Root Zone Microbial Communities and Restoration of Plant Communities in Owens Valley, California - Phase 1

Abstract

Abstract:The future quality and quantity of water for Los Angeles, CA, depends on effective environmental management of both water and land use in Owens Valley. Long-term environmental monitoring will be used to assess progress towards attaining sustainable restoration goals. Reestablishment of native plant communities on previously cultivated lands is a major land management goal. Establishment of desired plant communities may, in turn, depend on relationships between soil microorganisms and plants. These interrelationships depend on soil characteristics affecting the microbial communities. This study was designed to provide survey information on microbial communities in soils from native and disturbed areas at ten locations spanning Owens Valley. At each location, five surface soil samples were collected along a 150-m transect through native vegetation, and ten soil samples were collected along a 300-m transect through disturbed areas. Soils were characterized by soil texture, total carbon, total nitrogen, organic carbon, organic nitrogen, leachable carbon, leachable nitrogen, carbon and nitrogen isotopic ratios, microbial community biomass, and lipid profiles of soil microbial community compositions. Analysis of variance, Tukey's test for comparing multiple means, hierarchical cluster analysis, and principal component analysis were used to show differences in soil characteristics. While native and disturbed soil samples were shown to differ in many characteristics, the largest and most frequently shown differences were related to the soil microbial communities. Total soil microbial biomass was significantly and consistently higher in native soils than soils from disturbed areas. Large and significant quantitative differences were also seen in the sterol content of soils supporting native plant and those of disturbed areas. The level of fungal sterol ergosterol was consistently and significantly higher in soils supporting native vegetation than in soils from disturbed areas, indicating mycorrhizae as potentially important plant symbionts. The presence of phytosterols and other unidentified sterols was also higher in the native plant soils. In conclusion, soils supporting native plant communities were most different from those in disturbed areas in characteristics related to soil microbiology.