Pacific Southwest Research Station

Kings River Experimental Watershed

VEGETATION

In order to better understand the role that watershed-level treatments play in shaping the plant community, vegetation transects have been established on each of the eight KREW watersheds. This kind of information is particularly important in the Sierra Nevada, home to approximately 3500 plant species, 405 of which occur nowhere else in the world (Shevock 1996). A large portion of the range is National Forest land, and understanding how to properly manage those species is crucial to their maintenance. In addition, treatment effects to the riparian plant community are not well-known, yet current management practices are designed to avoid the riparian zone. It is likely that natural disturbances prior to European settlement bore no such discrimination. Therefore, the KREW vegetation study is designed to underscore the riparian zone response, and hopefully shed some light on this issue.

The vegetation sampling design and protocol were developed by consulting numerous papers and other researchers that deal with similar projects. Transects have been established in both upland and riparian areas of each watershed. Each watershed contains at least 5-10 riparian and 10-20 upland transects, depending on the area of the watershed and length of the stream channel (Figure A). All transects will be sampled annually, resulting in several years each of pre- and post-treatment data; sampling began in June 2003. Each transect is 20 m long and consists of three sampling types: 1 X 1 m quadrats for the herbaceous layer, line-intercept for the shrub and canopy layer and a 10 X 20 m belt transect for trees (Figure B). Upland transects are co-located at a subset of the sampling grid points, and riparian transects are located along the stream, oriented perpendicular to the channel (Figure A). Soil pits for characterization are also co-located on the same upland grid points. For a more thorough description of the vegetation methods and their justification, see the KREW Study Plan (Hunsaker et al. 2004).

Figure A: Sample watershed showing stratified random distribution of 14 upland transects and regular distribution of 7 riparian transects.

Figure B: Aerial layout for riparian transects.

References

Shevock, J.R. 1996. Status of Rare and Endemic Plants. In: Sierra Nevada Ecosystem Project: Final Report to Congress. pp. 691-707. Centers for Water and Wildland Resources, University of California, Davis.