The vegetation of the Rae Lakes Basin, southern Sierra Nevada [California]

Stands of subalpine-alpine vegetation from the southern Sierra Nevada were sampled (n = 97) and compared using Braun-Blanquet methodology. The study was undertaken (1) to characterize, using floristic criteria, the prinicpal vegetation types occurring within the study area; (2) to consider the influence of environmental factors on vegetational patterns; and (3) to provide a basis for making floristic and vegetational comparisons within the study area and elsewhere. The vegetational relevés (stand surveys) were organized into tables and assigned rank in a hierarchical system solely on the basis of floristic affinities. Five alliances and twelve associations were recognized and described phytosociologically and ecologically. Four major environmental features were considered to order the vegetation in the landscape: moisture regime, snow cover, elevation, and substrate stability. Festucion brachyphyllae occurs in truly alpine sites within the study area. Primulion suffrutescentis is characteristic of both mid-and high-elevation sites, especially on north slopes where the snow lies late and the growing season is short. Pino-Caricion exsertae occurs on the gravelly slopes and terraces in the mid-elevation Pinus albicaulis subalpine forest. Monardello-Holodiscion microphylli is characteristic of the usually dry, stabilized talus of mid-elevations. Dodecathion redolentis represents the mid-elevation meadow of streamsides and topographic lows that remain moist to wet throughout the season. A total of 277 vascular plant taxa belonging to 38 families were found within the study area.