OOS 5-7
Potential for application of filamentous cyanobacteria on chaparral restoration sites
Filamentous cyanobacteria contribute importantly to soil crust on public lands throughout the western United States. These organisms are thought to protect the soil from surface erosion, facilitate native plant establishment, contribute directly or indirectly to fixation of atmospheric nitrogen, and, perhaps most importantly, suppress by unknown mechanism the germination and growth of certain weedy annual grasses. In spite of their perceived value in wildland restoration, filamentous cyanobacteria have not been routinely included in restoration programs.
This presentation provides a brief review of experimental and observational explorations of filamentous cyanobacteria on National Forest lands in southern California. The objective was to record soil and site conditions in which cyanobacterial inoculation may be feasible and beneficial, to culture site-specific cyanobacteria, and to evaluate methods of field inoculation.
In a field inoculation trial, locally collected soil crust was applied to small plots that consisted of depressions in the soil, with inoculated and uninoculated plots in alternating positions at the intersections of 30-by-40-meter grids. Eight such grids were established on four widely separated locations on the Cleveland National Forest in southern California. Soil samples from the inoculation points and corresponding control positions were collected six weeks after inoculation and stored dry.
Results/Conclusions
Direct measurement of cyanobacteria filaments proved inconclusive in field samples. A bioassay of subsamples is underway, with regrown filaments to be measured microscopically by a line-intercept technique.
Further study needs to be made to develop efficient and effective cyanobacteria establishment techniques for southern California soils and climate. Progress with this will help provide an important tool for restoration projects.