Is the macrophyte diversification along the trophic gradient distinct enough for river monitoring?

Krzysztof Szoszkiewicz,Karol Pietruczuk,Anna Budka,Daniel Gebler,Dariusz Kayzer

doi:10.1007/s10661-016-5710-8

Abstract

The variation of a number of parameters characterizing aquatic plant assemblages in rivers across a wide trophic gradient was investigated to evaluate their usefulness for a Polish national river monitoring system. Analyses were conducted at 100 sites included in the national river monitoring system, representing a uniform river type, i.e., small- and medium-sized lowland rivers with a sandy substrate. Results of botanical surveys, which were supplemented with comprehensive monthly quality records, were obtained from the national monitoring database. By analyzing the Jaccard distances of the botanical metrics using the adonis function, the variation in species composition between rivers of different trophic status was determined. The group consisting of the most degraded rivers was the most homogeneous in terms of botanical composition. The cleanest rivers displayed a high level of heterogeneity within their group, as numerous different unique species were found there at low frequencies. The variation of the macrophyte metrics used to assess the ecological status (Macrophyte Index for Rivers (MIR) and River Macrophyte Nutrient Index (RMNI)) reflected a trophic gradient. We confirmed that vegetation diversification along a trophic gradient is evident enough to detect degradation in a five quality class system.

Highlights

Macrophytes are aquatic plants growing in water which are large enough to be visible with the naked eye and are almost always identifiable in the field
Several systems based on aquatic plants have been developed, and some of them have been integrated into national monitoring programs, e.g., in the UK (Willby et al 2009), France (Haury et al 2006), Germany (Schaumburg et al 2004) and Poland (Szoszkiewicz et al 2010)
Our study aimed to identify the variation of different macrophyte metrics along a trophic gradient and to verify the taxonomic distinctness of macrophyte communities developing in waters with different levels of eutrophication

Summary

Introduction

Macrophytes are aquatic plants growing in water which are large enough to be visible with the naked eye and are almost always identifiable in the field. A significant and apparent response of vegetation provides a useful indication of persistent and long-term habitat changes in aquatic ecosystems, which have been widely used as indicators of water quality in streams and rivers for many decades (Wiegleb 1979; Haslam 1982; Holmes et al 1999; Ceschin et al 2010). Nowadays, this group of organisms is an obligatory element in the monitoring of the ecological status of surface waters in EU countries under the Water Framework Directive (WFD, European Commission 2000). Several systems based on aquatic plants have been developed, and some of them have been integrated into national monitoring programs, e.g., in the UK (Willby et al 2009), France (Haury et al 2006), Germany (Schaumburg et al 2004) and Poland (Szoszkiewicz et al 2010)

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Results