Gravel dredging alters diversity and structure of riverine fish assemblages

• Published in: Freshwater biology 2013-02, Vol.58 (2), p.261-274
• Main Authors: FREEDMAN, JONATHAN A., CARLINE, ROBERT F., STAUFFER JR, JAY R.
• Format: Article
• Language: English
• Subjects: Agnatha. Pisces; Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; Dredging; Etheostoma; Fish; Fresh water ecosystems; Freshwater; Fundamental and applied biological sciences. Psychology; habitat alteration; nutrient pathways; Principal components analysis; reproductive guilds; sedimentation; stable isotope analysis; Synecology; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution
• ISSN: 0046-5070; 1365-2427
• DOI: 10.1111/fwb.12056

Summary 1. Human activities affect fish assemblages in a variety of ways. Large‐scale and long‐term disturbances such as in‐stream dredging and mining alter habitat and hydrodynamic characteristics within rivers which can, in turn, alter fish distribution. Habitat heterogeneity is decreased as the natural riffle–pool–run sequences are lost to continuous pools and, as a consequence, lotic species are displaced by lentic species, while generalist and invasive species displace native habitat specialists. Sediment and organic detritus accumulate in deep, dredged reaches and behind dams, disrupting nutrient flow and destroying critical habitat for habitat specialist species. 2. We used standard ecological metrics such as species richness and diversity, as well as stable isotope analysis of δ13C and δ15N, to quantify the differences in fish assemblages sampled by benthic trawls among dredged and undredged sites in the Allegheny River, Pennsylvania, U.S.A. 3. Using mixed‐effects models, we found that total catch, species richness and diversity were negatively correlated with depth (P