PARENT SESSION
Oral Session # 11: Ecological Studies on Military Installations.
Presiding: B Collins
Monday, August 4. 8:00 AM to 11:30 AM, SITCC Meeting Room 203.
Soil mineralization potential as an indicator of ecological disturbance.
Kovacic, David1, Krzysik, Anthony2, Wallace, Michael1, Duda, Jeffrey3, Freeman, D. Carl4, Graham, John5, Zak, John6, Balbach, Harold7, 1 University of Illinois, Champaign, IL2 Prescott College, Prescott, AZ3 U.S. Geological Survey - Biological Resources Division, Seattle, WA4 Wayne State University, Detroit, MI5 Berry College, Mount Berry, GA6 Texas Tech University, Lubbock, TX7 U.S. Army Construction Engineering Research Laboratory, Champaign, IL
ABSTRACT- Military reservations contain some of the largest unbroken landscapes remaining in the United States. Their vast area and diverse vegetative cover, provide refuge for many rare plant and animal species. These same characteristics also make these lands ideal locations for military training. The combined fates of plants, animals, and continuing military training rely on sustainable ecosystem management. The development of a set of readily measured ecological indicators would help managers determine the integrity of various ecosystems on military lands. Early identification of at-risk habitats could prevent their loss or further degradation. Our objective was to determine if soil N dynamics could be used as an indicator of ecosystem integrity. In mature N limited forests, competition for ammonium released through mineralization is intense and soil inorganic N is low. Under such conditions populations of nitrifying bacteria are also low. Following disturbance and interrupted plant uptake, more N may be found in the soil. Populations of nitrifying bacteria increase under such conditions, and nitrate may become the dominant form of inorganic N present. We studied 9 forest sites at Ft. Benning, GA, representing a gradient of military training disturbance. We hypothesized that following incubation low disturbance soils would produce the highest levels of ammonium, while high disturbance soils would produce low levels of ammonium and the highest levels of nitrate. After a 4-week incubation, soil N exhibited significant trends across the three disturbance levels. Average mineralized soil ammonium-N was 1073, 728, and 240 mg m-2 in the low, moderate and high training intensity soils, respectively. Average soil nitrate-N formed was 277, 597, and 1503 mg m-2 in the low, moderate, and high training intensity soils, respectively. Soil mineralizable N may be an effective ecological indicator for determining ecosystem condition on military training lands.
Key words: ecological indicators, military training lands, mineralizable N