Tom L. Ashwood

Effect of military training on indicators of soil quality at Fort Benning, Georgia

Abstract The purpose of this research was to investigate the effects of soil disturbance on several key indicators of soil quality at Fort Benning, Georgia. Military activities at Fort Benning that result in soil disturbance include infantry, artillery, wheeled, and tracked vehicle training. Soil samples were collected along a disturbance gradient that included: (1) reference sites, (2) light military use, (3) moderate military use, (4) heavy military use, and (5) remediated sites. With the exception of surface soil bulk density, measured soil properties at reference and light use sites were similar. Relative to reference sites, greater surface soil bulk density, lower soil carbon concentrations, and less carbon and nitrogen in particulate organic matter (POM) were found at moderate use, heavy use, and remediated sites. Studies along a pine forest chronosequence indicated that carbon stocks in POM gradually increased with stand age. An analysis of soil C:N ratios, as well as soil carbon concentrations and stocks, indicated a recovery of soil quality at moderate military use and remediated sites relative to heavy military use sites. Measurements of soil carbon and nitrogen are ecological indicators that can be used by military land managers to identify changes in soil from training activities and to rank training areas on the basis of soil quality.

The Role of Soil Classification in Geographic Information System Modeling of Habitat Pattern: Threatened Calcareous Ecosystems

ABSTRACT Maps of potential habitat distribution are needed for regional population models of rare species, but reliable information from ground surveys is not always available. Existing data sources from disciplines other than ecological research often are underused. In this article, we discuss the development of a geographic information system (GIS) model that predicts potential habitats from ecosystem information contained in the US soil classification and soil survey. Soil classification and survey were used in the GIS model in an earlier study on the US Department of Energys Oak Ridge Reservation, Tennessee, to predict threatened calcareous habitats. The model predicts potential habitats from the combination of (a) soil taxon as an indication of long-term ecosystem processes; (b) geologic parent material; and (c) slope class. Satellite imagery was added to indicate current successional state. In this study, we tested the models predictive ability by using data from the Cedar Creek Slope Glades Preserve at the 44,000-ha US Department of Defense Fort Knox Military Reservation, Kentucky. We then used the model to predict occurrences of potential suitable habitat on the remainder of the Fort Knox reservation, including heavily impacted ordnance and tank training areas that are unsafe for public access. The soil component of the model also was applied to a 1.2 × 106–km2 region of the US, by using the US Department of Agriculture–National Resources Conservation Service (USDA-NRCS) State Soil Geographic Database (STATSGO) combined with official soil series descriptions. Soil taxa from the USDA-NRCS Soil Taxonomy were demonstrated to be associated with threatened calcareous habitats of rare plant species. These soil taxa were lithic mollisols (rendolls and udolls; Food and Agriculture Organization of the United Nations (FAO) rendzinas and chernozems) and alfisols (udalfs; FAO luvisols). The combined soil/geology/slope GIS approach has potential for prediction of rare ecosystems with narrow edaphic constraints. The approach would be useful in long-term planning for conservation management and restoration, especially where intensive ground surveys are expensive and/or impractical and where disturbance history obscures patterns of historical distribution.

monitoring bioaccumulation of contaminants in the belted kingfisher (ceryle alcyon)

The belted kingfisher (Ceryle alcyon), acommon piscivore in the eastern United States, hasbecome a common endpoint in ecological riskassessments (ERA) because of their high consumptionof potentially contaminated aquatic prey. Whilebioaccumulation data and biosurveys may be used tosupport conclusions of ERAs for kingfishers, thereare currently no published data on contaminantconcentrations in kingfishers. Additionally,methods available for collecting biological samples(e.g., feathers, eggs, food debris, etc.) fromkingfisher burrows can be detrimental to thereproductive success of the birds. We present amethod for obtaining samples from burrows during orfollowing the nesting season. The method wasapplied to kingfisher burrows on the Oak RidgeReservation (ORR) in eastern Tennessee. Feathers,eggshells, and nestlings were collected from burrows and analyzed. In addition, carcasses ofthree adult kingfishers found dead on the ORR wereanalyzed. Metals and radionuclides were accumulatedby both juvenile and adult birds. Body burdens ofcadmium, lead, and cesium-137 in adult birds were belowlevels associated with toxicity. Concentrations of selenium and mercury were observed at potentiallytoxic levels. Contaminants in eggshells andnestling feathers indicate exposure, however, thereis insufficient information to evaluate thetoxicological significance of this contamination.

Toward an Ecological Framework for Assessing Risk to Vertebrate Populations from Brine and Petroleum Spills at Exploration and Production Sites

REFERENCE: Efroymson, R. A., Carlsen, T. M., Jager, H. I., Kostova, T., Carr, E. A., Hargrove, W. W., Kercher, J., and Ashwood, T. L., “Toward a Framework for Assessing Risk to Vertebrate Populations from Brine and Petroleum Spills at Exploration and Production Sites,” Landscape Ecology and Wildlife Habitat Evaluation: Critical Information for Ecological Risk Assessment, Land-Use Management Activities, and Biodiversity Enhancement Practices, ASTM STP 1458, L. Kapustka, H. Galbraith, M. Luxon, and G. R. Biddinger, Eds., ASTM International, West Conshohocken, PA, 2004. ABSTRACT: Brine and petroleum spills may affect terrestrial vertebrates through loss of reproductive habitat or reduced food availability rather than direct toxicity. A proposed ecological framework for evaluating impacts of these spills includes individual-based population models, a site conceptual trophic model, habitat suitability maps, and a stochastic brine spill generator. Simulation results for mammal populations in the Tallgrass Prairie Preserve petroleum exploration and production (EP above this threshold the time to extinction decreased with increasing spill area. Vole density was sensitive to the interaction of predation and fragmentation, with fragmentation causing population extinction in the presence of predation, yet stabilizing the population in the absence of predation. We anticipate that our results will aid in future development of “exclusion criteria” for leaving unrestored habitat at E&P sites.

Pearl Harbor bombing attack

Abstract Sediment cores collected from Middle Loch and West Loch of Pearl Harbor were dated using fallout 137 Cs and excess 210 Pb and analysed for several major elements and trace metals. Results indicate that sediment deposited immediately following the 7 December, 1941, bombing attack on Pearl Harbor contained elevated levels of several trace metals. The bombing attack resulted in about six times more lead input to this estuarine area than the total combined lead input from sewage and naval maintenance operations during the succeeding 45 years. Although buried under 1 m of sedimentary material, this lead burden remains an environmental concern because dredging activities, ship traffic, and tropical storms could potentially resuspend this contaminated layer.