The project area surrounding the municipalities of Gravina in Puglia and Altamura is characterised by two kinds of EU habitats, classified with the Nature 2000 code 6220 and 62A0.
Here below a scientific description of these habitats and of their peculiarity in the project area.
Thero-Brachypodietea sub-steppe paths with grasses and annuals (Pseudo-steppe with grasses and annuals of the Thero-Brachypodietea – Natura 2000 Code: 6220*)
The habitat Pseudo-steppe with grasses and annuals of the Thero-Brachypodietea (Nature 2000 code: 6220*) is featured by xerophilous grasslands meso and thermo-Mediterranean with sward low and rich in therophites, on oligotrophic soils with substrates rich in bases, often calcareous.
This habitat, therefore, includes aspects of the vegetation of Mediterranean environment related to the so-called “pseudo-steppes” with herbaceous perennial and annual herbs. These communities generally semi-natural originate from involution of scrubland vegetation for overgrazing, fire or trimming. This habitat in Italy is present especially in the South and in the Islands.
From the conservation point of view, the habitat 6220 results particularly interesting being included in the Annex I of the Directive 92/43/EEC «Habitat» as priority one, a habitat for which the EU has a particular responsibility for the high environmental value.
The wording Thero-Brachypodietea present in this habitat’s name refers to the phyto-sociological class in which were historically framed the secondary grassland communities usually present in the Mediterranean environment. According to some authors, the syntaxonomic framework of these communities foresees the breakdown in different classes floristically and ecologically defined.
The community of plants, mostly perennial, are framed in the phyto-sociological classes Lygeo-Stipetea and Poetea bulbosae, while the communities of annual plants in the class Tuberarietea guttatae (syn = Helianthemetea guttati).
In the first class are framed communities of perennial Mediterranean grasses, mostly xeromorph, organized in low turf more or less continuous with groups of characteristic higher grasses on hydromorphic, non-salinized soils.
From the point of view of the dynamic of the fitocenotic successions, they represent one of the evolutionary stages towards the evergreen Mediterranean sclerophyllous forests of Quercetea ilicis.
The second class includes the semi-arid or humid meadows, widespread especially in the western Mediterranean region (purely oceanic) of the thermo-Mediterranean climate up to the supra-Mediterranean one, maintained sparse and fertilized by the sheep grazing and dominated by low perennials, camefite emicrittofite as Poa bulbosa, Trifolium ssp. and Plantago spp.
In the third class, Tuberarietea guttatae, are framed the communities of pioneer and ephemeral plants active in spring and early summer, dominated by low therophytes (even graminoidi) not nitrophilous distributed in the Mediterranean region with radiation in the Euro-Siberian region, but only on dry land and initial areas of Sub-Mediterranean and steppe.
Considering just the phytosociological habitat of this class included in the habitat 6220, we have that acidophilic or calcifuges communities are located in the order Tuberarietalia guttatae while those that are found on rich carbonate, clay, dolomite or gypsum soil in Brachypodietalia distachyi.
In the project area, the vegetation featuring this habitat is mixed with grassland vegetation of the habitat 62A0 within the clearings of some forest areas and along the edge of the paths.
The main threats to this habitat are made by a) the abandonment of pastoral systems, b) the overgrazing, c) the passage of fire, d) forestation and by e) the conversion into agricultural land.
Considering the first two threats, it should be underlined that the herbaceous communities of this habitat strictly depend on grazing. The absence of such activity rapidly triggers the dynamic succession towards the stages of prairie shrubs and/or wood, while overgrazing results in a depletion of the herbaceous communities, soil exposure to agents that cause erosion and excessive soil fertility, which facilitates the entry and expansion of plant species nitrophilous.
Dry grasslands of the Sub-Mediterranean eastern region (Scorzoneratalia villosae)
(Eastern sub-Mediterranean dry grasslands [Scorzoneretalia villosae] – Natura 2000 Code: 62A0)
The habitat eastern sub-Mediterranean dry grasslands (Scorzoneretalia villosae) (Nature 2000 Code: 62A0) is characterized by sub-Mediterranean xeric grasslands with Balkan imprint within the order Scorzonero-Chrysopogonetalia (= Scorzoneratalia villosae).
The habitat is found in north-eastern (eastern Friuli, along the southern edge of the Alps, till the eastern Lombardy) and south-eastern (Molise, Puglia and Basilicata) Italy.
In South-eastern Italy the communities included in this habitat fall within and endemic alliance (Hippocrepido glaucae-Stipion austroitalicae) floristic and ecologically well differentiated which group xeric grasslands of the class Festuco Brometea with accentuated characters of Mediterranean. These xeric grassland even if presenting some affinities with the trans-Adriatic and north-Adriatic ones are featured both for their endemic quota and for the presence of species which seem to have found here their sinecological optimum.
In the project area this habitat’s grasslands are much more diffused than those described within the previous habitat. These grasslands are constituted especially of xerogramineti with special features, dominated by Stipa austroitalica ssp. austroitalica, Festuca Circummediterranea and Koeler splendens, which usually grow on rocky, shallow soils.
The conservation status of this habitat in some areas is not good, for phenomena of overgrazing, which lead to a trivialization of the floristic cortege and to the ingression of nitrophilous entities, and for practices of “stone clearance,” which, especially in the past, resulted in the almost total destruction of the habitat.
The threats for this habitat are the same specified for the habitat 6220.
The most characteristic element in the landscape of the Province of Bari is the karst, which has its highest expression of the Murge Plateau, which is the portion of the province with the highest biodiversity.
The general lack of surface hydrography, the lack of trees coverage and the high summer temperatures have led to the evolution of a very special environment with huge extensions of steppe habitats in which a wildlife refuge is now rare in other regions of Italy, where the agricultural transformation in recent decades has strongly affected the sheep-breeding and its associated habitats.
The Alta Murgia is the most extensive and representative area of steppe of the peninsular Italy as a whole and is characterized by the presence of the two priority habitats described above.
These habitats are associated with significant populations of species typical of the steppe areas like Calandra lark (Melanocorypha calandra), Calandrella lark (Calandrella brachydactyla), Wood lark (Lullula arborea), Tawny pipit (Anthus campestris).
In this area lives one of the most important European population of Lesser Kestrel (Falco naumanni), a priority species from the conservation and scientific research point of view.
Also significant is the breeding population of Lanner (Falco biarmicus), another priority species, while Little Bustard (Tetrax tetrax) is now extinct.
In general, the plateau of the Murge has a high diversity of plunderers, both diurnal and nocturnal, like the Kestrel (Falco tunninculus), the Sparrow – hawk (Accipiter nisus), the Barn Owl (Tyto alba), the Owl (Athena noctua), the Screech Owl (Asio otus) and the Horn Owl (Otus scops).
Rupicolous habitats, ravines and sinkholes are inhabited by numerous other species like the Blue Rock – Thrush (Monticola solitarius), the Roller (Coracias garrulus), the Raven (Corvus corax), the Black – Throated Wheatear (Oenanthe hispanica).
A species of remarkable bio-geographic value found in the wooden areas is the Cirl Bunting (Emberiza melanocephala).
Faunal aspects related to the class of mammals are less present than the birds, however, in the project area are detectable species absent or rare in the rest of the region.
Interesting is the presence of Porcupine (Hystrix cristata), that – despite what happens in the rest of the Italy – in Apulia shows a contraction of its habitat, and the Wildcat (Felis silvestris), of which, however, recent observations are not known.
The environment still in good condition makes possible the presence of many other species of mammals such as the Badger (Meles meles), the Fox (Vulpes vulpes), the Beech – Marten (Martes foina), the Weasel (Mustela nivalis), very numerous in this part of the region.
Totally lacking big animals such as Cervidae (Deer, Roe Deer, Fallow Deer) and carnivores like the Wolf.
The only exception is the Boar (Sus scrofa), but their number has increased due to policies of reintroduction of the species.
The data concerning the small forest mammals such as the Shrews (Sorex samniticus) and the Arvicula (Clethrionomys glareolus) are very few, although they are very common on Italian territory because of the lack of uniformity of their habitat.