Coastal shrublands of Humboldt and Del Norte Counties, California

Coastal shrublands of Humboldt and Del Norte Counties, California were classified and described based on data from 140 plots sampled at 46 sites. Twinspan was used to separate plots into groups. Indicator species analysis was used to determine which species were most characteristic of each Twinspan group. Ordination was used to validate or reject Twinspan groups and as an aid in determining the environmental factors that were most influential in the vegetation patterning within these coastal shrublands. Three major types and five sub-types of coastal shrubland were found. The Thicket bramble series was dominated by some combination of thimbleberry, salmonberry, salal, and California blackberry. The Thicket bramble series was further split into two associations. The Coyote brush series is dominated by coyote brush. The Coyote brush series was further split into three associations. The Yellow bush lupine series is recognized based on the previous work of others. Stands of the Thicket bramble series are found at wet sites and those sheltered from salt spray. Stands of the Coyote brush series are found at drier sites and those directly exposed salt spray. Stands of the Yellow bush lupine series are restricted to coastal dunes.