The establishment of ecological networks reflects the most recent policy and practices in environmental management and conservation. It corresponds fully both to the concept for biodiversity conservation at a territorial level and the new approach, the constitution of one functional system. The present understanding of the ecological networks states that the network is a uniform system of interrelated territories with high nature value and the conservation measures applied are coordinated. The main goal is the long-lasting and sustainable conservation of species, natural habitats and landscapes as well as all nature resources. It is accepted that the ecological network consists of four main components – core zones, zones of restoration, buffer zones and ecological corridors. The ecological corridors provide the conditions for sufficient exchange of genetic material between the relatively isolated local populations and the formation of one metapopulation. Otherwise the isolated, small populations are doomed to extinction and the vitality of the large populations decreases when conditions become critical. An important element of the above-ground corridors are construction of highways and railways, which are the main fragmenting factor. Depending on the conservation objects – nature complexes, organisms or habitats – there are numerous ways to establish ecological networks with various means of interconnections: wetlands of international importance, sites of world culture and nature heritage, biosphere reserves, important bird areas, important plant areas, herpetologically important areas, prime butterfly areas, pan-European ecological network, EMERALD ecological network, European network of biogenetic reserves and last, but not least the European ecological network NATURA 2000. The European ecological network NATURA 2000 (http://www.natura.org) is of the highest importance for the preservation of the natural habitats. It is a pan-European system of protected areas and ecological corridors whose identification is based on scientific criteria, thus putting into force the EU Directives 79/409 for the protection of birds and 92/43 for the conservation of the natural habitats and the habitats of the wild flora and fauna. The conservation measures in these directives postulate the establishment of a multifunctional uniform network of key areas – Special Protection Areas (SPA) and Sites of Community Importance (SCI), interconnected by ecological corridors that guarantee the maintenance and restoration of the favourable conservation status of the natural habitats and the habitats of the respective species in their natural areas of distribution. Directive 92/43 postulates the rules for the establishment of this ecological network.
The favourable conservation status is a measure for the effectiveness of the implementation of Directive 92/43. The state of a species is considered favourable when its population and area of distribution are stable or are increasing and its habitats are large enough for the long-term maintenance of its population. The state of a natural habitat is considered favourable when its area of distribution is stable or is increasing, its structure and function are stable and the status of the species typical for this habitat is favourable. The natural habitats (90 in number) and plant and animal species (approximately 262 in number) in Bulgaria that are to be protected in the NATURA sites are listed in the annexes of the two Directives and respectively in Annex 1 and Annex 2 of the Bulgarian Biodiversity Act. Special mechanisms have been developed that allow changes in the annexes of the directives which will reflect the taxonomic status of the species and their status as well as changes that will occur after the accession of new states to the EU. The goal of the European Ecological Network NATURA 2000 is to achieve effective conservation of the protected sites as well as the integration of the conservation activities with the principles of sustainable use of the biological diversity as a part of the natural resources of the member states. This network is being developed in all members states of the EU, applying one and the same standardized procedure to all countries. The member states and candidate countries identify and suggest a list of sites (called sites of community interest) for the conservation of habitats (Annex I) and species (Annex II) from Directive 92/43. This list is to be sent in the European Commission in the form of specific documents: standard forms accompanied by maps, photos, etc. The information about the suggested sites is evaluated by the Commission with the help of the European Environmental Agency for each biogeographic region of the EU in each country. Consequently, again for each country and each biogeographic region, the procedure called ‘biogeographic seminar’ is implemented. It is a discussion organized by the EC on the list of sites and species suggested to be protected as well as the sites of community interest. Representatives of the state authorities of the respective member states, experts and NGOs take part in this seminar. After the seminar the Commission officially evaluates and accepts the list of sites of community interest. The Commission can oblige the respective country to add new species, habitats or sites, if the suggested lists are considered incomplete. Consequently, the member states are obliged to proclaim these areas as Special Protection Areas with orders of the minister of the relevant authority, to identify priorities based on their importance for the natural habitats or species habitats, to define the restrictive regimes. The member states are obliged to formulate conservation goals for the Special Protection Areas, including management plans that correspond to the ecological demands of the habitat types and species within their borders. The prevention measures play a major role in the conservation process. They include specific impact assessments of all plans, programs and projects within the protected zones or in close proximity (when a negative impact on the zone is envisaged), as well as mitigation and compensation measures.
The establishment of the NATURA 2000 network in Bulgaria is postulated by the Biodiversity Act, where the sites of this network are called “protected zones”. The process began in 2002 together with the accession of Bulgaria to the EU and finished in 2008 when the protected sites were accepted by the EC after the biogeographic seminar for Bulgaria and Romania that took place in June 2008 in the town of Sibiu, Romania. For a small number of species and habitats in Bulgaria, the European Commission has decided that further designation of protected sites is necessary to consolidate the network. According to the two EU Directives 335 protected sites constitute the European Ecological Network NATURA 2000 in Bulgaria (114 according to the Bird Directive and 231 according to the “Habitats” Directive). The total area is 3 901 084 ha that constitutes 34,3 % of the country’s territory (Fig. 1). The distribution of the habitats according to the main types of ecosystems and nature phenomena is presented in Table 1.
Fig. 1. Protected sites from the European Ecological Network NATURA 2000.
Table 1. Area coverage (in hectares) of the natural habitats included in NATURA 2000.
| Natural habitats | ha |
|---|---|
| Coastal and halophytic habitats | 13 312 |
| Coastal sand dunes and continental dunes | 1 892 |
| Fresh-water habitats | 13 400 |
| Moderate continental scrub | 56 667 |
| Sclerophilous scrub | 13 794 |
| Natural and semi-natural herbaceous formations | 350 636 |
| Mires, bogs and fens | 2 085 |
| Rock habitats | 41 732 |
| Forests | 1 216 898 |
The biogeographic regions are represented in the network in Bulgaria as follows: alpine – 38 zones, continental – 285 zones, and Black Sea region – 46 zones. The Bulgarian part of the European Ecological Network NATURA 2000 encompass 90 habitat types (Table 2), or 38,86% of all 231 habitat types presently identified and designated in the EU (Annex I of Directive 92/43/EEC). The habitats in Bulgaria are distributed according to the main categories as follows “Forests” – 27, or 33,75% of all habitats in Europe, followed by “Natural and semi-natural herbaceous formations” – 18, or 58,06% respectively. Third place is occupied by “Coastal and halophytic habitats” – 12, or 42,86%. Relatively high at national level is the number of “ Moderate continental scrub” – 8, or 66% of all habitats of this type in Europe. The remaining habitat types are distributed as follows: “Rock habitats and caves” –7, or 50%; “Fresh-water habitats” ‑ 6, or 31,58%; “Coastal sand dunes and continental dunes” – 6, or 28,57%; “Mires, bogs and fens” – 4, or 33,33% and “Sclerophyllous scrub (matoral)” – 2, or 15,38% of the number of these habitats in Europe. The data presented in Table 2, the areas and assessments of the national coverage and representativeness of the habitats, are discussed and accepted by an expert group identified by Order 860/20.11.2007 of the Minister of Environment and Waters. According to the Habitat Directive (92/43) and the Interpretation Manual EUR 27, the priority habitat types in Bulgaria (Table 2) are 27, i.e. 30% of the total number of habitats included in the NATURA 2000 network in Bulgaria. They represent 36,62% of the priority habitats in the European Union. Twenty-two species of vascular plants distributed in Bulgaria are included in the Annexes of Directive 92/43 – 1 fern species, 16 species of seeded plants and 5 moss species. Approximately 100 localities of these species are included in the protected zones of the NATURA 2000 network.
The animals (including some extinct species) from Annex 2 of Directive 92/43, whose habitats are protected within the protected zones in the country are distributed as follows: mammals – 26 species, amphibians and reptiles – 14 species, fishes – 28 species and invertebrates – 39 species. One hundred and thirty-three bird species from Directive 79/409 have been found in Bulgaria (Kostadinova & Gramatikov 2007).
Table 2. Nature habitats from Annex 1 of the Habitat Directive in Bulgaria. The priority habitats are marked with an asterisk (*).
| Code | Natural habitat | National coverage [ha] | Percent of the network [%] | Number of zones where it occurs |
|---|---|---|---|---|
| 1110 | Sandbanks which are slightly covered by sea water all the time | 3 900 | 59 | 8 |
| 1130 | Estuaries | 62 | 54 | 4 |
| 1140 | Mudflats and sandflats not covered by seawater at low tide | 150 | 51 | 12 |
| 1150* | Coastal lagoons | 3 051 | 92 | 7 |
| 1160 | Large shallow inlets and bays | 10 423 | 26 | 9 |
| 1170 | Reefs | 889 | 86 | 9 |
| 1210 | Annual vegetation of drift lines | 82 | 38 | 9 |
| 1240 | Vegetated sea cliffs of the Mediterranean coasts with endemic Limonium spp. | 85 | 44 | 9 |
| 1310 | Salicornia and other annuals colonising mud and sand | 212 | 87 | 5 |
| 1340* | Inland salt meadows | 300 | 46 | 2 |
| 1410 | Mediterranean salt meadows | 92 | 55 | 6 |
| 1530* | Pannonic salt steppes and salt marshes | 13 175 | 31 | 13 |
| 2110 | Embryonic shifting dunes | 667 | 58 | 14 |
| 2120 | Shifting dunes along the shoreline with Ammophila arenaria (white dunes) | 165 | 73 | 11 |
| 2130* | Fixed coastal dunes with herbaceous vegetation (grey dunes) | 401 | 89 | 9 |
| 2180 | Wooded dunes of the Atlantic, Continental and Boreal region | 115 | 100 | 4 |
| 2190 | Humid dune slacks | 19 | 67 | 5 |
| 2340* | Pannonic inland dunes | 1 000 | 90 | 7 |
| 3130 | Oligotrophic to mesotrophic standing waters with vegetation of Littorelletea uniflorae and/or Isoeto-Nanojuncetea | 2346 | 54 | 17 |
| 3140 | Hard oligo-mesotrophic waters with benthic vegetation of Chara spp. | 20 | 31 | 9 |
| 3150 | Natural eutrophic lakes with Magnopotamion or Hydrocharition-type vegetation | 11 000 | 68 | 34 |
| 3160 | Natural dystrophic lakes and ponds | 150 | 44 | 5 |
| 3260 | Water courses of plain to montane levels with the Ranunculion fluitantis and Callitricho-Batrachion vegetation | 6 000 | 60 | 36 |
| 3270 | Rivers with muddy banks with Chenopodion rubri p.p. and Bidention p.p. vegetation | 2 105 | 45 | 25 |
| 4030 | European dry heaths | 200 | 99 | 2 |
| 4060 | Alpine and Boreal heaths | 46 000 | 82 | 18 |
| 4070* | Bushes with Pinus mugo | 14 972 | 95 | 9 |
| 4080 | Sub-Arctic Salix spp. scrub | 41 | 100 | 3 |
| 4090 | Endemic oro-Mediterranean heaths with gorse | 12 531 | 28 | 9 |
| 40A0* | Subcontinental peri-Pannonic scrub | 870 | 94 | 17 |
| 40B0 | Rhodope Potentilla fruticosa thickets | 1 | 100 | 1 |
| 40C0* | Ponto-Sarmatic deciduous thickets | 2 | 91 | 5 |
| 5130 | Juniperus communis formations on heaths or calcareous grasslands | 1 021 | 79 | 10 |
| 5210 | Arborescent matoral with Juniperus spp. | 18 441 | 70 | 23 |
| 6110* | Rupicolous calcareous or basophilic grasslands of Alysso-Sedion albi | 3 139 | 51 | 116 |
| 6150 | Siliceous alpine and boreal grasslands | 12 000 | 59 | 6 |
| 6170 | Alpine and subalpine calcareous grasslands | 5 000 | 73 | 5 |
| 6210 | Semi-natural dry grasslands and scrubland on calcareous substrates (Festuco-Brometalia) (*important orchid sites) | 161 136 | 81 | 77 |
| 6220* | Pseudo-steppe with grasses and annuals of the Thero-Brachypodietea | 49 062 | 69 | 27 |
| 6230* | Species-rich Nardus grasslands, on siliceous substrates in mountain areas (and submountain areas, in Continental Europe) | 50 000 | 60 | 14 |
| 6240* | Sub-Pannonic steppic grasslands | 65 600 | 34 | 24 |
| 6250* | Pannonic loess steppic grasslands | 30 176 | 30 | 33 |
| 6260* | Pannonic sand steppes | 401 | 100 | 2 |
| 62A0 | Eastern sub-Mediterranean dry grasslands | 49 306 | 85 | 37 |
| 62C0* | Ponto-Sarmatic steppes | 3 000 | 82 | 8 |
| 62D0 | Oro-Moesian acidophilous grasslands | 53 600 | 64 | 16 |
| 6410 | Molinia meadows on calcareous, peaty or clayey-silt-laden soils (Molinion caeruleae) | 380 | 100 | 6 |
| 6420 | Mediterranean tall herb humid grasslands of the Molinio-Holoschoenion | 50 | 48 | 5 |
| 6430 | Hydrophilous tall herb fringe communities of plains and of montane to alpine levels | 16 900 | 58 | 57 |
| 6440 | Alluvial meadows of river valleys of the Cnidion dubii | 400 | 28 | 3 |
| 6510 | Lowland hay meadows | 4 802 | 85 | 42 |
| 6520 | Mountain hay meadows | 47 887 | 40 | 23 |
| 7140 | Transition mires and quaking bogs | 1 265 | 76 | 11 |
| 7210* | Calcareous fens with Cladium mariscus and species of the Caricion davallianae | 25 | 100 | 1 |
| 7220* | Petrifying springs with tufa formation (Cratoneurion) | 20 | 77 | 16 |
| 7230 | Alkaline fens | 2 010 | 54 | 6 |
| 8110 | Siliceous screes of montane to snow levels (Androsacetalia alpinae and Galeopsetalia ladani) | 28 833 | 54 | 11 |
| 8120 | Calcareous and schist screes of the montane to alpine levels | 2 000 | 51 | 6 |
| 8210 | Calcareous rocky slopes with chasmophytic vegetation | 23 760 | 40 | 45 |
| 8220 | Siliceous rocky slopes with chasmophytic vegetation | 12 531 | 63 | 23 |
| 8230 | Siliceous rock with pioneer vegetation of the Sedo-Scleranthion or of the Sedo albi-Veronicion dillenii | 8 782 | 67 | 56 |
| 8310 | Caves not open to the public | 1 850 | 93 | 52 |
| 8330 | Submerged or partially submerged sea caves | 50 | 23 | 4 |
| 9110 | Luzulo-Fagetum beech forests | 8 471 | 76 | 32 |
| 9130 | Asperulo-Fagetum beech forests | 271 017 | 63 | 40 |
| 9150 | Medio-European limestone beech forests of the Cephalanthero-Fagion | 107 669 | 62 | 51 |
| 9170 | Galio-Carpinetum oak-hornbeam forests | 249 115 | 47 | 60 |
| 9180* | Tilio-Acerion forests of slopes, screes and ravines | 38 558 | 41 | 71 |
| 91AA* | Eastern White oak woods | 74 734 | 59 | 46 |
| 91BA | Moesian Silver fir forests | 27 606 | 77 | 27 |
| 91CA | Rhodopide and Balkan Range Scots pine forests | 150 305 | 68 | 21 |
| 91D0* | Bog woodland | 67 | 65 | 5 |
| 91E0* | Alluvial forests with Alnus glutinosa and Fraxinus excelsior (Alno-Padion, Alnion incanae, Salicion albae) | 12 000 | 69 | 104 |
| 91F0 | Riparian mixed forests of Quercus robur, Ulmus laevis and Ulmus minor, Fraxinus excelsior or Fraxinus angustifolia, along the great rivers (Ulmenion minoris) | 5 871 | 89 | 48 |
| 91G0* | Pannonic woods with Quercus petraea and Carpinus betulus | 71 216 | 43 | 63 |
| 91H0* | Pannonic woods with Quercus pubescens | 18 988 | 39 | 63 |
| 91I0* | Euro-Siberian steppic woods with Quercus spp. | 54 692 | 47 | 31 |
| 91M0 | Pannonic-Balkan Turkish oak- Sessile oak forests | 753 315 | 49 | 145 |
| 91S0* | Western Pontic beech forests | 41 430 | 86 | 12 |
| 91W0 | Moesian beech forests | 127 907 | 57 | 52 |
| 91Z0 | Moesian Silver lime woods | 29 022 | 50 | 72 |
| 9260 | Castanea sativa woods | 2 824 | 71 | 5 |
| 9270 | Hellenic beech forests with Abies borisii-regis | 426 | 97 | 7 |
| 92A0 | Salix alba and Populus alba galleries | 4 442 | 45 | 31 |
| 92C0 | Platanus orientalis and Liquidambar orientalis woods | 291 | 89 | 11 |
| 92D0 | Southern riparian galleries and thickets (Nerio-Tamaricetea and Securinegion tinctoriae) | 120 | 77 | 6 |
| 9410 | Acidophilous Picea forests of the montane to alpine levels (Vaccinio-Piceetea) | 84 167 | 76 | 15 |
| 9530* | (Sub-)Mediterranean pine forests with endemic black pines | 39 490 | 47 | 17 |
| 9560* | Endemic forests with Juniperus spp. | 603 | 100 | 3 |
| 95A0 | High oro-Mediterranean pine forests | 15 400 | 100 | 9 |
The protection of the natural habitats and species within the European Ecological Network Natura 2000 needs the active participation of the whole society. This participation should be based on sustainable economic development, reasonable use of natural resources in the protected zones of the network, education of ecological attitude and popularisation of the importance of the ecological network for our future existence as a part of life on the Earth. Preserved nature is also a sort of capital for a successful economy and livelihood through ecotourism, ecological farming and stockbreeding, sustainable forestry, etc. It is very important for the local people and communities, especially in areas with high biodiversity and low rates of industrialization. Nature conservation means also conservation of soil, water, air and all natural resources upon which our future depends.