Of the 8 ecosystem groups identified in Europe (according to the Corine Biotopes Project classification), 6 are identified in Macin Mountains: forests, shrubs and meadows, rivers, swamps, rocklands and debris, archaeological sites. The most representative and expanded forest ecosystems are defined by the Moesian-Western Pontic sessile oak, hornbeam and silver lime forests with Fraxinus coriarefolia, Nectaroscordum siculum ssp. bulgaricum, in combination with forests of sessile oak, Oriental hornbeam, lime tree and other xerothermal forests (situated on altitudes higher than 250m); there are also associations of western Pontic forests of white oak, Oriental hornbeam and flowering ash with Paeonia peregrina, Asparagus verticillatus şi Pyrus elaeagrifolia (150 - 250 m). In the park there are fragile habitats of meadows, hay-fields with forests and silicious rocklands, characterized by a great diversity of rare or vulnerable species that grow on biotopes with extereme conditions (climate and edaphic conditions) or situated at the limit of the natural vegetation habits which need to be conserved through the establishment of new protected areas.  The forest ecosystems which are situated at the limit of the natural vegetation can also be defined as fragile because of the shrubs’ difficult natural regeneration caused by unfavourable climate conditions, overgrazing and continual decreasing of valuable native species in ecosystems (sessile oak, oak,  European ash, etc.). The most serious threat for biodiversity is represented by the destruction of the rocky zones with rare species, because of the granite quarries. The list of priority habitats is included in Annex 2.3.3.

The priority habitats of MMNP according to the Paleartic classification in 1999 are:

§      Habitat: !41.1 Beech forest

o     Habitat: 41.1F Beech forests in Dobrudja

Association and forest type:

-         Tilio-Corydali-Fagetum;

-         Carpino-Fagetum tilietosum tomentosae;

-         5314 Hill mixed hardwood stand with sessile oak and beech of medium productivity;

-         4231 Dobrudjan beech-hornbeam association with Carex pilosa.

§      Habitat: !41.2 Oak and hornbeam forests

o     Habitat: 41.2C22 Forests of sessile oak with hornbeam in Moldova and Muntenia

Association and forest type:

-         Tilio tomentosae – Carpinetum betuli;

-         5321 Sessile oak-mixed hardwood stand of high productivity;

-         5322 Hill mixed hardwood stand with sessile oak of high productivity;

-         5323 Hill mixed hardwood stand with sessile oak of medium productivity;

-         5324 Hill mixed hardwood stand with sessile oak of medium productivity ;

§      5331 Dobrudjan hill mixed hardwood stand of medium productivity

o     Habitat: !41.7 Termophyle and sub-Mediterranean oak forests

o     Habitat: 41.73724 Moesian forests of white oak with Galium dasypodum

Association and forest type:

-         Galio dasypodi - Quercetum pubescentis;

-         8221 Pure white oak in forest steppe growing on a loess or loam substratum (smoke tree facies);

-         8223 Pure white oak in Dobrudjan forest steppe on superficial soil.

o     Habitat: 41.73723 Moesian forests of white oak with Paeonia peregrina

Association and forest type:

-         Paeonio peregrinae – Carpinetum orientalis;

-         8212 Pure white oak on deep soil in Dobrudja;

-         8213 Pure white oak with Oriental hornbeam in the forest zone;

-         8224 White oak with Oriental hornbeam in forest steppe;

-         8531 Dobrudjan mixed hardwood stand with white oak;

-         8221 Pure white oak in forest steppe growing on a loess/loam substratum (situations in Dobrudja – hornbeam and flowering ash); (14) Mixture of sessile oak and white oak; (29) Mixed hardwood stand with white oak; (17) Mixture of white oak and Italian oak;

-         8531 Dobrudjan hardwood stand with white oak;

-         8224 White oak with Oriental hornbeam in forest steppe.   

o     Habitat: 41.7683 Forests of hornbeam, lime tree, oak in Dobrudja – association Carpino -Tilienion tomentosae, which comprises the following 3 sub-units:

-       Habitat: 41.76831 Forests of sessile oak with Paeonia peregrina in Dobrudja

Association and forest type:

-         Fraxino orni – Quercetum dalechampii;

-         5161 Normal sessile oak stand with oriental hornbeam (m);

-         5162 Sessile oak stand with Oriental hornbeam of medium productivity (i);

-         5163 Sessile oak with smoke tree.

-       Habitat: 41.76832 Sessile oak, leme tree, Oriental hornbeam, European ash forests in Dobrudja

Association and forest type:

-         Nectaroscordo - Tilietum tomentosae (inclusiv  Galantho plicatae - Tilietum tomentosae)

-         5332 Sessile oak stand – Dobrudjan mixed hardwood stand of low productivity (i);

-         5333 Dobrudjan mixed hardwood stand of low productivity (i);

-         5325 Forest steppe mixed hardwood stand with sessile oak. 

-       Habitat: 41.76833 Forests of greyish oak, lime tree, oriental hornbeam in Dobrudja

Association and forest type:

-         Querco pedunculiflorae  - Tilietum tomentosae (Syn.: Polyquerco - Tilietum tomentosae  - in Sanda 2002);

-         8511 Forest steppe mixed hardwood stand with greyish oak;

-         8521 Dobrudjan oak stand with mixed hardwood stand and white/greyish oak;

-         8422 Mixture of sessile oak and greyish oak in Dobrudja.

o     Habitat: 41.7A221 Pontic forests of greyish oak and Tartarian maple

Association and forest type:

-         Quercetum pedunculiflorae (Syn.: Violo suavis - Quercetum pedunculiflorae, Centaureo stenolepi - Quercetum pedunculiflorae - in Sanda 2002), including Quercetum pedunculiflorae subas. Carpinetosum;

-         8111 Pure greyish oak growing on highly degraded Chernozem with a loess substratum;

-         8115 Forest steppe greyish oak of medium productivity;

-         8116 Late flourishing greyish oak growing in Dobrudjan forest steppe, of medium productivity;

-         8311 Mixture of greyish and white oak;

-         8511 Mixed hardwood stand of forest steppe with greyish oak (white oak facies);

-         8512 Mixed hardwood stand of forest steppe growing on hills (white oak, lime tree, elm, European ash;

-         8513 Dobrudjan oak stand-mixed hardwood stand with greyish oak.      

§      Habitat:

-       !93 Forest steppes

-       34.92 Pontic-Sarmatian steppes;

-       34.9211 West-Pontic steppes with thyme (Thymus zygoides);

-       34.9213 West-Pontic steppes with Stipa sp.;

-       31.8B721 Pontic-Sarmatian shrubs withcommon hawthorn (Crataegus sp.);

-       31.8B71 Pontic-Sarmatian steppes with shrubs;

-       41.73723 Moesian forests of white oak (Quercus pubescens) with Paeonia peregrina;

-       41.7A221 Pontic open woods of greyish oak (Quercus pedunculiflora) with Acer tataricum;

-       41.73724 Moesian forests of white oak (Quercus pubescens) with Galium dasypodium.

 

According to the CORINE classification, in MMNP there are the following types of habitats:

1. Rockland habitats: The saxicole vegetation includes a series of species adapted to the ecological conditions specific to the rocklands, such as: Alyssum saxatile, Moehringia grisebachii, Campanula romanica, Dianthus nardiformis, Sempervivum ruthenicum Polypodium vuIgare, Asplenium trichomanes, Asplemium.Ruta muraria, Cystopteris fragilis, Silene compacta etc. This type of habitat is spread on most of Pricopan Summit and the western and southern parts of Macin Mountains.

2. Steppe habitats: The herbaceous species, representative for steppe habitats are (most of them grow on a rock bed): Allium rotundum, Artemisia austriaca, Botriochloa ischaemum, Convolvulus canthabrica, Dianthus nardiformis, Festuca valesiaca, Kochia prostrata, Poa bulbosa etc. Vegetal associations (phitocenoses) characteristic to this type of habitat are: Festucetum valesiacae, Poaetum bulbosae and Teucrium polium - Scleranthus perennis (on the sides of Pricopan Summit and at its bottom, south-western part of Macin Summit), Kochietum prostratae (at the bottom of Pricopan Summit sides), Andropogonetum ischaemi (on Pricopan Summit and in the steppe and forest steppe on Macin Summit), Agropyretum cristatae (at the bottom of Cheia hill) and Sambucetum ebuli (the place of the former sheepfold of Pricopan Summit).

3. Forest habitats: The forest habitats inside MMNP fit into the class of Balkan mesophylous forests. Associations are defined by the species Quercus petraea, Q. dalechampii, Q. polycarpa, mixed with lime tree species (Tilia cordata, T. tomentosa, T. platyphylos), European ash (Fraxinus excelsior, F. ornus), hornbeam (Carpinus betulus) and Oriental hornbeam (Carpinus orientalis). The associations characteristic to this habitat are Galantho (plicatae) – Tilietum (tomentosae), Nectaroscordo - Tilietum (tomentosae), Querco (pedunculiflorae) – Tilietum (tomentosae), Tilio (tomentosae) - Carpinetum (betuli) and in the Dobrudjan beech-hornbeam stand association with  Carex pilosa (the last type of vegetation has a limited distribution in the Beech Valley).

4. Forest steppe habitats: The transition habitats between forest steppe and mesophylous forests are represented by xerothermal sub-Mediterranean forests, with a fragmented structure. The vegetal association characteristic to this transition habitat is Paeonio (peregrinae) - Carpinetum (orientalis). The typical forest steppe habitats are characterized by an alternance of forest patches and steppe meadows or rocklands. The associations characteristic to this type of habitat are Achilleo (coarctatae) - Quercetum pubescentis and Gymnospermio (altaicae) - Celtetum glabratae.

5. Wet lands: This type of habitat is located in the spring zones and along water courses (most of them having a temporary character). The species characteristic for the wet lands are: Phragmites australis, Solanum nigrum, Potentilla reptans, Heleocharis palustris, Juncus gerardi, Lythrum thymifolia, L. salicaria, etc.