A5080172446- Fish Ecology and Management Studies
- Freshwater macroinvertebrate diversity and ecology
- Soil and Water Nutrient Dynamics
- Aquatic Invertebrate Ecology and Behavior
- Environmental Toxicology and Ecotoxicology
- Hydrology and Watershed Management Studies
- Hydrology and Sediment Transport Processes
- Climate change and permafrost
- Environmental DNA in Biodiversity Studies
- Aquatic Ecosystems and Phytoplankton Dynamics
- Water Quality and Pollution Assessment
- Isotope Analysis in Ecology
- Ecology and biodiversity studies
- Marine and fisheries research
- Arctic and Antarctic ice dynamics
- Cryospheric studies and observations
- Soil erosion and sediment transport
- Insect and Pesticide Research
- Peatlands and Wetlands Ecology
- Diatoms and Algae Research
- Petroleum Processing and Analysis
- Pharmaceutical and Antibiotic Environmental Impacts
- Pesticide and Herbicide Environmental Studies
- Mine drainage and remediation techniques
- Marine and coastal ecosystems
Wilfrid Laurier University
2018-2024
Environment and Climate Change Canada
2012-2022
University of New Brunswick
2012-2022
University of Fredericton
2016
Impact
2003-2009
National Water Research Institute
2000-2005
Acadia University
2005
University of Calgary
1989-1991
Abstract Numerous international scientific assessments and related articles have, during the last decade, described observed potential impacts of climate change as well other environmental stressors on Arctic ecosystems. There is increasing recognition that projected changes in freshwater sources, fluxes, storage will have profound implications for physical, biogeochemical, biological, ecological processes properties terrestrial However, a significant level uncertainty remains relation to...
An experiment in >1000 river and riparian sites found spatial patterns controls of carbon processing at the global scale.
This overview of non-visual communication in freshwater benthic animals emphasizes recent studies the effect chemical and mechanical signals on predator-prey interactions macroinvertebrates amphibians. Prey species use to modify their morphological development, life history strategy, feeding, predator avoidance behavior. The advantages are that they can be used dark or turbid environments by do not have image-forming eyes. Chemical more persistent than signals, allow species-level...
Field experiments were conducted to investigate the responses of benthic macroinvertebrate communities experimental additions fine sediments into riffles having a flow with either low tractive force so deposited or sufficient transport added sediments. Sediment deposition had no measurable impact on most taxa, only negative effects being significantly higher drift rates and lower densities for Paraleptophlebia. by saltation created physical disturbance that reduced total >50% in 24 h...
The linkage of trait responses to stressor gradients has potential expand biomonitoring approaches beyond traditional taxonomically based assessments that identify ecological effect provide a causal diagnosis. Traits-based information may have several advantages over methods. These include providing mechanistic linkages biotic environmental conditions, consistent descriptors or metrics across broad spatial scales, more seasonal stability compared with taxonomic measures, and seamless...
Inputs of nutrients (P and N) to freshwaters can cause excessive aquatic plant growth, depletion oxygen, deleterious changes in diversity fauna. As part a "National Agri-Environmental Standards Initiative," the Government Canada committed developing environmental thresholds for protect ecological condition agricultural streams. Analysis data from >200 long-term monitoring stations across detailed study at ∼70 sites showed that land cover was associated with increased nutrient concentrations...
Manipulative field experiments were conducted in Carnation Creek, British Columbia, to determine whether particle-size composition of the stony substrate influenced macroinvertebrate microdistribution if detritus was standardized. A standardized quantity alder (Alnus rubra) added five mixtures ranging from homogeneous gravel a heterogeneous gravel, pebble, and cobble mixture, substrates imbedded riffle allow colonization. Densities biomasses most taxa (16 19) not significantly different...
The present study examined the effects of pulse exposures insecticide imidacloprid on mayfly, Epeorus longinmanus Eaton (Family Heptageniidae), and an aquatic oligochaete, Lumbriculus variegatus Miller Lumbriculidae). Pulse are particularly relevant for examination, because this is relatively soluble (510 mg/L) most likely to be at effect concentrations during runoff events. Experiments recovery organisms after a 24-h exposure over environmentally realistic range (0, 0.1, 0.5, 1, 5, 10...
Intensification of permafrost thaw has increased the frequency and magnitude large slope disturbances (mega slumps) in glaciated terrain northwestern Canada. Individual thermokarst up to 40 ha area have made volumes previously frozen sediments available for leaching transport adjacent streams, significantly increasing sediment solute loads these systems. To test effects this climate-sensitive disturbance regime on ecology Arctic we explored relationship between physical chemical variables...
Abstract Arctic regions support a wide variety of freshwater ecosystems. These naturally oligotrophic and cold‐water streams, rivers, ponds lakes are currently being impacted by diverse range anthropogenic pressures, such as accelerated climate change, permafrost thaw, land‐use eutrophication, brownification the replacement northern biota with expansion more southern species. Multiple stressors rapidly changing systems aquatic habitats becoming suitable for species originating from southerly...
Rivers and streams contribute to global carbon cycling by decomposing immense quantities of terrestrial plant matter. However, decomposition rates are highly variable large-scale patterns drivers this process remain poorly understood. Using a cellulose-based assay reflect the primary constituent detritus, we generated predictive model (81% variance explained) for cellulose across 514 globally distributed streams. A large number variables were important predicting decomposition, highlighting...
To minimize environmental impacts that may result from any engineered modifications of stream or river systems, a basic understanding ecology is required. Most fundamental theories have developed largely studies warm-temperate and tropical streams rivers. As these evolved over the last few decades, floods were recognized increasingly as dominant hydrologic events control numerous abiotic biotic forms processes, both within channel on adjacent riparian floodplains. Over approximately same...
We tested the hypothesis that predation risk from diurnal fish influences diel foraging periodicity of mayfly grazer, Baetis tricaudatus Dodds, in a size-dependent manner by examining habitat use and activity mayflies streams with without these predators. In each stream was determined counting number small (3 mm total length) large (6 larvae on upper surfaces replicate, natural cobble during 4-8 sampling periods within 24-h cycle over three seasons. Additionally, were collected preserved so...
Abstract Regional assessments on large rivers often are complicated because these ecosystems receive multiple, interacting effluent discharges. Confounding factors, such as mixing hydraulics and historical loading effects, can result in equivocal field data that lend weak inference to ecological risk assessments. Our approach this problem develops a strategy defines important mechanisms of pollutant effects through the combined use laboratory measurements, riverside mesocosm experiments,...
Abstract Northern river ecosystems are subject to a variety of stressors having multifaceted (and sometimes opposing) effects, making interpretation at regional scale difficult. We have addressed this problem by using weight-of-evidence approach that combines analysis field data (to determine patterns) with experimental hypothesis testing mechanisms). Two the more important sources aquatic impacts in western Canada pulp mill and municipal effluents. Their on benthic biota were evaluated for...
Summary 1. Employing field‐deployed mesocosms, we examined the effects of 12‐h pulse and 20‐day press (continuous) exposures common agricultural insecticide, imidacloprid, on nymph abundance, emergence patterns adult body size Epeorus spp. (Heptageniidae) Baetis (Baetidae). 2. In exposures, reduced density was driven by survivorship; in may reflect increased because stress. 3. Once exposed to mayflies developed less emerged smaller than their control counterparts. Concentrations as low 0.1 μ...
Manipulative field enclosure/exclosure experiments were carried out in Carnation Creek, British Columbia to determine if patch-restricted coho fry (Oncorhynchus kisutch) affected the distribution and abundance of macroinvertebrates drift or benthos. Enclosures/exclosures with standardized substrate, detritus, current velocity buried streambed during low discharge period, four treatments used: no fish, ambient double quadruple fish densities. Density, biomass, size not significantly by...