Adaptive
Management of Phytophthora ramorum in the Big Sur ecoregion
Principal
Investigators: David Rizzo (UC Davis), Matteo Garbelotto (UC
Berkeley)
Co-Principle
Investigators: 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
Project summary:
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?