Synecology of Beach Vegetation Along the Pacific Coast of the United States of America: A First Approximation

Abstract

Thirty-four beaches, located between central Washington and the Mexican border (approximately 47-33? N), were sampled for cover by replicate strip transects, and the results summarized by composite profile diagrams. The zonation patterns of twenty species revealed that the majority could be found in the leading (seaward) edge of vegetation, but most taxa increased in cover with increasing distance from mean tide line; that is, few species exhibited an ecological optimum in the most severe part of the vegetated beach. Even in the most inland portion of the beach plant cover and species richness were typically low (about five species, 2000 cover). Cluster analysis revealed five grouips of stands. The groups were poorly correlated with latitude, except for a major break at 370 N in central California. Regressions showed, as a first approximation, that community composition correlated with factors that reflect protection from disturbance by waves, man, or introduced taxa. Beach vegetation seems less well correlated with macroclimate than inland vegetation. However, the distribution limits of some species did correlate well with macro-climate.