South Coast Research Extension Center
Question: Are hydraulic traits in dominant coastal sage scrub shrub species plastic in response to altered precipitation regimes and does plasticity in these traits change the shrubs risk of drought induced mortality.
Motivation: Future climate states are projected to bring greater inter and intra-annual precipitation variation across the globe. Biodiverse Mediterranean climates such as Southern California are especially at risk and understanding how these species will respond to an important limiting resource will be important for understanding the future composition of our landscapes.
Five dominant coastal sage scrub shrub species (Artemisia californica, Malosma laurina, Salvia mellifera, Ericameria palmeri, and Eriogonum fasciculatum) were seeded in January 2017 and grown in plots along a precipitation gradient simulated by overhead irrigation with rain fall excluded. Nine structures represent 9 treatments (40%, 55%, 70%, 85%, 100%, 115%, 130%, 145%, and 160% mean annual precipitation (MAP = 36cm)), each containing 4 individuals of each species (N=36/sps.). Plants entrenched in their watering treatments are irrigated weekly from mid December to the end of April. In 2018-2019 we will impose a lethal drought to measure mortality risk.