Robert B. Brua

Toward a knowledge infrastructure for traits-based ecological risk assessment.

The trait approach has already indicated significant potential as a tool in understanding natural variation among species in sensitivity to contaminants in the process of ecological risk assessment. However, to realize its full potential, a defined nomenclature for traits is urgently required, and significant effort is required to populate databases of species-trait relationships. Recently, there have been significant advances in the area of information management and discovery in the area of the semantic web. Combined with continuing progress in biological trait knowledge, these suggest that the time is right for a reevaluation of how trait information from divergent research traditions is collated and made available for end users in the field of environmental management. Although there has already been a great deal of work on traits, the information is scattered throughout databases, literature, and undiscovered sources. Further progress will require better leverage of this existing data and research to fill in the gaps. We review and discuss a number of technical and social challenges to bringing together existing information and moving toward a new, collaborative approach. Finally, we outline a path toward enhanced knowledge discovery within the traits domain space, showing that, by linking knowledge management infrastructure, semantic metadata (trait ontologies), and Web 2.0 and 3.0 technologies, we can begin to construct a dedicated platform for TERA science.

Physical and ecological thresholds for deposited sediments in streams in agricultural landscapes.

Excessive sedimentation in streams and rivers remains a pervasive problem for the protection of aquatic habitat and the sustainability of aquatic communities. Whereas water quality criteria have been determined for suspended sediments in many jurisdictions across North America, comparably little has been done for deposited (also known as bedded) sediments. Through Canadas National Agri-Environmental Standards Initiative, assessment techniques and analytical tools were developed for estimating environmental thresholds for deposited sediments in agricultural watersheds in New Brunswick (NB) and Prince Edward Island (PEI) in the Atlantic Maritimes of Canada. Physical thresholds were developed through assessment of geomorphic metrics, which were then analyzed using y-intercept and 25th percentile approaches. For NB, there was strong agreement in physical thresholds for both analytical approaches (e.g., percent fines <2 mm were 7.5 for y-intercept and 6.9 for 25th percentile approaches). In contrast, physical thresholds for PEI differed considerably between approaches (e.g., percent fines <2 mm were 6.1 for y-intercept and 19.6 for 25th percentile approaches), likely due to a narrower range in agricultural land cover. Cross-calibration of our provisional physical thresholds for NB with ecological (i.e., benthic macroinvertebrate) assessments show that ecological thresholds, calculated as change-points in relationships between Ephemeroptera-Plecoptera-Trichoptera relative abundance or Modified Family Biotic Index and geomorphic criteria, were more liberal than physical thresholds. These results suggest that provisional thresholds developed using geomorphic criteria should demarcate change from the least disturbed condition and reduce the risk of sedimentation degrading benthic ecosystems.

Eutrophication of agricultural streams: defining nutrient concentrations to protect ecological condition.

Inputs of nutrients (phosphorus, P, and nitrogen, N) to coastal and fresh waters can accelerate eutrophication, resulting in excessive aquatic plant growth, depletion of oxygen, and deleterious changes in abundance and diversity of organisms. Using long-term (approximately 1995-2005) monitoring data from agriculturally-dominated watersheds in southern Ontario and Quebec, Canada, we developed and tested several approaches for setting targets for N and P. Our research showed that it is possible to set scientifically-credible targets for total P and total N to protect ecological condition of streams in agricultural landscapes, and define achievable targets attainable following adoption of beneficial management practices.

Comparison of benthic macroinvertebrate communities by two methods: Kick- and U-net sampling

The assessment of benthic invertebrate community condition is an integral component of freshwater biomonitoring and water quality determination. Several sampling devices have been developed to collect benthic macroinvertebrates, including qualitative, semi-quantitative, and quantitative methods. In this study, we compared several benthic macroinvertebrate metrics and community assemblage measures calculated from data obtained from two sampling methods, namely the Kick- and U-net sampling devices. We reasoned that if the two methods produced similar values for benthic metrics and community composition, then samples collected by these methods should be able to be combined to build larger data sets for use in regional bioassessment analyses. No statistical differences between Kick- and U-net methods were found among standard benthic macroinvertebrate metrics, except for Kick-nets collecting more Chironomidae. Invertebrate assemblages were very similar between collection methods, although slightly greater taxonomic richness was found in U-net samples. Bray–Curtis similarity was typically >75% between methods within a stream, while classification strength-sampling-method comparability, an approach for analyzing differences in similarity between groups, indicated invertebrate assemblage similarity between collection methods was virtually identical at approximately 100%. Since these two methods produce similar results, we conclude that benthic macroinvertebrate data collected by these methods can be combined for data analysis and bioassessments with the caveat that mesh size of the sample nets is similar. In addition, if the primary study objective is to assess macroinvertebrate biodiversity, then the U-net sampling device may be more appropriate, despite the slightly greater time needed to complete field sample collection, as it tended to collect a greater diversity of species.

Development of reference conditions for suspended solids in streams

Our aim was to develop protective physical and biological thresholds that identify the upper limit of the least disturbed (reference) condition for total suspended solids (TSS). The study focuses on streams in agricultural regions across Canada from which we collected contemporary TSS and benthic invertebrate data, and compiled long-term TSS data sets. Reference conditions for TSS were analyzed by five approaches previously applied in Canada, Australia and New Zealand, and the USA. In addition, ecological reference conditions for TSS were developed using regression-tree analysis to determine change-points along TSS gradients for three invertebrate metrics (percentage Ephemeroptera-Plecoptera-Trichoptera, total richness, and modified family biotic index). Increased agricultural land-cover was linked to higher TSS in most agricultural regions which, in turn, was associated with degraded environmental conditions and a reduction in the relative abundance of pollution-intolerant taxa. The five physical approaches produced a narrow range of regional TSS reference condition values (2.7 to 6.2 mg L–1). Ecological reference conditions for TSS ranged from 3.5 to 11.1 mg L–1 across Canada. We conclude that long-term TSS databases may serve to generate interim sediment criteria because ecological reference conditions were similar to those calculated from physical data alone. These interim sediment criteria may be appropriate targets for use in evaluation of restoration programs designed to improve environmental quality of aquatic ecosystems (e.g., beneficial or best management practice applications).

Developing metabolomics-based bioassessment: crayfish metabolome sensitivity to food and dissolved oxygen stress

There is a need to develop bioassessment tools that can diagnose the effects of individual stressors that can have multiple ecological effects. Using nuclear magnetic resonance (NMR)-based metabolomics, our experiments aimed to identify the sensitivity of metabolites to changes in food availability and dissolved oxygen (DO) concentrations, and compare these results to identify metabolites that may differentiate between the effects of these two stressors. Forty-eight, laboratory-raised, red swamp crayfish (Procambarus clarkii) were randomly assigned and exposed to one of three food availability or DO treatment levels (high, normal, low). Starved crayfish had lower amounts of amino acids than fed crayfish, suggesting catabolic effects of starvation on tail muscle tissue for energy requirements. In contrast, crayfish exposed to hypoxic conditions experienced changes in abundance of metabolites primarily associated with energy metabolism. Tail muscle was the only tissue sensitive to food and DO stress, suggesting the need to select tissues for monitoring appropriately. Our evaluation of environmental metabolomics as a tool for bioassessment indicates that several identified metabolites in crayfish tail muscle may be able to diagnose food and oxygen stress. Further study is required to determine if these metabolic effects are linked with changes of individual fitness and higher levels of biological organization, such as population size.