The toponym of Galanchio indicates a brackish area that extends for about twenty hectares near the Cornacchiaia Reserve in the Tombolo Estate of the Regional Park of Migliarino, San Rossore, Massacciuccoli (PI), on the right bank of the Navicelli canal (central point: 43° 35. 467’ N, 10° 18.984’ E). The area is located about 800 meters from the sea line, at an altitude from –0.6 to 1 m asl and is characterized by two semi-permanent ponds: Galanchio W, about 3 hectares, and Galanchio E, about 2 hectares.

Moving away from the sea, proceeding eastwards, there is another semi-permanent brackish pond of about 2 hectares, here called Cornacchiaia (Fig. 1).

Figure 1. 

Geographic position of the study area and the three brackish ponds investigated (W, E, C) (Map data Geoscopio Regione Toscana, CTR).

The whole area represents the remains of a much larger brackish area of ancient ecclesial properties which consisted of extensive woods and wild marshes. This landscape survived until the early 1900s, when the massive reclamation interventions began to change the physiognomy of the area. The progressive disappearance of the wetlands and the large forest followed, and the land was subsequently used for agricultural purposes (Rupi 1995).

The landscape of the area, from the reclamation onwards, had several changes until the end of the 80s of the last century. In 1954, 26 years after the reclamation, the Galanchio area was completely dry and used for agricultural purposes. Starting from 1978 the first wetland, corresponding to Galanchio E, reappeared within the agricultural matrix. Since 1988 the reappearance of the second area, corresponding to Galanchio W, has been observed. Since then, there have been no significant changes in their extent. Currently, the two brackish ponds of Galanchio are included within agricultural areas and consequently very disturbed at their edges by agricoltural works. The Cornacchiaia pond, located within a sparse wooded matrix, is much less disturbed (Fig. 2).

Figure 2. 

The agro-forested landscape of the study area (dot line indicates areas with saline soils) (Map data 2019 Google Earth Pro).

From a pedological point of view, the whole area falls within an ancient humid retrodunal depression, consisting of mixed sediments. The three ponds are instead attributable to silty sand deposits and the analysis of electrical conductivity on soil samples surrounding the study area, reveals an average salinity of 1800 μS / cm (AA.VV. 2005).

For the climatic characterization the thermo-pluviometric data of the meteorological station of San Piero a Grado (Pisa, Italy) were used. The total average annual rainfall, for the period 1997-2016, exceeds 934.9 mm with a maximum rainfall in the autumn. The average annual temperature is 14.5º C, with a maximum of about 30º C in July and August.

The thermoudogram shows a period of summer drought with water deficit from June to September. Based on the bioclimatic classification of Pesaresi et al. (2017), the study area bioclimate belongs to the Mediterranean macro-bioclimate, mesomediterranean thermotype, lower subhumid ombrotype.

A total of 65 relevés were carried out in homogeneous areas within the brackish portions of the area excluding the transition areas. The method followed the Braun-Blanquet phytosociological approach (Braun-Blanquet 1983; Westhoff and van der Maarel 1978; Biondi 2011). In order to identify the different groupings, data relevés were analyzed with PAST 3.14 software (matrix of 61 species x 65 relevés. Cluster analysis, using UPGMA and Bray-Curtis index were assessed. Subsequently, the Detrended Corrispondence Analysis (DCA) was applied to the matrix data, with the aim of obtaining an evaluation to see what information it may provide additional to that given by the cluster analysis. For multivariate analysis purposes, the cover values were transformed according to the method proposed by van Der Maarel (1979). Plant species nomenclature follows Bartolucci et al. (2018) and the subsequent updates summarized in the Portal to the Flora of Italy (2019).

For the syntaxonomic references at the ranks of alliance, order and class, we referred to Biondi et al. (2014) and Mucina et al. (2016). The names of syntaxa comply with the International Code of Phytosociological Nomenclature (ICPN) (Theurillat et al. 2020). For the correlation between vegetation types and habitat types, we referred to the Italian Interpretation Manual for the Habitats of Directive 92/43/ EEC (Biondi et al. 2009; Biondi et al. 2012).

CRYPSIDETUM ACULEATAE (Bojko 1932 n.n.) Wenzel 1934 (Tab. 1, Annex I Habitat: 1310).

These almost monospecific phytocoenoses are found only in the Cornacchiaia area, in three little ponds that dry up completely in the summer. On their surface some therophytic coenoses dominated by Sporobolus aculeatus (L.) P. M. Peterson (= Crypsis aculeata (L.) Aiton.) are identifiable. This species is a rather rare annual prostrate grass, also reported for the neighboring Tenuta of San Rossore although only as a sporadic presence in drainage discharges (Tomei et al. 2004), abundant and widespread species of the annual glasswort Thero-Salicornietea, such as Salicornia perennans or Suaeda maritima, and species of the Juncetea maritimi are also found. From a syntaxonomic point of view, these populations can be referred to the Crypsidetum aculeatae association, a coenosis found only for the Adriatic, Ionian, Sardinia and high Lazio coasts (Biondi et al. 1992; Corbetta et al. 1992; Frondoni and Iberite 2002; Tomaselli et al. 2010). In Tuscany this association is reported only for the Padule Orti-Bottagone (LI) (Viciani and Lombardi 2001).

PARAPHOLIDETUM FILIFORMIS Brullo, Scelsi & Siracusa 1994. (Tab. 2, Annex I Habitat: 1310).

This type of vegetation consists of ephemeral grasslands on humid soils with low salinity. In the study area it is relegated to the halomorphic soils of the East pond, which is wet during the winter-spring period but never submerged. Here, the phytocoenosis makes catenal contact with perennials formations of Salicornietea fruticosae and with the annual ones of the Thero-Salicornietea. This association, reported for other brackish coastal sectors of the peninsula (Lazio, Sicily, Puglia) (Frondoni and Iberite 2002; Brullo and Giusso del Galdo 2003; Tomaselli et al. 2010) is new for Tuscany.

SUAEDO MARITIMAE-SALICORNIETUM PATULAE (Brullo & Furnari 1976) Géhu & Géhu-Franck 1984 (Tab. 3, Annex I Habitat: 1310).

The Suaedo maritimae-Salicornietum patulae association is common to all three brackish areas, although with different extensions due to a different degree of drought in the summer. Where greater are the surfaces that dry up and where greater is the rise of the salts, as occurs in the eastern Galanchio pond, the association reaches the maximum diffusion and coverage. Among the species present in the phytocenosis, the annual halophilous Salicornia perennans subsp. perennans and Suaeda maritima are dominant, although, not infrequently, an important cover of perennials species such as Aeluropus littoralis subsp. littoralis and Puccinellia festuciformis can be observed.

Suaedo maritimae-Salicornietum patulae is the most widespread association of brackish areas in the Mediterranean area (Gehù 1992) and, consequently, for the Italian coastal areas also (Géhu et al. 1984; Biondi 1999). In Tuscany, the association has been identified both in the neighboring Tenuta di San Rossore (Sani and Tomei 2006) and in other brackish areas of the coastal sector (Arrigoni et al. 1985; Viciani and Lombardi 2001; Andreucci 2004).

SUAEDETUM MARITIMAE (Cornad, 1935) Pignatti 1953 (Tab. 4, Annex I Habitat: 1310).

This community is found on humid and well nitrified soils with abundant organic substance. Here, Suaeda maritima forms large spots, accompanied by a few other species of the Thero-Salicornietea, such as Soda inermis and Salicornia perennans. In the investigated area it appears not very widespread and, for Tuscany, it has previously been reported only in the Orbetello Lagoon (Gr) (Andreucci, 2004).

PUCCINELLIO FESTUCIFORMIS-SARCOCORNIETUM PERENNIS (Br.-Bl. 1931) Géhu 1976 (Tab. 5, Annex I Habitat: 1420).

This association is uneven in both Galanchio ponds, with different extensions but always limited to the areas where the soil remains humid also in summer. It is not present in the Cornacchiaia area, where in Summer, the soils dry out completely. This plant community is characterized by Salicornia perennis Mill. subsp. perennis, a perennial prostrate species, which often forms the characteristic isodiametric "carpets" in a matrix of species such as Puccinellia festuciformis, to which are added Halimione portulacoides, Aeluropus littoralis and Parapholis filiformis. In the scientific literature, this association has sometimes been assigned to Sarcocornietum deflexae (Géhu and Biondi 1994), assuming that only Sarcocornia fruticosa var. deflexa was present in the Mediterranean coasts, while Salicornia perennis was typical of the Atlantic coasts only. In agreement with other authors (Viciani and Lombardi 2001; Frondoni and Iberite 2002) we prefered to attribute this phytocenosis to Puccinellio festuciformis-Sarcocornietum perennis, recognizing in it the presence of Salicornia perennis (= Sarcocornia perennis). This association is quite widespread along the Italian brackish coastal areas (Gehù et al. 1984) and in Tuscany it is also present in other sectors of the southern coast of the region (Arrigoni et al. 1985; Viciani and Lombardi 2001; Andreucci 2004).

PUCCINELLIO FESTUCIFORMIS-HALIMIONETUM PORTULACOIDIS Géhu et al. 1992 (Tab. 6, Annex I Habitat: 1420).

This association is closely linked to the association described above and its environmental context. Found only in the eastern pond of Galanchio, it is characterized by the dominance of Halimione portulacoides over Salicornia perennis and is located at the border of brackish areas with agricultural disturbance. This association is not very frequent in Italy (Corbetta and Pirone 1999; Frondoni and Iberite 2002) and in Tuscany it is reported only in Palude di Orti-Bottagone (LI) (Viciani and Lombardi 2001).

ELYTRIGIO ELONGATAE-INULETUM CRITHMOIDIS Br.-Bl. (1931) 1952) (Tab. 7, Annex I Habitat: 1410).

Along the drainage ditches surrounding the two Galanchio ponds, and often inside the ditches themselves, phytocoenoses characterized by a high coverage of Limbarda crithmoides, associated with Thinopyrum acutum (= Elytrigia atherica (Link) Kerguélen) and to a lesser extent Limonium narbonense can be found. This plant community can be referred to Elytrigio elongatae-Inuletum crithmoidis, although Thinopyrum elongatum (= Elytrigia elongata (Host) Nevski) has never been found. The association is not very widespread along the Italian coasts and, even less so in the Tuscan ones, where it has been reported in a couple of stations (Viciani and Lombardi 2001; Foggi et al. 2006). It should also be emphasized that these populations, developing near or inside the drainage channels, are annually destroyed by agricultural procedures.

LIMONIO NARBONENSIS-JUNCETUM GERARDI Géhu et Biondi 1994 (Tab. 8, Annex I Habitat: 1410).

In the area inside the eastern pond of the Galanchio and to a limited extent in that of the Cornacchiaia, sub-halophilous rushes dominated by Juncus gerardi subsp. gerardi can be observed. These "islands", characterized by the constant presence of Limonium narbonense, are surrounded by populations of Aeluropus littoralis subsp. littoralis, which, however, penetrates them abundantly. It has been described in Italy for the Adriatic and Tyrrhenian coasts, although in the latter it appears less common (Géhu and Biondi 1996; Frondoni and Iberite 2002).

PUCCINELLIO FESTUCIFORMIS-AELUROPETUM LITORALIS (Corb. 1968) Géhu et Costa 1984 in Géhu et al. 1984 (Tab. 9, Annex I Habitat: 1410).

Around the populations of Limonio narbonensis-Juncetum gerardi and in catenal contact with the reed beds of the northern edge of the eastern pond of Galanchio, there are large surfaces with dense covers of Aeluropus littoralis. This plant community occupies surfaces that remain humid also during the summer. The high coverage of Aeluropus littoralis and the presence of Puccinellia festuciformis, although not constant, leads us to attribute this phytocoenosis to the association Puccinellio festuciformis-Aeluropetum litoralis. This, despite the frequent presence of Bolboschoenus maritimus which would differentiate it from the characterization described by Gehù et al. (1984) and Poldini et al. (1999) and Sciandrello and Tomaselli (2014) for these phytocoenoses on the Adriatic side. In Tuscany this association has never been described.

JUNCO MARITIMI-SPARTINETUM JUNCEAE (O. de Bolòs 1962) Filigheddu, Farris & Biondi 2000 (Tab. 10, Annex I Habitat: 1410).

Only in the westernmost pond, on permanently humid surfaces, dense populations of the neophyte Sporobolus pumilus (Roth) P.M.Peterson & Saarela (= Spartina versicolor Fabre), almost always associated with Juncus maritimus, can be encountered. This community can be attributed to the Junco maritimi-Spartinetum junceae association, already described for the Pisan coast where it is quite widespread in the wet sandy silt belts close to the dunes without marked salinity (Bertacchi and Lombardi 2014). Other reports of this association concern Lazio (Frondoni and Iberite 2002), Sardinia (Filigheddu et al. 2000), Sicily (Sciandrello et al. 2019), and the Adriatic coast (Pirone et al. 2014)

JUNCETUM MARITIMI-ACUTI Horvatic1934 (Tab. 11, Annex I Habitat: 1410).

The communities of Juncus acutus and J. maritimus, attributable to the association Juncetum maritimi-acuti, frequent and extended in all the humid sectors of the Pisan coast, can be found here almost exclusively in the Cornacchiaia area. This is due to the fact that naturally they would occupy those silt-sandy areas surrounding the Galanchio ponds but intended, instead, for cultivation. Reported for Tuscany only in the southernmost station of Scarlino (Viciani et al. 2001), it is also cited for Lazio (Frondoni and Iberite 2002), Nord Adriatic coast (Piccoli 1995) and Sicily (Brullo and Sciandrello 2006).

PHRAGMITETUM AUSTRALIS Savič 1926 nom. mut. propos. (Tab. 12).

The almost monophytic reed beds of Phragmites australis characterize and constitute the vegetal landscape of all the ditches and canals and frame the wetter and saltier areas of the study area. In these communities, corresponding to Phragmitetum australis, the cryptogenic Periploca graeca, characteristic of the nearby forests of Fraxinus angustifolia subsp. oxycarpa (Willd.) Franco & Rocha Afonso, often interpenetrates. The diffusion of Periploca graeca within helophytic vegetation has already been reported for nearby Massaciuccoli lake by Lastrucci et al. (2017).