Professor Katharine Suding

Department of Environmental Science, Policy and Management

“Evaluating the Influence of Mycorrhizal Colonization on Native and Exotic Grassland Communities in California”

In California grasslands many of the native grass species have been replaced by exotic annual grasses and these native species only comprise a small percentage of the herbaceous cover (Biswell 1956; Heady et al.1991). Understanding how the remnant native species have been able to persist in spite of this invasion is key to the conservation of these native communities.  One potential mechanism that could influence competition dynamics between native and exotic species is the extent of the symbiotic relationship between mycorrhizae and native and exotic grasses. Mycorrhizae can affect plant competition dynamics by influencing plant nutrient acquisition of phosphorus and nitrogen (Pringle et al 2009), which can potentially lead to beneficial feedbacks between the mycorrhizae and plant.  We hypothesized that the native grass communities would have a higher mycorrhizal colonization rate than exotic grass communities. We compared mycorrhizal presence and colonization on root samples from 5 native and exotic grass communities located in Orange County, California. To determine presence and colonization roots were stained with Trypan blue and examined under a compound light microscope. A higher colonization percentage would allow native species to better compete against the exotic grasses. Field roots were used in the experiment.  Additionally, colonization data was compared against extracellular enzyme data to look for a correlation between mycorrhizal colonization and nutrient uptake.

Bardo attends Skyline College in San Bruno where he maintains a 2.99 GPA. He is the first in his family to attend college. He received an award for outstanding research presentation in biology during the 2010 SACNAS conference. Bardo will attend UC Davis in Fall 2011 and major in Biology.