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Ecosystem Classification and Relationships for Pleistocene Lake Thompson Bed, Mojave Desert, California
Robert Lichvar
出版
US Army Corps of Engineers, Engineer Research and Development Center, Cold Regions Research and Engineering Laboratory
, 2004
URL
http://books.google.com.hk/books?id=-1_gNwAACAAJ&hl=&source=gbs_api
註釋
A four-year study was undertaken in 1997 to understand ecosystem relationships between vegetation and edaphic features at Edwards Air Force Base, California (Edwards AFB). This report presents the comprehensive analysis and discussion for the entire Lake Thompson Bed contained within Edwards AFB. This study used the ecological land classification (ELC) method for developing ecosystem maps. The concept of an ELC is to integrate ecosystems and landforms into one coherent system with functionally related parts. The study area for the ecosystem map is the boundary of the Pleistocene Lake Thompson Bed within Edwards AFB. The ELC maps are secondary products developed from primary field data. Two mapping teams independently mapped the vegetation communities and the landforms of the study area. The characteristics of the landform and vegetation map units were used to create and describe map units for ELC maps. Samples were collected around Pleistocene Lake Thompson Bed to characterize soil chemistry, vegetation, geomorphic, and other descriptive environmental features. Analyses of the data attempted to test the interaction between geomorphic features, vegetative communities, and sampled environmental parameters. Overall, it appears that soil texture plays an important role in the development and relationships with geomorphology, soil chemistry, and vegetation. Geologically the playa surface was less heterogeneous initially, in terms of geomorphic units. As Lake Thompson Bed began to dry out in response to climate changes, dunes and alluvial fans began to form. The result was a landscape with a higher degree of soil texture variability than had existed on the initial lakebed surface. Soil texture sorting across the landscape, along with climate changes, drove the current distribution pattern of vegetation.