Macrophytic Distribution and Trophic State of Some Natural and Impacted Watercourses - Belgium Wallonia

Abstract

In the present paper we investigated macrophyte community structure in 60 natural and impacted stream and river sites distributed throughout the Walloon river network. The objectives were to describe the distribution of macrophyte assemblages in relation to physico-chemical parameters of their environment and to assess the variability in ecological metrics within these watercourses. Two-way clustering allowed us to simultaneously assign sample units and species to groups by performing two separate cluster analyses. Indicator species analysis allowed us to assess the degree to which a species indicated a group, based on its constancy and distribution of abundance. Six end-groups were identified as a result of using twoway clustering and indicator species analysis techniques. Hygroamblystegium fluviatile, Chiloscyphus polyanthos and Lemanea fluviatilis were found to characterize acidic and low impacted streams and rivers (G1), while Ranunculus fluitans was found in all low impacted large streams (G2). Potamogeton pectinatus, proved to be more common in eutrophicated waters in the calcareous areas particularly in the ʺLoess low plateauxʺ region (G6).Cinclidotus riparius, Fissidens crassipes and Pellia endiviifolia, appeared in rivers situated in the Condroz region (G4), which was characterized by a high concentration of nitrogen.

Contribution to the Macrophytic Typology of Belgian Reference Watercourses

“…The Sossey-Alaoui and Rosillon work [14] around diversely impacted watercourses inside the monitoring network of the Walloon Region had highlighted six "groups" relatively different from our clusters. In both analyses, the large rivers group and the group of Belgian Lorraine (nonimpacted watercourses) stand out clearly and are similar, but the others differ.…”

“…The land cover, the shading, and the substrate were estimated and the width was measured in the field; the others parameters were established on the map. The main characteristics (land cover and altitude) of the Walloon natural regions have been provided in a previous article [14].…”

“…In Western Europe, macrophytic typologies were established by Butcher for Britain [9], by Holmes et al for England, Wales, and Scotland [10], by Grasmück et al for French Lorraine [11], by Chatenet et al for French Limousin [12], and by Sossey-Alaoui for Luxemburg [13]. The recent work of Sossey-Alaoui and Rosillon [14] analysed a set of plant data coming for the entire watercourses monitoring network of the Wallonia Region. All these works included impacted and nonimpacted watercourses.…”

Methodological aspects of moss sample preparation. Effects of freezing and duration of washing on the cellular distribution of elements in Fontinalis squamosa Hedw.

“…Mouvet, 1985;Fernández et al, 2000;Vázquez et al, 2013). Bryophyte species that have been used to monitor aquatic environments include the moss Fontinalis squamosa (Burton and Peterson, 1979;Gonç alves et al, 1994;Martínez-Abaigar et al, 2002;Zechmeister et al, 2003;Birk and Willby, 2010;Sossey-Alaoui and Rosillon, 2013), which is widely distributed throughout NW Spain (Vázquez et al, 2007).…”

Trend Analysis in Ecological Status and Macrophytic Characterization of Watercourses: Case of the Semois-Chiers Basin, Belgium Wallonia

“…The Semois-Chiers waterbodies are covered by the Walloon network for monitoring surface water status. Between 2007 and 2013, this network undertook several macrophytic surveys of waterbodies [27]. The reference macrophytic communities were waterbodies classified by the Walloon Government as being areas showing little or no human impact [28].…”