Detailed Natura 2000 and CORINE Biotopes habitat maps of the island of Elba (Tuscan Archipelago, Italy)

Abstract

The island of Elba (Tuscan Archipelago, Italy) Natura 2000 habitat map (1:25,000) and the CORINE Biotopes habitat map (1:25,000) were derived from the phytosociological map of Elba integrated with recent studies and field knowledge of the vegetation units. Conventional geographical information system queries were used to manage and select the spatial information. For each map polygon, the following attributes were assigned: (i) habitat typology and (ii) percentage cover of each habitat type. Where multiple habitat types were associated with the same polygon, the percentage cover of each habitat type was estimated. A total of 27 Natura 2000 habitat types and 58 CORINE Biotopes habitat types were identified, these being distributed in single and/or multiple typological units. Distribution and covers of the different habitat types are discussed. The usefulness of this kind of map for monitoring and managing conservation actions is discussed.

Keywords:

• Mediterranean
• vegetation
• monitoring
• conservation
• GIS

1. Introduction

The term habitat, although widely used, is ambiguous because it has been developed with contrasting meanings in different contexts (Bunce et al., 2008, 2012, 2013; Dennis, Shreeve, & Van Dyck, 2003; Hall, Krausman, & Morrison, 1997, etc.). Its use is thus potentially confusing making it difficult to apply. Despite this, for the pragmatic definition given in the European Directives (European Commission, 2013; Evans, 2006, 2010), habitats remain a central pillar of European nature conservation policy. This is because the maintenance of a series of habitats in good condition is considered to be one of the best ways to conserve species (Bunce et al., 2013).

According to the European Directives, the field identification of a habitat is based on matching it to one (or more) vegetation types (Biondi et al., 2012; Biondi, Casavecchia, & Pesaresi, 2010; Bunce et al., 2013; European Commission, 2013; Evans, 2006; Rodwell et al., 2002; Viciani, Lastrucci, Dell'Olmo, Ferretti, & Foggi, 2014a). For this reason, several national vegetation-mapping and data-archiving projects are currently being carried out (e.g. Bonis & Bouzillé, 2012; Dimopoulos et al., 2012; Font, Pérez-García, Biurrun, Fernández-González, & Lence, 2012). Some of these are related to national habitat mapping projects (e.g. Ichter, Savio, Evans, & Poncet, 2012). In Italy, a similar project ‘VegItaly’ has been initiated (Gigante et al., 2012; Landucci et al., 2012), but it is far from complete in many regions, with Tuscany being one of the regions in which work is ongoing (Viciani et al., 2014a). The Tuscan Regional Administration has not yet commenced a comprehensive vegetation-mapping project, either for the whole territory or areas that might reasonably be considered part of the essential support framework for active in situ conservation (i.e. the Natura 2000 sites). Accurate habitat mapping is an important tool in conservation (Asensi & Díez-Garretas, 2007; Biondi et al., 2007; Loidi, Ortega, & Orrantia, 2007; Pavone et al., 2007) and especially so in areas considered hot spots of biodiversity, such as in the Mediterranean basin (Médail & Quézel, 1999; Myers, Mittermeier, & Mittermeier, 2000). The aim of this study is to develop a habitat map for the Mediterranean island of Elba, which forms part of the Tuscan Archipelago in central Italy. The study is based on existing knowledge of the phytosociological vegetation units.

2. The study area

Elba is situated in the Mediterranean biogeographic region (http://www.eea.europa.eu/data-and-maps/figures/biogeographical-regions-in-europe-1) and is the largest island of the Tuscan Archipelago; it is located between Corse and Tuscany, about 10 km offshore from the Piombino promontory (Figure 1). It has an area of about 223 km² and a coastline of 147 km, which alternates between beaches and rocky headlands, with both gentle slopes and sheer cliffs. It has a varied orography, with mount Capanne (1018 m asl) being the highest point. Elba also has a complex geological history and structure, with prevalence of Neogene and Quaternary magmatic rocks in the western areas and of marls, limestones, shales, ophiolites and metamorphic rocks in central and eastern areas (Carmignani & Lazzarotto, 2004). The climate is typically Mediterranean, with a primary maximum of precipitation in autumn, a second maximum in winter and a main minimum in summer (Foggi et al., 2006a). The island as a whole is part of the Mediterranean macrobioclimate, pluviseasonal-oceanic bioclimate (Blasi, 2010a), but some locally different bioclimatic subareas can be identified (Foggi et al., 2006a).

Figure 1. Location of the island of Elba and of the Tuscan Archipelago.

The landscape is dominated by a typical Mediterranean sclerophyllous – evergreen forest and by its degradation stages, such as high and low matorrals, garrigues and discontinuous ephemeral grasslands (Foggi et al., 2006a). More than half of the island surface is part of the Tuscan Archipelago National Park; this territory hosts Sites of Community Importance and Special Protection Areas of great relevance for biodiversity conservation. Over the last 50 years the island was involved in a transition from an economy based largely on agricultural exploitation to one based on tourism development, determining a substantial shift in land use.

3. Methods

All the cartographic and phytosociological information available for Elba was interpreted on the basis of field knowledge. This resource was mainly Foggi et al. (2006a, 2006b) and Carta (2009), but also included preliminary habitat maps (Viciani et al., 2012), studies on vegetation series by Blasi (2010a, 2010b), Viciani, Lastrucci, Geri, and Foggi (2014b) and some older studies, such as Vagge and Biondi (1999) and Biondi, Vagge, and Mossa (2000).

The vegetation survey by Foggi et al. (2006a, 2006b) was carried out on the Island during the period 2000–2006 adopting the phytosociological method (Biondi, 2011; Braun-Blanquet, 1964). Over 400 phytosociological relevés were surveyed and analysed across the whole island, leading to the identification of 64 vegetation types (of various syntaxonomical ranks) (Foggi et al., 2006a). The interpretation of aerial georeferenced orthophotos, according to the ‘Photo-guided method’ (Küchler & Zonneveld, 1988; Zonneveld, 1979) together with the study of the spatial distribution of vegetation types (recognised in the field on both physiognomical and phytosociological bases), allowed the identification of vegetation types at a scale of 1:10,000. Using this information, the island's vegetation map (1:25,000) was drawn up. This comprised units both of natural and semi-natural vegetation as well as of land use (for further details on the vegetation-mapping method, see Foggi et al., 2006a). The vegetation map includes a total of 71 typologies (Foggi et al., 2006b). In addition, new data on the previously poorly known, annual hygrophytic vegetation of Isoëto-Nanojuncetea class on Elba were published by Carta (2009). All these vegetation data were taken into account to build the habitat maps.

Information used to interpret the habitat types was derived from European Commission (EC) documents and from the literature (Angelini, Bianco, Cardillo, Francescato, & Oriolo, 2009; Biondi & Blasi, 2009; Biondi et al., 2010, 2012; Commission of the European Community, 1991; European Commission, 2013; Evans, 2006, 2010). The map of conservation-interest habitats (sensu 92/43 EC Directive, Natura 2000) was created using a geographical information system (GIS). The correspondence between the available syntaxonomical information and the mapped Natura 2000 habitat types is reported in Table S1. After this, the map of all the habitats sensu CORINE Biotopes was developed and the related geo-database created. The correspondence between the syntaxonomical/land-use information and the mapped CORINE Biotopes habitat types is reported in Table S2.

To extract and select the information used, conventional GIS queries have been employed. The following attributes were assigned to each map polygon: (i) habitat typology, (ii) percentage cover occupied by each habitat type. Where more than one habitat type co-occurred within the same polygon without being possible to separate them (very small and very fragmented units), we used the ‘mosaic’ concept. In such cases the relative percentage cover of the habitat types constituting the mosaic was estimated on the basis of professional and scientific experience acquired while conducting the field relevés. The equivalent area occupied by each habitat type was then calculated. The minimum mapping unit was assumed to be 2000 m². Habitat types covering polygons smaller than 2000 m² were treated as points. Both the Natura 2000 habitat map and the CORINE Biotopes map were produced at 1:25,000.

4. Results and discussion

A total of 27 Natura 2000 habitat types were identified, distributed in single and/or multiple typological units (Table 1). A Natura 2000 habitat map of Elba was produced (Main Map).

Table 1. Natura 2000 habitat types for the island of Elba, with surface areas (ha) and cover percentages, with respect to the total area covered by Natura 2000 habitats.

Natura 2000 habitat code	Natura 2000 habitat name	Area (ha)	%
1160	Large shallow inlets and bays	4.2	0.05
1210	Annual vegetation of drift lines	0.2	0.00
1240	Vegetated sea cliffs of the Mediterranean coasts with endemic Limonium spp.	174.3	2.00
1310	Salicornia and other annuals colonising mud and sand	0.3	0.00
1410	Mediterranean salt meadows (Juncetalia maritimi)	1.3	0.02
1420	Mediterranean and thermo-Atlantic halophilous scrubs (Sarcocornietea fruticosi)	0.8	0.01
2110	Embryonic shifting dunes	0.4	0.00
2210	Crucianellion maritimae fixed beach dunes	0.2	0.00
2230	Malcolmietalia dune grasslands	0.1	0.00
2250^a	Coastal dunes with Juniperus spp.	0.7	0.01
2260	Cisto-Lavanduletalia dune sclerophyllous scrubs	0.5	0.01
3120	Dwarf amphibious vegetation of oligotrophic waters of the West Mediterranean with Isoetes spp.	<0.1	0.00
3170^a	Mediterranean temporary ponds	<0.1	0.00
4090	Endemic oro-Mediterranean heaths with gorse	166.2	1.90
5210	Arborescent matorral with Juniperus spp.	30.6	0.35
5320	Low formations of Euphorbia close to cliffs	116.2	1.33
5330	Thermo-Mediterranean and pre-desert scrub	379.6	4.35
6220^a	Pseudo-steppe with grasses and annuals of the Thero-Brachypodietea	319.5	3.66
6420	Mediterranean tall humid herb grasslands of the Molinio-Holoschoenion	42.3	0.48
8130	Western Mediterranean and thermophilous scree	9.2	0.11
8220	Siliceous rocky slopes with chasmophytic vegetation	349.7	4.01
91E0^a	Alluvial forests with Alnus glutinosa and Fraxinus excelsior	75.2	0.86
91F0	Riparian mixed forests of Quercus robur, Ulmus laevis and U. minor, Fraxinus excelsior or F. angustifolia	5.3	0.06
9260	Castanea sativa woods	400.0	4.58
9330	Quercus suber forests	288.7	3.31
9340	Quercus ilex and Quercus rotundifolia forests	5009.9	57.39
9540	Mediterranean pine forests with endemic Mesogean pines	1354.2	15.51
Natura 2000 habitat total cover area	8729.8	100.0
Natura 2000 habitat cover with respect to Elba Island total area: 39.1%

^aPriority habitat.

The map of all habitats sensu CORINE Biotopes, covering all of Elba, was produced subsequently (Main Map). As expected, the CORINE Biotopes habitat list was more complex with 58 different typologies detected (Table 2). Only two vegetation types had surfaces too small to be mapped (just a few squares metres). These cases were treated as point habitats and were marked on the maps as simple points (see map).

Table 2. CORINE Biotopes habitat types for the island of Elba, with surface areas (ha) and cover percentages with respect to the entire Elba land area.

CORINE Biotopes habitat code	CORINE Biotopes habitat name	Area (ha)	%
12.332	Sea inlets – Mediterranean Zostera beds	4.2	0.02
15.11	Glasswort swards – Thero-Salicornietalia	0.3	0.00
15.5	Mediterranean salt meadows – Juncetalia maritimi	0.8	0.00
15.6	Saltmarsh scrubs – Arthrocnemetea fruticosi	1.3	0.01
16.11	Unvegetated sand beaches	49.4	0.22
16.2112	Mediterranean embryonic dunes	0.4	0.00
16.223	Ibero-Mediterranean grey dunes	0.2	0.00
16.228	Dune malcolmia annual-herb communities	0.1	0.00
16.27	Dune juniper thickets and woods	0.7	0.00
16.28	Dune sclerophyllous scrubs	0.5	0.00
17.2	Shingle beach drift lines – Cakiletea maritimae p.	0.2	0.00
18.22	Mediterranean cliff communities – Crithmo-Limonietalia	174.3	0.78
22.34	Perennial and annual communities of Mediterranean temporary ponds and river bank	<0.1	0.00
31.75VII	Cyrno-Sardian and Elba Genista desoleana hedgehog-heaths	166.2	0.74
31.86	Bracken flelds	149.9	0.67
31.8A	Tyrrhenian sub-Mediterranean deciduous thickets	157.4	0.70
32.132	Juniperus phoenicea s.l. arborescent matorral	30.6	0.14
32.21	Thermo-Mediterranean brushes, thickets and heath-garrigues	715.0	3.20
32.217	Coastal Helichrysum garrigues	116.2	0.52
32.23	Diss-dominated garrigues	379.6	1.70
32.31	Meso-Mediterranean silicicoulous high maquis	808.7	3.62
32.311	Western Mediterranean high maquis	3681.4	16.49
32.32	Low ericaceous maquis	1409.5	6.31
32.34	Low Cistus maquis	638.9	2.86
32.35	Low Cistus-Lavandula stoechas maquis	787.6	3.53
32.441	Spiny spurge garrigues	19.3	0.09
34.511	Retuse torgrass swards	373.9	1.67
35.3	Mediterranean siliceous grasslands	319.5	1.43
37.4	Mediterranean tall humid grasslands	42.3	0.19
37.71	Watercourse veils	129.8	0.58
41.811	Meso-Mediterranean hop-hornbeam woods	7.8	0.03
41.9	Chestnut woods	400.0	1.79
42.82	Mesogean pine forests	308.1	1.38
42.83	Stone pine forests	840.6	3.76
42.84	Aleppo pine forests	205.4	0.92
44.311	Sedge ash-alder woods	75.2	0.34
44.62	Mediterranean riparian elm forests	5.3	0.02
45.214	Central Italian cork-oak forests	288.7	1.29
45.318	Northern and central Italian holm-oak forests	3943.2	17.66
45.323	Sardinian supra-Mediterranean holm-oak forests	981.9	4.40
45.324	Italian supra-Mediterranean holm-oak forests	84.8	0.38
53.11	Common reed beds	13.2	0.06
53.17	Halophile clubrush beds	0.9	0.00
61.3B	Central Mediterranean screes	9.2	0.04
62.24	Cirno-Sardian montane cliffs	349.7	1.57
82.11	Field crops	895.0	4.01
82.3	Extensive cultivation	738.9	3.31
83.11	Olive groves	134.7	0.60
83.15	Fruit orchards	55.4	0.25
83.21	Vineyards	404.1	1.81
83.322	Eucalyptus plantations	3.9	0.02
83.324	Locust tree plantations	19.5	0.09
83.325A	Other broad-leaved plantations	0.7	0.00
83.325B	Other broad-leaved plantations	1.4	0.01
85.1	Large parks	416.9	1.87
86.1	Towns	1667.8	7.47
86.41	Quarries	317.5	1.42
89	Industrial lagoons and reservoirs, canals	2.3	0.01
Total area		22,330.5	100.0

The Natura 2000 habitats cover almost 40% of the total land area of Elba, and have a total area of about 8700 ha. Four priority habitat types cover about 1.8% (Table 1, Figure 2) but only three were large enough to be mapped as polygons (coastal dunes with Juniperus spp., pseudo-steppe with grasses and annuals of the Thero-Brachypodietea and alluvial forests with Alnus glutinosa and Fraxinus excelsior, codes 2250, 6220 and 91E0, respectively). It is noted that the two punctual habitats are also of high conservation relevance. They correspond to dwarf amphibious Mediterranean vegetation and belong partly to priority European interest habitats as listed in Annex I of the EU Habitats Directive. As shown in Figure 3, the main Natura 2000 habitats represented were forests, followed by sclerophyllous matorrals and then the other typologies. Within these forest habitats, the woods dominated by Quercus ilex and Mediterranean pines are by far the most widespread typologies and represent more than 80% of the total cover of the island Natura 2000 habitat types (Table 1, Figure 2). Natura 2000 matorral habitats and natural and semi-natural grassland communities do not reach high percentages but are nevertheless widespread throughout Elba. The rocky habitats are concentrated mainly on two sites – Mt Capanne and Mt Volterraio. Coastal and halophytic Natura 2000 habitats appear to be about 2% in cover. They are well-represented only by the habitat code 1240 (vegetated cliffs with Limonium spp.), while dune habitats cover only 0.02%, due both to the island's geomorphology and also to the intense pressure of tourism on the larger sandy beaches. As mentioned above, freshwater habitats of dwarf amphibious Mediterranean vegetation (Natura 2000 codes 3120 and 3170) are present but without significant cover values, as is often the case in the Mediterranean area (Grillas, Gauthier, Yavercovski, & Perennou, 2004).

Figure 2. Cover percentages of Natura 2000/not Natura 2000 habitats on Elba.

Figure 3. Cover percentages of Natura 2000 habitats on Elba with respect to the total area covered by Natura 2000 habitats, grouped into broad environmental typologies.

The mapping of CORINE Biotopes habitat types was more complex (Table 2), also because CORINE Biotopes typologies were allowed to cover the entire land area of the island. Some typologies correspond exactly to Natura 2000 habitats (e.g. saltmarsh scrubs, Juniperus phoenicea s.l. arborescent matorral, cork-oak forests), others are defined more precisely (e.g. Mediterranean pine forests, grouped under a single Natura 2000 code but separated in the CORINE Biotopes legend, according to the dominant species). Many others are not included in the Natura 2000 list, even though they often correspond to natural and semi-natural habitat types (e.g. several high and low maquis typologies). The percentage subdivision into broad environmental typologies is shown in Figure 4. Forests cover about 32% of Elba in total land area. This high percentage is interesting for a Mediterranean island inhabited and exploited for thousands of years, and differentiates Elba from other islands of the Tuscan Archipelago, where wooded areas are extremely reduced: examples are on the islands of Capraia (Foggi & Grigioni, 1999), Giannutri (Foggi et al., 2011), and some other islands in the Mediterranean (Bartolo, Brullo, Minissale, & Spampinato, 1988). Agricultural land and artificial landscapes (urban areas included, see CORINE Biotopes Manual, Commission of the European Community, 1991) cover about 21% of the area. This value is higher than on other islands of the Tuscan Archipelago (see Foggi et al., 2011; Foggi, Cartei, & Pignotti, 2008; Foggi & Grigioni, 1999; Foggi & Pancioli, 2008; Viciani, Albanesi, Dell'Olmo, & Foggi, 2011) and is testimony to the intense human presence on the island. It is worth noting that on Elba (as on many Mediterranean islands) heaths, thickets and sclerophyllous scrubs comprise the largest CORINE Biotopes comprehensive typology (more than 40%, see Figure 3), while they represent only about 8% in the cover of Natura 2000 habitat types. This has also been reported for other Mediterranean areas (see Pasta & La Mantia, 2009).

Figure 4. Cover percentages of CORINE Biotopes habitats on Elba with respect to the entire Elba land area, grouped into broad environmental typologies.

5. Conclusions

An accurate phytosociological vegetation map involves a number of activities from several points of view (e.g. a large amount of fieldwork, plant identification, creation of databases, statistical analyses and syntaxonomical checks). Even though some authors (see e.g. Chiarucci, 2007) suggest that all this work is not always adequately rewarded in terms of scientific impact, it is nevertheless often useful for a range of purposes. In particular, an important role of phytosociology relates to the identification of habitats deserving the highest conservation effort (see Biondi et al., 2012). Therefore, the availability of cartographic documentation based on phytosociological data allows documents to be derived such as the mapping of habitats of conservation interest or of Corine habitats that are important tools for the management and planning of actions to protect the territory. Moreover, the detection of habitats and species listed as being of Community interest is crucial to the designation of Sites of Community Interest (SCI) by the Member States as stated in the Habitats Directive (Commission of the European Communities, 1992). Furthermore, where there is an obligation on behalf of the Member State to guarantee a Favourable Conservation Status, with requirements for monitoring and reporting, at least for the habitats and species for which the SCI has been designated (Ostermann, 1998), Natura 2000 habitat maps represent an extremely valuable tool for gaining new knowledge and for monitoring habitats in the SCIs. This is particularly true nowadays, as the attention of conservationists is increasingly being focused on evaluating not only species but also communities (e.g. habitats, biotopes, ecosystems and ecological communities, see Gigante, Buffa, Foggi, Venanzoni, & Viciani, 2013; Keith et al., 2013; Kontula & Raunio, 2009; Nicholson, Keith, & Wilcove, 2009; Rodriguez et al., 2011, 2012; Rodwell, Janssen, Gubbay, & Schaminée, 2013).

Disclosure statement

No potential conflict of interest was reported by the authors.

Software

The maps were created and edited using the Esri ArcGIS 9.2.

ORCID

Daniele Viciani http://orcid.org/0000-0003-3422-5999