Phytosphere Research

Exotic and Native Plant Monitoring at Jepson Prarie Preserve


T. J. Swiecki and E. A. Bernhardt
Phytosphere Research, Vacaville CA

Download the full report (Adobe Acrobat PDF - 6 MB)

Additional key words: weed management, vernal pools, GIS, GPS


This report describes the development of a monitoring system to assess populations of selected exotic and native plants at the Jepson Prairie Preserve. The monitoring system is primarily based on the use of permanent belt transects (20 m wide) that traverse all of the pastures at the preserve. Transects are divided into 50 m long segments for purposes of data collection and analysis. Percent cover for each monitored species within each transect is estimated visually and assigned to one of three cover categories. Specific point/polygon mapping is used in conjunction with the transect system to monitor rarely occurring target weeds. Initial monitoring along the transects was conducted during a one week period in mid-April 2001. Two transects were resurveyed in June 2001 for comparison with spring monitoring. This report discusses the sampling method in detail and presents results of the baseline monitoring. Preliminary statistical analyses show significant associations between plant cover and soil type, burning, and grazing intensity. Among the target weeds surveyed, perennial pepperweed (Lepidium latifolium) appears to have spread significantly since 1995.

This project is funded by a CALFED grant to the Solano Land Trust (formerly Solano County Farmlands and Open Space Foundation).