Stream Fish Dynamics in the Southeastern Coastal Plain: Novel Detection Methods and Community Stability

Author

• Catherine A. Masatani, Clemson UniversityFollow

Date of Award

5-2026

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Forestry and Environmental Conservation

Committee Chair/Advisor

Brandon Peoples

Committee Member

Zanethia Barnett

Committee Member

Kyle Barrett

Abstract

Freshwater ecosystems are increasingly threatened by climate change and rapid human population growth, accelerating biodiversity loss and habitat degradation. Streams in the South Carolina Coastal Plain exhibit dynamic flow regimes, including drought-driven intermittency and hurricane-induced flooding, while also experiencing substantial anthropogenic modification. Despite these pressures, nonnative species occurrence and patterns of fish community dynamics remain understood. This study evaluated (1) the distribution and detection of nonnative fishes and (2) intra-annual variability in fish community structure across a dynamic stream network. We conducted repeat sampling (3-4 visits) at 45 stream sites in and around the Francis Marion National Forest from May to December 2024. Fish communities were surveyed using two-pass electrofishing and eDNA to compare detection probabilities, alongside measurements of habitat, water quality, and watershed-scale land cover and network characteristics. Single-season occupancy models were used to estimate detection probabilities and identify drivers of nonnative species occurrence. We used multivariate statistics to evaluate how habitat and landscape heterogeneity influence intra-annual patterns of fish community structure. Nonnative Green Sunfish (Lepomis cyanellus) were detected exclusively at urban sites. Detection patterns from eDNA were congruent with electrofishing results, indicating both methods are effective for detecting nonnative fish in this system. Despite pronounced seasonal habitat fluctuations, fish community composition was not strongly influential of community variability. Instead, forested land cover was the only variable with a significant positive effect on fish community variability. This research improves our understanding of nonnative species occurrence and fish community response to anthropogenic impacts and environmental variability in Coastal Plain ecosystems.

Recommended Citation

Masatani, Catherine A., "Stream Fish Dynamics in the Southeastern Coastal Plain: Novel Detection Methods and Community Stability" (2026). All Theses. 4738.
https://open.clemson.edu/all_theses/4738