California State University Bakersfield
Welcome to the Webpage of
Dr. Anna L. Jacobsen
Plant Ecology and Evolutionary Biology
Plant Structure-Function
Biology Lecturer and Postdoctoral Researcher
Research
Community convergence among arid and semi-arid shrublands
A major theme of my research involves examining the xylem structural and functional adaptations among shrubs occurring in arid and semi-arid plant communities from around the world. I am particularly interested in functional plant anatomy and the relationship between community, whole plant traits, and plant cellular traits as they relate to abiotic stresses such as water stress.
The three plant communities in which I am currently doing much of my research include the California sage scrub of the Santa Monica Mountains, California (above left), the chaparral in the Santa Monica Mountains, California (above right), and the Mojave Desert scrub of Red Rock Canyon State Park, California (below).
Research on these communities has included longitudinal studies examining plant water relations and seasonal changes in physiology and water use strategies of species within these communities. Current research on plants in these three communities focuses on the wood anatomical traits of these species as it relates to the plant community in which they occur and their functional xylem traits related to water use. The latest research at these sties is being conducted in collaboration with Dr. Uwe Hacke of the University of Alberta.
International Research and Mediterranean-type climate regions
The research mentioned above fits into one of my ongoing research projects investigating the water use strategies of plant communities within the Mediterranean-type climate regions of the globe. There are five Mediterranean-type climate regions globally that are dominated by evergreen, tough-leaved shrub species. Do plants and plant communities in these different regions use similar strategies in response to the prolonged period of summer water stress that typifies these regions?
The question of Mediterranean-type community convergence in water use strategies is currently be investigated through a series of studies comparing plant communities in southern California to plant communities in the Cape Region of South Africa, including the fynbos and succulent Karoo (see picture below from study site in South Africa). This work is being conducted in collaboration with Dr. R. Brandon Pratt of CSUB and Dr. Karen Esler of Stellenbosch University among others.
Fire effects on community composition and structure
I am currently involved in several collaborative research projects investigating plant species and community response to fire, particularly in response to additionally stresses such as heavy browse or drought as well as the effect of changes from the natural fire regime of an ecosystem (such as shortened fire return interval). This work is being conducted in the Santa Monica Mountains of southern California, on Santa Catalina Island off the coast of Los Angeles, California, and in the Western Cape Region of South Africa. This work involves collaboration with many other researchers and several undergraduate and graduate students.