A Comparison of Two Macroinvertebrate Multi-Plate Sampling Methods to Inform Great Lakes Monitoring and Remediation...

Area of Science:

• Environmental Science
• Ecology
• Water Quality Assessment

Background:

• Hester-Dendy (HD) samplers are standard for macroinvertebrate bioassessment by government agencies.
• The Niagara River, a Great Lakes Area of Concern, required a study to identify tributary impacts on water quality.

Purpose of the Study:

• To compare the effectiveness of two distinct HD sampler versions in assessing macroinvertebrate communities in urban tributaries.
• To evaluate the impact of different sampling methods on water quality bioassessment outcomes.

Main Methods:

• Two co-located HD samplers (NYSDEC and US EPA) were deployed in urban tributaries of the Niagara River.
• Macroinvertebrate communities were analyzed using multivariate ordination (NMDS, MRBP) and various ecological indices.
• Sampler variations included plate number/size, spacing, and deployment method.

Main Results:

• Both HD sampler methods detected community differences across stations, though some grouping by month and method occurred.
• Water quality assessments from the two methods were comparable but not identical.
• No statistical difference was found in total taxa or EPT richness between samplers.
• Significant differences were observed in metrics like percent tolerant collector-gatherer individuals.

Conclusions:

• Despite methodological variations, both HD sampler versions provide robust and comparable water quality assessments.
• Sampler deployment position was identified as a primary factor influencing observed community differences.
• The study validates the use of HD samplers for bioassessment in complex urban watersheds.