Soils supporting granite prickly-phlox may be moderately acid [46,59,126,136], neutral [46,118,124,124], or moderately alkaline [59,118,124,136]. In Rocky Mountain juniper/antelope bitterbrush communities, granite prickly-phlox grew in soils with pH ranging from 6.6 to 6.8 [59]. In Rocky Mountain juniper/big sagebrush woodland, it grew in soils with pH ranging from 7.0 to 7.6 [59,136]. Granite prickly-phlox also occurred with trace cover in a needle-and-thread grass/mountain muhly grassland where soil pH ranged from 6.2 to 6.8 [136], and in a bristlecone pine woodland where soil pH ranged from 5.9 to 8.1 [144].
Granite prickly-phlox occurs in soils derived from many parent materials, including sandstone [77,91,126], granite [61,91,126], rhyolite [63], dolomite [91], limestone [9,61,126], gneiss [59,136], and schist [59,136]. It commonly occurs on substrates derived from volcanics [9,63,113,119], such as basalt at Craters of the Moon National Monument, Idaho [6,34], and andesite at Carson Pass, California [123]. In Oregon, granite prickly-phlox occurred in soils derived from pumice [134]. In big sagebrush steppe of the Snake River Plains, granite prickly-phlox density generally increased with lava flow age and crevice depth, with granite prickly-phlox apparently preferring old, soil-covered lava flows to young lava flows [43].
Granite prickly-phlox occurs in calcareous soil [44,84,98,144], but growth appears greater in noncalcareous soil [47,84,144]. In the White Mountains, Marchand [84] found that the distribution of the silvery lupine-big sagebrush-granite prickly-phlox association was negatively related to percent exchangeable potassium. In this study, granite prickly-phlox occurred on calcium carbonate (limestone- and dolomite-derived) and noncarbonate (basalt-, sandstone-, and adamellite-derived) substrates but was most common on noncarbonate substrates. It may have had a strong affinity for noncarbonate substrates, because carbonate substrates had low percent exchangeable potassium, high pH, low soil temperature, and low available phosphorus and iron [84]. In another study in the White Mountains, granite prickly-phlox occurred on dolomite (1.9 plants/50 m, 0.3% cover), sandstone (4.2 plants/50 m, 0.7% cover), and granite (3.9 plants/50 m, 0.7% cover), appearing less well developed on dolomite than other substrates. Dolomitic substrates had more available moisture, higher pH, and lower amounts of available phosphorus compared with other substrates [144]. In the San Bernardino Mountains of southern California, granite prickly-phlox occurred only on noncarbonate substrates [47].
Moisture: Granite prickly-phlox tolerates and is most common on xeric soils [1,59,105,123,136,147] but also grows on mesic soils [118]. Smith [118] stated that granite prickly-phlox in North Park, Colorado, occurred most commonly on sites with "good moisture relationships with respect to both summer and winter precipitation" but also occurred on drier sites where snow accumulated and stored moisture was "good". For more information, see Climate.
Topography: Granite prickly-phlox typically occurs in open, exposed places on flat to steep sites (range: 0-65°) [1,63,82,99,105,110,124,136] on all aspects [13,59,119,124,128,147]. It occurs on washes, bajadas, mesas, and buttes in the desert plains [17,48,67,99,142] and on dry eastern slopes and summits of the montane, subalpine, and alpine zones of the Sierra Nevada and the Cascade Range [41,42,60,63,67,72,77,120,126,137]. Granite prickly-phlox habitat on San Bernardino National Forest, California. Photo courtesy of Thomas Stoughton, CalPhotos.
Granite prickly-phlox is common on exposed, windy ridges and summits that are often swept free of snow in winter [1,22,105,123,124,125]. In these areas, it often grows in microsites where snow may accumulate, such as between boulders, in rock crevices [9,105,118], and on leeward slopes [124]. It also occurs in areas where soils are unstable, where wind and water cause soil erosion and deposition such as steep, unstable scree slopes [105], and where freeze-thaw cycles create frost scars and turf banks [90,123]. In Utah, it occurred on sand dunes and "dune-like" mounds [44,86], and in Nevada and New Mexico it occurred on alluvial fans [13,45,128] and canyon floodplains [13,128]. Granite prickly-phlox often occurs on rough, broken topography such as the "breaks" of the Upper Rio Puerco watershed of New Mexico [45] and stream terrace benches in north-central Washington [147] and central Nevada [13].
Although granite prickly-phlox may occur on all aspects, it is most common on south-, east-, southeast-, and southwest-facing slopes [1,13,90,105,115,120,136], particularly at high elevations [76,90,105,120]. It occurred on rock piles and ledges on south- and east-facing slopes on the rims of sheer-walled cirques in the White Mountains [90]. In Canyon de Chelly National Monument in Colorado, it occurred on south-facing slopes [115]. Granite prickly-phlox occurred on south-east facing slopes in Douglas-fir-limber pine forest in the Crested Butte area of Colorado [76]. In Rocky Mountain juniper/antelope bitterbrush woodlands, it occurred on steep (50-75%), rocky, east-, south-, and west-facing slopes, and in Rocky Mountain juniper/big sagebrush woodlands it occurred on steep (45-75%), rocky, south-facing slopes [59]. In Zion National Park, Utah, granite prickly-phlox occurred only at sites with high solar irradiation [56] (see Seedling establishment and plant growth). However, granite prickly-phlox occurred on steep, mesic, north-facing canyons in white fir-singleleaf pinyon woodland in the high desert ranges of the eastern Mojave Desert [61,126,132] and on north-, northwest-, and west-facing slopes in singleleaf pinyon/big sagebrush/Sandberg bluegrass woodlands in central Nevada [13]. In the Cheyenne River Basin, granite prickly-phlox occurred on north- and west-facing slopes in skunkbush sumac/bluebunch wheatgrass [124].
Elevation: Granite prickly-phlox has a wide elevational range [64]. Across its distribution, it occurs from 3,600 feet to 13,100 feet (1,100-4,000 m):
Elevational ranges of granite prickly-phlox across its geographic distribution Area Location Range (feet) Arizona northeastern Arizona 6,600-7,500 [53,115] California throughout 4,000-13,100 [60,61,77,90,97,112,119,120] Colorado throughout 4,500-9,000 [57,136] Idaho southern Idaho 4,900-7,700 [2,6] Montana west-central Montana up to 8,000 [73] Nevada throughout 3,600-11,200 [67,99,128] south-central Nevada primarily from 3,400-5,000 but up to 7,800 feet [9] New Mexico throughout 6,000-7,500 [85] Utah northern Utah 6,600-7,200 [86] eastern Utah 4,700-8,150 [49] Great Basin throughout 4,000-12,000 [93,138]
Climate: Granite prickly-phlox tolerates cold, harsh winters and dry, hot summers [43,46,111,146]. It occurs in alpine zones in the White Mountains, which are cold (mean annual temperature: 28 °F (-2 °C)), semiarid (mean annual precipitation: 15.5 inches (39.4 cm)) [90], and characterized by extremes of low temperature, wind, low atmospheric pressure, and high ultraviolet radiation [111]. Precipitation falls mostly in winter as snow [90].
Granite prickly-phlox occurs in areas with high-magnitude diurnal and seasonal temperature fluctuations [2,123]. At the Navajo National Monument in northern Arizona, it occurred in Colorado pinyon-Utah juniper woodland where annual temperatures ranged from -9 to 100 °F (-23 to 38 °C), with a mean of 50 °F (10 °C) [19]. In black sagebrush communities in northern Nevada, mean annual temperature was 48 °F (9 °C), with average winter (December-February) temperature of 36 °F (2 °C) and average summer (July-August) temperature of 69 °F (21 °C) [148]. At the Idaho National Engineering Laboratory in southeastern Idaho, granite prickly-phlox occurred in big sagebrush steppe where mean annual temperature was 42 °F (6 °C) [2].
Granite prickly-phlox occupies sites where precipitation is low and seasonally variable. On many sites where granite prickly-phlox occurs, most precipitation falls in winter and spring, and soils are dry by the end of summer [2,2,46,86,90,105,115,123]. As a result, available moisture is out of phase with temperatures suitable for growth [146]. Conversely, in Colorado pinyon-Utah juniper woodland in northeastern Arizona, the wet season occurs from late summer to fall [19], partially overlapping the granite prickly-phlox growth period. Typically, pinyon-juniper woodlands in New Mexico and eastern Arizona receive more warm-season precipitation and have greater production potential for plants in general than pinyon-juniper woodlands in Nevada and northwestern Utah (Clary 1975 cited in [33]). As of this writing (2010), it was unclear how granite prickly-phlox growth is affected by regional climate differences. Across granite prickly-phlox's range, mean annual precipitation ranges from approximately 10 inches (250 mm) [99] to 50 inches (1,270 mm) [77].
Throughout granite prickly-phlox's range, growing seasons are short [61,77]. Granite prickly-phlox was a common shrub in whitebark pine-mountain hemlock forest in subalpine regions of California, where the growing season ranges from 49 to 63 days [77]. Frost can occur during half of the year or more [23]. At the Idaho National Engineering Laboratory, granite prickly-phlox occurred in big sagebrush steppe where the frost-free period is about 90 days [2], and it occurs where the number of frost-free days averages 155 days in Colorado pinyon-Utah juniper woodland at the Navajo National Monument [19].
Granite prickly-phlox often occurs on wind-swept sites where snow cover is limited (see Topography). In the Sierra Nevada, it occurred at sites that were wind-exposed and relatively snow free in winter—so little meltwater was received in spring—and at sites where snow cover was variable. However, all sites where granite prickly-phlox occurred were well-drained, so even where meltwater was available in spring, soils were droughty by the end of summer [105,123].