Research in the lab focuses on plant ecological and evolutionary responses to environmental disturbance and variation. Core interests include forest and grassland responses to climate change, fire and drought.
Effects of increasing rainfall variability on grasslands
Using observational and experimental studies to understand the population-level effects severe climatic events on California annual grasslands. With Susan Harrison, we are using rain addition and exclusion experiments at McLaughlin UC Natural Reserve (photo shows Marina building a rain-exclosure shelter) to study demographic responses of several forb species to the combination of water availability and invasive grass competition.
Postfire forest regeneration
Large, intense fires can produce huge patches of nearly 100% tree mortality, with large interior areas far from seed sources. If the post-fire goal is restoration of resilient forest stands, what is the best way to accomplish this, given limited funds and personnel? When and where will natural tree recruitment work on its own? When tree regeneration is slow, what is the best way to give these forest stands an "assist", and how can we use ecological processes to our advantage in reforestation? With funding from the Joint Fire Science Program and collaboration from US Forest Service, we are investigating these questions in the Northern Sierra Neveda.
Evolutionary ecology of colonizing species.
Species in genus Erodium (Geraniaceae) have naturalized in both California and Chile and have remarkably wide distributions ranging from deserts to wet coastal areas and mountain foothills. What allows relatively recent colonizers like these to attaing such broad ecological ranges? Using field and greenhouse experiments, we are identifying the sources of phenotypic and demographic variation in naturalized exotic species of Erodium in populations in California and Chile. In collaboration with Brooke Jacobs and Ernesto Gianoli, we have surveyed 20 populations from each continent to compare patterns of spread, population performance, and phenotypic plasticity and local adaptation. We have grown these in common garden experiments in Davis to assess the roles of plasticity and local adaptation in these replicate invasions. With Tina Heger we are also comparing to populations in the native range in Europe and developing molecular markers.