Impact of hydromorphological pressures on the macrophytes bioindicators of the ecological water quality in Mediterranean rivers

Abstract

One of the important tools to evaluate the ecological quality of surface water is the Macrophytes indices based on the bioindication capacity of aquatic plants. In Mediterranean rivers (France, Spain, and Portugal), the development of some macrophytes indices like l’Indice Biologique Macrophytes Rivières (IBMR), the biological metric score (BMS), as well as the Fluvial Macrophyte Index (IMF) are founded on the determination of the indicator values of the floristic reference lists. The aim of this study was to test the impact of the eco-Mediterranean differences (from one country to another) on the indicator taxa by comparing the indicator values of the Euro‐ Mediterranean macrophyte indices. With this in mind, we explore the possibility of the introduction of the Euro‐Mediterranean macrophytes-based indices in Morocco (i.e. the hydrological basin of Sebou (HBS)) as a part of a preliminary attempt to develop the first Afro-Mediterranean macrophyte index. We confirm that the ecological amplitude and species optima vary between Mediterranean ecoregions, and indicator taxa differ between countries: There are medium to small correlations between Mediterranean indices: IBMR/BMS (p = 0.000, R2 = 0.57), IMF/BMS (p = 0.000, R2 = 0.34), and IBMR/IMF (p = 0.000, R2 = 0.30). Five species exhibit major differences in indicator values: Zannichelliapalustris and Potamogetonpectinatus have more eutrophic indicator values in France (IBMR) than in Spain (IMF). Potamogetonnodosus, Amblystegiumriparium and Lycopuseuropaeus have broader ecological amplitudes in Portugal (BMS) than in France (IBMR) and in Spain (IMF), where it is restricted to eutrophic conditions. Furthermore, the three indicator systems include different indicator-taxon numbers. The comparison of the HBS elaborated list with the Euro‐Mediterranean indices revealed the low level of common taxa approximately 6.76% of all indicator species used in the French index (IBMR), 10.48% in the Portuguese index (IMF) and 12.38% in the Spanish index (BMS). These results show the inadequacy of the trophic indices approach with the HBS conditions and thus the need for the development of an index based on biotic indices approach.

The effect of altered flow regimes on aquatic primary producer communities: Diatoms and macrophytes

“…Primary producers are an essential part of aquatic ecosystems, and their role as bioindicators and sensitivity to eutrophication and organic pollution has been extensively studied. In the last decades, there is a growing recognition that flow regime is also a key driver for primary producers in streams and rivers (Abati et al, 2016; Abdellah & Saad, 2019; Bergey et al, 2010; Franklin et al, 2008). The ecological response of primary producers to flow alteration can be identified in terms of changes in biomass and community structure and composition.…”

Exploring the Utility of Macrophyte Metrics for Evaluating the Quality of Rivers in Morocco: Insights from the Macrophyte Biological Index for Rivers

“…The robustness of the IBMR scores for various Oum Er-rbia river sites indicates that this metric cannot be considered relevant (difference significantly greater than 1). The low values of IBMR and its instability can be explained by a low richness in contributing species (Demars et al, 2012;Maissour and Benamar 2019). Thus, the Oum Errbia river is characterized by the dominance of algal flora, notably Spirogyra sp., Vaucheria sp., and Cladophora sp., which are considered ubiquitous taxa (Nouri et al, 2022), they can grow to the detriment of sensitive species and directly affect the IBMR score (Treguier and Lietout 2019).…”

Macrophyte communities as bioindicator of stormwater pollution in rivers: a quantitative analysis

“…The pollutants that come with stormwater can be buried in bottom sediments or accumulate in the tissues of aquatic biota ( Gołdyn et al, 2018 ; Barałkiewicz et al, 2014 ). Many studies have shown that macrophytes are able to significantly reduce the concentration of harmful substances ( Ladislas et al, 2012 ) and be indicators of the quality of the environment ( Kohler & Schneider, 2003 ; Maissour & Benamar, 2019 ). The work of ( Barałkiewicz et al, 2014 ) showed that a reservoir located in the riverbed can contribute to the elimination of pollutans from stormwaters, despite the very short residence time of water in it.…”