Bryophytes and macro-algal growths as a part of macrophyte monitoring in rivers used for ecological assessment

Abstract

Key-words:aquatic macrophyte, IBMR, river, Slovakia, Water Framework Directive Altogether, 62 taxa of macrophytes including 18 bryophytes and 16 macro-algal growths were determined at 87 survey sites (73 rivers) representing the both ecoregions in Slovakia (Pannonian and Carpathian) during the years 2010-2013. Bryophytes represented the dominant community in the Carpathians, while the occurrence of macro-algal growths was relatively balanced in both ecoregions. Ordination analyses (DCA) showed an obvious shift within studied survey sites from vascular plants to bryophytes, while macro-algal growths were more or less uniform distributed in the whole ordination space. Based on stepwise (forward) selection in CCA, altitude and water surfaces as a land use type were the main environmental factors responsible for this pattern and explained 13.7% of the variability. Variation partitioning showed that the shares of environmental variables on the total variation decreased in the following order: both groups together 8.3% (landscape and geographical variables, physicochemical variables), followed by landscape and geographical variables (5.8%) and purely physicochemical variables which had an insignificant effect on macrophyte composition. The importance of both groups (bryophytes and macro-algal growths) in ecological assessment was also confirmed by their contribution to the mean IBMR value determined for each water body type. Anyway, our study showed that their contribution to ecological assessment is not focused only on small mountain streams where they are dominant. They may obviously affect ecological assessment also in many water body types in lowland rivers and large upland rivers as well. Directive Cadre sur l'Eau montré un changement évident dans les sites de l'étude des plantes vasculaires vers les bryophytes, tandis que le développement des macro-algues était plus ou moins uniformément distribué. Basé sur une sélection progressive pas à pas en CCA, altitude et surfaces en eau comme le mode d'utilisation des terres ont été les principaux facteurs environnementaux responsables de cette tendance, expliquant 13,7 % de la variabilité. Le partitionnement de la variabilité a montré que la part des variables environnementales sur la variation totale a diminué dans l'ordre suivant : les deux groupes ensemble (8,3 %) (variables du paysage et géo-graphiques, variables physico-chimiques), suivis par le paysage et les variables géographiques (5,8 %) et les variables purement physico-chimiques qui avaient un effet négligeable sur la composition des macrophytes. L'importance de ces deux groupes (bryophytes et macro-algues) dans l'évaluation écologique a éga-lement été confirmée par leur contribution à la valeur IBMR moyenne déterminée pour chaque type de masse d'eau. Quoi qu'il en soit, notre étude a montré que leur contribution à l'évaluation écologique ne se concentre pas uniquement sur les petits ruisseaux de montagne où ils sont dominants. Ils peuvent évidemment avoir aussi une incidence sur l'évaluation...

The Macrophyte Index for Rivers (MIR) as an Advantageous Approach to Running Water Assessment in Local Geographical Conditions

“…The results obtained showed a strong relationship between macrophytes and water quality, compared with various other studies based on macrophytes [28,37,[40][41][42] and other organisms [39]. The strong relationship was clearly due to some extent to the quality of the data based on a single river type, where a lack of typological homogeneity is regarded as one of the major sources of uncertainty in ecological assessment [43].…”

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

“…Many authors stated that Cladophora sp. is one of the most common taxa among all filamentous algae in rivers (Dodds & Gudder 1992;Szoszkiewicz et al 2010Szoszkiewicz et al , 2014Baláži & Hrivnák 2015;Papastergiadou et al 2016). However, compared to vascular plants, the occurrence of other macro-algae was rare.…”

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