The relationship between macrophyte assemblages and environmental variables in drainage and irrigation canals in Slovakia

Abstract

Our study provides new knowledge about macrophyte assemblages and environmental variables of Slovak drainage and irrigation canals. The canal system, comprising ca. 15% of all flows in Slovakia, is one of the oldest in Central Europe. This information represents a first step toward exploitation of macrophytes as an obligatory biological quality element for the assessment of ecological potential according to the requirements of the Water Framework Directive. Among 61 canals studied, a total of 85 aquatic plant species (35 hydrophytes, 16 amphiphytes and 34 helophytes) were recorded during the years 2012-2014, including three neophytes and 18 threatened species. Physico-chemical variables explained the highest proportion of species variability, whilst hydromorphological variables and landscape variables were much less significant. Chemical oxygen demand, ammonium nitrogen, electrical conductivity, water pH, flow velocity and water depth were identified as most important drivers of species composition of aquatic macrophytes and explained 21.1% of the variability. The CCA results revealed differences in species composition of canals reflecting the geographical origin and environmental conditions as well, relating to South-Eastern and South-Western Slovakia. In conclusion, macrophytes in drainage and irrigation canals are able to reflect several environmental variables and might provide valuable information for bioindication in assessing the ecological potential.

Delineating the influence of water conditions and landscape on plant communities in eutrophic ditch networks

“…All the plant species recorded in the ditches, especially the dominant ones, were typically nutrient-rich-tolerant species (Melzer 1999;Sondergaard et al 2010). Overall, our results are in line with Baláži and Hrivnák (2016), who only found a limited effect of landscape variables on vegetation in ditches and canals in Slovakia compared to local environmental conditions. In our study, only the proportion of woodlands, slightly correlated to the hedge cover index along the ditches, was a significant predictor of hydrophyte richness and species composition.…”