Hostname: page-component-7b7567c8c-7pwfn Total loading time: 0 Render date: 2026-11-14T07:16:33.444Z Has data issue: false hasContentIssue false
  • English
  • Français

New record of the alien seagrass Halophila stipulacea (Hydrocharitaceae) in the western Mediterranean: a further clue to changing Mediterranean Sea biogeography

Published online by Cambridge University Press:  06 May 2009

Maria Cristina Gambi,
Fabio Barbieri and
Carlo Nike Bianchi
Maria Cristina Gambi*
Affiliation:
Laboratorio di Ecologia del Benthos – Stazione Zoologica Anton Dohrn, Napoli, Italy
Fabio Barbieri
Affiliation:
Palinuro Sub, Via Porto, Palinuro (Salerno), Italy
Carlo Nike Bianchi
Affiliation:
DipTeRis (Dipartimento per lo studio del Territorio e delle sue Risorse), Università di Genova, Corso Europa 26, 16132 Genoa, Italy
*
Correspondence should be addressed to: M.C. Gambi, Laboratorio di Ecologia del Benthos – Stazione Zoologica, Anton Dohrn, Napoli, Italy email: gambimc@szn.it

Abstract

The occurrence of the tropical seagrass species Halophila stipulacea (Hydrocharitaceae) is reported within the harbour of Palinuro (Salerno, central Tyrrhenian Sea, Italy). The bottom covered by the seagrass has been evaluated in about 16 m2, fragmented in various small patches distributed in a narrow belt between 0.5 and 5 m depth, and all settled on dead matte of the endemic Mediterranean seagrass Posidonia oceanica. Mean density was 10,500 shoots m−2. This record documents a displacement of about 180 km north of the previously documented limit of Halophila stipulacea in the western Mediterranean, likely mediated by pleasure boat traffic and anchoring, and favoured by climate change. This record illustrates a further example of the changing Mediterranean Sea biogeography: north–south patterns in biotic ranges will probably replace the presently well established west–east patterns in the Mediterranean Sea of tomorrow.

Keywords

marine angiospermsintroduced speciesHalophila stipulaceaTyrrhenia Seaclimate change

Information

Type
Research Article
Information
Marine Biodiversity Records , Volume 2 , January 2009, e84
Copyright
Copyright © Marine Biological Association of the United Kingdom 2009

INTRODUCTION

Halophila stipulacea (Forsskål) Ascherson (Hydrocharitaceae) is a tropical seagrass distributed along the coasts of the western Indian Ocean and the Red Sea (den Hartog, Reference Hartog, McRoy and Helferich1977; Larkum & den Hartog, Reference Larkum, Hartog and Larkum1989; Short et al., Reference Short, Coles, Pergent-Martini, Short and Coles2001). Although plant fragments belonging to this species were found in the eastern Mediterranean in 1894 (Fritsch, Reference Fritsch1895), the first record of living plants in well established meadows came thirty years later from Rhodes (Forti, Reference Forti1927; Issel, Reference Issel1928). Such early occurrences with respect to the opening of the Suez Canal in 1869, coupled with the wider and abundant distribution of the species in the Aegean Sea during the 1950s, induced Pérès & Picard (Reference Pérès and Picard1958) to affirm that H. stipulacea was a ‘paleomediterranean’ element that had survived the late Miocene crisis (Taviani, Reference Taviani2002) as a relict in the eastern Mediterranean Sea. In his seminal review of lessepsian migration (penetration of Red Sea species into the Mediterranean Sea through the Suez Canal), Por (Reference Por1971) argued to the contrary that Halophila stipulacea had been one of the first invaders into the Mediterranean Sea because it was ‘pre-adapted’ to cross the salinity barriers through the Canal. Apparently, the species remained restricted to the eastern Mediterranean for several decades (Lipkin, Reference Lipkin1975a, Reference Lipkinb; Van Der Velte & den Hartog, 1992; Kashta & Pizzuto, Reference Kashta and Pizzuto1995), but then showed a progressive colonization towards the western areas through Malta (Lanfranco, Reference Lanfranco1970) and the Ionian coast of Sicily (Biliotti & Abdelaad, Reference Biliotti and Abdelahad1990; Alongi et al., Reference Alongi, Cormaci and Pizzuto1992). In the western basin, it was first observed in 1995 at the island of Vulcano in the Aeolian Archipelago, southern Tyrrhenian Sea (Acunto et al., Reference Acunto, Maltagliati, Rindi, Rossi, Cinelli and Lardicci1997; Procaccini et al., Reference Procaccini, Acunto, Famà and Maltagliati1999). For more than ten years the species was not reported north of this latter location. This paper reports on the occurrence of Halophila stipulacea within the harbour of Palinuro (Salerno), a Tyrrhenian Sea locality about 180 km north of Vulcano Island, and gives some information on the settlement characteristics, plant density and morphological features. The record is discussed in the frame of the changing Mediterranean Sea biogeography (Bianchi, Reference Bianchi2007).

MATERIALS AND METHODS

Study site

The settlement of the species, with a small patch (>1 m2), was first observed within the harbour of Palinuro (40°01.680′N 15°16.736′E) in September 2006. The harbour of Palinuro is a sheltered inlet protected by an artificial dock (Figure 1). The bottom is sandy and interspersed with a bed of the Mediterranean endemic seagrass Posidonia oceanica, from 1 m to around 10 m in depth. Due to the presence of numerous moorings, chains, anchors and lines of pleasure and fishing boats, the P. oceanica bed is quite degraded and regressed, showing a large amount of dead matte. Sampling of shoots for morphology, and estimates of shoot density were conducted by SCUBA diving in mid-June 2007. Quantitative samples were taken over a surface of 10 × 10 cm (4 replicates) in different patches of H. stipulacea at 2 m depth. In each quantitative sample, the number of shoots was counted to estimate shoot density, and ten plants were randomly selected and measured (number of leaves, leaf length and width) to evaluate shoot morphology.

Fig. 1.

Map of the harbour of Palinuro (Salerno, Campania coast), with indication of Halophila stipulacea occurrence. Soundings in metres. The position of the hydrothermal vent is taken from Alvisi et al. (Reference Alvisi, Barbieri and Colantoni1994).

A qualitative sample was also taken at 2 m depth in a patch where larger shoots of Halophila stipulacea were observed to vertically overgrow living Posidonia oceanica shoots. Twenty of such shoots were measured to characterize their morphology and evaluate their differences with shoots of quantitative samples collected far from the edge of the P. oceanica bed Piazzi et al., Reference Piazzi, Balestri and Cinelli2005; Van Tussenbroek et al., Reference Van Tussenbroek, Wong and Marquez-Guzman2008.

All collected shoots were washed from the sediments and fixed in 4% formalin. For each sample the presence of male flowers was noted and the flowering percentage (no. of flowering shoots/total no. of shoots × 100) was calculated (Pergent & Pergent-Martini, Reference Pergent and Pergent-Martini1988). Leaf morphological variables collected on shoots in the middle of the patch and at the edge of the P. oceanica meadow were compared with a t-test.

RESULTS

Species identification features: Halophila stipulacea is the only non-indigenous seagrass species to date to be reported from both the eastern and western Mediterranean Sea (Lipkin et al., Reference Lipkin, Beer, Zakai, Green and Short2003; Procaccini et al., Reference Procaccini, Buia, Gambi, Perez, Pergent, Pegent-Martini, Romero, Green and Short2003). Specimens collected in the Palinuro Harbour were checked for identification using the key provided by Kuo & den Hartog (Reference Kuo, Hartog, Short and Coles2001). The morphological features of our specimens match well with the H. stipulacea description and diagnostic characters of this key. In particular, typical of this species are the linear, oblong and membranous blades (up to 60 mm long), with 10–40 branched cross veins and serrulate margins (Figure 2A). Also very clear is the most distinctive character of H. stipulacea, represented by a pair of large, persistent, transparent scales, elliptic in shape and covering the short petiole, as illustrated in Figure 2A & F. Male flowers with tepals 3–4 mm long, and anthers 2–3.5 mm long (Figure 2F). Our specimens were also compared with herbarium specimens available at the Botany Department of the University of Catania (www.dipbot.unict.it/frame/vegetazionemarina.htm) collected along the coast of Sicily (identified by Professor G. Giaccone), as well as with the iconography available in various publications. Several shoots, also bearing male flowers as in Figure 2F, are deposited at the herbarium of the Stazione Zoologica (Laboratorio di ecologia del benthos) for reference.

Fig. 2.

(A) Close up picture of some shoots of Halophila stipulacea in the harbour of Palinuro (Tyrrhenian Sea) (Photograph: F. Barbieri); note the main diagnostic character for identification of the species: a pair of large, persistent, transparent scales, elliptic in shape and covering the short petiole; (B) shoots of Halophila stipulacea in the harbour of Palinuro (Tyrrhenian Sea) settled on a dead matte of Posidonia oceanica (Photograph: F. Barbieri); (C) a patch of Halophila stipulacea settled on the dead matte of Posidonia oceanica and interspersed with Posidonia shoots (Photograph: M.C. Gambi); (D) Halophila shoots merged with Posidonia oceanica shoots in Palinuro Harbour (Photograph: M.C. Gambi); (E) a school of the herbivore fish Sarpa salpa foraging within a patch of Halophila stipulacea in the harbour of Palinuro (Photograph: M.C. Gambi); (F) a mature male flower of Halophila stipulacea collected in the harbour of Palinuro (Photograph: B. Iacono).

In June 2007 Halophila stipulacea was distributed within the harbour of Palinuro in a limited area, a narrow belt from 0.5 to 5 m depth in front of the small beach that lines the southern side of the harbour (Figure 1). In this area (approximately 25 m wide and 50 m long) various patches were present and all were found on dead Posidonia oceanica matte (Figure 2B,C). The majority of the patches were <1 m2, while two patches were bigger, one ~9 m wide × 7 m long and the other 2 m × 1.5 m, both located at 2 m depth. As a whole, considering all patches, we have estimated a bottom coverage by the plant of ~16 m2. In several patches H. stipulaceae was in contact with living P. oceanica shoots (Figure 2C,D). Halophila stipulacea shoots in contact with living P. oceanica had generally a vertical (ortothropous) growth over the P. oceanica leaves, and showed significant higher dimensions (both for length and width) than shoots settled in the middle of the patch (see Table 1; t-test, P < 0.01).

Table 1.

Shoots density and plant features of the Halophila stipulacea settlement in the harbour of Palinuro (June 2007).

*, single value.

In a small patch at 5 m depth, a school of Sarpa salpa was observed to forage within the patch itself (Figure 2E). However, no signs of direct grazing on Halophila leaves were detected, so it is likely that the fish school grazed upon the leaf epiphytes or upon small macroalgae interspersed with H. stipulaceae shoots.

Only male flowers were observed, mainly concentrated in the terminal portion of the horizontal stolons. Most flowers were at an early stage of development, with relatively few mature ones (Figure 2F).

DISCUSSION

The limited and fragmented extension of Halophila stipulacea patches recorded in the harbour of Palinuro suggests a recent colonization event of this plant in the area, probably due to the anchoring of pleasure boats coming from the Aeolian Archipelago, Sicily. It is a known fact that anchors can be an effective way of dissemination of alien marine macrophytes (Boudouresque & Verlaque, Reference Boudouresque, Verlaque and Briand2002). A similar dispersion vector has been speculated by Lipkin (Reference Lipkin1975a) as regards to the initial introduction of this species in the eastern Mediterranean, through multiple occasions either as fragments in fishing gears or attached to the hull of ships passing the Suez Canal. In this respect, it is also worth reporting that a similar mechanism of introduction has been hypothesized for a H. stipulacea settlement reported in the tropical West Atlantic (Grenada, West Indies) by Ruiz & Ballantine (Reference Ruiz and Ballantine2004). These authors stated that, ‘as there is little commercial shipping between Grenada and the Mediterranean, the most likely vector was a tourist pleasure yacht, and that the species has the potential to survive such trans-oceanic transfer’. A similar hypothesis was also formulated along the Campania coast at Punta Licosa, not far from Palinuro, for the introduction of a small patch of the alien macroalga Caulerpa taxifolia (Russo et al., Reference Russo, Balzano and Carrada2003).

Tourist traffic of pleasure boats is quite intense between Palinuro—one of the most attractive tourist areas along the Campania shoreline—and the northern coast of Sicily (Aeolian Archipelago), or the southern Tyrrhenian coast of Calabria, where H. stipulacea and C. taxifolia are well established, respectively.

Halophila stipulacea patches were only observed within the dead matte of Posidonia suggesting that this species needs a certain degree of organic matter and fine fraction in the sediment to settle. In addition, the dead matte is a low competition habitat where generally other fast growing plants, such as Cymodocea nodosa, Nanozostera noltii (=Zostera noltii = Zostera nana) and Caulerpa spp. settle preferentially (Montefalcone et al., Reference Montefalcone, Morri, Peirano, Albertelli and Bianchi2007). Mean shoot density in Palinuro (2 m depth) was lower than that observed in the meadow at Vulcano Island, where density ranged between 13,000 and 15,000 shoots m–2 at 5 to 25 m depth (Procaccini et al., Reference Procaccini, Acunto, Famà and Maltagliati1999), or in the Giardini Naxos (eastern Sicily), where density at 4 m surpassed 19,000 shoots m–2 (Cancemi et al., Reference Cancemi, Terlizzi, Scipione and Mazzella1994). This fact may further support the hypothesis of a recent colonization. Finding male flowers only is usual in the Mediterranean and is consistent with observation in other locations (Cancemi et al., Reference Cancemi, Terlizzi, Scipione and Mazzella1994; Procaccini et al., Reference Procaccini, Acunto, Famà and Maltagliati1999). This suggests the hypothesis of the introduction of male specimens only, or the difficulty of female flowers to develop under the Mediterranean environmental conditions. Therefore, the main propagation of the species is by fragmentation and vegetative stolonization. Shoot features (no. of leaves, leaf length and width) were also lower than those recorded at Vulcano, except for the shoots collected at the edge with living P. oceanica. Although settlement of H. stipulacea was still spatially limited, the availability of large areas of dead matte within the Palinuro Harbour suggest that the plant has potential favourable conditions for further colonization and expansion in the area.

BIOGEOGRAPHIC CONSIDERATIONS

For nearly a century after its ingress into the Mediterranean Sea, Halophila stipulacea remained confined to the eastern basin, conforming to a typical pattern for lessepsian migrants: Por (Reference Por1990) defined the geographical limits to the expansion of Red Sea species in the Mediterranean as the ‘Andispara line’ to the north (Andispara being an island in the Aegean) and recent findings also along the coast of Albania (Xhulaj & Kashta, Reference Xhulaj, Kashta and Pergent-Martini2007), and the Strait of Sicily to the west. These boundaries match what Bianchi (Reference Bianchi2007) called the ‘15°C divide’ (i.e. the climatological surface isotherm for February), seen as a physiological barrier for the establishment of species with tropical affinities and origins in the Mediterranean Sea. In the latter two decades, however, H. stipulacea crossed the 15°C divide and started to go west (Figure 3). While its settling at Vulcano Island was to date an isolated patch merely facing the western basin, as the Aeolian area is still connected biogeographically to the Ionian Sea (Bianchi, Reference Bianchi2004), the present record at Palinuro provides proof of its expansion in the north-western Mediterranean. Both Vulcano and Palinuro settlements are intriguingly close to shallow-water hydrothermal vents (Dando et al., Reference Dando, Stüben and Varnavas1999), and De Biasi & Aliani (Reference De Biasi and Aliani2003) provided suggestive evidence that these vents may act as stepping stones for lessepsian migrants. The vent within Palinuro Harbour, located in close vicinity to the patches of Halophila stipulacea (Figure 1), maintains water temperature at 21.5°C in its immediate surroundings (Alvisi et al., Reference Alvisi, Barbieri and Colantoni1994), and this may set more favourable conditions for the settlement of this seagrass.

Fig. 3.

The Mediterranean Sea with surface isotherms of February (climatological means: Bianchi, Reference Bianchi2007). The 14°C and the 15°C ‘divides’ (see text) are highlighted by a thicker tract. Diamonds illustrate records of Halophila stipulacea: white and grey symbols show the records before 1980 and those of the 1990s, respectively (see text for references), the black symbol corresponds to the present finding at Palinuro (Salerno, Campania coast).

Due to the increased occurrence of warm-water species in recent years, it has been said that the Mediterranean Sea is undergoing a process of ‘tropicalization’ (Bianchi & Morri, Reference Bianchi and Morri2003). Tropical species have been entering the Mediterranean either through the Suez Canal or the Gibraltar Strait for decades, but they used to remain in the eastern or western basin, respectively, thus conforming to—and in a sense even reinforcing—the traditional physiographic and biogeographic subdivision of the Mediterranean Sea (Bianchi et al., Reference Bianchi, Boero, Fraschetti, Morri and Argano2002). However, just like H. stipulacea did, many lessepsian species have recently crossed the Strait of Sicily from east to west (see Pipitone et al., Reference Pipitone, D'Anna, Coppola, Di Stefano and Badalamenti2004 for a recent example). On the other side, Atlantic species have travelled the opposite way, passing from west to east: Atlantic and Red Sea migrant syngnathid fish now thrive together in Turkish waters (Gokoglu et al., Reference Gokoglu, Bodur and Kaya2004). The case of the Atlantic crab Percnon gibbesi perfectly mirrors that of Halophila stipulacea: it has crossed the Strait of Sicily (Bellantoni & Corazza, Reference Bellantoni and Corazza2003) and travelled eastward along the coasts of Calabria (Faccia & Bianchi, Reference Faccia and Bianchi2007) to eventually reach the Levant Sea (Yokes & Galil, Reference Yokes and Galil2006). To the north, P. gibbesi has apparently stopped at the Pontine Islands (Russo & Villani, 2004), which is in the same biogeographic sector as Palinuro (Bianchi & Morri, Reference Bianchi and Morri2000) and close to the ‘14°C divide’, the claimed northern boundary for Mediterranean warm-water species (Bianchi, Reference Bianchi2007) (Figure 3). However, we should consider that the examples given above refer to animals which are mobile and have large scale dispersive stages (larvae), and therefore higher potential for expansion in respect to macrophytes.

The traditional major biogeographic boundary between western and eastern Mediterranean is thus apparently fading in favour of a south–north boundary: recent re-appraisals of faunal distributions within the Mediterranean found such south–north subdivision for corals (Morri et al., Reference Morri, Vafidis, Peirano, Chintiroglou and Bianchi2000), sponges (Pansini & Longo, Reference Pansini and Longo2003) and pycnogonids (Chimenz-Gusso & Lattanzi, Reference Chimenz-Gusso and Lattanzi2003). Bianchi (Reference Bianchi2007) suggested that the alleged biotic differences between western and eastern Mediterranean are due more to differences in temperature regime than to the physical barrier of the Strait of Sicily, as it was traditionally assumed: this has profound implications, as the sea warming trend observed in the Mediterranean (Bianchi, Reference Bianchi1997; Bianchi & Morri, Reference Bianchi and Morri2004) can move isotherms but cannot change the morphology of the straits.

The northward expansion of Halophila stipulacea, Percnon gibbesi and many other, including native species in both the eastern and western basins (Grubelić et al., Reference Grubelić, Antolić, Despalatović, Grbec and Paklar2004; Sara et al., Reference Sara, Bianchi and Morri2005) occurred in exactly the same time frame of a major climatic event that upset the hydrological patterns of the whole Mediterranean in the 1980s and 1990s (Malanotte-Rizzoli et al., Reference Malanotte-Rizzoli, Manca, Ribera d'Alcala, Theocharis, Brenner, Budillon and Ozsoy1999), with dramatic effects on the marine ecosystems (Briand, Reference Briand2000). Along the coast of Campania, the region where the ‘14°C divide’ is passing and Palinuro is located, various phenomena and events related to seawater thermal anomalies have been recently documented (Gambi, Reference Gambi2006; Gambi et al., Reference Gambi, Cigliano and Iacono2006; Cigliano & Gambi, Reference Cigliano and Gambi2007), including the increased occurrence and frequency of several native or introduced warm-water species (Dappiano et al., Reference Dappiano, Iacono and Gambi2002; Dappiano & Gambi, Reference Dappiano and Gambi2004). Whatever the specific mechanism of dissemination (we postulated boat traffic), the present finding of H. stipulacea at Palinuro perfectly fits the frame of a scenario hypothesized by Bianchi (Reference Bianchi2007) for the changing marine biogeography of the Mediterranean of tomorrow: the traditionally acknowledged subdivision between a species-richer western basin and a species-poorer eastern basin, viewed as a legacy of the Quaternary colonization waves from the Atlantic filtered out toward the east by the sill of the Sicily Strait (Bianchi et al., Reference Bianchi, Boero, Fraschetti, Morri and Argano2002), is being replaced by a newly established subdivision between a southern (sub)tropical and a northern warm-temperate Mediterranean Sea.

ACKNOWLEDGEMENTS

Professor Giuseppe Giaccone kindly provided the iconography of the herbarium specimens of Halophila stipulacea at the Botany Department of the University of Catania for reference. Carla Morri (Genoa) provided literature references and critical advice. Serena Coraggioso (Palinuro) helped with the map of Figure 1. Thanks are also due to Francesca Ferraris and Alessio Rovere (Genoa) for cartographic support. The study of the penetration of lessepsian migrants in the western Mediterranean Sea falls within the scope of the on-going project ‘The impacts of biological invasions and climate change on the biodiversity of the Mediterranean Sea’ (Italy–Israel Cooperation—R & D Proposal for 2007).

References

REFERENCES

Acunto, S., Maltagliati, F., Rindi, F., Rossi, F., Cinelli, F. and Lardicci, C. (1997) Indagine su una prateria di Halophila stipulacea (Forssk.) Aschers. (Hydrocharitaceae) dell'Isola di Vulcano. In Piccazzo Ed. Atti 12° Congresso dell'Associazione Italiana di Oceanologia e Limnologia. Isola di Vulcano 18 – 21 Settembre 1996. Genova: AIOL, 51–60.Google Scholar
Alongi, G., Cormaci, M. and Pizzuto, F. (1992) La macroflora epifita delle foglie di Halophila stipulacea (Forssk.) Aschers. del porto di Catania. In Proceedings 23rd Congress Italian Society of Marine Biology (SIBM). Biologia Marina, Supplemento Notiziario Societa Italiano di Biologia Marina 1, 287–288.Google Scholar
Alvisi, M., Barbieri, F. and Colantoni, P. (1994) Le grotte marine di Capo Palinuro. Memorii Istituto Italiano di Speleologia 6, 143–181.Google Scholar
Bellantoni, N. and Corazza, C. (2003) Segnalazione del granchio tropicale Percnon gibbesi (H. Milne-Edwards, 1853) (Decapoda, Grapsidae) nello Stretto di Messina, versante calabrese. Annali del Museo Civico di Storia Naturale di Ferrara 5 (2002), 129–130.Google Scholar
Bianchi, C.N. (1997) Climate change and biological response in the marine benthos. Proceedings of the Italian Association for Oceanology and Limnology 12, 3–20.Google Scholar
Bianchi, C.N. (2004) Proposta di suddivisione dei mari italiani in settori biogeografici. Notiziario della Società Italiana di Biologia Marina 46, 57–59.Google Scholar
Bianchi, C.N. (2007) Biodiversity issues for the forthcoming tropical Mediterranean Sea. Hydrobiologia 580, 7–21.CrossRefGoogle Scholar
Bianchi, C.N., Boero, F., Fraschetti, S. and Morri, C. (2002) La fauna del Mediterraneo. In Argano, R. et al. (eds) La fauna in Italia. Milano: Touring Club Italiano, pp. 247–335.Google Scholar
Bianchi, C.N. and Morri, C. (2000) Marine biodiversity of the Mediterranean Sea: situation, problems and prospects for future research. Marine Pollution Bulletin 40, 367–376.CrossRefGoogle Scholar
Bianchi, C.N. and Morri, C. (2003) Global sea warming and “tropicalization” of the Mediterranean Sea: biogeographic and ecological aspects. Biogeographia 24, 319–327.Google Scholar
Bianchi, C.N. and Morri, C. (2004) Climate change and biological response in Mediterranean Sea ecosystems – a need for broad-scale and long-term research. Ocean Challenge (2003) 13, 32–36.Google Scholar
Biliotti, M. and Abdelahad, N. (1990) Halophila stipulacea (Forssk.) Aschers. (Hydrocharitaceae): espèce nouvelle pour l'Italie. Posidonia Newsletter 3, 23–26.Google Scholar
Boudouresque, C.F. and Verlaque, M. (2002) Assessing scale and impact of ship-transported alien macrophytes in the Mediterranean Sea. In Briand, F. (ed.) Alien marine organisms introduced by ships in the Mediterranean and Black Seas. CIESM, Monaco, Workshop Monographs no. 20, 53–61.Google Scholar
Briand, F. (ed.) (2000) The Eastern Mediterranean climatic transient, its origin, evolution and impact on the ecosystem. CIESM, Monaco, Workshop Series no. 10, 86 pp.Google Scholar
Cancemi, G., Terlizzi, A., Scipione, M.B. and Mazzella, L. (1994) II prato ad Halophila stipulacea (Forssk.) Aschers. di Giardini Naxos (Sicilia): caratteristiche della pianta e del popolamento a fauna vagile. Biologia Marina Mediterranea 1, 401–402.Google Scholar
Chimenz-Gusso, C. and Lattanzi, L. (2003) Mediterranean Pycnogonida: faunistic, taxonomical and zoogeographical considerations. Biogeographia 24, 251–262.Google Scholar
Cigliano, M. and Gambi, M.C. (2007) The long hot summer. A further mortality event of gorgonians along the Phlaegrean islands (Tyrrhenian Sea). Biologia Marina Mediterranea 14, 138–139.Google Scholar
Dando, P.R., Stüben, D. and Varnavas, S.P. (1999) Hydrothermalism in the Mediterranean Sea. Oceanography 44, 333–367.Google Scholar
Dappiano, M. and Gambi, M.C. (2004) New data on occurrence of themophile scleractinia (Cnidaria, Anthozoa) in the Phlaegrean islands (Ischia, Procida, Vivara—Gulf of Naples), with special attention to Astroides calycularis. In Marine Biogeography of the Mediterranean Sea: patterns and dynamics of biodiversity. Part II. Biogeographia 25, 31–46.Google Scholar
Dappiano, M., Iacono, B. and Gambi, M.C. (2002) Biocoenotic characterization and new records of benthic organisms in the Phlaegrean islands (Ischia, Procida and Vivara, Gulf of Naples) by means of visual census. Biologia Marina Mediterranea 9, 518–524.Google Scholar
De Biasi, A.M. and Aliani, S. (2003) Shallow water hydrothermal vents in the Mediterranean Sea: stepping stones for Lessepsian migration? Hydrobiologia 502, 37–44.CrossRefGoogle Scholar
Faccia, I. and Bianchi, C.N. (2007) Prima segnalazione del granchio Percnon gibbesi (H. Milne-Edwards, 1853) nella Calabria ionica. Thalassia Salentina (in press).Google Scholar
Forti, A. (1927) La propagazione dell'Halophila stipulacea (Forsk) Asch. anche nel Mediterraneo. Nuovo Giornale Botanico Italiano n.s. 34, 714–716.Google Scholar
Fritsch, C. (1895) Über die Auffindung einer marinen Hydrocharidae im Mittelmeer. Verhandlungen der Zoologisch Botanischen gesamten Wien 45, 104–106.Google Scholar
Gambi, M.C. (2006) “A qualcuno piace (più) caldo”: organismi marini e fenomeni indicatori di cambiamento climatico lungo le coste della Campania. 67° Congresso Unione Zoologica Italiana (UZI), Napoli 12–15 Settembre 2006, 36. [Abstract.]Google Scholar
Gambi, M.C., Cigliano, M. and Iacono, B. (2006) Segnalazione di un evento di mortalità di gorgonacei lungo le coste delle isole di Ischia e Procida (Golfo di Napoli, Tirreno). Biologia Marina Mediterranea 13, 583–587.Google Scholar
Gokoglu, M., Bodur, T. and Kaya, Y. (2004) First record of Hippocampus fuscus and Syngnathus rostellatus (Osteichthyes: Syngnathidae) from the Anatolian coast (Mediterranean Sea). Journal of the Marine Biological Association of the United Kingdom 84, 1093–1094.CrossRefGoogle Scholar
Grubelić, I., Antolić, B., Despalatović, M., Grbec, B. and Paklar, G.B. (2004) Effect of climatic fluctuations on the distribution of warm-water coral Astroides calycularis in the Adriatic Sea: new records and review. Journal of the Marine Biological Association of the United Kingdom 84, 599–602.CrossRefGoogle Scholar
Hartog, C. den (1977) Structure, function, and classification in sea grass communities. In McRoy, C.P. and Helferich, C. (eds) Sea-grass ecosystems. A scientific perspective. London: M. Dekker Inc., pp. 89–122.Google Scholar
Kashta, L. and Pizzuto, F. (1995) Sulla presenza di Halophila stipulacea (Forsskal) Ascherson (Hydrocharitales, Hydrocharitaceae) nelle coste dell'Albania. Bollettino Accademia Gioenia di Scienze Naturali 28, 161–166.Google Scholar
Kuo, J. and Hartog, C. den (2001) Sea grass taxonomy and identification key. In Short, F.T and Coles, R.G. (eds) Global seagrass methods. Amsterdam: Elsevier Sciences B.V., pp. 31–58.CrossRefGoogle Scholar
Issel, R. (1928) Cenni sui risultati ottenuti dalla Missione Zoologica nel Dodecaneso (1926) per quanto concerne la fauna e la flora marine, con alcune osservazioni generali. Archivio Zoologico Italiano 12, 259–271.Google Scholar
Lanfranco, E. (1970) The occurrence of Halophila stipulacea (Forsskal) Ascherson (Family: Hydrocharitaceae) in Maltese waters. Maltese Naturalist 1, 16–17.Google Scholar
Larkum, A.W.D. and Hartog, C. den (1989) Evolution and biogeography of sea grasses. In Larkum, A.W.D. et al. (eds) Biology of seagrasses. Amsterdam: Elsevier, pp. 112–156.Google Scholar
Lipkin, Y. (1975a) Halophila stipulacea, a review of a successful immigration. Aquatic Botany 1, 203–215.CrossRefGoogle Scholar
Lipkin, Y. (1975b) Halophila stipulacea in Cyprus and Rhodes, 1967–1970. Aquatic Botany 1, 309–320.CrossRefGoogle Scholar
Lipkin, Y., Beer, S. and Zakai, D. (2003) The seagrasses of the Eastern Mediterranean and the Red Sea. In Green, E.P. and Short, F.T. (eds) World Atlas of Seagrasses. UNEP World Conservation UK, pp. 65–73.Google Scholar
Malanotte-Rizzoli, P., Manca, B.B., Ribera d'Alcala, M., Theocharis, A., Brenner, S., Budillon, G. and Ozsoy, E. (1999) The Eastern Mediterranean in the 80s and in the 90s: the big transition in the intermediate and deep circulations. Dynamics of Atmospheres and Oceans 29, 365–395.CrossRefGoogle Scholar
Montefalcone, M., Morri, C., Peirano, A., Albertelli, G. and Bianchi, C.N. (2007) Substitution and phase shift within the Posidonia oceanica sea grass meadows of NW Mediterranean Sea. Esturaine, Coastal and Shelf Science doi:10.1016/j.ecss.2007.03.034CrossRefGoogle Scholar
Morri, C., Vafidis, D., Peirano, A., Chintiroglou, C.C. and Bianchi, C.N. (2000) Anthozoa from a subtidal hydrothermal area of Milos Island (Aegean Sea), with notes on the construction potential of the scleractinian coral Madracis pharensis. Italian Journal of Zoology 67, 319–325.CrossRefGoogle Scholar
Pansini, M. and Longo, C. (2003) A review of the Mediterranean Sea sponge biogeography with, in appendix, a list of the demosponges hitherto recorded from this sea. Biogeographia 24, 251–262.Google Scholar
Pérès, J.M. and Picard, J. (1958) Recherches sur les peuplements benthiques de la Méditerranée nord-orientale. Annales de l'Institute Océanographique, Paris 34, 213–291.Google Scholar
Pergent, G. and Pergent-Martini, C. (1988) Phénologie de Posidonia oceanica (Linnaeus) Delile dans le basin Méditerranéen. Annales de l'Institute Océanographique, Paris 64, 79–100.Google Scholar
Piazzi, L., Balestri, L. and Cinelli, F. (2005) Grazing of inflorescence of the seagrass. Posidonia oceanica L. Delile. Botanica Marina 43, 581–584.Google Scholar
Pipitone, C., D'Anna, G., Coppola, M., Di Stefano, G. and Badalamenti, F. (2004) First record of the Lessepsian fish Fistularia commersonii in the Western Mediterranean. Biologia Marina Mediterranea 11, 327.Google Scholar
Por, F.D. (1971) One hundred years of Suez Canal—a century of Lessepsian migration: retrospect and viewpoints. Systematic Zoology 10, 138–159.CrossRefGoogle Scholar
Por, F.D. (1990) Lessepsian migration: an appraisal and new data. Bulletin de l'Institute Océanographique de Monaco, numero spécial 7, 1–10.Google Scholar
Procaccini, G., Acunto, S., Famà, P. and Maltagliati, F. (1999) Structural, morphological and genetic variability in Halophila stipulacea (Hydrocharitaceae) populations of the Western Mediterranean. Marine Biology 135, 181–189.CrossRefGoogle Scholar
Procaccini, G., Buia, M.C., Gambi, M.C., Perez, M., Pergent, G., Pegent-Martini, C. and Romero, J. (2003) The seagrasses of the Western Mediterranean. In Green, E.P. and Short, F.T. (eds) World Atlas of Seagrasses. UNEP World Conservation UK, pp. 48–58.Google Scholar
Ruiz, H. and Ballantine, D. (2004) Occurrence of the sea grass Halophila stipulacea in the tropical West Atlantic. Bulletin of Marine Science 75, 131–135.Google Scholar
Russo, G.F., Balzano, R. and Carrada, G.C. (2003) Prima segnalazione di Caulerpa taxifolia ed ulteriori notizie sulla distribuzione di Caulerpa racemosa per le coste della Campania (Tirreno Centrale). Biologia Marina Mediterranea 10, 608–610.Google Scholar
Russo, G.F. and Villani, G. (2005) Spreading of the allochthonous species Percnon gibbesi in the central Tyrrhenian Sea. Biologia Marina Mediterranea 12, 329–330.Google Scholar
Sara, G., Bianchi, C.N. and Morri, C. (2005) Mating behaviour of the newly-established ornate wrasse Thalassoma pavo (Osteichthyes, Labridae) in the Ligurian Sea (north western Mediterranean). Journal of the Marine Biological Association of the United Kingdom 85, 191–196.CrossRefGoogle Scholar
Short, F.T., Coles, R.G. and Pergent-Martini, C. (2001) Global seagrass distribution. In Short, F.T. and Coles, R.G. (eds) Global seagrass methods. Amsterdam: Elsevier Sciences B.V., pp. 5–30.CrossRefGoogle Scholar
Taviani, M. (2002) The Mediterranean benthos from late Miocene up to present: ten million years of dramatic climatic and geologic vicissitudes. Biologia Marina Mediterranea 9, 445–463.Google Scholar
Van der Velte, C. and den Hartog, C. (1989) Continuing range extension of Halophila stipulacea (Forssk.) Aschers. (Hydrocharitaceae) in the Mediterranean—now found in Kefallonia and Ithaki (Ionian Sea). Acta Botanica Neerlandica 41, 345–348.CrossRefGoogle Scholar
Van Tussenbroek, B.I., Wong, J.G.R. and Marquez-Guzman, J. (2008) Synchronized antithesis and predation on pollen in the marine angiosperm Thalassia testudinum (Hydrocharitacea). Marine Ecology Progress Series 354, 119–124.CrossRefGoogle Scholar
Xhulaj, M. and Kashta, L. (2007) Halophila stipulacea (Forsskal) and Caulerpa racemosa (Forsskål) J. Agardh in Albania. In Pergent-Martini, C. et al. (eds) Proceedings of the 3rd Mediterranean Symposium on marine vegetation, Marseille 27–29 March 2007. Tunis: RAC/SPA Publishers, pp. 299–300.Google Scholar
Yokes, B. and Galil, B.S. (2006) Touchdown - first record of Percnon gibbesi (H. Milne-Edwards, 1853) (Crustacea: Decapoda: Grapsidae) from the Levantine coast. Aquatic Invasions 1, 130–132.CrossRefGoogle Scholar
Figure 0

Fig. 1.Map of the harbour of Palinuro (Salerno, Campania coast), with indication of Halophila stipulacea occurrence. Soundings in metres. The position of the hydrothermal vent is taken from Alvisi et al. (1994).

Figure 1

Fig. 2.(A) Close up picture of some shoots of Halophila stipulacea in the harbour of Palinuro (Tyrrhenian Sea) (Photograph: F. Barbieri); note the main diagnostic character for identification of the species: a pair of large, persistent, transparent scales, elliptic in shape and covering the short petiole; (B) shoots of Halophila stipulacea in the harbour of Palinuro (Tyrrhenian Sea) settled on a dead matte of Posidonia oceanica (Photograph: F. Barbieri); (C) a patch of Halophila stipulacea settled on the dead matte of Posidonia oceanica and interspersed with Posidonia shoots (Photograph: M.C. Gambi); (D) Halophila shoots merged with Posidonia oceanica shoots in Palinuro Harbour (Photograph: M.C. Gambi); (E) a school of the herbivore fish Sarpa salpa foraging within a patch of Halophila stipulacea in the harbour of Palinuro (Photograph: M.C. Gambi); (F) a mature male flower of Halophila stipulacea collected in the harbour of Palinuro (Photograph: B. Iacono).

Figure 2

Table 1.Shoots density and plant features of the Halophila stipulacea settlement in the harbour of Palinuro (June 2007).

Figure 3

Fig. 3.The Mediterranean Sea with surface isotherms of February (climatological means: Bianchi, 2007). The 14°C and the 15°C ‘divides’ (see text) are highlighted by a thicker tract. Diamonds illustrate records of Halophila stipulacea: white and grey symbols show the records before 1980 and those of the 1990s, respectively (see text for references), the black symbol corresponds to the present finding at Palinuro (Salerno, Campania coast).