Demography of the intertidal kelp Alaria marginata along the Big Sur coast (California).

摘要

Though Alaria marginata dominates exposed rocky intertidal shores along the Big Sur coast of California, this is the first population dynamics study of the alga. Experimental clearings and controls were established to assess recruitment timing and plant survivorship. Plants were collected monthly to determine population growth and reproduction. Results indicated Alaria was an annual. Sporophyte recruitment occurred in early spring and maximum growth rates were during April. Sorus development began as early as March, peaked during August–October, and decreased as adult plants were tattered or ripped from substrate by winter surf. Spore release was greatest between October and January, and apparently stimulated by high water motion. Survivorship of plants beyond one year was rare. Persistence of this large, annual, intertidal kelp appears to be related to massive spore production at the onset of fall storms, persistence of microscopic stages for three months, and rapid growth and maturation of sporophytes.