Agricultural Rivers at Risk: Dredging Results in a Loss of Macroinvertebrates. Preliminary Observations from the Narew Catchment, Poland

Abstract

Ecosystem deterioration in small lowland agricultural rivers that results from river dredging entails a significant threat to the appropriate ecohydrological conditions of these water bodies, expressed as homogenization of habitats and loss of biodiversity. Our study was aimed at a comparison of abundance and taxonomic structure of bottom-dwelling macroinvertebrates in dredged and non-dredged stretches of small lowland rivers and tributaries of the middle Narew River, namely: Czaplinianka, Turośnianka, Dąb, and Ślina. The experimental setup was (1) to collect samples of the bottom material from the river stretches that either persisted in a non-modified state (dredging was not done there in the last few years) or had been subjected to river dredging in the year of sampling; and (2) to analyze the abundance and taxonomic structure of macroinvertebrates in the collected samples. The study revealed that at the high level of statistical significance (from p = 0.025 to p = 0.001), the total abundance of riverbed macroinvertebrates in the dredged stretches of the rivers analyzed was approximately 70% lower than in non-dredged areas. We state that the dredging of small rivers in agricultural landscapes seriously affects their OPEN ACCESSWater 2015, 7 4512 ecological status by negatively influencing the concentrations and species richness of benthic macroinvertebrates.

Use of native macrophytes for recovery of the habitat structure and complexity of a lowland stream affected by river engineering works: Implications for management

“…Significant reductions in the density of benthic invertebrates and losses of species typical of slower‐flowing or vegetated reaches have been observed as a consequence of these actions (Cooper et al, ; Grygoruk, Frąk, & Chmielewski, ; Lewis et al, ; Robinson, Newell, Seiderer, & Simpson, ; Szlauer‐Łukaszewska & Zawal, ; Witt, Schroeder, Knust, & Arntz, ). Also, the impacts of dredging have been reported for birds (Howarth, Grant, & Hulbert, ), fishes (Kjelland, Woodley, Swannack, & Smith, ) phytoplankton, periphytic algae (Cabrita, ; Lewis et al, ; Prat et al, ), and diatoms from the epipelic biofilm (Licursi & Gómez, ).…”

Spatial Changes in Invertebrate Structures as a Factor of Strong Human Activity in the Bed and Catchment Area of a Small Urban Stream

“…Sudduth and Meyer [31] reported a high number of pollution-tolerant taxa related to urban stream banks in their study. Such a pattern is caused by the regulation of stream banks, leading to the homogeneity of the environment [32,33]. Only an appropriate bioengineering mechanism could slightly increase the abundance of sensitive species [31,34]; however, a lot of other factors also decrease the diversity of urban streams.…”

Ecological Monitoring, Assessment, and Management in Freshwater Systems

“…Grygoruk et al [15] studied the effects of dredging on the benthic macroinvertebrates in agricultural rivers. They demonstrated that the total abundance of riverbed macroinvertebrates in the dredged stretches of the rivers analysed was approximately 70% lower than that in non-dredged areas, and concluded that the dredging of small rivers in agricultural landscapes seriously affects their ecological status by negatively influencing the concentrations and species richness of benthic macroinvertebrates.…”