The stonewort vegetation is commonly classified into the phytosociologicalclass Charetea fragilis F. Fukarek ex Krausch 1964; however, the Characeaeare not exclusively found in vegetation stands ascribed to this class but alsoin other habitat types. In our preliminary investigations, we draw the attentionto the relationship between the classes Charetea fragilis and Potameteapectinati Klika in Klika & Novák 1941 in some Sicilian biotopes.In some cases, the Charetea vegetation is ecologically and spatially distinct,although close, from that referable to the Potametea. In some other cases, oneor more species of Characeae are structurally intrinsic to the vegetation of Potametea:one example is offered by the pools next to the Maulazzo dam [NebrodiMts.], where Chara cfr. conimbrigensis A.G. Cunha enters the Groenlandietumdensae Segal ex Schipper et al. in Schaminée et al. 1995, growing together withGroenlandia densa (L.) Fourr., Potamogeton natans L., Callitriche sp. pl.Another relevant case is the relationship of some Nitella species, such asN. capillaris (Krock.) J. Groves & Bull.-Webst. and N. opaca (C. Agardh ex Bruzelius)C. Agardh, with vegetation ascribed to the phytosociological allianceBatrachion fluitantis Neuhäusl 1959.In particular, the occurrence of the two different Nitella species goes alongwith two different species of Ranunculus subg. Batrachium, i.e. Ranunculussaniculifolius Viv. and R. aquatilis L., respectively, in two different sites. In thesecases, phenology could be an important adaptive trait, with the Characeaedeveloping earlier (between the end of winter and the beginning of spring)so to avoid the competition of the angiosperms that progressively developduring the spring months.Phenology is worth to be further investigated for the interactions not onlybetween Characeae and angiosperms, but also between Characeae and otherfreshwater algae, such as the filamentous Spirogyra sp. pl., ascribed to the Zygnematalesorder of Charophyceae. However, this succession was not observedin pools fed by water springs, that keep the water temperature lower acrossthe season. It is likely that the regression of Characeae as water temperatureincreases is regulated by competition with the vascular plant species and/orother more thermophilous representatives of the algal flora. In small waterponds, the livestock grazing and trampling is another important ecologicalfactor to be investigated, also for its effects on water turbidity and nutrientconcentrations.
|Titolo della pubblicazione ospite||22nd Meeting of the Group of European Charophytologists (GEC), Palermo, Italy 17-21 September 2018, Programme & Abstracts|
|Numero di pagine||1|
|Stato di pubblicazione||Published - 2018|