The steppes cover in Tunisia very large spaces and steppe ecosystem is rich from the point of view of the fauna and flora. The main steppe species are Haloxylon schmittianum, Anthyllis henoniana, Haloxylon scoparium, Stipa tenacissima, Stipagrostis pungens, Retama raeta, Seriphidium herba-album, and Rhanterium suaveolens.
The High Plains:
They are located between the Dorsal and Bel Abbes Majen and west of Meknassy in a region of high plains (over 400 m) and include several mountain ranges. Soils are predominantly carbonated, but there are also marl, gypsum and salt. The average annual rainfall varies from 100-200 mm near Gafsa up to 200-300 mm, along the Ridge and north-east of Gafsa. The mountain peaks in the area are 300 to 400 mm of rain per year. Bioclimatic is arid than cool winters and temperate in the west to the east.
The Phoenician juniper dominated the vegetation of the high steppes. He is currently confined to the plateaus and mountains, the plains are covered with associations alfa.
Some animal species living in the mountains down to the plains to feed and Drink. Among birds, the Houbara Bustard nests in the eastern part of the High Steppes. On the other hand, the striped hyena comes to hunt wild boar.
Alfa grass is used for the production of raw material for pulp mill Kasserine. The irrational exploitation of alfa plies is causing intense degradation processes. In addition, the cultivation of steppe lands and overgrazing have regressed the natural vegetation of the area.
Located east of the high steppes, they extend over relatively flat plains that go to the coast. The altitude is less than 250 m. The waters of the high steppes flow along wadis and temporary fail in the low steppes sebkhats. Shallow soils formed on limestone crust across much of the region. There are also Mediterranean red soils. The most of the lower steppes receives 200 to 300 mm of rain per year, with the rest, south of Sfax, receiving less than 200 mm. The Bioclimate varies from lower semi-arid near the coast to the arid lower southwest of El Djem; the majority being under a higher arid bioclimatic.
The majority of this inland vegetation cover dominated by jujube and sagebrush country. Associations to jujube, sagebrush, white asparagus and Rhantheriumsuaveolens. Sebkhats around the vegetation is halophyte. The fauna is similar to the high steppes.
The majority of inland low steppes and the coastal areas are cultivated and planted with olive trees. The rangelands cover very small areas and suffer excessive grazing. Poaching of wild boar and partridge is common.
The sub-desert steppes
They extend south of the lower steppes and are limited to the south and west by the Grand Erg Oriental. The altitude is less than 250 m, but rises near the high steppes and mountains of Matmata. The substrates are sandy loam, carbonate, gypsum or sandy.
The average annual rainfall varies from 100 to 200 mm. The average annual temperature of 19-20 ° C. Those of the winter down to 5-6 ° C; during the summer the average from 35 to 40 ° C. the Bio climates are arid lower cold winters, mild or temperate. Further south of the Sahara they are higher type or fresh temperate winters.
The vegetation cover is dominated by steppes chamaephytes. Among the species of the region, we find alfa, esparto, jujube, the retam, astragalus, tamarisk, sagebrush, Rantherium, Gymnocarposdecander, Aristida pungens, Calligonum comosum. The Saline soils are covered by halophytic vegetation.
The fauna comprises several species adapted to harsh climatic conditions of the region, including the Houbara Bustard, pale hare, gazelle dunes, Dorcas gazelle, and several species of reptiles (snakes, monitor lizards, snakes ...).
In the north, the steppes were grown in groves. The use of disc plow is in this region one of the main factors favoring wind erosion and consequently desertification. The Poaching hares and partridges are common. The region supports the installation of extinct species in the past as the dama gazelle M’horr, the antelope Addax and Oryx. A national park, of Sidi Toui with an area of 6315 hectares, was established in 1993 in this region. The Addax and the Ostrich are reintroduced it.