Semester of Graduation

Spring 2026

Degree

Master of Science (MS)

Department

School of Renewable Natural Resources

Document Type

Thesis

Abstract

Determination of benthic macroinvertebrate assemblage composition plays a vital role in assessment and management of lotic systems throughout the U.S. However, the validity of biomonitoring programs depends on accurate and precise measures of macroinvertebrate abundance, which in turn are dependent on sampling gears and protocols. The goal of this project was to assess how gear selection influences estimates of aquatic insect abundance and diversity, and how this selection can affect biological monitoring practices. I used 4 different gears in 3 southern Mississippi streams to aquatically and terrestrially collect aquatic insects seasonally throughout 2024. I identified and recorded all genera present within each gear-specific sample, and then aggregated data by season to identify possibly seasonal affects, by stream to correlate results with biomonitoring practices, and by site to identify relationships with environmental variables.

Although aquatic insect abundance was greatest in light trap samples, aquatic gears collected more diverse samples than terrestrial sampling methods across all aggregations of the data. D-frame net samples yielded greater abundance and diversity than Hess samples, although Hess samples  contained marginally higher overall %EPT (Ephemeroptera, Plecoptera, and Trichoptera) and Hilsenhoff Biotic Index (HBI) score than D-net samples. Results of Mississippi-Benthic Invertebrate Stream Quality (M-BISQ) analysis showed a large difference in scores between aquatic gears, which appeared to be related to gear specificity for particular groups of insects. Results indicate indicator metrics developed to have broad spatial applicability,  such as %EPT and HBI,  may not be drastically influenced by gear choice. However,  assessments based on more fine-scale monitoring programs similar to the M-BISQ may be impacted by gear selection. Integrating considerations of gear-specific sampling bias in lotic biomonitoring programs will improve managers’ abilities to assess biotic impacts of water quality changes through time.

Date

3-26-2026

Committee Chair

Michael Kaller

LSU Acknowledgement

1

LSU Accessibility Acknowledgment

1

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