The influence of snow on subalpine meadow community pattern, North Cascades, Washington

The relationships among community pattern, date of snowmelt, and microclimate were examined on Excelsior Ridge in the North Cascades. Nine communities were delineated and placed into three groups based on date of snowmelt and topographic location. The Veratrum viride, Valeriana sitchensis, Lupinus latifolius, and Carex spectabilis communities, all found on windward slopes, were released from snow from June to mid-July. The Phyllodoce empetriformis, Vaccinium deliciosum, and Saxifraga tolmiei communities were located on leeward slopes where snow melted in July. Sheltered basins, which retained snow until late July or early August, supported the Carex nigricans and Luetkea pectinata communities. The influence of time of snowmelt generally was reflected in soil temperature, so that earlier sites were warmer than later sites. A soil moisture gradient was not apparent among any of the communities.