Tuesday, August 7, 2007 - 10:30 AM

COS 38-8: Rare and common Dudleya species in the Santa Monica Mountains

Ann E. Dorsey, California State University, Northridge

Dudleyas are succulent perennials, five of which are restricted to the Santa Monica Mountains and federally listed as threatened.  Three common species occur locally as well.  This study compares differences in reproductive strategies, plant size, dormancy periods of each taxa within and between 3 watering regimes, and plant growth and survival in a coastal and an inland garden.  Rare taxa had a greater percentage of seedlings reproduce in their first spring, fewer average number of fruits, smaller seed sets, and tended to be smaller than the common taxa.  Germination percentages and seedling survival did not differ between rare and common taxa.  Ultimately, the purpose of the study is to find reasons for the differences in the abundances of these taxa.