Studying local species assemblages of salt-affected vegetation for monitoring Natura 2000 habitats

Abstract

This study aims to characterize saline habitats of the Tuscan coast based on the Natura 2000 Habitats Directive 92/43/ECC. These habitats include Atlantic salt meadows (1330), Mediterranean salt meadows (1410) Mediterranean and thermo-Atlantic halophilous scrubs (1420), and Mediterranean salt steppes (1510). We compiled vegetation data from a total of 418 plots carried out during our own fieldwork (N = 157) and published scientific literature (N = 261). We performed a Linear Discriminant Analysis to associate species to habitats and used the phi coefficient of association to identify diagnostic species of each habitat. For each habitat, we provide a regional syntaxonomic framework, constant species, cover coefficients, diagnostic species (phi) and “typical species”. We identified groups of species, that we called “local assembly of typical species”, composed by species with a phi coefficient > 20 and/or a cover coefficient > 50 that can be used to identify the habitats and to monitor their conservation status at the local level. This study revealed differences in the “local assembly of typical species” among habitats, characterized by fewer species in habitats 1420 and 1510, and many species in habitats 1410 and 1310. Our results showed that the habitat 1510 was recognizable only for the high cover value of Limonium narbonense and, at least in Tuscany, its syntaxonomic attribution to the order Limonietalia is uncertain. We tested this approach only for a few habitats, but a broader applicability based on other habitats is desirable.

The optimization of typical species inventory of habitat types of a NATURA 2000 site using a phytosociological approach

“…Analyses of nation-wide data sets reviewed the syntaxonomical classification of large vegetation groups (Bergmeier and Dimopoulos 2001;2008;Tsiripidis et al 2007), but there was not any critical review for this crosswalk even when new habitat types (European Commission 2013) were included in the national inventory. Recent studies demonstrating the strong links between vegetation science and the Habitat types Directive (Attorre et al 2018, Gennai et al 2022 show that the potential of using phytosociological concepts for the optimum implementation of Habitats Directive are still to be exploited. Phytosociological concepts and methods can be used for the typification and description of habitat types.…”

“…Phytosociological concepts and methods can be used for the typification and description of habitat types. The identification of typical species (Bonari et al 2018;Bonari et al 2021;Gennai et al 2022;Tsiripidis et al 2018), the assessment of the conservation status of structure and functions (Dimopoulos et al 2018;Tsiripidis et al 2018) or the study of impacts of climate change, as a threat to habitat types through the analysis of historical relevés (Evangelista et al 2016), are only some examples that show the important role of phytosociology in the implementation of Habitats Directive.…”

“…Typical species should reflect favourable structure and functions, meaning that they should be: (a) indicative of good habitat quality, (b) tightly related with the habitat types over large areas, and (c) sensitive to changes in the conditions of the habitat (Angelini et al 2018;Evans and Arvela 2011). Until recently, a few member states had compiled inventories of typical species for some habitat types (Ellwanger et al 2018) and even fewer for all habitat types (Angelini et al 2018;Ellwanger et al 2018;Gennai et al 2022;Tsiripidis et al 2018). The lack of a clear definition of typical species has allowed for the development of a number of methods to use them as an assessment criterion.…”

“…The lack of a clear definition of typical species has allowed for the development of a number of methods to use them as an assessment criterion. Some approaches for the compilation of typical species inventories include expert judgment (Dalle Fratte et al 2022) or numerical, analytical methods (Bendali and Godron 2021;Dalle Fratte et al 2022;Gennai et al 2022;Tsiripidis et al 2018). Recent studies showed the agreement of experts that plant sociology methods should be used in the conservation status assessment of habitat types (Gigante et al 2016) and that the use of diagnostic and characteristic species provides valuable information of the conservation status of habitat types (Bonari et al 2021).…”