Disturbance by aquatic plant management in streams: Effects on benthic invertebrates

Abstract

The effect of aquatic plant removal on benthic invertebrates and their habitat was studied in two macrophyte‐rich streams of the Swiss Plateau. In each stream, habitat conditions (macrophyte biomass, current velocity, water depth) and invertebrate densities were monitored in a control reach and in a reach where plants were removed by cutting. Biological samples were taken and physical parameters measured on three dates before and six dates after plant removal in both reaches. Responses to plant removal were similar in both streams; macrophyte cutting initially decreased mean plant biomass (ca. 85%) and total number of invertebrates (ca. 65%). Variation between replicates was, however, higher in one of the streams, causing fewer effects on plants and invertebrates to be statistically significant. Plant cutting affected mainly taxa that used macrophytes as habitat (e.g. Simuliidae, Chironomidae), whereas highly mobile taxa (e.g. Ephemeroptera) and taxa living on or within the bed sediments (e.g. Trichoptera, Bivalvia) were less affected. Taxa that decreased after plant removal recovered within 4–6 months, although recovery of macrophytes was quite different in both streams. Invertebrate recovery also seemed to be seasonally dependent, with cutting having a less severe impact during summer than spring. Our results suggest that macrophytes in streams should be removed only in summer, preferably leaving some plant beds to act as refugia for phytophilous invertebrates. © 1998 John Wiley & Sons, Ltd.

The food preferences of three-spined stickleback, Gasterosteus aculeatus L., downstream from a dam reservoir

“…and Parachironomus arcuatus, Chironomidae) (Dukowska et al 1999(Dukowska et al , 2005. On the other hand, macrophytes may create favorable conditions for pelophilous zoobenthos, such as Oligochaeta and large-sized Chironomini (Chironomidae), by trapping fine particulate organic matter on the bottom (Cogerino et al 1995, Kaenel et al 1998, Grzybkowska et al 2003.…”

Velocity and turbulence distribution around lotic macrophytes

“…Several researchers have investigated the spatial distribution of invertebrates within macrophytes (e.g. Tokeshi and Pinder 1985;Pinder 1992), and within the surrounding channel bed (Armitage 1995;Kaenel et al 1998). They have suggested that invertebrate taxa recorded in specific areas of plant stands may reflect their hydraulic requirements (Tokeshi and Pinder 1985;Gunn 1985;Pinder 1992;O'Hare and Murphy 1999) either directly in terms of tolerance to mean flows and turbulence intensity or indirectly through oxygen and food availability.…”

Effect of Flow Fluctuations on Patch Dynamics and Chironomid Distribution in a Medium-Sized Lowland River

“…Macrophytes also may create favorable conditions for pelophilous zoobenthos by trapping FPOM (Armitage 1984, Cogerino et al 1995, Pardo and Armitage 1997, Kaenel et al 1998, Gnybkowska et al 2003. In the Drzewiczka River, rnacrophyte cover was the dominant habitat during DI and was characterized by a high abundance of simuliids, orthoclads, and ephemeropterans associated with Potamogeton spp.…”