Pepperwood Preserve Woody Vegetation Research Plots|生态学研究数据集|气候变化影响数据集

Project goals: The goal of this project is to establish a network of research plots in woody vegetation of Sonoma County, California (in the North Bay region of the San Francisco Bay Area). The objective of plot installation is to assess species distributions and community structure along abiotic gradients and to serve as a baseline for long-term studies of vegetation dynamics in response to climate change and other drivers. This field study is integrated with ongoing monitoring of weather and climate and was designed relative to downscaled projections of future climate and water balance and projected vegetation change through the end of the 21st century.

Primary objectives:
1. To examine woodland vegetation community structure and species composition across fine-scale topographic and hydrologic gradients, providing a baseline for monitoring long-term change.
2. With additional focus on:
- The effects of plot orientation to marine layer, aspect, topographic position
- Distribution and possible hybridization between blue and Oregon oak, closely related species with
overlapping geographic range at Pepperwood Preserve
- Douglas-fir (Pseudotsuga menziesii) succession and effects of removal for oak woodland management
3. To create an infrastructure for future projects studying ecology and species interactions in woody plant communities occurring on contrasting topographic and hydrologic gradients.

Why this is important: Woodland and forest vegetation represents critical habitat in natural communities of the Bay Area, supporting a wide diversity of plant and animal species. A range of ecological processes can lead to vegetation change in these communities, including ecological succession, disease (e.g. sudden oak death), invasive species, changes in herbivore community, and wildfire. In the 21st century, rapid climate change is also expected to cause dramatic impacts on native plant communities. Climate will interact with the processes above, and may also cause direct impacts via drought, heat waves, etc. Detecting the impacts of climate change on vegetation requires long-term research, with quantitative baseline data and repeated resurveys. This projected established a network of permanent plots for longterm monitoring and demographic research on climate change and the interaction with other factors that may impact native vegetation.

Project overview: Fifty 20 x 20 m plots were established across topographic and hydrologic gradients throughout the preserve. Within each plot all saplings (>50 cm tall) and trees (> 1 cm diameter at breast height) were permanently tagged, identified, mapped and measured. All seedlings (<10 cm tall) and juveniles (10-50 cm tall) were counted and identified. Micrometeorological monitoring was initiated, and will be expanded in the future.

Project impact: This project supported the development and implementation of a woody vegetation monitoring and research study as a baseline for long-term study of vegetation change at Pepperwood Preserve, and a foundational model for future studies across the Bay Area. An outcome of the project is to apply results and lessons learned to vegetation management priorities of the Conservation Lands Network in the San Francisco Bay Area. Some of the outcomes will not be realized until we re-census the research plots (proposed 5 years re-census), while others can be developed immediately based on baseline data, such as the influence of topographical heterogeneity on community diversity at local scales.