Doctoral Dissertations

Date of Award


Degree Type


Degree Name

Doctor of Philosophy


Plants, Soils, and Insects

Major Professor

Michael Essington

Committee Members

Virginia Dale, Arnold Saxton, Daniel Yoder


The overall goals of this project were: (1) to develop a microbiological ecological indicator that would describe military land disturbance, (2) integrate previously collected ecological indicator data from five separate research teams, and (3) produce knowledge maps with the resulting information that illustrates how the selected indicators are involved in ecosystem processes. To address goal one, soil samples were obtained from four levels of military traffic (reference, light, moderate, and heavy) with an additional set of samples taken from previously damaged areas. Using the soil microbial biomass and community composition as ecological indicators, reproducible changes showed increasing traffic disturbance decreases soil viable biomass, biomarkers for microeukaryotes and Gram-negative bacteria, while increasing the proportions of aerobic Gram-positive bacterial and actinomycete biomarkers. To address the second goal, ecological indicator data was collected by five separate research teams. Landmanagement categories (LMCs) were developed that described the uses or causes of the ecological effect from military use(s) of land. A mechanism of multiple solutions was developed that combined the results and tested the efficacy of the proposed indicators. Results from the integration effort showed that Soil A horizon depth and soil compaction were important soil physical indicators of military land disturbance. Soil Nitrogen and Carbon content were important soil chemical indicators of land use. Soil mineralization rate, soil respiration, microbial composition and Beta Glucosidase activity were important microbiological indicators. Important plant indicators included tree stand age, canopy iv cover, understory cover, plant life form and legumes. To address the third goal several knowledge maps were developed, and the results from the integration of indicator data were pooled and studied for the relationships between them. By displaying the indicators in this fashion, it was hoped that the knowledge of what the indicators represent to the functioning of the ecological system could be understood. For the practitioner, this knowledge should lead to actionable products or at least a better understanding of what is being measured and how it relates to broader ecosystem dynamics.

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