Scientists at E2 have modeled the ecological effects of nutrient enrichment, trace metals, organic contaminants, agrochemicals, ionizing radiation, and high voltage electromagnetic radiation. We have also modeled the impacts of physical (e.g., habitat degradation, hydrological alterations) and biological (e.g., invasive species) stressors in terrestrial and aquatic ecosystems. We have developed extensive expertise in the application of numerical methods to conduct sensitivity and uncertainty analyses, scale and complexity, and hierarchical approaches. 

Comprehensive Aquatic System Assessment. Scientists at E2 have developed a comprehensive aquatic system modeling approach, based on a bioenergetics-based approach to describe population production within a dynamic physical-chemical environment. The approach estimates spatial-temporal patterns of ecological risks posed by multiple stressors within a stagnant or moving water body. Several CASM models have been developed using this approach to address different types of stressors (e.g., nutrients, trace elements, pesticides), different types of water bodies (e.g., lakes, rivers, estuaries), and vertical stratification. Currently, a new version is under development that will include processes of advective transport in a flowing water system to develop spatially explicit effects in a flowing stream.

Impacts on Aquatic Organisms from River Traffic. Navigational traffic on a river, such as the Upper Mississippi River in the US, causes resuspension of sediments and entrainment of fish and larvae in the propellers of the ships and barges. Resuspended sediments reduce the light availability, which directly impacts the growth and mortality of aquatic vegetation. Aquatic vegetation are also subjected to the risk of breakage from the huge waves generated in the wakes of large vessels.  Scientists at E2 have developed and applied existing models to assess the impacts of sediment resuspension on the growth of aquatic vegetation and the impacts of larval entrainment on long-term fish populations. We have also developed a model to assess and isolate plant breakages caused by wind-generated waves and waves generated in the wakes of vessels.  We have applied these models to a Navigation Study conducted on the Upper Mississippi River and Illinois River System.

Risk of Establishment of Nonnative Invasive Species Populations. Scientists at E2 have developed a methodology to link the rate of entry of a nonnative, invasive species (e.g., Asian long-horned beetle) and its biology and ecology to a habitat's ecology to determine the probability of establishment of a self-preserving population of the species in the habitat. We have applied the approach to assess the risk of establishment of insect populations in different regions of the US; insects enter the US on untreated solid wood packing materials. We extended the analysis to estimate and compare the risk reductions achieveable by treatment of wood using different physical/chemical treatment technologies.

Assessment of Risks from Multiple Stressors using Population Models. Scientists at E2 have developed sophisticated, interactive population models using demographic descriptions of population dynamics of several aquatic and terrestrial organisms. These models have been used to estimate the likelihood of invasive species (e.g., Asian longhorned beetle) establishment, risks posed by toxic chemicals to several species of fish, population-level impacts of commercial navigation, and risks posed by hydrologic modification of the Florida Everglades on roseate spoonbills.