Cellular slime molds of the Rocky Mountains [Soil fungi, occurrence, ecology; Western States (USA)]

Soil populations of cellular slime molds (CSM) are generally smaller and less diverse in soils of Rocky Mountain forests than in eastern deciduous forests. CSM were found at all elevations and habitats sampled, including desert scrub, pinyon-juniper, ponderosa pine, spruce-fir and tundra. Of these, which exist along an altitudinal gradient, the subalpine spruce-fir belt, the most humid of the forest belts in this relatively dry region, had the largest and most diverse populations. Almost all sites were dominated by Dictyostelium mucoroides and D. sphaerocephalum. Since Rocky Mountain soils are exposed to severe environmental fluctuations these two species are the most tolerant of the dictyostelids, particularly to moisture and temperature stresses. Dictyostelium septentrionalis was the only rare species discovered.