Research Article
Print
Research Article
The Fucales (Ochrophyta, Phaeophyceae) of the Island of Pantelleria (Sicily Channel, Mediterranean Sea): a new contribution
expand article infoGiuliana Marletta‡, Andrea Lombardo§
‡ Polytechnic University of Marche, Ancona, Italy
§ University of Catania, Catania, Italy

Corresponding author: Giuliana Marletta ( g.marletta@univpm.it )

Academic editor: Cecilia Maria Totti
© 2023 Giuliana Marletta, Andrea Lombardo.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation: Marletta G, Lombardo A (2023) The Fucales (Ochrophyta, Phaeophyceae) of the Island of Pantelleria (Sicily Channel, Mediterranean Sea): a new contribution. Italian Botanist 15: 137-163. https://doi.org/10.3897/italianbotanist.15.103217
Open Access

Abstract

In the past, only a few studies were carried out on the marine vegetation of the Island of Pantelleria, reporting a high level of biodiversity in this island. However, the most recent study, performed about 20 years ago, documented a total loss of Fucales below ca. 12 m of depth and their substitution with morphologically simpler species. In the present study, the current presence and distribution of Cystoseira s.l. and Sargassum around the Island of Pantelleria were assessed, comparing the current data with the previous studies on the marine vegetation of this island. Through monitoring activities (both snorkelling and scuba diving), 19 taxa were recorded: seven belonging to Cystoseira, six to Ericaria, four to Gongolaria, and two to Sargassum. Comparing these data with the previous studies, it was highlighted that most of the species previously reported are still present on the island. Moreover, approximately 20 years after their documented disappearance, deep-water species such as C. foeniculacea f. latiramosa, G. elegans, G. montagnei, G. montagnei v. compressa and Sargassum cf. acinarium were recorded during this study, suggesting a natural recovery for these Fucales. We recommend that, in order to guarantee a long-term conservation of these fucalean populations, it would be useful to establish a marine protected area in the Island of Pantelleria.

Keywords

Biodiversity, brown algae, Cystoseira, Ericaria, Gongolaria, marine vegetation, Sargassum

Introduction

The Island of Pantelleria is located in the Sicily Strait, 55 nautical miles (approx. 88.5 km) from Cape Granitola (Italy) and 39 miles (approx. 62.8 km) from Cape Bon (Tunisia), with a surface area of 83 km² and a morphology derived mainly from ancient volcanic activities (Bianchi and Acri 2003). The island is located in the Pantelleria Rift, the deepest part of the Strait of Sicily, and has an irregular elliptical shape with the longest axis NW–SE (Paladino et al. 1935). This island can be subdivided into two geomorphologically distinct areas: the SE area is elevated above the sea surface, while the NW area is lowland and hilly (Paladino et al. 1935). The SE rocky shore consists of high, jagged cliffs, steeply sloping to depths of 30–40 m, into a bottom with large boulders interspersed with coarse sand or gravel (Alongi et al. 2004).

The current knowledge of the marine biology of the Island of Pantelleria is based on a few studies, focusing mostly on marine botany (Giaccone et al. 1972; Barone et al. 1978; Calvo and Sortino 1979), which revealed a high level of biodiversity of the marine biota (Bianchi and Acri 2003). The most recent study on the marine vegetation of this island was performed by Alongi et al. (2004), who documented a total disappearance of Cystoseira s.l. species and their replacement with morphologically simpler seaweeds, such as Dictyopteris polypodioides (De Candolle) J. V. Lamouroux, Halopteris scoparia (Linnaeus) Sauvageau and Womersleyella setacea (Hollenberg) R. E. Norris, at depths below ca. 12. Alongi et al. (2004) suggested that the reasons of this loss could be an increase in seawater temperature and changes in deep circulation pattern.

Despite the high value and vulnerability of Cystoseira sensu lato (i.e., genera Cystoseira C. Agardh, Ericaria Stackhouse and Gongolaria Boehmer) and Sargassum C. Agardh species, data on the distribution and conservation status of these Fucales are surprisingly limited and ecological analyses for many areas are still rare (Mancuso et al. 2018). Due to the massive decline of these taxa in many Mediterranean areas (Cormaci and Furnari 1999; Thibaut et al. 2005; Serio et al. 2006; Tsiamis et al. 2013; Thibaut et al. 2015; Catra et al. 2019), there is an urgent need to assess in detail the current species distributions and the stressors threatening them (Mulas et al. 2020), particularly in islands where there is typically a high level of endemism. This is the case, for example, for Ericaria sedoides Neiva & Serrão, an endemic species of the African coasts of Algeria and Tunisia and the Island of Pantelleria (Colombo et al. 1982; Bouafif et al. 2014). The Sicilian Channel represents the eastern limit of its range (Colombo et al. 1982; Boudouresque et al. 1996) thus representing a geographical limit. Its relatively restricted range and rarity make it a vulnerable species justifying measures for its protection (UNEP-MAP-RAC/SPA 2012).

In consideration of this, the aims of this study were to assess the current occurrence and distribution of Cystoseira s.l. and Sargassum species around the Island of Pantelleria, approximately 20 years after the latest study on the macrophytobenthos of the island, comparing the current data with those of previous studies.

Methods

During the first week of July 2022, a monitoring activity was carried out around the Island of Pantelleria. In particular, eleven sites were examined, covering all sides of the island: Bue Marino, Kattibuale, Punta Spadillo, Gadir, Cala Tramontana, Cala Levante, Martingana, Scauri, Grotte Sataria, Kuddie Rosse and Arenella (Fig. 1). In the sites of Punta Spadillo, Cala Tramontana and Cala Levante, a total of four scuba dives (each of an average duration of one hour) was performed. The other sites were visually inspected by snorkelling (see Table 1). Unfortunately, it was not possible to carry out further scuba dives, due to adverse marine conditions.

Fucalean species were identified in situ and photographed using two underwater cameras Olympus TG-6 and TG-4. When species examination was impossible to obtain in the field, a few fragments of thalli (subsequently stored in the private collection of G.M.) were collected and identified in the laboratory according to Gómez-Garreta et al. (2001), Cormaci et al. (2012), Rodríguez-Prieto et al. (2013) and Blanfuné et al. (2022).

Figure 1. 

Island of Pantelleria A location of the island in the Mediterranean Sea B sites of the island investigated during this study.

Table 1.
Download as
CSV
XLSX

Detail of study sites, including GPS coordinates, dates and survey activities conducted during this study.

Site Coordinates Activity Date
Bue Marino 36°50.5'N, 11°57.55'E snorkelling 3rd July
Kattibuale 36°49.356'N, 11°59.436'E snorkelling 4th July
Punta Spadillo 36°49.473'N, 12°0.843'E scuba diving 4th July–5th July
Gadir 36°49.133'N, 12°1.9'E snorkelling 5th July
Cala Tramontana 36°48.015'N, 12°2.943'E scuba diving 4th July
Cala Levante 36°47.931'N, 12°3.163'E scuba diving 5th July
Martingana 36°44.838'N, 12°2.676'E snorkelling 8th July
Scauri 36°46.5'N, 11°57.15'E snorkelling 9th July
Grotte Sataria 36°46.133'N, 11°57.25'E snorkelling 7th July
Kuddie Rosse 36°48.908'N, 11°55.581'E snorkelling 6th July
Arenella 36°49.77'N, 11°55.97'E snorkelling 7th July

Results

During the monitoring activities, a total of 19 taxa was found: seven belonging to Cystoseira, six to Ericaria, four to Gongolaria, and finally two to Sargassum. The species and the sites where they were found are reported in Table 2.

Comparing our data with those previously reported by Giaccone et al. (1972), it is possible to note that 10 of the 18 fucalean species reported by these authors were also found during our monitoring activities (Table 3). On the contrary, the following taxa have not been observed: Cystoseira platyclada Sauvageau, Ericaria zosteroides (C. Agardh) Molinari & Guiry, Cystoseira jabukae Ercegovic, Cystoseira humilis Schousboe ex Kützing, Gongolaria sauvageauana (Hamel) Molinari & Guiry, Cystoseira crinitophylla Ercegovic, Sargassum trichocarpum J. Agardh and Sargassum hornschuchii C. Agardh.

Compared to the study by Alongi et al. (2004), only C. humilis was not recorded, while the other seven species identified by these authors were also found by us (Table 3).

Table 2.
Download as
CSV
XLSX

List of the species with their sampling depth found during the monitoring activity in the study sites: BM = Bue Marino; Kat = Kattibuale; PSpad = Punta Spadillo; Ga = Gadir; CTram = Cala Tramontana; CLev = Cala Levante; Mar = Martingana; Sca = Scauri; GSat = Grotte Sataria; KR = Kuddie Rosse; Ar = Arenella.

Taxa BM Kat PSpad Ga CTram CLev Mar Sca GSat KR Ar
Range of depth 0–1 m 0–1 m 0–48 m 0–1 m 0–30 m 0–35 m 0–3 m 0–1 m 0–1 m 0–1 m 0–3 m
Cystoseira compressa 0–1 m 0–1 m 0–6 m 0–1 m 0–3 m 0–5 m 0–1 m 0–1 m 0–1 m 0–1 m 0–1 m
Cystoseira compressa f. plana 0.2–1 m 0.5–1 m
Cystoseira compressa f. rosetta 0–0.5 m 0–1 m 0–0.5 m 0–1 m 0–0.5 m 0–0.5 m 0–1 m
Cystoseira pustulata 1–12 m 1–7 m 1–6 m 1–2 m 1 m
Cystoseira foeniculacea 0.5–1 m 0.5–1 m
Cystoseira foeniculacea f. latiramosa 20–30 m 18–22 m
Cystoseira foeniculacea f. tenuiramosa 8–10 m
Ericaria amentacea 0–0.2 m 0–0.2 m 0–0.2 m 0–0.2 m 0–0.2 m 0–0.2 m 0–0.2 m 0–0.2 m 0–0.2 m
Ericaria barbatula 0.5–1 m 0.5–1 m 0.5–2 m 0.5–1 m 0.5–1 m 0.5–3 m
Ericaria balearica 0.5–1 m 0.5–25 m 0.5–22 m 0.5–28 m 0.5–1 m 0.5–1 m 0.5–1 m
Ericaria cf. dubia 40 m 35 m
Ericaria crinita 1–3 m 0.5–2 m
Ericaria sedoides 0–1 m 0–1 m 0–1 m
Gongolaria barbata 0.5–1 m 1–2 m
Gongolaria elegans 1 m 1–15 m 1 m 1–8 m 1–12 m 1–3 m 1 m 1–3 m
Gongolaria montagnei 12–20 m 8–15 m 17–22 m
Gongolaria montagnei var. compressa 28–35 m 26–30 m 33–35 m
Sargassum cf. acinarium 30–45 m 28–30 m 32–35 m
Sargassum vulgare 1 m 1 m 1–25 m 1 m 1–16 m 1–18 m 1–3 m 1 m 1 m 1 m 1–3 m
Table 3.
Download as
CSV
XLSX

Comparison of records of fucalean taxa obtained in this study with previous studies. x indicates that the species was reported previously; – indicates that the species was not reported; ? means that that the authors only indicated the genus.

Taxa Giaccone et al. 1972 Alongi et al. 2004
Cystoseira compressa x x
Cystoseira compressa f. plana – –
Cystoseira compressa f. rosetta – –
Cystoseira pustulata – –
Cystoseira foeniculacea – –
Cystoseira foeniculacea f. latiramosa x –
Cystoseira foeniculacea f. tenuiramosa x x
Ericaria amentacea x x
Ericaria barbatula – x
Ericaria balearica – x
Ericaria cf. dubia – –
Ericaria crinita x –
Ericaria sedoides x x
Gongolaria barbata – –
Gongolaria elegans x –
Gongolaria montagnei x –
Gongolaria montagnei var. compressa – x
Sargassum cf. acinarium x ?
Sargassum vulgare x ?

For each species found during this study, we report below relevant information, including taxonomic and nomenclatural information (Basionym, Synonyms, Description, Habitat, Distribution, Remarks). The validity of the species names was checked by consulting Algaebase (Guiry and Guiry 2023).

Cystoseira compressa (Esper) Gerloff & Nizamuddin

Fig. 2A, B

Fucus compressus Esper, 1799. Basionym.

Cystoseira filicina Bory, Cystoseira abrotanifolia f. fimbriata Sauvageau, Fucus fimbriatus Desfontaines, 1799, Cystoseira fimbriata Bory, 1832. Synonyms.

Morphology of specimens from Pantelleria

This species is caespitose, attached to the substrate by a small discoid holdfast, from which several axes, both flattened and cylindrical, are issued, all devoid of spiniform appendages. The apices are tiny, smooth and not sharply protruding. Primary branches are generally flattened at the base, whereas they tend to be cylindrical at the apical parts. They are arranged distichously and alternating. Higher order branches can be flattened or cylindrical. In very sheltered environments this species shows numerous large isolate or grouped aerocysts. During the monitoring activities, this species was found fertile. Tiny lanceolate-fusiform receptacles are occurred in the terminal parts of branches. They were simple or branched and were located at the top of an aerocyst, to which they were connected by a small pedicel.

Habitat

C. compressa was found in all the inspected sites of the Island of Pantelleria, both during scuba dives and snorkelling activities. It was observed in the upper and middle infralittoral (from 0 to 6 m depth).

Distribution

This species is distributed in both the Atlantic Ocean (Nord-West Atlantic, Bermuda Islands and Nord-East Atlantic, from the Azores to Cape Verde) and Mediterranean Sea (Blanfuné et al. 2022).

Remarks

This species is quite common along the coasts of the island, where it is usually vicariant of E. amentacea.

Figure 2. 

Cystoseira compressa A habit B detail of flattened branches with distichous-alternate disposal.

Cystoseira compressa f. plana (Ercegovic) Cormaci, G. Furnari, Giaccone, Scammacca & D. Serio

Fig. 3A, B

Cystoseira abrotanifolia subsp. plana Ercegovic. Basionym.

Morphology of specimens from Pantelleria

This form is caespitose with a pyramidal shape, attached to the substrate by a discoid holdfast. The apices are smooth and not very protruding. All branches are flattened and arranged in a single plane with a distichous and pinnate disposal. They are crossed by a slightly protruding midrib, which is bordered by cryptostomata. During the monitoring activities, the thalli of this form were found reproductive. The receptacles are carried on terminal branches and are branched in a single plane.

Habitat

C. compressa f. plana was observed at Bue Marino and Martingana in shallow (0.2–1 m) and sheltered waters.

Distribution

This form has been recorded for Sicily, Adriatic Sea, Cyprus, Spain, Greece, Tunisia and Turkey (Blanfuné et al. 2022).

Figure 3. 

Cystoseira compressa f. plana A habit B detail of receptacles.

Cystoseira compressa f. rosetta (Ercegovic) Cormaci, G. Furnari, Giaccone, B. Scammacca & Serio

Fig. 4A, B

Cystoseira compressa subsp. rosetta Ercegovic. Basionym.

Cystoseira compressa subsp. rosetta Ercegovic. Synonym.

Morphology of specimens from Pantelleria

This form is cespitose, with flattened habit, forming a rosette. It is attached to the substate by a small discoid holdfast. The apices are smooth. Primary branches are short (1–4 cm), strongly flattened and foliaceous. They are usually crossed by brownish transversal stripes. The branches are arranged with a distichous and alternating disposal. The cryptostomata are not very prominent and are disposed on longitudinal series. During the monitoring activity, we did not find fertile thalli of this form.

Habitat

C. compressa f. rosetta occurred on wave-exposed coasts at Kattibuale, Gadir, Cala Tramontana, Martingana, Grotte Sataria, Kuddie Rosse and Arenella, in the upper infralittoral (0–1 m).

Distribution

It is distributed in the whole Mediterranean Sea and along the North-West Atlantic, Bermudas Islands and East Atlantic, from Azores to Cape Verde (Blanfuné et al. 2022).

Remarks

During the monitoring, thalli of this form were found isolated in shaded habitats, such as in small crevices between rocks.

Figure 4. 

Cystoseira compressa f. rosetta A habit (the arrow indicates the thallus) B detail of primary branches with brownish transverse bands and cryptostomata disposed in longitudinal series.

Cystoseira pustulata (Ercegovic) Neiva & Serrão

Fig. 5A–C

Cystoseira abrotanifolia subsp. pustulata Ercegovic. Basionym.

Cystoseira compressa subsp. pustulata (Ercegovic) Verlaque. Synonym.

Morphology of specimens from Pantelleria

C. pustulata is a caespitose species, attached to the substrate with a small discoid holdfast. It has smooth apices, and cylindrical, thin and short axes. Primary branches are compressed, almost at the base, while higher order branches are cylindrical and always slender. This species bears protruding cryptostomata, which give it a pustulate habit. During the monitoring, this species was found fertile. The receptacles were borne in the terminal portions of the branches, fusiform in shape, isolated or rarely bifurcated.

Habitat

This species was found at Punta Spadillo, Cala Tramontana, Cala Levante, Martingana and Kuddie Rosse. It was detected during both snorkelling surveys and scuba dives, from the upper to the middle infralittoral (from 1 to 12 m depth).

Distribution

According to Neiva et al. (2022), who recently elevated it to species rank, C. pustulata is distributed in the Azores, Canary Islands, Spain, Italy, Malta and Greece.

Remarks

Some authors previously considered this species conspecific with C. humilis Schousboe ex Kützing. However, Neiva et al. (2022) demonstrated that C. pustulata is an independent species and reported it for Pantelleria. Therefore, we believe that the past records of C. humilis by Giaccone et al. (1972) and Alongi et al. (2004) might actually refer to this new taxon.

Figure 5. 

Cystoseira pustulata A, B habit C detail of receptacles.

Cystoseira foeniculacea (Linnaeus) Greville

Fig. 6A–D

Fucus foeniculaceus Linnaeus. Basionym.

Cystoseira abrotanifolia (Linnaeus) C. Agardh, C. concatenata (Linnaeus) C. Agardh, C. discors (Linnaeus) C. Agardh, C. ercegovicii Giaccone, Fucus abrotanifolius Linnaeus, F. barbatus Linnaeus, F. concatenatus Linnaeus, F. discors Linnaeus, Phyllacantha concatenata (Linnaeus) Kützing. Synonyms.

Morphology of specimens from Pantelleria

C. foeniculacea is a caespitose species, with numerous axes that originate from an irregular discoid holdfast. The axes bear numerous small protuberances that give them a knotty habit. The apices are spinose and not sharply protruding. Axes can be flattened and branched distichously. Secondary branches can be flattened or cylindrical. Higher order branches are filiform, divaricate, alternating in several planes. During the monitoring activity, this species was not reproductive.

Habitat

This species was found in shallow (0.5–1 m) and sheltered habitats (as rock pools) partially covered by coarse gravel and cobbles at Kuddie Rosse and Cala Levante.

Distribution

The species is widely distributed in the Mediterranean Sea and occurs also in the Atlantic Ocean, from Scotland to Cape Verde (Blanfuné et al. 2022).

Figure 6. 

Cystoseira foeniculacea A, B habit C, D detail of axes with distichous branching.

Cystoseira foeniculacea f. latiramosa (Ercegovic) A. Gómez Garreta, M. C. Barceló, M. A. Ribera & J. R. Lluch

Fig. 7A, B

Cystoseira discors subsp. latiramosa Ercegovic. Basionym.

Cystoseira ercegovicii f. latiramosa (Ercegovic) Giaccone, Cystoseira schiffneri f. latiramosa (Ercegovic) Giaccone. Synonyms.

Morphology of specimens from Pantelleria

This form is caespitose, attached to the substrate by an irregular discoid holdfast, from which cylindrical and knotty axes originate. The apices of axes are spinose. All branches are flattened, with a central midrib and toothed margins. Branching is sparse and distichous-alternate. During the monitoring activities, this species was found fertile. The receptacles are apical, lanceolate-fusiform, briefly pedicellate, isolated or branched.

Habitat

C. foeniculacea f. latiramosa was observed during scuba dives at Punta Spadillo and Cala Tramontana, in deep waters (from 18 to ca. 30 m of depth).

Distribution

This form has been reported from Spain, Corsica, Tunisia, Malta, Italy, Adriatic, Greece, Cyprus and Turkey (Blanfuné et al. 2022).

Remarks

C. foeniculacea f. latiramosa is considered a rare seaweed in phase of regression (Rodríguez-Prieto et al. 2013), due to its distribution in deep environments, which are nowadays particularly subjected to trawling, pollution, deposition of marine litter, over-sedimentation, and competition with invasive alien species. Therefore, the record of this species in the waters of the Island of Pantelleria is particularly interesting and should receive special attention.

Figure 7. 

Cystoseira foeniculacea f. latiramosa A, B habit with knotty axes and flattened and distichous-alternate branching.

Cystoseira foeniculacea f. tenuiramosa (Ercegovic) A. Gómez Garreta, M. C. Barceló, M. A. Ribera & J. Rull Lluch

Fig. 8A, B

Cystoseira discors f. tenuiramosa Ercegovic. Basionym.

Cystoseira ercegovicii f. tenuiramosa (Ercegović) Giaccone, Cystoseira schiffneri f. tenuiramosa (Ercegović) Giaccone. Synonyms.

Morphology of specimens from Pantelleria

C. foeniculacea f. tenuiramosa is caespitose, fixed to the substrate by a discoid holdfast from which several cylindrical axes originate. The apices are prominent and spinose. Primary branches are cylindrical, sometimes compressed, and knotty. Higher order branches are filiform, cylindrical and without spinose appendages.

Habitat

During the monitoring activities, this form was only observed at Cala Levante at 8–10 m depth.

Distribution

This form is distributed both in the Atlantic Ocean (Canary Islands) and in the Mediterranean Sea (Adriatic, Balearic Islands, Cyprus, Spain, France, Greece, Italy, Tunisia and Turkey) (Blanfuné et al. 2022).

Figure 8. 

Cystoseira foeniculacea f. tenuiramosa A habit B detail of a prominent and spinose apex.

Ericaria amentacea (C. Agardh) Molinari & Guiry

Fig. 9A–C

Cystoseira ericoides var. amentacea C. Agardh. Basionym.

Cystoseira stricta var. amentacea (Bory) Giaccone, Halerica amentacea (C. Agardh) Kützing, Carpodesmia amentacea (C. Agardh) Orellana & Sansón. Synonyms.

Morphology of specimens from Pantelleria

E. amentacea is a caespitose species, fixed to the substrate by a robust crustose holdfast. In situ it shows a blue-violet iridescence, especially near the apices and young branchlets. The apices are spinose and not very prominent. The axes are cylindrical and short. All branches are covered by simple or bifid spinose appendages. During the monitoring activities, this species was found fertile. Receptacles are compact, terminal and spinose, with conceptacles present at the base of each spinose appendage.

Habitat

During the monitoring, this species was observed forming a continuous belt in the infralittoral fringe along exposed and semi-exposed coasts at Bue Marino, Punta Spadillo, Gadir, Cala Tramontana, Martingana, Scauri, Grotte Sataria, Kuddie Rosse and Arenella.

Distribution

According to Neiva et al. (2022), this entity falls within the Ericaria selaginoides complex haplogroup A, which is distributed in the Atlantic, south-eastern Iberian Peninsula, Balearic Islands and the Island of Pantelleria.

Remarks

Comparing the distribution reported by Alongi et al. (2004) with our data, the distribution of this species appears to have remained almost stable at the investigated sites.

Figure 9. 

Ericaria amentacea A, B habit C branches with fertile receptacles.

Ericaria barbatula (Kützing) Molinari & Guiry

Fig. 10A, B, C, D

Cystoseira barbatula Kützing. Basionym.

Cystoseira graeca Schiffner ex Gerloff & Nizamuddin, Carpodesmia barbatula (Kützing) Orellana & Sansón. Synonyms.

Morphology of specimens from Pantelleria

E. barbatula is caespitose, attached to the substrate by an irregular basal disc, from which several cylindrical, thin and blackish axes take origin. The axes are tuberculate for the presence of basal stumps of the fallen primary branches. The apices are strongly prominent and smooth. Primary and higher order branches are cylindrical. During the monitoring activities, this species was found fertile. The receptacles are borne on the apical parts of branchlets and are compact, tuberculate; they can bear 1–2 spinose appendages.

Habitat

E. barbatula was observed during snorkelling in shallow environments (from 0.5 to 3 m of depth) along sheltered and moderately exposed coasts at Bue Marino, Kattibuale, Martingana, Scauri, Kuddie Rosse and Arenella.

Distribution

Cyprus, Greece, Libya, Malta, Italy and Tunisia (Blanfuné et al. 2022).

Remarks

Comparing our data with the study by Alongi et al. (2004), this species appears to have expanded its distribution along the island since then. According to Neiva et al. (2022), this entity falls in the Ericaria crinita complex, which includes samples identified as E. crinita, E. barbatula and E. giacconei D. Serio & G. Furnari.

Figure 10. 

Ericaria barbatula A branches with fertile receptacles) B habit C, D prominent and smooth apex.

Ericaria balearica (Sauvageau) Neiva, Ballesteros & Serrão

Fig. 11A–D

Cystoseira balearica Sauvageau. Basionym.

Cystoseira brachycarpa var. balearica (Sauvageau) Giaccone. Synonyms.

Morphology of specimens from Pantelleria

This species is caespitose, with an irregular, spreading holdfast, from which several axes are issued. The axes are cylindrical and knotty due to the presence of basal stumps of the fallen branches. This species shows a dark blue-green iridescence in situ, especially in the apical parts of branchlets. The apices are not prominent and bear spinose appendages. Primary branches are cylindrical and are spinose only in the basal parts. Higher order branches are cylindrical as well, but they are not spinose. During the monitoring activities, this species was not reproductive.

Habitat

E. balearica was observed during both scuba dives and snorkelling activities at Bue Marino, Punta Spadillo, Cala Tramontana, Cala Levante, Scauri, Grotte Sataria, Kuddie Rosse. In the Island of Pantelleria it is widely distributed from the upper to the lower infralittoral (from 0.5 to 28 m of depth).

Distribution

According to Neiva et al. (2022), this species is distributed in the Balearic Sea and the Island of Pantelleria.

Remarks

This species was reported from the island by Alongi et al. (2004) as Cystoseira brachycarpa J. Agardh. Recently, Neiva et al. (2022) concluded that E. brachycarpa (J. Agardh) Molinari & Guiry and E. balearica are two cryptic species with different biogeographical distribution.

Figure 11. 

Ericaria balearica A, B habit C, D detail of not prominent apices with spinose appendages.

Ericaria cf. dubia (Valiante) Neiva & Serrão

Fig. 12A–C

Cystoseira dubia Valiante. Basionym.

Morphology of specimens from Pantelleria

In the examined specimens, the holdfast could not be observed in detail because it was sunken in coarse gravel. The axes are creeping on the substrate and issue on the upper side erect primary branches in which two portions can be recognized: a cylindrical basal one and a flattened and ribbon-like upper one. Primary branches are distichous, without spinose appendages, with an entire margin and an evident midrib. During the monitoring this species was not found reproductive.

Habitat

Ericaria cf. dubia was observed during scuba dives at Punta Spadillo and Cala Levante, at 40 and 35 m depth, respectively.

Distribution

This species is distributed in the Adriatic Sea, Greece, Italy, Syria, Tunisia, Turkey and Middle East (Blanfuné et al. 2022).

Remarks

The identification at species level was not certain because we did not manage to observe the holdfast, apex and receptacles of this entity.

Figure 12. 

Ericaria cf. dubia A, B habit C detail of flattened branches with distichous disposal and an evident midrib.

Ericaria crinita (Duby) Molinari & Guiry

Fig. 13A–C

Cystoseira crinita Duby. Basionym.

Cystoseira granulata Schousboe, Fucus crinitus Desfontaines, Carpodesmia crinita (Duby) Orellana & Sansón. Synonyms.

Morphology of specimens from Pantelleria

E. crinita is a caespitose species, adhering to the substrate by an irregular discoid holdfast, from which several cylindrical and knotted axes are issued. The apices are protruding and covered by spinose appendages. Primary branches are cylindrical, with a pyramidal habit. Higher order branches are cylindrical, thin, more or less twisted and usually devoid of spines. During the monitoring activities, this species was found fertile. Receptacles are borne on terminal branchlets; they are compact, cylindrical, swollen, single or once branched, usually without spiny appendages.

Habitat

This species was observed during snorkelling activities at Martingana and Arenella, in shallow (0.5–3 m) and sheltered habitats.

Distribution

This species is widespread in the Mediterranean Sea and Canary Islands (Blanfuné et al. 2022).

Remarks

This species was found by Giaccone et al. (1972) in several sites of the island. Subsequently, it was not reported by Alongi et al. (2004). Our record seems to suggest that E. crinita might be in a phase of recovery and expansion on the island. According to Neiva et al. (2022), this entity is part of the Ericaria crinita complex, which includes samples identified as E. crinita, E. barbatula and E. giacconei.

Figure 13. 

Ericaria crinita A habit B detail of receptacles C detail of prominent apex with spinose appendages.

Ericaria sedoides Neiva & Serrão

Fig. 14A–C

Fucus sedoides Desfontaines. Basionym.

Fucus ericoides var. sedoides Turner, Cystoseira sedoides C. Agardh. Synonyms.

Morphology of specimens from Pantelleria

E. sedoides is a non-caespitose species, adhering to the substrate by a discoid holdfast from which a single cylindrical, trunk-like axis originates. This species is easily recognized by its typical brush-like habit. The axis is very thick and usually poorly branched. The apex is not very prominent and usually is covered by branches that form a compact terminal rosette. All branches are covered by spinose appendages, which are slender, bifid and uniformly distributed along the branches. Primary branches are short (1–3 cm) and their attachment is perpendicular to the main axis. Secondary branches are usually simple and do not reach the top of primary branches. During the monitoring activities, this species was not found fertile.

Habitat

This species was observed during snorkelling activities in the upper infralittoral (0–1 m) along semi-exposed and exposed coasts at Bue Marino, Kuddie Rosse and Arenella.

Distribution

E. sedoides is endemic to Algeria, Tunisia and the Island of Pantelleria (Blanfuné et al. 2022).

Figure 14. 

Ericaria sedoides A, B habit C not prominent apex, covered by the branches.

Gongolaria barbata (Stackhouse) Kuntze

Fig. 15A–D

Abrotanifolia barbata Stackhouse. Basionym.

Cystoseira barbata var. hoppei (C. Agardh) J. Agardh, Cystoseira barbata f. hoppei (C. Agardh) Woronichin, Cystoseira hoppei C. Agardh, Fucus barbatus Goodenough & Woodward, Treptacantha barbata (Stackhouse) Orellana & Sansón. Synonyms.

Morphology of specimens from Pantelleria

G. barbata is a non-caespitose species, attached to the substrate by a small discoid holdfast, from which a single trunk-like, cylindrical axis is issued. The apex is smooth and prominent, protruding above the insertion of primary branches. These are cylindrical, while higher order branches are filiform and can bear aerocysts, either isolated or in chains. During the monitoring activities, this species was found fertile. Receptacles are borne on terminal branchlets, are compact, single, cylindrical-lanceolate or spindle-shaped, sometimes with a terminal spine, and pedicellate when they grow over an aerocyst.

Habitat

During the monitoring activities, this species was observed in the upper infralittoral (0.5–2 m) in sheltered habitats (such as rock pools) at Kuddie Rosse and Arenella.

Distribution

G. barbata is widely distributed in the Mediterranean Sea, and it also known from the Atlantic Ocean, in the Canary Islands and Savage Islands (Blanfuné et al. 2022).

Remarks

This species had not been reported from the island before.

Figure 15. 

Gongolaria barbata A habit B detail of aerocysts surmounted by receptacles C detail of spindle-shaped receptacles D Detail of prominent and smooth apex.

Gongolaria elegans (Sauvageau) Molinari & Guiry

Fig. 16A–C

Cystoseira elegans Sauvageau. Basionym.

Treptacantha elegans (Sauvageau) Orellana & Sansón. Synonyms.

Morphology of specimens from Pantelleria

G. elegans is a non-caespitose species, attached to the substrate by a robust discoid holdfast. The axis is short, trunk-like and cylindrical, not or poorly branched. The apex is spinose and not prominent. With the surrounding tips of primary branches, usually it forms a typical spinose rosette. Primary branches are cylindrical and bare in their basal parts. Higher order branches are cylindrical and covered with bifid spinose appendages. This species bears spinose and ovoid tophules, grouped along the axis. During the monitoring activities, this species was not found fertile.

Habitat

G. elegans was observed during both snorkelling activities and scuba dives, from the upper to the middle infralittoral (from 1 to 15 m) in moderately exposed/exposed waters at Kattibuale, Punta Spadillo, Gadir, Cala Tramontana, Cala Levante, Martingana, Kuddie Rosse and Arenella.

Distribution

This species is distributed in Spain, France, Morocco, Algeria, Tunisia, Italy, Adriatic, Greece, Cyprus and Turkey (Blanfuné et al. 2022).

Remarks

This species was found by Giaccone et al. (1972), but Alongi et al. (2004) did not record it. Our record suggests that G. elegans might be in phase of expansion on the island.

Figure 16. 

Gongolaria elegans A, B habit C detail of the apex surrounded by the buds of primary branches, which form a wide spinose rosette.

Gongolaria montagnei (J.Agardh) Kuntze

Fig. 17A–C

Cystoseira montagnei J. Agardh. Basionym.

Cystoseira spinosa Sauvageau, Cystoseira adriatica Sauvageau, Phyllacantha montagnei (J. Agardh) Kützing, Treptacantha montagnei (J. Agardh) Orellana & Sansón, Treptacantha ballesterosii Orellana & Sansón. Synonyms.

Morphology of specimens from Pantelleria

G. montagnei is a non-caespitose species, fixed to the substrate by a robust discoid holdfast. The axis is trunk-like and cylindrical, unbranched or poorly branched. The apex is spinose and not prominent. Primary branches are cylindrical and bear numerous sparse bifid or multifid spinose appendages. Secondary branches are shorter and less branched, with divaricate and bifid spinose appendages. This species has oblong and spinose tophules. During scuba dives, we observed new primary branches arising from tophules. During the monitoring activities, this species was not found fertile.

Habitat

This species was observed during scuba dives at Punta Spadillo, Cala Levante and Cala Tramontana, in the middle-lower infralittoral (from 8 down to a depth of 22 m).

Distribution

G. montagnei is widely distributed in the Mediterranean Sea (Blanfuné et al. 2022).

Figure 17. 

Gongolaria montagnei A habit B detail of not prominent and spinose apex C preliminary appearance of new primary branches from tophules.

Gongolaria montagnei var. compressa (Ercegovic) Verlaque, Blanfuné, Boudouresque & Thibaut

Fig. 18A–C

Cystoseira adriatica subsp. compressa Ercegovic. Basionym.

Cystoseira adriatica subsp. compressa Ercegovic, Cystoseira platyramosa Ercegovic, Cystoseira adriatica subsp. intermedia Ercegovic, Cystoseira adriatica var. intermedia (Ercegovic) Giaccone, Cystoseira spinosa var. compressa (Ercegovic) Cormaci, G. Furnari, Giaccone, Scammacca & D. Serio, Cystoseira montagnei var. compressa (Ercegovic) M. Verlaque, Blanfuné, Boudouresque, Thibaut & Sellam. Synonyms.

Morphology of specimens from Pantelleria

This form is non-caespitose, adhering to the substrate by a discoid holdfast. The axis is trunk-like, simple, and usually shorter than in the autonymous form. All branches are flattened, with an alternate arrangement. They have serrated edges and a midrib. Spinose appendages can be present in the apical parts of secondary branches. The tophules are borne near the base of the axis, oblong and spinose. During the monitoring activities, this form was not found fertile.

Habitat

G. montagnei var. compressa was observed during scuba dives at Punta Spadillo, Cala Levante and Cala Tramontana. In these sites, it grows in the lower infralittoral/circalittoral (from ca. 26 to 35 m of depth), on bottoms largely covered by detritus and subject to unidirectional currents.

Distribution

G. montagnei var. compressa is known from Spain, France, Italy, Adriatic, Greece, Libya and Turkey (Blanfuné et al. 2022).

Remarks

This seaweed was reported by Alongi et al. (2004) with a very limited coverage at Cala Levante. Therefore, it might currently be in a phase of increase.

Figure 18. 

Gongolaria montagnei var. compressa A habit B flattened branches with midrib C detail of spinose tophules.

Sargassum cf. acinarium (Linnaeus) Setchell

Fig. 19A, B

Fucus acinarius Linnaeus. Basionym.

Fucus acinarius S. G. Gmelin, Fucus linariifolius Turner, Fucus linifolius Turner, Sargassum linifolium C. Agardh, Sargassum linifolium f. gibraltica Grunow, Sargassum vulgare var. linifolium (C. Agardh) Zanardini. Synonyms.

Morphology of specimens from Pantelleria

Sargassum cf. acinarium is attached to the substrate by small discoid holdfast. Primary branches are cylindrical and knotty. Foliaceous branches are narrow (ca. 0.5–1 cm) with an evident midrib, acute apex and denticulate or entire margin. This species has spherical aerocysts with a cylindrical pedicel. During the monitoring, some specimens showed receptacles.

Habitat

S. cf. acinarium was observed during scuba dives at Punta Spadillo, Cala Tramontana and Cala Levante, in the lower infralittoral/circalittoral (from 28 to 45 m).

Distribution

This seaweed is distributed in the north-western Atlantic (from Spain to Guinea-Bissau) and in the Mediterranen Sea (Blanfuné et al. 2022).

Remarks

The identification at species level was not certain because it was not possible to collect the receptacles of this entity.

Figure 19. 

Sargassum cf. acinarium A habit B narrow foliaceous branches with an evident midrib.

Sargassum vulgare C. Agardh

Fig. 20A–C

Sargassum vulgare C. Agardh, nom. illeg. Basionym.

Fucus salicifolius S. G. Gmelin, Sargassum megalophyllum Montagne, Sargassum coarctatum Kützing, Sargassum vulgare var. megalophyllum (Montagne) Vickers. Synonyms.

Morphology of specimens from Pantelleria

S. vulgare is attached to the substrate by a small discoid holdfast. The axis is cylindrical and short. Primary branches are cylindrical and smooth or knotty, bearing sparse secondary branches with distichous-alternate arrangement. Foliaceous branches are abundant, lanceolate, with an evident midrib and serrate or wavy margins. The aerocysts are spherical, with a short cylindrical or flattened pedicel. During the monitoring this species was found fertile. The receptacles are fusiform or warty, simple or bifid, borne at the top of a short sterile, cylindrical and branched pedicel.

Habitat

S. vulgare was observed both during the snorkelling activities and scuba dives in all examined sites, from the upper infralittoral to the lower infralittoral (from 1 to 25 m) and in both sheltered and wave-exposed habitats.

Distribution

S. vulgare is widely distributed in the Atlantic Ocean and in the Mediterranean Sea (Blanfuné et al. 2022).

Remarks

Together with C. compressa and E. amentacea, this species was among the most common fucalean seaweeds along the coasts of the island.

Figure 20. 

Sargassum vulgare A, B habit C detail of warty receptacles on a short pedicel.

Discussion

The present study allowed to provide an assessment of the current presence and distribution of Cystoseira s.l. and Sargassum species along the Island of Pantelleria, approximately 20 years after the most recent study on the marine flora of this island. The monitoring activities unraveled the occurrence of 19 taxa: seven belonging to Cystoseira, six to Ericaria, four to Gongolaria, and two to Sargassum. Unfortunately, due to the adverse sea conditions it was possible to carry out only a low number of scuba dives, thus this did not enable us to make a more accurate identification of Sargassum cf. acinarium and Ericaria cf. dubia. Moreover, the recent taxonomic and biogeographic revision of Cystoseira s.l. species demonstrated the necessity to combine morphological studies with genetic analyses, to reveal the possible existence of new entities or cryptic species (Neiva et al. 2022). This is the case of C. pustulata, which had previously been identified by some authors as C. humilis, but Neiva et al. (2022) highlighted that these are two separate species with well-defined and distinct biogeographical ranges. Neiva et al. (2022) analysed genetically many samples from the island of Pantelleria, but for other taxa additional studies based on molecular analyses should be carried out in the near future.

Comparing these data with the previous studies by Giaccone et al. (1972) and Alongi et al. (2004), we can confirm that most of the species found by these authors are still present on the island. However, we observed an important difference among the species reported by Giaccone et al. (1972) and those found by Alongi et al. (2004). Indeed, Alongi et al. (2004) did not record some lower infralittoral/circalittoral species documented by Giaccone et al. (1972). In this study, deep-water species such as C. foeniculacea f. latiramosa, G. elegans, G. montagnei, G. montagnei v. compressa and Sargassum cf. acinarium were detected again about fifty years after the study of Giaccone et al. (1972). Moreover, we noted the presence of Ericaria cf. dubia, a species previously not documented for Pantelleria. This might indicate a possible natural recovery trend for these Fucales in the island, similar to what was observed at the Medes MPA (Spain) and at Ustica MPA (Italy), where there was a gradual recovery of Cystoseira s.l. populations at ca. 10–20 years after their disappearance (Bonaviri et al. 2009; Hereu and Quintana 2012; Sala et al. 2012). As suggested by Gianni et al. (2013), this progressive recolonization can happen thanks to the existence of fragmented reproductive populations in scattered refuge areas, even if at low densities. Therefore, it is likely that over the years it has occurred a gradual expansion of residual populations, survived in refuge sites in the Island of Pantelleria, which could be overlooked in previous surveys.

These deep species could be seriously impacted by the intense fishing activity carried out around the island, which could harm the populations through trawling or anchoring. Therefore, to guarantee a long-term conservation of these fucalean species, it would be helpful to establish a marine protected area in the Island of Pantelleria. Indeed, the marine environment of this island is currently not subjected to any kind of environmental protection, although a proposal to establish a marine protected area was forwarded approximately 20 years ago (Picchetti et al. 2010).

Recently, we (Lombardo and Marletta 2023) also reported a high potential diversity of marine Heterobranchia in the waters of Pantelleria. Therefore, we argue that it would be recommendable to establish a zonation of the island and regulate the anthropic activities, in order to preserve the high biodiversity of the Island of Pantelleria.

Acknowledgements

The authors wish to thank Prof. Fabio Rindi for his interesting and valuable comments and suggestions.

References

  • Alongi G, Catra M, Cormaci M, Furnari G, Serio D (2004) Spring marine vegetation on rocky substrata of Pantelleria Island (the Straits of Sicily, Italy). Nova Hedwigia 79(3–4): 447–478. https://doi.org/10.1127/0029-5035/2004/0079-0447
  • Bianchi F, Acri F (2003) The Island of Pantelleria (Sicily Strait, Italy): towards the establishment of a marine protected area. First oceanographic investigations. Bollettino di Geofisica Teorica ed Applicata 44(1): 3–9.
  • Blanfuné A, Verlaque M, Boudouresque CF, Rozis E, Thibaut T (2022) Les forêts marines de France et de Méditerranée. Guide de détermination des espèces-ingénieurs. Sargassaceae, Fucales, Phaeophyceae. Presses Universitaries de Provence, 207 pp.
  • Bonaviri C, Fernández TV, Badalamenti F, Gianguzza P, Di Lorenzo M, Riggio S (2009) Fish versus starfish predation in controlling sea urchin populations in Mediterranean rocky shores. Marine Ecology Progress Series 382: 129–138. https://doi.org/10.3354/meps07976
  • Bouafif C, Ouerghi A, Langar H (2014) Cystoseira sedoides (Desfontaines) C. Agardh des côtes Tunisiennes: état actuel des connaissances. In: Langar H, Bouafif C, Ouerghi A (Eds) Proceeding of the 5th Mediterranean Symposium on Marine Vegetation. UNEP/MAP – RAC/SPA, Portorož, 52–57.
  • Boudouresque CF, Beaubrun PC, Relini G, Templado J, Van Klaveren MC, Van Klaveren P, Walmsley JG, Zotier R (1996) Critères de sélection et liste révisée des espèces en danger et menacées (marines et saumâtres) en Méditerranée. GIS Posidonie, 73 pp.
  • Calvo S, Sortino M (1979) Tipologia e distribuzione della vegetazione sommersa del Porto di Pantelleria (Canale di Sicilia). Informatore Botanico Italiano 11: 189–195.
  • Catra M, Alongi G, Leonardi R, Negri MP, Sanfilippo R, Sciuto F, Serio D, Viola A, Rosso A (2019) Degradation of a photophilic algal community and its associated fauna from eastern Sicily (Mediterranean Sea). Mediterranean Marine Science 20(1): 74–89. https://doi.org/10.12681/mms.17765
  • Colombo P, Curcio MF, Giaccone G (1982) Biologia dello sviluppo di un endemismo mediterraneo del genere Cystoseira (Phaeophyceae, Fucales): Cystoseira sedoides C. Agardh. Naturalista Siciliano 6: 81–93.
  • Cormaci M, Furnari G (1999) Changes of the benthic algal flora of the Tremiti Islands (Southern Adriatic) Italy. In: Kain JM, Brown MT, Lahaye M (Eds) Sixteenth International Seaweed Symposium. Developments in Hydrobiology. Hydrobiologia, Springer, Dordrecht, 398/399, 75–79. https://doi.org/10.1007/978-94-011-4449-0_9
  • Cormaci M, Furnari G, Catra M, Alongi G, Giaccone G (2012) Flora marina bentonica del Mediterraneo: Phaeophyceae. Bollettino dell’Accademia Gioenia di Scienze Naturali di Catania 45(375): 1–508.
  • Giaccone G, Scammacca B, Cinelli F, Sartoni G, Furnari G (1972) Studio preliminare sulla tipologia della vegetazione sommersa del Canale di Sicilia e isole vicine. Giornale Botanico Italiano 106(4): 211–229. https://doi.org/10.1080/11263507209426550
  • Gianni F, Bartolini F, Airoldi L, Ballesteros E, Francour P, Guidetti P, Meinesz A, Thibaut T, Mangialajo L (2013) Conservation and restoration of marine forests in the Mediterranean Sea and the potential role of Marine Protected Areas. Advances in Oceanography and Limnology 4(2): 83–101. https://doi.org/10.1080/19475721.2013.845604
  • Gómez-Garreta A, Barceló-Martí MC, Ribera-Siguan MA, Rull-Lluch J (2001) Cystoseira C. Agardh. In: Gómez-Garreta A (Ed.) Flora Phycologica Iberica (Vol. 1 Fucales, 1st edn.). Universidade de Murcia, Múrcia, 99–166.
  • Guiry MD, Guiry GM (2023) AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org [searched on 3 April 2023]
  • Hereu B, Quintana X (2012) El Fons Marí de les Illes Mesed i el Montgrí, Quatre Dècades de Recerca per a la Conservació. Càtedra d’Ecosistemes Litorals Mediterranis, 193 pp.
  • Lombardo A, Marletta G (2023) Diversity of the Marine Heterobranchia Fauna at the Island of Pantelleria, Sicily Channel, Mediterranean Sea: First Contribution. Acta Zoologica Bulgarica 75(1): 37–48.
  • Mancuso FP, Strain EMA, Piccioni E, De Clerck O, Sarà G, Airoldi L (2018) Status of vulnerable Cystoseira populations along the Italian infralittoral fringe, and relationships with environmental and anthropogenic variables. Marine Pollution Bulletin 129(2): 762–771. https://doi.org/10.1016/j.marpolbul.2017.10.068
  • Mulas M, Neiva J, Sadogurska SS, Ballesteros E, Serrão EA, Rilov G, Israel Á (2020) Genetic affinities and biogeography of putative Levantine-endemic seaweed Treptacantha rayssiae (Ramon) M.Mulas, J.Neiva & Á.Israel, comb. nov. (Phaeophyceae). Cryptogamie, Algologie 41(10): 91–103. https://doi.org/10.5252/cryptogamie-algologie2020v41a10
  • Neiva J, Bermejo R, Medrano A, Capdevila P, MillaFigueras D, Afonso P, Ballesteros E, Sabour B, Serio D, Nóbrega E, Soares J, Valdazo J, Tuya F, Mulas M, Israel Á, Sadogurska SS, Guiry MD, Pearson GA, Serrão EA (2022) DNA barcoding reveals cryptic diversity, taxonomic conflicts and novel biogeographical insights in Cystoseira s.l. (Phaeophyceae). European Journal of Phycology: 1–25. https://doi.org/10.1080/09670262.2022.2126894
  • Picchetti G, Caravello A, Ghelia M, Di Martino V (2010) Proposta per il parco nazionale nello stretto di Sicilia: la A.M.P. di Pantelleria. 41st S.I.B.M. Congress: 82–83.
  • Rodríguez-Prieto C, Ballesteros E, Boisset F, Afonso Carrilo J (2013) Guía de las Macroalgas y Fanerógamas Marinas del Mediterráneo Occidental. Ediciones Omega, 656 pp.
  • Sala E, Ballesteros E, Dendrinos P, Di Franco A, Ferretti F, Foley D, Fraschetti S, Friedlander A, Garrabou J, Guclusoy H, Guidetti P, Halpern BS, Hereu B, Karamanlidis AA, Kizilkaya Z, Macpherson E, Mangialajo L, Mariani S, Micheli F, Pais A, Riser K, Rosenberg AA, Sales M, Selkoe KA, Starr R, Tomas F, Zabala M (2012) The structure of Mediterranean rocky reef ecosystems across environmental and human gradients, and conservation implications. PLoS ONE 7(2): e32742. https://doi.org/10.1371/journal.pone.0032742
  • Serio D, Alongi G, Catra M, Cormaci M, Furnari G (2006) Changes in the benthic algal flora of Linosa Island (Straits of Sicily, Mediterranean Sea). Botanica Marina 49(2): 135–144. https://doi.org/10.1515/BOT.2006.018
  • Thibaut T, Blanfune A, Boudouresque CF, Verlaque M (2015) Decline and local extinction of Fucales in the French Riviera: the harbinger of future extinctions? Mediterranean Marine Science 16(1): 206–224. https://doi.org/10.12681/mms.1032
  • Thibaut T, Pinedo S, Torras X, Ballesteros E (2005) Long-term decline of the populations of Fucales (Cystoseira spp. and Sargassum spp.) in the Albères coast (France, North-western Mediterranean). Marine Pollution Bulletin 50(12): 1472–1489. https://doi.org/10.1016/j.marpolbul.2005.06.014
  • Tsiamis K, Panayotidis P, Salomidi M, Pavlidou A, Kleinteich J, Balanika K, Küpper FC (2013) Macroalgal community response to re-oligotrophication in Saronikos Gulf. Marine Ecology Progress Series 472: 73–85. https://doi.org/10.3354/meps10060
  • UNEP-PAM-RAC/SPA (2012) Protocol concerning specially protected areas and biological diversity in the Mediterranean. Annex II. List of endangered or threatened species. Paris, France, 8–10 February 2012, 7–7.
login to comment