Spatial Variation of Soil Properties Relating to Vegetation Changes

Bekele and Hudnall provide an interesting perspective on the spatial variation of soil chemical properties in a natural area undergoing transition from prairie to forest. Their focus is on the unique calcareous prairie ecosystem of Louisiana where prairie remnants are being encroached upon by the forest, primarily eastern red cedar (Juniperus virginiana L.). Bekele and Hudnall were especially interested in investigating any differences in spatial variability among similar sites and in documenting the scale at which the variability occurs. Geostatistical methods have been used to describe and model spatial patterns in soil data for more than 20 years. The accessibility of user-friendly geostatistical software packages has increased the use of spatial analysis of soil’s data but carries the risk that these tools are used without due consideration of the underlying theory, especially in the field of semivariogram modeling or recommended good practices. The feedback between plant community composition and species distribution and soil properties in natural systems has promise to provide enhanced insight into the short- and long-term relationships between plants and soil properties. This is an intriguing area of research that couples plant ecology and soil science and should provide valuable information on the interaction of soils with the processes of plant succession and competition. Researchers in this area are urged to be cautious in verifying the assumptions behind popular geostatistical methods and explicit in describing the important steps such as trend analysis, which can reveal critical interpretive information.