Ecology of aquatic Ranunculus communities under the Mediterranean climate

Abstract

The Iberian Peninsula encompasses more than 80% of the species richness of European aquatic ranunculi. The floristic diversity of the phytocoenosis characterised by aquatic Ranunculus and the main physical– chemical factors of the water were studied in 43 localities of the central Iberian Peninsula. Four aquatic Ranunculus communities are found in most of the aquatic environments. These are species-poor and have an uneven distribution: three species of Batrachium are heterophyllous and their communities are distributed in different aquatic ecosystems on silicated substrates; one species is homophyllous and its community occurs in various aquatic ecosystems with carbonated waters. In the Mediterranean climate, Ranunculus species are present in different habitats, as shown by the results of all the statistical analyses. Ranunculus trichophyllus communities occur in base-rich waters with a high buffering capacity (2273.44 794.57 mg CaCO3 L 1) and a high concentration of cations (Ca2+, 121 33.12 mg L 1; Mg2+, 71.64 82.77 mg L 1), nitrates (2.89 4.80 mg L 1), ammonium (2.19 1.36 mg L 1) and sulphates (216.25 218.54 mg L 1). Ranunculus penicillatus communities are found in flowing waters with a high concentration of phosphates (0.48 0.6 mg L 1) and intermediate buffering capacity (683.66 446.76 mg CaCO3 L 1). Both Ranunculus pseudofluitans and Ranunculus peltatus communities grow in waters with low buffering capacity (R. pseudofluitans, 385.91 209.2 mg CaCO3 L 1; R. peltatus, 263.3 180.36 mg CaCO3 L 1), and a low concentration of cations (R. pseudofluitans: Ca2+, 12.57 9.42 mg L 1; Mg2+, 3.42 1.67 mg L 1; R. peltatus: Ca2+, 15 18.26 mg L 1; Mg2+, 6.26 8.89 mg L 1) and nutrients (R. pseudofluitans: nitrates, 0.23 0.2 mg L 1; phosphates, 0.09 0.1 mg L 1; R. peltatus: nitrates, 0.19 0.21 mg L 1; phosphates, 0.09 0.12 mg L 1); the first in flowing waters, the latter in still waters.