Ecological classification of land and conservation of biodiversity at the national level: The case of Italy

Biological Conservation 147 (2012) 174–183

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Ecological classification of land and conservation of biodiversity at the national level: The case of Italy Giulia Capotorti a, Domenico Guida b, Vincenzo Siervo b, Daniela Smiraglia c,⇑, Carlo Blasi a,d a

Interuniversity Research Center ‘‘Biodiversity, Plant Sociology and Landscape Ecology’’, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy Department of Civil Engineering, University of Salerno, Via Ponte don Melillo, 84084 Fisciano (SA), Italy c Department of Economics and Statistics, University of Salerno, Via Ponte don Melillo, 84084 Fisciano (SA), Italy d Department of Environmental Biology, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy b

a r t i c l e

i n f o

Article history: Received 16 February 2011 Received in revised form 15 December 2011 Accepted 22 December 2011 Available online 14 January 2012 Keywords: Hierarchical approach Land unit Gap analysis Environmental quality assessment Conservation strategies

a b s t r a c t The aims of this study are to describe the ecological classification of land in Italy and to show how the resulting land units can act as reliable frameworks for coarse scale environmental analyses that can be used to implement national conservation strategies. We first collected, homogenised and drew physical thematic maps, which were then linked to biological and human features. We then performed a gap analysis of land heterogeneity compared with Natural Protected Areas and Natura2000 network on the basis of three categories: Total gaps, Partial gaps, and Protected. Moreover, we assessed the conservation status of the land units by summarising the environmental quality using the Index of Landscape Conservation. We identified and mapped 3 Land Regions, 24 Land Systems, and 149 Land Facets. Total gaps account for 28% of the country, Partial gaps for 38% and Protected for 34%. The Natura2000 network is more representative than the system of National Protected Areas of the overall land heterogeneity as regards both the types (18 out of 24) and extent (72%) of the Land Systems. Low conservation status prevails in the Land Facets of the Mediterranean Region located along the coasts and plains on sedimentary deposits, whereas high and very high conservation status is found along the higher belts of the Alpine and Apennine chains. These results highlight the potential use of ecological land classification for biodiversity monitoring and conservation purposes, e.g. when identifying land units that need to be recovered or targeted for enhanced biodiversity and ecosystem services protection. Ó 2011 Elsevier Ltd. All rights reserved.

1. Introduction Ecosystems result from complex interactions between physical and biological factors, and human activities (CBD, 2004; Pickett and Cadenasso, 2002; Tansley, 1935). Given the importance of land management and biodiversity conservation, ecosystems need to be described, characterised and spatially located (Sims et al., 1996). The need to ensure ecosystem diversity at different spatial scales is now fully acknowledged by international strategies for the protection of biodiversity and for sustainable development. The Convention on Biological Diversity (1992), the European Habitats Directive (1992), the Pan European Biological and Landscape Diversity Strategy (1996), and the European Landscape Convention (2000) have all focused on environmental heterogeneity in terms of ecosystem diversity and/or landscape diversity as a result of the action and interaction of natural and/or human factors. ⇑ Corresponding author. Present address: Department of Environmental Biology, Sapienza University of Rome, P.le Aldo Moro 5, 00185 Rome, Italy. Tel./fax: +39 0649912420. E-mail address: [email protected] (D. Smiraglia). 0006-3207/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.biocon.2011.12.028

Following the boost received from these initiatives, in recent times ecological classifications of land have been receiving an increasing amount of attention. They offer the opportunity to capture ecosystem patterns and associated ecological processes that occur at the landscape scale (Bailey, 1996; McMahon et al., 2004), such as biotic response to climate change (Beier and Brost, 2010), rates of primary production (Dale et al., 2000) and hydrological regimes, (Higgins et al., 2005) as well as to address environmental challenges under an ecosystem management perspective (Hobbs and McIntyre, 2005; Yaffee, 1999). The ecological classification of land identifies land units on the basis of their homogeneity according to physical and biological features at various scales (Bailey, 2004; Cleland et al., 1997; Zonneveld, 1995). Land units provide a geographical framework that can be used to address environmental issues according to ecological boundaries (Gallant et al., 2004; Omernik, 2004) and, more specifically, they represent a surrogate for the manifold aspects of biodiversity that can effectively be used to support conservation policies (Oliver et al., 2004; Pressey et al., 2000; Wessels et al., 1999). In Italy, the conservation of natural resources and environmental services is based above all on National Protected Areas (NPAs),

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Sites of Community Interest (SCIs) and Special Protection Areas (SPAs) under the Habitats Directive (92/43/EEC) as well as on the fulfilment of strategic objectives in the National Biodiversity Strategy (Andreella et al., 2010). In 2005, a project designed to complete and update the environmental information available and to provide a uniform ecological classification of land units at the national level was undertaken by the ‘‘Biodiversity, Plant Sociology and Landscape Ecology’’ Interuniversity Research Center at the Sapienza University of Rome, with the support of the Italian Ministry for the Environment, Land and Sea Protection. A top-down deductive process (Bailey, 2004; Klijn et al., 1995; Sayre et al., 2009) was adopted to highlight the role of physical determinism in characterising the territory. The aims of this paper are (i) to describe the land units that emerge from the afore-mentioned project and (ii) to verify whether environmental analyses based on such land units are effective for formulating priority conservation targets in Italy. 2. Materials and methods 2.1. Study area Italy is located in the southern Europe, central Mediterranean basin. It covers approximately 300,000 square kilometres and is particularly heterogeneous in climate, physiography, vegetation cover and land use. There are two major ranges of mountains (the Alps and the Apennines), extensive hilly zones, wide river valleys (first and foremost the Po plain), many large and small islands, and a long coastline. Land cover is characterised predominantly by agricultural areas (52%), while 42% of the country is covered by natural and semi-natural areas, most of which are forests (25%). Artificial areas, which cover almost 5%, prevalently consist of urban areas located along the coasts and in the wide plains. 2.2. Data The project for the ecological classification of land in Italy systematically collected, homogenised and drew original thematic maps of physical factors at the national level and combined them with the biological and human features in the country. Moreover, the hierarchical framework adopted for each thematic layer was used to identify and map the environmental heterogeneity across the Italian peninsula at various scales. We considered climate as the leading determining factor for the diversity of natural communities and for the geographic distribution of ecosystems (Bailey, 1996; Metzger et al., 2005). Physiography was taken into account as the second most important determining factor for environmental diversity. However, the documents available for both lithology and morphology at the national level were fragmented, non-digitalised or at different geographical scales. We therefore drew up new national physiographic maps, on the basis of hierarchical legends, that are consistent with the land classification process. We did not take into account soil types because the accuracy of the available map at the national level, which only describes the dominant soil types within ecopedological units at a 1:250,000 scale (http:// eusoils.jrc.ec.europa.eu/library/data/250000/Italy.htm), prevented us from further refining physiographic land units according to detailed soil properties. To characterise and analyse the land units, we made use of additional data such as maps of the NPAs, Natura2000 sites, Potential Natural Vegetation (PNV) and Land Cover (LC). At present, NPAs and Natura2000 sites represent the main legal instruments for biodiversity conservation, though they may not be sufficient to protect the various components of biological and landscape

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diversity. NPAs are legally designated according to the National Framework Law L. 394/91 and are governed by specific plans aimed at the conservation of biodiversity components and natural processes, promotion of sustainable activities, education, training and scientific research, and protection and reconstitution of the hydrogeological equilibrium. However, such plans have yet to be definitively approved for all the areas. Natura2000 sites are designated according to the European Habitats Directive, whose aim is to maintain natural habitats and wild species of Community interest at a favourable conservation status. Their effectiveness is evaluated by the Italian Ministry of the Environment, which issues a public report on the monitoring results that have been achieved every 5 years. However, such monitoring is not aimed at enhancing the representativeness of the Natura2000 network as regards biodiversity features of national interest. PNV, defined as the vegetation in a given habitat that would develop at once to a mature stage without human influences (Tüxen, 1956), can be used as an expression of the biotic potential of a region (Loidi et al., 2010) to assign biological connotations to physical land units. The classification process and environmental analysis were performed using ArcGis 9.2. The source and level of detail of each thematic feature as well as the methodological principles used for the classification process and environmental analyses are explained in the following subsections. 2.2.1. Climatic features A phytoclimatic map of Italy (scale 1:250,000) was recently produced (Blasi and Michetti, 2007) on the basis of monthly temperature/rainfall variables for the period 1955–1985 and the indices proposed by Rivas-Martínez (1996). The map is hierarchically arranged in 3 Climatic Regions (Mediterranean, Transitional and Temperate), 9 Bioclimates (from Mediterranean oceanic to Temperate continental) and 28 Phytoclimatic classes (from Inframediterranean dry to Criorotemperate ultrahyperhumid). The macroclimatic features used for the land classification were extracted from the first level of this map (see Fig. 1). 2.2.2. Lithological features An original lithological map was derived from the homogenisation of geological maps at the national and regional scale, including the Structural Model of Italy at a scale of 1:500,000 (Bigi et al., 1992) and the geological sheets at scales of 1:100,000/1:50,000 of the National Geological Service. We drew up the legend by taking into account the IAEG-UNESCO recommendations (1976) and using the criteria of multiscale hierarchy. Therefore, the legend levels (Table 1) are based on the following criteria: main lithogenetic process (I level), secondary lithogenetic process (II level), lithogenetic environment (III level), mineralogy/petrography (IV level), grain/crystal size/orientation (V level), structure/texture (VI level), physical state (VII level), chemical state (VIII level). The II level was chosen as the most appropriate tier to delineate the national lithological map (scale 1:250,000), except for the metamorphic lithotype (I level) and the terraced clastic sedimentary lithotype (III level). This map includes eight different lithological classes, plus lakes, glaciers and lagoons which are kept as distinct units (see Fig. 1). 2.2.3. Geomorphological features An original geomorphological map was drawn up by elaborating a Digital Terrain Model, with a grid cell of 75 m. We applied the Topographic Position Index (Jenness, 2006; Tagil and Jenness, 2008), a semiautomated method to define basic landforms developed by Weiss (2001) and implemented in the Dalrymple et al. (1968) nine-unit slope model, to match the geomorphological diversity of Italy. We defined a hierarchical multiscale legend

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Fig. 1. Hierarchical land classification of Italy. Land Regions reflect macrobioclimate features; Land Systems subdivide Land Regions according to lithological features; Land Facets subdivide Land Systems according to morphological features.

(Table 2) in this case as well. The legend levels reflect general morphoevolution (I level), general morphogenesis (II level), local morphogenesis (III level), compound geomorphic processes (IV level), single geomorphic process (V level), and morphomechanism (VI level). When drawing up the national geomorphological map (scale 1:100,000), we adopted the I level legend, which includes seven different morphological classes (see Fig. 1).

2.2.4. Biological and human features The Official List of NPAs includes national parks, regional parks, natural reserves, biotopes and natural monuments (871 sites, with those terrestrial accounting for almost 10% of Italy), while the Natura2000 network includes 2288 sites listed as Sites of Community Interest (SCIs) and 597 sites listed as Special Protection Areas (SPAs), with those terrestrial accounting for almost 19% of Italy (http://www.minambiente.it, year of reference 2009). As there is

a partial overlap between these protected sites, if merged, their overall coverage is approximately 21%. Information on PNV was provided by the Map of Vegetation Series of Italy (scale 1:500,000), published in 2010 with the relative regional monographs (Blasi, 2010). The document illustrates 279 types of natural potential plant communities and describes the range of dynamic stages associated with each vegetation series, i.e. the actual plant communities that would develop to the same mature stage under uniform environmental conditions (Biondi, 2011; Rivas-Martínez, 2005). The LC map is the product of the CORINE Land Cover I&CLC2000 project (http://www.sinanet.apat.it, published in 2004), which in Italy comprises 69 types of land cover at the V level of the legend. The land cover types were reclassified into six environmental quality categories according to the concept of ‘‘naturalness’’, sensu Machado (2004), and taking into account the distance of vegetation covers from the PNV:

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Table 1 Hierarchical levels, criteria and map scale ranges used to define classes of the lithological legend. As an example, we show the hierarchical arrangement of the ‘‘Sedimentary’’ lithology. Level

I

II

III

IV

V

VI

VII

VIII

Criterion

Main lithogenetic process 1:1,000,000/ 1:500,000 1 Sedimentary

Secondary lithogenetic process 1:500,000/ 1:250,000 1.1 Clastic

Lithogenetic environment

Mineralogy/ petrography

Grain/cristal size/orientation

Structure/ texture

Physical state

Chemical state

1:250,000/ 1:100,000 1.1.1 Eluvial

1:100,000/ 1:50,000 1.1.1.1 Arenaceous

1:50,000/ 1:25,000 1.1.1.1.1 Pebbly

1:25,000/ 1:10,000 1.1.1.1.1.1 Matrixsupported

1:10,000/1:5,000

1:5000/1:2000

1.1.1.1.1.1.1 Loose/Incoherent

1.1.1.1.1.1.1.1 Fresh

Map scale range Class

1.2 Biogenic 1.3 Organic 1.4 Pyroclastic

1.1.1.2 Carbonate . . .. . .

1.1.2 Slope detrital 1.1.3 Fluvial 1.1.4 Lacustrine/ Palustrine 1.1.5 Lagunal 1.1.6 Eolian 1.1.7 Paralic . . .. . . . . .. . . . . .. . .

1.1.1.1.2 1.1.1.1.3 1.1.1.1.4 1.1.1.1.5 . . .. . .

Gravelly Sandy Silty Clayey

1.1.1.1.1.2 Clastsupported 1.1.1.1.1.3 Openwork . . .. . . . . .. . . . . .. . . . . .. . .

1.1.1.1.1.1.1.2 Weathered 1.1.1.1.1.1.1.3 Decomposed . . .. . .

1.1.1.1.1.1.2 Dense 1.1.1.1.1.1.3 Consistent . . .. . .

. . .. . .

. . .. . .

. . .. . . . . .. . .

. . .. . . . . .. . . . . .. . .

Table 2 Hierarchical levels, criteria and map scale ranges used to define classes of the geomorphological legend. As an example, we show the hierarchical arrangement of the ‘‘Summit’’ geomorphology. Level

I

II

III

IV

V

VI

Criterion

General morphoevolution 1:250,000/1:100,000

General morphogenesis 1:100,000/1:50,000

Local morphogenesis 1:50,000/1:25,000

Compound geomorphic processes 1:25,000/1:10,000

Single geomorphic process 1:10,000/1:5000

Morphomechanism

1 Summit

1.1 Karst plateau

1.1.1 Doline

1.1.1.1 Doline bottom

1.1.1.1.1 Sinkhole

1.1.1.1.1.1 Lapiez 1.1.1.1.1.2 Karren . . .. . .

Map scale range Class

1.2 Ridge 1.3 Crest 1.4 Mesa

1.1.2 Uvala 1.1.3 Polje . . .. . . . . .. . . . . .. . .

1st category: Areas occupied by artificial areas. 2nd category: Areas occupied by extensive arable land under rotation system. 3rd category: Permanent crops and pastures. Such areas in many cases contain some low-system orchard plantations. 4th category: Heterogeneous agricultural areas mixed with areas of spontaneous vegetation. 5th category: Areas covered by secondary vegetation, i.e. grasslands and shrubs, deriving from deciduous and evergreen forest re-colonisation.

1.1.1.2 Doline sideslope 1.1.1.3 Doline shoulder . . .. . . . . .. . .

1.1.1.1.2 Pond . . .. . . . . .. . .

1:5000/1:2000

6th category: mature forests, natural areas covered by little or no vegetation and wetlands. 2.3. Land classification process The methodology used to classify and map progressively more homogeneous land unit types according to abiotic control factors (see Fig. 1) followed a hierarchical top-down approach and the scheme proposed for Italian landscapes (Blasi et al., 2000, 2005). The physical unit types obtained are then combined with

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information on potential vegetation and actual land cover, thereby providing a biophysical classification of land. At coarse levels, the scheme subdivides land into: (i) Land Regions, from scales of 1:1,000,000 to 1:250,000, determined by macro-bioclimatic features and characterised in terms of zonal vegetation series; (ii) Land Systems, at a scale of 1:250,000, delimited within Land Regions according to diagnostic lithological features and characterised by the typical combination of the vegetation series; (iii) Land Facets, from scales of 1: 250,000 to 1:50,000, delimited within the Land Systems according to diagnostic geomorphological features and characterised in terms of main distinctive vegetation series and landscape conservation status. The final digital map of the land classification was drawn up at the standard scale of 1:250,000, with a minimum mapping unit of 50 ha. 2.4. Environmental analyses In order to set priorities for land unit types conservation, a gap analysis (Jennings, 2000; Scott et al., 2001) was performed. We assess the representativeness of the terrestrial NPAs and Natura2000 networks as regards physical heterogeneity and associated ecological features. As Italy is characterised by deep climatic gradients and the uneven distribution of several lithotypes, we considered Land Systems as the most appropriate means of identifying the typical combinations of vegetation series combined to this outstanding heterogeneity that lack protection. For this purpose, NPAs and Natura2000 data sets were intersected with the Land Systems map and the number and percentage of Land System included in the two protection networks were calculated. We employed the 10% target and categorised any Land System type accounting for less than 10% in both the NPAs and Natura2000 as a ‘‘Total gap’’, any type accounting for less than 10% in either the NPAs or the Natura2000 as a ‘‘Partial gap’’, and any type accounting for more than 10% in both the NPAs and Natura2000 as ‘‘Protected’’. Rosati et al.’s protection threshold and categories (2008) were used to compare our results with those obtained by the afore-mentioned authors for the PNV types in Italy. Besides being assumed to be indicative of the ‘‘minimal portion of an ecosystem analysis unit’s area needed in the conservation estate’’ (Dietz and Czech, 2005), the 10% target also represents an indicator for the achievement at the national level of the 4th target of the Global Strategy for Plant Conservation for 2010 (i.e. at least 10% of each ecological region effectively conserved) and is particularly significant in Italy because it represents the conservation goal of the National Biodiversity Strategy according to the Framework Law L. 394/ 1991 on Protected Areas. Moreover, an analysis of the landscape conservation status was performed to assess the environmental conditions of the Land Facets, and consequently identify areas that need recovery and/or conservation actions. Starting from the categories of environmental quality of land cover types, which are based on the relationship between present land use and environmental potential, we calculated the Index of Landscape Conservation (ILC) (Blasi et al., 2008; Ferrari et al., 2008; Pizzolotto and Brandmayr, 1996) by summing the cumulative percentage areas of these categories (xi). The index can be expressed as

A¼

n X

xi  100

i¼1

where n is the number of categories. The maximum value of A will be Amax = 100  (n  1) and the ILC is

ILC ¼ 1  ðA=Amax Þ:

The index varies between 0 (high level of artificialisation) and 1 (high level of naturalness). The ILC was calculated both on a nationwide scale and for each Land Facet. Land Facets were grouped into 5 classes of conservation status according to their ILC value: very low (0 < ILC < 0.2), low (0.2 < ILC < 0.4), medium (0.4 < ILC < 0.6), high (0.6 < ILC < 0.8) and very high (0.8 < ILC < 1). 3. Results 3.1. Hierarchical classification of land in Italy The land classification process led to the identification and mapping of 3 Land Regions, 24 Land Systems and 149 Land Facets (Fig. 1). The Mediterranean Land Region covers 25% of the national territory and is characterised by a summer drought lasting longer than two months, a reduced difference between summer and winter temperatures, and precipitation concentrated in the autumn/ winter period. The vegetation potential is mainly represented by evergreen sclerophyllous forests or shrub. The Temperate Land Region covers 58% of the national territory and is characterised by brief or absent summer aridity, a generally marked difference between winter and summer temperatures, and precipitation concentrated in the spring/summer period. The vegetation potential is mainly represented by broadleaved deciduous forests. The Transitional Land Region covers 18% of the national territory and is characterised by thermic or pluviometric variants of the Mediterranean and Temperate Land Regions. The vegetation potential is mainly represented by deciduous forests with seral stages characterised by sclerophyllous shrub. More information about zonal vegetation series at Land Region level were described in Appendix A. The 24 Land Systems are fairly evenly scattered throughout the three Land Regions. The larger Land Systems fall within the Temperate Land Region and are associated with sedimentary terrigenous, clastic and carbonate lithological types (Fig. 2a), whereas the smaller Land Systems are always associated with sedimentary chemical and intrusive igneous lithological types. PNV features regarding the combination of the vegetation series at this level were described in more detail in Appendix A. Each Land Facet was characterised in terms of: distinctive vegetation series, which represent the biotic feature induced by the interaction between zonal climate, lithology and geomorphology; the number of vegetation series that cover more than 5%, which represents the within-unit diversity in biological potential; the total extent in Italy and percentage cover by Administrative Regions (see Appendix A), which provide the geographic pattern of the Land Facets; the percentage cover of NPAs and of Natura2000 sites, which indicates the level of protection; the ILC, which represents the human influence on the naturalness of actual land cover (Appendix A). 3.2. Gap analysis Total gaps, which are found in 6 out of the 24 Land Systems in all three Land Regions (Fig. 2b), account for 28% of the national territory (Fig. 2c) and are distributed above all in the clastic and terraced clastic lithological types in the Po plain and south-eastern peninsula (Fig. 3). Partial gaps, which are found in 10 types of Land Systems and account for 38% of the national territory, are exclusively due to NPAs; they occur above all in the Temperate Terrigenous Sedimentary Land System of the north Appennine, though they are also widespread in the Mediterranean Land Systems, especially in the islands of Sardinia and Sicily, south-eastern Italy and in some large plains along the southern Tyrrhenian coast. Either total or partial gaps occur in all 8 Mediterranean Land Systems,

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(a) Temperate

Terrigenous sedimentary Terraced clastic sedimentary Clastic sedimentary Chemical sedimentary Carbonate sedimentary Metamorphic Intrusive igneous Effusive igneous

14.8 8.1 13.0 0.3 11.3 7.0 1.2 1.9

Transitional

Terrigenous sedimentary Terraced clastic sedimentary Clastic sedimentary Chemical sedimentary Carbonate sedimentary Metamorphic Intrusive igneous Effusive igneous

6.6 1.8 1.8 0.2 3.3 1.4 1.2 1.5

Mediterranean

Terrigenous sedimentary Terraced clastic sedimentary Clastic sedimentary Chemical sedimentary Carbonate sedimentary Metamorphic Intrusive igneous Effusive igneous

5.5 4.1 4.8 0.6 5.3 0.9 1.1 2.4

0

5

10

15

20

%

(b)

60 Transitional

NPAs Natura2000

Te mperate 48.6

Mediterranean

36.9

42.3

50

17.2 3.3

2.6

Clastic sedimentary

Terraced clastic sedimentary

4.9

8.7

9.8

3.8

8.4

11.2

12.7

Chemical sedimentary

6.2 Terraced clastic sedimentary

17.4

18.9

23.9 6.1 2.8

Clastic sedimentary

9.7

10.7

10.6

16.7

18.7

18.2 3.8

12.2

10.8

13.3

11.5 4.7 2.0

0.5

4.0

5.6

6.8

13.4

15.4

16.7 5.2

3.3

3.4

10

6.4

13.6

13.8

20

27.2

28.8

30 21.0

%

40

(c)

Terrigenous sedimentary

Carbonate sedimentary

Metamorphic

Intrusive igneous

Effusive igneous

Terrigenous sedimentary

Chemical sedimentary

Carbonate sedimentary

Metamorphic

Intrusive igneous

Effusive igneous

Terrigenous sedimentary

Terraced clastic sedimentary

Clastic sedimentary

Chemical sedimentary

Carbonate sedimentary

Metamorphic

Intrusive igneous

Effusive igneous

0

Temperate Region

40

Transitional Region Mediterranean Region

35 14.8

30 25

%

21.5 3.2

20 21.3

15 10 5

20.1 12.7

1.8 4.7

0

Total gaps

Partial gaps

Protected

Fig. 2. Results of Land System level: (a) Extent of different Land Systems in Italy, arranged according to reference Land Regions. Percentage values refer to the whole country, (b) Representativeness of NPAs and Natura2000 sites for Land Systems. Percentage of each Land System - within Mediterranean, Transitional, and Temperate Land Regions covered by NPAs (white columns) and Natura2000 sites (grey columns), (c) Total gaps, partial gaps and non-gaps in protection of Land Systems at the national level. Percentage values refer to the whole country. Each column represents the relative extent of the protection category, with a further subdivision for each of the three Land Regions (in colour).

though the gaps in the 4 Land Systems of the Temperate Region are more extensive, accounting for 36% of the national territory. Half of the Transitional Land Systems, containing the largest ones, are Pro-

tected (4 Land Systems that account for 13% of the national territory). The most extensive Protected Land Systems are the Temperate Carbonate Sedimentary, the Temperate Metamorphic

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prevalently covered by arable land and, to a lesser extent, by artificial surfaces and complex cultivation patterns. 3.3.3. Medium This class, which covers 20% of the country, is evenly distributed throughout the Italian peninsula and Sicily and Sardinia (Fig. 4c). It consists predominantly of igneous and metamorphic deposits on the hilly belt close to mountain chains in all three Land Regions. The medium ILC value reflects a high degree of evenness in environmental quality categories of the land cover types. 3.3.4. High This class is mainly located close to the Apennine chain (Fig. 4d) and covers 24% of the Italy. The dominant landforms are slope and piedmont on sedimentary deposits and secondary igneous and metamorphic deposits in all three Land Regions. Although some land cover heterogeneity exists, these Land Facets are characterised by a high degree of natural and semi-natural vegetation cover and agricultural lands associated with extensive areas of natural vegetation.

Fig. 3. Geographic distribution of protection gaps and non-gaps for Land Systems in Italy.

3.3.5. Very high This class covers 25% of the country and is located along the higher belts of the Alpine and Apennine chains (Fig. 4e). The dominant morphologies are valleys and mountain tops on igneous deposits and secondary sedimentary and metamorphic deposits in all three Land Regions. The very high ILC values are related to the dominance of natural and semi-natural land covers with very high environmental values. 4. Discussion

and the Transitional Terrigenous Sedimentary Land Systems, all located in the mountain belt. If the Natura2000 network and NPAs are considered separately, the former is more representative of national land heterogeneity as regards both the types (18 out of 24) and size of the Land Systems (72%). 3.3. Assessment of landscape conservation status The ILC calculated for the overall Italian territory is 0.59. However, each Land Region is characterised by a different ILC class: the ‘‘low’’ class prevails in the Mediterranean Land Region (55%), whereas the ‘‘high’’ and ‘‘very high’’ are the main classes in the Transitional (48%) and in Temperate Land Regions (36%) respectively. The geographic distribution of the ILC classes and characteristics of the Land Facets included are described below (Fig. 4). 3.3.1. Very low This class covers less than 1% of the national territory and is located exclusively along the medium-Adriatic and northern Tyrrhenian coasts. It only includes the Coastal Land Facet of the Terraced Clastic Sedimentary Land System and the Coastal Land Facet of the Terrigenous Sedimentary Land System within the Temperate Region (Fig. 4a). Very low ILC values are related to the prevalence of artificial surfaces and, secondly, to the presence of arable lands. 3.3.2. Low This class covers approximately 31% of the national territory and is distributed in the Po plain, south-eastern Italy, central Tyrrhenian coasts, southern Sicily and western Sardinia (Fig. 4b). The Land Facets with low landscape conservation status prevalently consist of coast, plain and table-land morphologies on sedimentary deposits within all the three Land Regions. They are

4.1. Strength and weakness of the proposed ecological classification of Italian land This research implements the existing global and European broad-scale projects for the ecological classification of land, which are aimed at establishing spatial reference systems for environmental assessment, protection, management and planning (Bailey, 1995; Mücher et al., 2010; Sayre et al., 2007). Indeed, we used accurate basic maps that allow to represent in detail the biophysical richness and diversity of Italy at the national level. This improvement allows the Italian Ministry for the Environment, which commissioned the project and is the main partner of the Joint Committee for the State-Region Conference in charge of the fulfillment of the National Biodiversity Strategy to 2020, to have at its disposal a multilevel framework that contextualises the focal points of the Strategy more effectively. Indeed, as Land Regions express the main vegetation characteristics linked to robust macro-bioclimatic units, they represent the most suitable level for modulating ‘‘adaptation and mitigation measures against climate change’’ (focal point 2). The Land System level represents the most appropriate means of ‘‘maximising protection of biodiversity and ecosystem services’’ (focal point 1/a) because it is representative of the sets of vegetation series combined with soil catenas and hydrologic cycles, that are typical of each lithological substrate within the different climatic Regions. Therefore, systematic protection of Land Systems can support conservation of the dynamic stages of these sets of vegetation series as well as conservation of the ecosystem services associated to soil formation and retention and water regulation and supply. Land Facets represent an effective means of ‘‘maximising recovery of biodiversity and ecosystem services’’ (focal point 1/b) under a national perspective by providing detailed information on the spatial pattern of natural potentialities, in terms of specific vegetation features associated

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Fig. 4. Geographic distribution of the ILC classes in Italy: (a) very low conservation status (0 6 ILC < 0.2); (b) low conservation status (0.2 6 ILC < 0.4); (c) medium conservation status (0.4 6 ILC < 0.6); (d) high conservation status (0.6 6 ILC < 0.8); (e) very high conservation status (0.8 6 ILC 6 1).

with topographic conditions and soil properties. They thus enable to assess to what extent the actual land cover reflects these potentialities in distinct geographic areas. Despite the robustness of the basic physical maps, the classification scheme is weakened by the association of physically distinct land units with known distributions of vegetation series. The ‘‘one to many’’ relationship between Land Facets and distinctive vegetation series, as in the case of the Transitional Effusive Igneous Valley Land facet, suggests that some geomorphological types need to be described in more detail. However, ‘‘many to one’’ relationships also emerged, as in the cases of the several Land Facets within the Mediterranean Metamorphic Land System characterised by the same Quercus ilex vegetation series, or the Piedmont-slope Land Facets of the Mediterranean Chemical, Clastic and Terrigenous Land Systems characterised by the same Quercus pubescens vegetation series, thus revealing some weaknesses in vegetational knowledge at the national level. 4.2. Strength and weakness of the environmental analyses Methods for the assessment of landscapes and protection networks for ecosystem conservation, management and planning purposes at coarse scales are considerably more widespread in other countries (e.g. Oldfield et al., 2004; Silva et al., 2006) than in Italy. At present, this work provides a reliable framework for environmental analysis that can be used to implement national conservation strategies with priority targets complementary to those at the species or habitat levels (e.g., Blasi et al., 2011; D’Amen et al., 2011; Marchetti et al., 2010). In particular, the gap analysis based on Land Systems diversity can effectively support a proactive means (sensu Brooks et al., 2006) of maintaining the range of dynamic stages of

vegetation series that may be expected at different sites and that are not at all protected, as in the case of hygrophilous biological communities of the riparian zone associated with the clastic lithotypes within the Temperate and Transitional Regions. The environmental assessment based on the evaluation of the landscape conservation status at the Land Facet level instead supports reactive approaches based on the distribution of endangered ecosystems, as in the case of coastal and plain ecosystems on sedimentary deposits, where human activities have reached an unsustainable level and interventions for the recovery of natural and semi-natural habitats are urgently required. When the ILC instead yields medium values, as for most of the Land Facets in the hilly belt of sedimentary deposits, the strategies that should be promoted most are those designed to overcome conflicts between economic exploitation of land and preservation of biological resources and services, such as the valorisation of agrarian systems of high nature value according to the Axis 2 of the National Strategic Plan for the Rural Development 2007–2013 (PSN – http:// www.reterurale.it/downloads/cd/PSN/Psn_21_06_2010.pdf). Although the environmental analyses at the national level inevitably present some shortcomings, they all provide inspiring hints for further investigations. The main limitations of the gap analysis are (i) the adoption of a single and arbitrary target that does not vary according to the different land types and is not based on the actual species occurrence within these types, and (ii) the evaluation of only the representativeness of the national protection site networks, neither of their efficiency nor vulnerability bias (sensu Pressey and Taffs, 2001). Nevertheless, the 10% target allowed to compare the gaps in the Land Systems with those obtained for PNV diversity (Rosati et al.,

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2008), thereby placing the critical conservation states that emerged from both analyses within a more accurate framework as regards biophysical heterogeneity. Indeed, the most widespread ‘‘Total gaps’’ are confirmed for the ecosystems belonging to the Temperate macroclimate, particularly as regards the combination of vegetation series typical of the clastic lithological type. However, we have now identified further priorities for proactive conservation policies and vulnerability assessments, such as the combination of vegetation series typical of the chemical lithotype within the Temperate Region, the clastic lithotype within the Transitional Region and the terraced clastic lithotype within the Mediterranean Region, all of which are afforded very poor coverage by the existing protection networks. ‘‘Partial gaps’’ confirm that the Natura2000 network, which extends over a larger area and contains a far higher number of sites, is also more representative than the system of NPAs, which have often been selected according to socio-economic, aesthetic and political rather than ecological criteria (Maiorano et al., 2006). Therefore, ‘‘Partial gaps’’ indicate which Land System types require further NPAs in order to fill the gaps in the promotion of sustainable activities and the conservation of natural processes and components, besides the conservation of natural habitats and wild species of European interest. Moreover, the ‘‘Protected’’ category allows the identification of biophysical systems that are likely to be over-represented, such as the combination of calcicolous vegetation series typical of the carbonate deposits in both the Temperate and Transitional Regions, and consequently reduce the overall efficiency of the protection networks. The main shortcoming as regards the analysis of landscape conservation status is the short-term validity of the LC maps. Indeed, when this project was conducted the data available at the national level were based on the I&CLC2000, which may no longer be strictly representative of the current environmental conditions. The ILC values presented here however act as useful reference points for the monitoring process recently undertaken in Italy at different administrative levels and aimed at environmental accountability. Another potential shortcoming of this paper is that in this preliminary work we did not explicitly explore the relationship between ILC evaluation and the gap analysis. We may, however, already state that Land Facet types with a high and very high conservation status should be chosen to house new protected areas, particularly if they fall within Total gap areas or if they are in a position that is strategic for the enhancement of the connectivity of the protected areas network. In conclusion, the results that emerge from this project may serve as a basis to tackle a number of multi-scale problems in the field of landscape management and to plan effective and complementary interventions within the framework of the recently approved National Biodiversity Strategy, particularly as regards the working fields on ‘‘Species, habitats and landscapes’’, ‘‘Protected areas’’, and ‘‘Agriculture’’. Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at doi:10.1016/j.biocon.2011.12.028. References Andreella, M., Biliotti, M., Bonella, G., Cinquepalmi, F., Dupré, E., La Posta, A., Luchetti, D., Pettiti, L., Tartaglini, N., Vindigni, V., 2010. La Strategia Nazionale per la Biodiversità. Un percorso condiviso e partecipato. Ministero dell’Ambiente e della Tutela del Territorio e del Mare, Roma. Bailey, R.G., 1995. Ecoregions of the Continents, US Department of Agriculture, Forest Service, Washington. Bailey, R.G., 1996. Ecosystem Geography. Springer-Verlag, New York. Bailey, R.G., 2004. Identifying ecoregion boundaries. Environmental Management 34 (Suppl. 1), S14–S26.

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