Spatial Analysis of Baseline Data of Surface Soil and Landcover Classes of the North Etiwanda Preserve after Five Years of Drought Stress (2011-2015) in a Mediterranean Climate Region in Southern California.
Kuo, Tina Ting-wan
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The North Etiwanda Preserve (NEP) is a conservation area in a Mediterranean climate located in Southern California. This study focused on surface soil characters at the NEP to understand the soil stability and to find the erosion rate as well as the surface soil condition and the coverage of vegetation communities of the preserve area after five years of drought stress. Digitized main habitat types and areas as well as enhanced raster images were used to create landcover maps to display the vegetation composition of each habitat. A geodatabase was created to map the landcover maps. The vegetation was identified and data was collected using the point intercept method at 1-meter intervals on the 12-meter transects. Soil samples from 36 sampling sites were collected and were tested for soil parameters (soil structure, texture, temperature, pH value, soil water % weight, bulk density, CEC, etc.). Quality control of the maps was done by comparing the mapped classes with field surveys and soil lab results. The user’s accuracy of the produced landcover class maps was 86.4 %. The canopy percentage coverage of plant communities and of dominant species were calculated. The surface soil run-off volume of each surveyed location was calculated using the Universal Soil Loss Equation: A = RKLSCP. The NEP had shallow soil organic layers and low CEC. Hot spots of soil erosion were located along the fire break area. Soil erosion rate was higher within the burned area when compared to the east side of the preserve where vegetation communities were at the mature successional stage. The surface soil condition of the NEP are strongly influenced by vegetation types and the litter/wood cover.The pioneer vegetation communities mainly grew within the disturbed areas, which were vulnerable to soil erosion and changes of successional stages