2-BIOGEOGRAPHICAL CHARACTERIZATION OF THE TERRITORY (FLORA)

Until the 17^th century, the coastal territory of the Low Belice hosted wide formations of scrub-forest and brush land.  Some remaining strips of these plant consortiums can be still found above all in correspondence with rocky terrains and sunken valleys,  saved up to the recent past of the intense work for cultivation because of the difficulty to create a mechanized agriculture. Examples of this landscape can be found in a valley called  “ Castello della Pietra “ , in the “Riserva Zangara”, area to the north of Castelvetrano, in the “ Bosco del Principe “ situated to the south, and in the aereas that from diga Delia (Delia dam) go northwords to Salemi , a territory locally called  “la Montagna” (the Mountain).

The constant anthropization since the paleolithic has replaced the original vegetation above all with herbaceous plants (wheat, melon, etc..) and woody plants (olive groves, vineyards). Perhaps today’s “sciare” present to the south on soils with a neutrocline and subacid reaction  hosted forestry consortiums of  Erico-Quercionilicis as it is witnessed by examples of  cork oaks  widespread above all in the municipalities of Castelvetrano, Campobello; instead elsewhere prevailed consortiums of Pistaciolentisci-Quercetum ilici confined in the canyons and where there are steep slopes. The most exposed and sunny terrains  were characterized by a combination of  olive dwarf palm and kermes oak. ( Rhamno alaterni, Euphorbietumdendroidis, Rhamnooleoidis,Chamaeropohumili,Quercetumcocciferae.)

Hygrophilous vegetation

In correspondence of the river you can observe the presence of various aspects of stratified hygrophilous vegetation. The herbaceous layer of the community,  dominated by medium and large size helophytes, are more frequent in the end portion, where the arboreal cover becomes scarce. Here you can notice and observe interesting aspects with Carexotrubae, C. pendula, Cyperuslongus, Scirpoidesholoschoenus and Phragmithesaustralis, belonging to the Phragmito-Magnocaricetea category and related to two phytocoenosis: Phragmitetumaustralise Cyperolongi-Caricetumotrubae. In smaller  gutters it was possibile to observe some consortiums related to the Helosciadetumnodiflori, a combination characterized by small hygrophilous species, with a prostrated posture and usually rooting at the nodes, such as Apiumnodiflorum, Nasturtium officinale and Juncusfontanesii. A particular type of cane thicket, depending on the presence of a greater wealth of nitrates either in the waters or in the soil, is the Calystegiosylvaticae-Arundinetumdonacis. This vegetation, dominated by the Rhyne barrel (Arundodonax) is refered to a different category of vegetation(Galio-Urticetea) because of the prevalence inside it of nitrophilous tall herbs like Arum italicum.

Where any type of  arboreal cover disappears and there is a disorder that does not allow even the survival of the reeds, the previous communities regress  in favour of  pastures rich in hemicryptophytes characterized by species like  Menthasuaevolens, Pulicaria dysenthericae Juncusinflexus. These aspects, included in the Mentho-Juncioninflexi alliance, are present in the area of the Zangara  riserve , above all principalmente outside the  Vallone Landro, probably in correspondence of the site where the rice field had been grown in the past. The Eupatorium cannabinum  belongs to this community.

Instead, in the area where the vegetation has been able to evolve , in particular in the upper part of the stream, some  hygrophilous groupings such as Rubusulmifolius have been observed. All this can be referred to some aspects of the Rubo ulmifolii-Dorycnietumrecti, a dense formation of mantle being dominated by the leguminosa Dorycniumrectum, emicriptofita that colonizes small portions of land and the basis of hollows and small streams.

The most advanced aspects of the riparian vegetation, characterized by the presence of different shrubs and trees, can be referred to the two categories  Nerio-Tamaricetea and Querco-Fagetea. To the first belong the communities of  tamarisks present between the end portino of the Vallone Landroand the Belice river, that is sometimes subjected to short periods of summer water crisis.