PARENT SESSION
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.

Spatial life history influences the risks associated with habitat loss and fragmentation associated with petroleum exploration and extraction. ^*JAGER, HENRIETTE I. and EFROYMSON, REBECCA A. , ¹ PO Box 2008, Oak Ridge, TN, USA

ABSTRACT- Population-level risks associated with petroleum and other activities that degrade animal habitat are difficult to generalize because of differences among species. This study is designed to understand how one might classify species by their spatial life histories with the goal of extrapolating to similar species. We generalized an individual-based landscape model designed to quantify the effects of petroleum-related habitat loss and fragmentation on bird and mammal populations. Stochastic landscapes differing in the proportion of area made unsuitable by brine spills, and in the fragmentation of, spills were created and used to quantify population responses. Our simulations assume that brine-impacted areas pose a similar risk to all species. We compared species with different spatial life histories, focusing on the following factors: (1) behavioral avoidance of spills; (2) risk associated with dispersal, and (3) reproductive resilience. Preliminary results show that species that do not avoid spill habitat experience steeper demographic declines as brine-impacted areas grow, but they are less sensitive to fragmentation. Species that avoid spill habitat decline more slowly with increasing habitat loss. However, these species are sensitive to fragmentation when movement risks are high, because they must travel farther to form territories. Allee effects, which are stronger in species with low reproductive resilience, strongly influence responses to both fragmentation and habitat loss.

KEY WORDS: individual-based model, spatial life history, habitat loss, habitat fragmentation, Allee effects