Ecology and Evolutionary Biology

Environmental indicators for longleaf pine (Pinus palustris) ecosystems need to include some measure of understory vegetation because of its responsiveness to disturbance and management practices. To examine the characteristics of understory species that distinguish between disturbances induced by military traffic, we randomly established transects in four training intensity categories (reference, light, moderate, and heavy) and in an area that had

Ecological indicators can be used to assess the condition of the environment, to provide an early warning signal of changes in the environment, or to diagnose the cause of an environmental problem. Ideally the suite of indicators should represent key information about structure, function, and composition of the ecological system. Three concerns hamper the use of ecological indicators as a resource management tool. (1) Monitoring programs often depend on a small number of indicators and fail to consider the full complexity of the ecological system. (2) Choice of ecological indicators is confounded in management programs that have vague long-term goals and objectives. (3) Management and monitoring programs often lack scientific rigor because of their failure to use a defined protocol for identifying ecological indicators. Thus, ecological indicators need to capture the complexities of the ecosystem yet remain simple enough to be easily and routinely monitored. Ecological indicators should meet the following criteria: be easily measured, be sensitive to stresses on the system, respond to stress in a predictable manner, be anticipatory, predict changes that can be averted by management actions, be integrative, have a known response to disturbances, anthropogenic stresses, and changes over time, and have low variability in response. The challenge is to derive a manageable set of indicators that together meet these criteria. Published by Elsevier Science Ltd.

How can ecologists be more effective in supporting ecologically informed rural land-use planning and policy? Improved decision making about rural lands requires careful consideration of how ecological information and analyses can inform specific planning and policy needs. We ...

Roads and vehicles change the environmental conditions in which they occur. One way to categorize these effects is by the spatial scale of the cause and the impacts. Roads may be viewed from the perspective of road segments, the road network, or roads within land ownership or political boundaries such as counties. This paper examines the hypothesis that the observable impacts of roads on the environment depend on spatial resolution. To examine this hypothesis, the environmental impacts of vehicles and roads were considered at four scales in west central Georgia in and around Fort Benning: a second-order catchment, a third-order watershed, the entire military installation, and the five-county region including Fort Benning. Impacts from an experimental path made by a tracked vehicle were examined in the catchment. Land-cover changes discerned through remote sensing data over the past three decades were considered at the watershed and installation scales. A regional simulation model was

Indicators are needed to assess environmental sustainability of bioenergy systems. Effective indicators will help in the quantification of benefits and costs of bioenergy options and resource uses. We identify 19 measurable indicators for soil quality, water quality and quantity, greenhouse gases, biodiversity, air quality, and productivity, building on existing knowledge and on national and international programs that are seeking ways to assess sustainable bioenergy. Together, this suite of indicators is hypothesized to reflect major environmental effects of diverse feedstocks, management practices, and post-production processes. The importance of each indicator is identified. Future research relating to this indicator suite is discussed, including field testing, target establishment, and application to particular bioenergy systems. Coupled with such efforts, we envision that this indicator suite can serve as a basis for the practical evaluation of environmental sustainability in a variety of bioenergy systems.

Our hypothesis is that a high diversity of dominant life forms in Tennessee forests conveys resilience to disturbance such as climate change. Because of uncertainty in climate change and their effects, three climate change scenarios for 2030 and 2080 from three General Circulation Models (GCMs) were used to simulate a range of potential climate conditions for the state. These climate

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 Energy's 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 model's 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 ϫ 10 6 -km 2 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.

Characterizing how resource use and management activities affect ecological conditions is necessary to document and understand anthropogenic changes in ecological systems. Resource managers on military installations have the delicate task of balancing the training needs of soldiers effectively with the need to maintain a high quality of ecological conditions. This study considers ways that ecological indicators can provide information on impacts that training has on environmental characteristics that occur at different scales and in different sectors of the environment. The characteristics examined include soil chemistry, soil microbes, and vegetation. A discriminant function analysis was conducted to determine whether ecological indicators could differentiate among different levels of military use. A combination of 10 indicators explained 90% of the variation among plots from five different military use levels. Results indicated that an appropriate suite of ecological indicators for military resource managers includes soil, microbial, and vegetation characteristics. Since many of these indicators are related, managers at this location potentially have freedom to choose indicators that are relatively easy to measure, without sacrificing information. Published by Elsevier Ltd.

The many ways that people have used and managed land throughout history has emerged as a primary cause of land-cover change around the world. Thus, land use and land management increasingly represent a fundamental source of change in the global environment. Despite their global importance, however, many decisions about the management and use of land are made with scant attention to ecological impacts. Thus, ecologists' knowledge of the functioning of Earth's ecosystems is needed to broaden the scientific basis of decisions on land use and management. In response to this need, the Ecological Society of America established a committee to examine the ways that land-use decisions are made and the ways that ecologists could help inform those decisions. This paper reports the scientific findings of that committee.

We study economic and environmental aspects of farming practices of a sample of 91 family farms around the city of Ouro Preto, in Brazil's state of Rond6nia, in western Amazonia, from four overlapping r,~,'spectives. First, we estimate production functions for six activities on muitiproduct farms, finding evidence of increasing returns to scale in cattle activity and possible evidence of nonindependence of profit and utility maximization in several subsistence crops. Second, we examine determinants of overall current farm revenue and wealth, finding possible evidence of overuse of land and underinvestment in cattle, decapitalization of farms over time, overpopulation, and a trade-off between children and capital accumulation. Third, we study interactions between burning strategies, diversification of f~rm activities, locational choice, length of tenure on a farm, and soil quality. Longer tenure on a farm and larger area in perennial crops appear to reduce the frequency of burning, while greater area in annual crops increases the frequency. Larger pasture area tends to reduce the frequency of burning below an annual periodicity. Less frequent burning appears to be accompanied by greater diversification of farm income sources. Fourth, we study the determinants of deforestation on lots, finding a negative effect of clearance costs and productivity of land in cultivation on the clearance of new land. However, the evidence for the relationship between cattle activit~ and deforestation is mixed: a larger number of * Corresponding author. Prepared by the Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA, managed by Martin Marietta Energy Systems, Inc. for the U.S. Depaament of Energy under contract no. DE-ACO5-840R21400.

Time series of thematic land-cover maps are used to measure changes in land cover over time. However, pixel-to-pixel comparisons of such maps are often not advisable when these maps are generated from different sources (i.e., satellite data, aerial photography, or historical land survey data). The purpose of this study was to examine the historical changes in land cover from 1827 to 1999 using landscape metrics calculated on maps created from different sources. Regression and power law analyses were conducted to identify significant trends and threshold effects associated with land-cover change at Fort Benning, Georgia. Results indicated that since 1827 the landscape has become more fragmented with the introduction of farming, military training, and forest management practices.

AGRIS record. Record number, US9158660. Titles, Climate change and forests. Personal Authors, Binkley, CS. Publisher, School of Forestry, Northern Arizona University. Publisher Place, [Flagstaff (USA)]. Publication Date, [1990]. AGRIS Subj. Cat. ...

In their Reports in the 29 February issue (“Land clearing and the biofuel carbon debt,” J. Fargione et al., p. 1235, and “Use of US croplands for biofuels increases greenhouse gases through emissions from land-use change,” T. Searchinger et al., p. 1238), the authors do not provide ...