Regional Ecological Risk Assessment Research Articles

Regional ecological risk assessment for the introduction of Gambusia affinis (western mosquitofish) into Montana watersheds

Qualitative risk assessment methodologies were used to assess the risk of establishment and consequent impacts on native minnows and species of concern (SOC) associated with the intentional or unintentional introduction of the mosquito biological control agent, Gambusia affinis, to various Montana watersheds. Gambusia affinis introductions for mosquito control have been made throughout the world; some introductions have resulted in deleterious effects on native species. We used average January water temperatures, the presence of dams, and the presence of native minnows and SOC to define endpoints for our assessment. Our results suggest that a section of the Missouri River running between Wolf Creek and Landusky had the highest overall risk score, which corresponds to the highest likelihood of establishment and effects on native minnows and SOC. We also demonstrate how rivers with the highest temperatures are not necessarily at the highest risk of having deleterious effects on minnows and SOC; conversely, these rivers were found to be at highest risk of a population of G. affinis establishing.

Study on the procedure and approach for ecological risk regionalisation

Ecological risk regionalisation is a process for determining the distribution of eco‐risk. The basis of ecological risk regionalisation is regional ecological risk assessment. Existing procedures for ecological risk assessment often aim at natural ecosystems and are used mainly for retrospective evaluation of risks. This paper presents a tiered ecological risk assessment procedure (TERAP) for complex ecosystems. The approach is not only for current evaluation, but also for retrospective and future evaluations. Based on the TERAP, a regional ecological risk assessment model was constructed. The TERAP has three tiers: the first is demarcation of the area affected by a particular stressor; the second is a semi‐quantitative assessment of the risk index which is gained from the vulnerability index and integrated into the hazard index; the third is quantitative loss evaluation under the risk index. The main factors in the ecological risk assessment model are ecosystem attributes and socio‐economy status. According to the main factors in the model, the change in the ecosystem into the future is simulated and the socioeconomic mathematical model is constructed. In this paper, taking Chongming Island as an example, the approach taken for simulation of the future ecosystem is analysis with the CLUE‐S model. The end purpose of current and future ecological risk regionalisation is to direct region programming and risk management.

Conceptual Model Development for Invasive Species and a Regional Risk Assessment Case Study: The European Green Crab, Carcinus maenas, at Cherry Point, Washington, USA

The goal of this article was to generate a method of regional scale ecological risk assessment using an adaptation Relative Risk Model (RRM). As a case study we performed a quantitative, regional risk assessment of an invasive species, the European green crab (Carcinus maenas) at Cherry Point, Washington, USA. The conceptual model was modified from the RRM and incorporates the structure of the hierarchical patch dynamic paradigm. The ranks and filters were integrated to determine the relative contribution of each source of C. maenas to risk as well as the risk to selected biological endpoints, habitats and sub-regions for two source scenarios: (1) current conditions (2004) and (2) future conditions during an El Nino year. The results suggest that the habitat and endpoint with the greatest risk are the eelgrass habitat and the juvenile Dungeness crab, respectively. The Cherry Point subregion was identified as the area having the most risk in the first source scenario, while the Lummi Bay sub-region is most at risk during an El Nino event. The risk of impacts is substantially higher for all endpoints, habitats and sub-regions when El Nino–driven current dispersal is considered. The methodology applied in this case study can be modified and applied to determine the risk of introduction and impacts of other invasive species to the Strait of Georgia, Puget Sound, and other coastal areas.

Ten Years of the Relative Risk Model and Regional Scale Ecological Risk Assessment

ABSTRACT It has been 10 years since the publication of the relative risk model (RRM) for regional scale ecological risk assessment. The approach has since been used successfully for a variety of freshwater, marine, and terrestrial environments in North America, South America, and Australia. During this period the types of stressors have been expanded to include more than contaminants. Invasive species, habitat loss, stream alteration and blockage, temperature, change in land use, and climate have been incorporated into the assessments. Major developments in the RRM have included the extensive use of geographical information systems, uncertainty analysis using Monte Carlo techniques, and its application to retrospective assessments to determine causation. The future uses of the RRM include assessments for forestry and conservation management, an increasing use in invasive species evaluation, and in sustainability. Developments in risk communication, the use of Bayesian approaches, and in uncertainty analyses are on the horizon.

Regional Ecological Risk Assessment of a Near Shore Marine Environment: Cherry Point, WA

ABSTRACT We conducted a regional ecological risk assessment for a near shore marine environment in northwestern Washington State using the Relative Risk Model. The objectives of this study were threefold: (1) to analyze cumulative impacts from multiple sources of chemical and non-chemical stressors in the near shore region and upland watersheds of Cherry Point (2) to determine the utility of Monte Carlo type uncertainty analysis in a rank-based regional risk assessment and (3) to investigate the effects of model habitat characterization on risk estimates. We used geographic information systems to compile and compare spatial data to determine ranks for sub-regions within the study area. By quantitatively combining ranks with exposure and effects filters, we estimated total relative risk between sub-regions and relative contributions of stressors. Finally, we used Monte Carlo analysis and an alternative ranking scheme to evaluate the effects of model and parameter uncertainty on risk predictions. The regional risk assessment results suggest the major contributors of risk are vessel traffic, upland urban and agricultural land use and shoreline recreational activities. This assessment demonstrated the applicability of regional risk assessment to marine near shore regions and the benefit of Monte Carlo analysis in describing uncertainty in a Relative Risk Model regional risk assessment.

Probe into the method of regional ecological risk assessment—a case study of wetland in the Yellow River Delta in China

Ecological risk assessment (ERA) is a new field of study for evaluating the risks associated with a possible eco-environmental hazard under uncertainty. Regional ERA is more complex than general ERA, as it requires that risk receptors, risk sources, risk exposure, uncertainty and especially spatial heterogeneity all be taken into account. In this paper, a five-step process of regional ERA is developed and tested through a wetland case study in the Yellow River Delta in China. First, indices and formulas are established for measuring degrees of ecological risk and damage to ecosystems. Using a combination of remote sensing data, historical records and survey data, and with the assistance of GIS techniques, the indices and formulas are then applied to the wetland in the study area. On the basis of the assessment results, we propose a number of countermeasures for the various risk zones in the Yellow River Delta.

Hazard prioritization in ecological risk assessment through spatial analysis of toxicant gradients

The analysis of spatial relationships among the distribution of environmental stressors and observed or predicted adverse effects may be a useful method of prioritizing hazards in regional ecological risk assessment (ERA). Geographic information systems were used to compare the spatial distribution of toxicant concentrations in sediments of Chesapeake Bay with the distribution of areas in the basin where ecological impacts have historically been observed. Toxicants were then prioritized based upon the strength of their spatial association with the high impact areas. This method of hazard identification/prioritization was validated against the Chesapeake Bay Program's lists of toxics of concern and toxics of potential concern (TOC and TOPC, respectively). Of the 18 toxicants on the TOC/TOPC lists that were considered in the current study, 15 (83%) were identified as priority contaminants in the current study, 11 (73%) of which were either of primary or secondary concern. The use of spatial analysis tools in ERA may lead to more rapid and rigorous methods for prioritizing environmental risks.

Developing A Regional Ecological Risk Assessment: A Case Study of a Tasmanian Agricultural Catchment

A regional ecological risk assessment was conducted for the Mountain River catchment in Tasmania, Australia. The Relative Risk Model was used in conjunction with geographic information systems interpretations. Stakeholder values were used to develop assessment endpoints, and regional stressors and habitats were identified. The risk hypotheses expressed in the conceptual model were that agriculture and land clearing for rural residential are producing multiple stressors that have potential for contamination of local waterbodies, eutrophication, changes in hydrology, reduction in the habitat of native flora and fauna, reductions in populations of beneficial insects in agricultural production systems, increased weed competition in pastures, and loss of aesthetic value in residential areas. In the risk analysis the catchment was divided into risk regions based on topography and land use. Stressors were ranked on likelihood of occurrence, while habitats were ranked on percentage land area. Risk characterization showed risks to the maintenance of productive primary industries were highest across all risk regions, followed by maintenance of a good residential environment and maintenance of fish populations. Sensitivity analysis was conducted to show the variability in risk outcomes stemming from uncertainty about stressors and habitats. Outcomes from this assessment provide a basis for planning regional environmental monitoring programs.

Regional ecological risk assessment of selenium in Jilin province, China

Integrating the biokinetic model of selenium with Monte Carlo analysis, this article carries out a quantitative study on ecological risk assessment in blood selenium levels of residents in Jilin province. The result shows that the established biokinetic model can be employed to predict the blood selenium levels of residents in a region. The predicted average blood selenium is 0.044 μg/ml and standard deviation is 0.013 μg/ml. Compared with the determined average blood selenium (0.043 μg/ml) and standard deviation (0.019 μg/ml), there was no obvious difference between each other ( P>0.05). The predictive risk degree (19.8%) is also similar to that of the Keshan disease occurrence (16.4%) of residents in Jilin province. The advance of the ecological risk assessment model of selenium offers a good example for the study on predictive models of other trace elements in the human body.

Use of Small Forage Fish for Regional Streams Wildlife Risk Assessment: Relative Bioaccumulation of Contaminants

Selection of fish species for sampling to assess extent and potential effects of fish tissue contaminants is a criticalconsideration in the design of regional probability-designsurveys. The ideal species would be ubiquitous, bioaccumulatetoxic chemicals, and be prey of consumers of concern(piscivorous wildlife, humans). In first to third order streams,small short-lived forage fish (minnows (F. Cyprinidae), darters (F. Percidae), and sculpins (F. Cottidae), are more frequently found and therefore likely to be prey to more species ofwildlife than those of sportfish whose adults grow to a largesize (suckers (F. Catostomidae), trout (F. Salmonidae), bass, andsunfish (F. Centrarchidae), and carp). Targeting smaller foragefish should also produce a larger number of individuals persample on average than may be achieved with the larger species.An analysis of fish collected in 1993 and 1994 as part of theMid-Atlantic Highlands Assessment (MAHA) showed that, asexpected, forage fish were more ubiquitous than sportfishspecies. Analysis also revealed that, on a regional basis, forage fish bioaccumulated comparable levels to sportfish, ofsome widely occurring contaminants such as DDT, MeHg, and PCBs.Results indicated that smaller forage fish can be used asindicator species for a regional assessment for mostcontaminants (Zn being the one clear exception), that was notsignificantly different from one based on the larger species.Forage fish may therefore be an excellent choice as indicatorspecies for regional streams ecological risk assessment studies.

Design considerations and a suggested approach for regional and comparative ecological risk assessment

Click to increase image sizeClick to decrease image sizeKey words: regional risk assessmentecological risk assessmentranking risks

Ecological benefits assessment: A policy‐oriented alternative to regional ecological risk assessment

Abstract As the focus of many environmental and resource management decisions shifts to larger ecological units such as watersheds and ecoregions, the respective roles of ecological risk and ecological benefits must be reassessed. At larger ecological scales, risk becomes much more difficult to characterize because of the focus on the system rather than individual species. However, quantifying the monetary value of many ecological benefits is also difficult because no direct measures of their value exist, and the indirect techniques used by economists are not fully accepted in some policy‐making settings. This dilemma may be resolved by considering ecological resource/service flows, which are ecological benefits in physical rather than monetary units. By assessing the whole range of resource/service flows and the changes to each that would result from different management/control alternatives, scientists would be able to provide policy‐makers a much better basis for their decisions, and the resulting asse...