Special Session - Landscape ecological modeling and ecological risk assessment: at the cross roads Chair(s): Cole, Marlene¹, Johnson, Alan ², Linkov, Igor¹, ¹ ICF Consulting, Lexington, MA² Clemson University, Clemson, SC
Wednesday, March 31, 2004 1:00 PM - 4:40 PM Apollo Room 1

Landscape ecological modeling and ecological risk assessment are often used to support environmental decision making. While each operates within its own set of methods and tools, decision-making may benefit from the fusion of the two disciplines. This session will bring together researchers involved in landscape ecological analyses and spatially explicit ecological risk assessments. Ecological risk assessment, which has much regulatory utilization and guidance, provides a systematic approach to predict the likelihood of undesired effects arising from environmental stressors. Stressors may include chemical contaminants or other ecological disturbances (land use changes, altered hydrology, invasive species, genetically modified organisms, climate change, etc.). Landscape-level approaches could benefit ecological risk assessment in a number of ways, including: (1) explicit consideration of scale and spatial organization during problem formation, (2) accounting for spatial heterogeneity in exposure characterization, (3) extrapolation from small-scale studies to broad-scale effects, (4) selection of appropriate assessment and measurement endpoints, (5) spatial analysis of uncertainties, and (6) the use of maps or other spatial visualization techniques for risk communication. In turn, ecological risk assessment can benefit landscape ecology because: (1) it has an existing regulatory presence (and is often required), (2) its framework lends itself to addressing environmental questions, and (3) it provides direct application to environmental decision making.

Incorporation of Landscape Characteristics and Receptor Organism Movement in Spatially Explicit Exposure Assessment. Linkov, Igor¹, Cole, Marlene^*,1, Grebenkov, Alexandre ², Andrizhievski, Anatoly ², Lukashevich, Alexey ², Trifonov, Alexandr ², Kapustka, Lawrence ³, ¹ ICF Consulting, Lexington, MA, USA² Joint Institute of Power and Nuclear Research, Sosny, Minsk, Belarus³ Ecological Planning and Toxicology, Inc., Corvallis, OR, USA

ABSTRACT- Various industrial activities have resulted in the physical disturbance and/or hazardous pollutant contamination of large areas of otherwise valuable habitat. We will present a methodological approach and a software prototype for spatially explicit risk assessment of contaminated terrestrial ecosystems designed to be implemented as part of a risk-based decision protocol to support the assessment of ecological value and site reuse options for such areas. The software prototype employs site-specific spatial data along with habitat suitability index (HSI) models to account for differential attraction to various habitat types within the site. Our spatially explicit foraging model provides a time series estimation of soil and food contamination that receptor organisms may encounter and accumulate in their daily movements. For areas containing spatially localized contaminants, the software estimates exposure levels for wildlife as functions of spatial factors, such as the average foraging area of the organism, the size of the habitat being assessed, and the distribution of contamination. Species exhibiting different foraging strategies may experience significantly different chemical exposures from the same site, even if their foraging areas overlap. Currently, exposure estimates and subsequent ecological risk projections generally assume a static and continuous exposure of an organism to a contaminant concentration represented by some descriptive statistic, such as the mean or maximum concentration. These assumptions are generally overly conservative and ignore some of the major advantages offered by advanced risk assessment techniques, such as the ability to account for site-specific conditions and to conduct iterative analyses.

KEY WORDS: habitat, ecological risk assessment, spatial model, spatially explicit, movement