Biologia 66/6: 1027—1043, 2011 Section Botany DOI: 10.2478/s11756-011-0113-3 Plant communities structure and composition in three coastal wetlands in southern Apulia (Italy) Valeria Tomaselli1*, Romeo Di Pietro3 &SaverioSciandrello2 1C.N.R., Institute of Plant Genetics, via G.Amendola 165/A, I-70126 Bari, Italy; e-mail: [email protected] 2Department of Botany, University of Catania, via A. Longo 18,I-95125 Catania, Italy; e-mail: [email protected] 3Department DATA, University of Rome La Sapienza, via Flaminia 70,I-00196 Rome, Italy; e-mail: [email protected] Abstract: In this paper the results of a study on the composition and the distribution of the plant communities in three coastal areas of southern Apulia are presented. A total of about 180 vegetation relevés were performed following the Braun- Blanquet phytosociological method. Vegetation data were analysed using both classification (UPGMA, similarity ratio) and ordination methods (including Non-metric Multidimensional Scaling (NMS) and Detrended Correspondence Analysis (DCA). The relevés are distributed in the following classes: Molinio-Arrhenateretea, Phragmito-Magnocaricetea, Juncetea maritimi, Sarcocornietea fruticosae, Saginetea maritimae, Thero-Salicornietea, Helianthemetea guttati. Detailed information about structure and zoning of the detected plant communities are here provided. Two new associations, belonging to the Alkanno-Maresion nanae alliance (microphytic ephemeral plant communities growing on sandy soils, Helianthemetea guttati class) have been described here, both in the “Torre Guaceto” site. The area of “Le Cesine” showed the highest total number of plant communities, while the “Saline di Punta della Contessa” site revealed the largest number of Sarcocornietea fruticosae plant communities. Key words: Apulia; coastal wetlands; cluster analysis; ordination; salt marshes; vegetation; southern Italy Introduction son they require constant protection. Their monitor- ing and safeguard is one of the priorities for a suit- Coastal wetlands, with their habitats of salt marsh veg- able management of coastal environments. In recent etation, are distributed throughout the Mediterranean decades, these habitats have been subject to intense area (Géhu 1999). In addition to hosting very rare human pressure, largely due to tourist activities and plant species and communities, the coastal wetlands the subsequent building and infrastructure prolifera- are important areas for the nesting and the staging of tion and to the development of intensive agriculture. birds. In the Adriatic region, the salt marsh vegeta- Moreover, the creation of industrial areas has led to tion prevails in the western and northern coasts, the the devastation of highly valuable coastal areas. Having east coast being mostly rocky (Pandža et al. 2007). a comprehensive knowledge framework on these areas Within the Italian side of the Adriatic Sea, the salt and their conservation status is an essential starting- marsh vegetation has been the object of various phy- point for the planning of future measures of protec- tosociological studies (Pignatti 1966; Corbetta 1968; tion. Géhu et al. 1984; Biondi et al. 1989; Géhu & Biondi The present study is a part of an INTERREG 1996; Piccoli et al. 1996; Biondi 1999; Poldini et al. project III A Italy-Greece 2000–2006 (Development of 1999; Pirone et al. 2001). Nevertheless, a systematic an integrated informative system for the monitoring study on the vegetation of these areas is still lacking, and the management of Natura 2000 protected areas in and the only phytosociological data available to date Geece and in Italy), aimed at the monitoring and the come from a few contributions that are often limited management of common ecosystems. The study is fo- to very small areas (Corbetta 1970; Macchia & Vita cused on three of the most significant coastal humid ar- 1973; Taffetani & Biondi 1989; Mariotti et al. 1992; eas of Apulia region: “Torre Guaceto”, “Saline di Punta Beccarisi et al. 2003a,b; Biondi et al. 2006). It is well- della Contessa” and “Le Cesine”, on the Adriatic side of known that coastal wetlands are habitats of great bio- southern Apulia. Composition of the vegetation occur- logical importance and high taxonomical richness, but, ring in these three coastal areas is here analyzed, focus- at the same time, they are extremely vulnerable to ing particularly on plant communities of salt marshes human activities and disturbances and, for this rea- and their zoning. * Corresponding author c 2011 Institute of Botany, Slovak Academy of Sciences 1028 V. Tomaselli et al. Fig. 1. Study area. Fig. 2. Cluster analysis of halophilous and hygrophilous perennial vegetation. Material and methods areas for agriculture, the coastal lagoons occupy only small surfaces. The main risk factors are coastal erosion and fire, Study area (Fig. 1) which periodically afflicts the protected area. Torre Guaceto is a Ramsar site, a Marine Protected Area Saline di Punta della Contessa (LS) is a Regional Nat- and a National Natural Reserve. The Natural Reserve covers ural Park which covers an area of 1960 ha. It is also a pSCI an area of about 1.200 ha. According to the EU Directives (IT9140003) and a SPA (IT9140003). Most of the protected “Habitat” and “Bird”, this site is a proposed Site of Com- area is occupied by farmlands, while the wet area lies be- munity Interest (pSCI) (IT9140005) and a Special Protec- tween the cultivated groves and the sandy coastline. The tion Area (SPA) (IT9140008). The coastal strip is charac- retrodunal coastal area consists of a system of intercon- terized by both rocky and sandy shores. Owing to drainage nected ponds and marshes which are characterised by sev- works and partial silting in the past century to create new eral halophytic communities. The main risk factor is the Plant communities in coastal wetlands in southern Apulia 1029 Fig. 3. NMS ordination analysis of halophilous and hygrophilous perennial vegetation Axis 1 explains a part of the variance (r squared 0.384; the total of explained variance is of 0.745) and is related mainly to a soil salinity gradient. The distribution along the axis 2 and the axis 3 does not seem to reveal any particularly defined correlation (r squared values are, respectively, 0.219 and 0.142). presence of some industrial factories which produce high and fire. In recent decades, marine erosion has caused a levels of pollutants in waters and soils. Marine erosion has progressive reduction of the sandbank, causing a slight but caused a progressive reduction of the sandbank, leading to progressive increase in salt rates of the coastal lagoons. the increasing salinity in the retrodunal lagoons. Le Cesine (LC) is a Ramsar site and a National Natural Reserve covering about 350 ha. It is also a pSCI (IT9150032) Vegetation sampling and analysis and SPA (IT9150014). The coastal strip consists almost en- The vegetation analysis was carried out following the z¨urich- tirely of sandy shores. The retrodunal humid area is one of montpellier phytosociological method (Braun-Blanquet the most important in southern Italy and it is formed by 1964). Phytosociological relevés (180 relevés) have been per- two large water pools and various channels, marshes, and formed in the period April 2007–October 2009 and mapped wet grasslands. The main risk factors are coastal erosion using GPS. The size of plots varies from a maximum of 100 1030 V. Tomaselli et al. Fig. 4. DCA of the data-set of sub-halophilous helophytic communities and grasslands. The r squared values of axes 1 and 2 are, respectively, 0.324 and 0.204 and are related to an increasing soil salinity and to a decreasing flooding period. m2 to 5 m2, depending on vegetation type and microtopog- larity ratio. Clusters of relevés were classified into syntaxa raphy. according to Rivas-Martinez et al. (2001, 2002). We referred The nomenclature of plant species follows Conti et al. to Perez Prieto & Font (2005) for the Helianthemetea guttati (2005). A specific data base has been implemented with co- class. ordinates, list of plant species, cover values, geographical The ordination of the data-sets was performed us- and topographic features of each phytosociological relevé. ing the PC-ORD 4.34 software. In the ordination anal- The phytosociological relevés have been arranged in two dif- yses we ran both Nonmetric Multidimensional Scaling ferent matrix: halophilous-higrophilous perennial vegetation (NMS) and Detrended Correspondence Analysis (DCA), (112 plots × 154 species) and therophytic vegetation (both based on the Euclidean distance. The two methods gave xerophilous and hygrophilous, 96 plots × 180 species). Rare consistent ordination diagrams. NMS is a non-parametric species were not excluded from the analysis. For each data- ordination technique based on the ranked compositional set, similarity analyses of the relevés were carried out us- dissimilarities among sites, and therefore has advantages ing the SYN-TAX 2000 software (Podani 2001). Original over parametric ordination techniques in which the un- Braun-Blanquet sampling scale has been transformed into derlying assumptions are rarely satisfied in field com- the ordinal scale according to Van der Maarel (1979). A munity data (Clarke 1993). The autopilot routine in hierarchic classification method (UPGMA) was performed. the NMS program of PC-ORD showed that a three Dissimilarity of the relevés was measured using the Simi- axes NMS was appropriate, though we have chosen to Plant communities in coastal wetlands in