Floristic and ecological diversity of Ranunculus aquatic habitats in the sub-Atlantic range: implications for conservation

Abstract

Ranunculus communities have been identified by the European Community Directive on Conservation of Natural and Semi-Natural Habitats as a key habitat in need of protection. The ecological requirements and floristic composition of three Ranunculus communities were investigated in North-Eastern France. We also aimed to determine the relationships between environmental parameters, Ranunculus abundance and species richness. R. fluitans communities clearly differed from the other communities by a higher evenness and species richness and by the occurrence of specific species. In contrast, R. penicillatus and R. peltatus communities displayed similar floristic content. Three different sub-associations were however identified within these communities. If alkalinity was determinant in isolating R. fluitans communities from the other stretches, the ecological ranges of the three communities strongly overlapped while considering parameters linked with other resources or with physical constraints. Further, no significant correlations were highlighted between environmental parameters, Ranunculus abundance and species richness. With respect to conservation, these observations may indicate the particular difficulty in defining each Ranunculus habitat on a European scale, and identify several key points which need to be taken into account when evaluating their status.

Distribution and environmental requirements of stream habitat with Ranunculion fluitantis and Callitricho‐Batrachion vegetation in lower Belgium (Flanders)

“…However, rather few studies have specifically addressed HT 3260, and those doing so were often limited or focused on particular syntaxonomic units and river types. So far, emphasis has been mainly on the Ranunculion communities of submontane, Mediterranean or limestone regions (Mony et al, 2006;Lumbreras et al, 2009;Lansdown and Pankhurst, 2010;Lumbreras et al, 2013). Low-gradient streams with muddy to fine-sandy substrata, such as commonly occur in lower Belgium and adjacent regions, have been considered more sparingly (Hatton-Ellis and Grieve, 2003;Hurford and Guest, 2010).…”

Bioindicator role of aquatic Ranunculus in Mediterranean freshwater habitats

“…Furthermore, this area, which should have been influenced by past oscillations between the Mediterranean and temperate climate (Moreno et al, 1990), hosts the highest densities of aquatic plants endemic to Europe and the Mediterranean (Cook, 1983). The distribution of Ranunculus communities is related to environmental factors such as mineralization and nutrient levels (Spink et al, 1997;Mony et al, 2006;Lumbreras et al, 2009). Ranunculus communities are explicitly cited as characterizing watercourses of plain to montane levels with Ranunculion fluitantis and Callitricho-Batrachion vegetation (habitat code 3260), a freshwater habitat type listed in the European Habitats Directive, which is designed to protect biodiversity in Europe (EC, 2007).…”

Distribution patterns of Batrachium communities in Mediterranean hard waters

“…Water crowfoot are mainly found in Eurasia (Cook, 1963;Lumbreras et al, 2011). Batrachium species grow in a wide range of freshwater ecosystems, including different types of water flow and regime (still and flowing waters; permanent and seasonal waters) and nutrient states (Spink et al, 1990;Mony et al, 2006). Water ecology has been widely related with Batrachium distribution-patterns (Géhu and Meriaux, 1983;Boeger, 1992;Spink et al, 1990;Mony et al, 2006).…”

“…Batrachium species grow in a wide range of freshwater ecosystems, including different types of water flow and regime (still and flowing waters; permanent and seasonal waters) and nutrient states (Spink et al, 1990;Mony et al, 2006). Water ecology has been widely related with Batrachium distribution-patterns (Géhu and Meriaux, 1983;Boeger, 1992;Spink et al, 1990;Mony et al, 2006). Within water factors, alkalinity has been highlighted as a major factor responsible for distribution in species from different genera such as Isoetes, Potamogeton and Ranunculus (Vestergaard and Sand-Jensen, 2000;Lumbreras et al, 2009).…”

“…Some habitat studies on Batrachium communities have been undertaken in Western Europe (Mony et al, 2006;Lumbreras et al, 2009Lumbreras et al, , 2013. However, there are as yet no specific studies on the distribution patterns of Batrachium communities growing in baserich waters.…”