A phytosociological survey of aquatic vegetation in the main freshwater lakes of Greece

Abstract

Aims: This study aims to contribute to the knowledge of European freshwater lake ecosystems with updated and new information on aquatic plant communities, by conducting national-scale phytosociological research of freshwater lake vegetation in Greece. Moreover, it investigates the relationship between aquatic plant communities and lake environmental parameters, including eutrophication levels and hydro-morphological conditions. Study area: Lakes in Greece, SE Europe. Methods: 5,690 phytosociological relevés of aquatic vegetation were sampled in 18 freshwater lake ecosystems during 2013–2016. The relevés were subjected to hierarchical cluster and indicator species analyses in order to identify associations and communities of aquatic vegetation, as well as to describe their syntaxonomy. Multiple regression analysis was applied to investigate the relationship between vegetation syntaxa and environmental parameters of lakes, i.e. physico-chemical parameters and water level fluctuation. Results: Ninety-nine plant taxa belonging to 30 different families were recorded. Forty-six vegetation types were identified and described by their ecological characteristics, diagnostic taxa and syntaxonomical status. Thirteen vegetation types, the largest number belonging to the vegetation class Charetea, are considered to be new records for Greece. The distribution of the vegetation types recorded in the 18 freshwater lakes was found to depend on environmental parameters and levels of eutrophication. Conclusions: An updated aquatic vegetation inventory was produced for Greek lakes, and primary results showed that the presence/absence of aquatic plant communities and the community composition in freshwater lakes can be utilized to assess the pressure of eutrophication on lake ecosystems. Taxonomic reference: Euro+Med (2006–). Abbreviations: MNT = Mean number of taxa; WFD = Water Framework Directive.

Multiple-Facet Diversity Patterns of Aquatic Vegetation in Lakes along a Trophic Gradient

“…In our results, however, we found that syntaxonomic richness followed a similar pattern to that of species richness (highly correlated), i.e., slightly higher numbers of plant communities were observed in lakes with moderate trophic levels, slightly lower numbers in lakes with low and high trophic levels, and significantly lower numbers in lakes with very high trophic levels. This result may be attributed to the fact that macrophyte communities contain a small number of taxa [55] and reinforces the "hump-back" model of diversity of macrophyte communities in lakes in the middle of the trophic gradient. However, variation in syntaxonomic richness values was also an issue for lakes with low and moderate trophic levels, reinforcing the need for the identification of parameters other than nutrient loading.…”

“…In order to calculate syntaxonomic diversity, i.e., the richness of plant communities in each transect, we used the results of the phytosociological analysis in Zervas et al [55]. Each relevé was coded according to its community affiliation, and syntaxa richness in each transect was calculated using vegan package for R [54].…”

Contribution to the knowledge of Mediterranean wetland vegetation: Lemnetea and Potamogetonetea classes in Western Sicily

“…The dominant species develops in several habitat types, often forming mono-paucispecific stands (Maiorca et al 2007;Sburlino et al 2004;Šumberová 2011a;Bolpagni and Piotti 2015;Spampinato et al 2019). The association can be found on marginal zone of still and nutrient-rich freshwater bodies, in very shallow sectors (Zervas et al 2020).…”

“…However, other authors, including Müller (1977), Scoppola (1982), andPott (1995), do not find the ground for the definition of a specific syntaxon due to the wide ecological and biogeographical values of this species (Sburlino et al 2004). The Lemnetum minoris is rather common in Europe including the Mediterranean area (Ninot et al 2000;Brullo et al 2002;Šumberová 2011a;Felzines 2012;Zervas et al 2020). The dominant species develops in several habitat types, often forming mono-paucispecific stands (Maiorca et al 2007;Sburlino et al 2004;Šumberová 2011a;Bolpagni and Piotti 2015;Spampinato et al 2019).…”

“…Syntaxonomic note -Widespread association, reported for several European countries, including some Mediterranean areas and Sicily (Géhu and Biondi 1988;Baldoni and Biondi 1993;Ninot et al 2000;Venanzoni and Gigante 2000;Brullo et al 2002;Ferrez et al 2011;Raimondo et al 2011;Šumberová 2011b;Zervas et al 2020). It is often mono-or paucispecific, typical of freshwater and brackish habitats, from eutrophic to hypertrophic, polluted waters, with high turbidity and anoxic conditions (Baldoni and Biondi 1993;Ceschin and Salerno, 2008;Landucci et al 2011;Azzella et al 2013).…”