Adaptive Management of Phytophthora ramorum in the Big Sur ecoregion

The Big Sur area is one of the most ecologically diverse regions in California. Although the forests of Big Sur are protected by numerous preserves, state parks, county parks and the Los Padres National Forest, they are still threatened by exotic species, climate change and alterations of key ecosystem processes such as a fire. At this time, one of the most significant threats is the invasive pathogen Phytophthora ramorum, the causal agent of the forest disease sudden oak death. While the last few years of research have produced a great deal of information on the disease, many questions remain. The forests of Big Sur are a key environment to address some of these questions due to the extensiveness of the forests, the relatively high impact of the disease in this area and the diversity of environments and disturbance histories. In addition, while there are areas in Big Sur with high levels of mortality due to sudden oak death, there are also forests that have as of yet escaped the pathogen. The goal of this project is to establish a network of ecological monitoring plots across the Big Sur region. Information obtained from these plots will help to evaluate the current distribution of P. ramorum in the area, to gain a better understanding of the impacts of P. ramorum on the forest structure and community and to learn what factors influence disease establishment and spread. Data on environment, vegetation and disease level will be analyzed to better understand ecological drivers of the composition and dynamics of these coastal forests. We will encourage other researchers to use this plot network to address additional ecological questions pertaining to these forest communities. Information from plot studies will contribute to the development of a collaborative science-based plan to manage P. ramorum. This research does not involve active management trials, which are being implemented by collaborators at other locations in the region. Our research questions can be summarized as follows: 1. What is the current distribution of P. ramorum in Big Sur forests? 2. What structural, compositional and environmental variables contribute to P. ramorum establishment or spread in a forest? 3. How is P. ramorum-associated mortality affecting the forest structure and forest community? 4. What is the relationship between changes in forest cover and recruitment due to P. ramorum-associated mortality and other conservation threats (e.g., invasive species, fire suppression)? 5. How does plant community composition and structure vary as a function of biophysical factors and disturbance history? 6. How does the size, growth rate, and age structure of tanoak (L. densiflorus) vary as a function of biophysical factors and disturbance history? 7. How does the vertical structure and spatial pattern of canopy trees vary as a function of biophysical factors and disturbance history?


David Rizzo (UC Davis), Matteo Garbelotto (UC Berkeley)


Frank W. Davis, Mark Borchert (US Forest Service), Ross Meenemeyer (Sonoma State), Max Moritz (UCB)

Funding Agency: 

USDA Forest Service

Project Period: 

August, 2005 to August, 2007

Research Area: