biological diversity and tropical forests in tunisia - PART

Mean annuah temperatures along this section of coast are slightly
higher than 18 C. Mean annual precipitation north of Menzel Temime, on
Cap Bon, is about 500 mm. From Menzel Temime to Enfida annual rainfall
averages 400 - 500 mm; between Enfida and Mahdia the rate decreases to 300
- 400 mm and south of Mahdia it ie less than 300 mm. The bioclimate is
Semi-arid Superior from Kelibia to Nabeul, with winter variants of hot to
mild. At Hammamet the bioclimate is Semi-arid, hot wknter variant, and
south of enfida the bioclimate is Semi-arid Inferior, mild winter variant.
A. Vegetation
Vegetation associations south of El Haouaria are not as diverse as
those to the north. From El Haouaria to Dar Chichou the climax vegetation
type is kermes oak (see Section 3.1.2). South of the oak maquis the
climax vegetation is Olea-lentiscus formations until Hammamet, then thuya
--
Callitris articulata until Enfida, followed by the Low Steppes. Most of
the vegetation is not at the climax stage and many of the associations
currently found on this section of the coast are characterized by:
with many types of mosaics indicated by:
Artemisia herba alba
Asarum vulgare
Stipa parviflora (sub-association)
Solanum sodomaeum (variant)
Zizyphus lotus
and Heliacthemum lippii Echiochilon fruticosum
H. racemosum Atractylis serratuloides
Lygeum spartum Lavandula multifida
Phlomis floccosa
or Cynodon Artemisia campestris
Another association is indicated by:
Corynephorus articulatus Lupinus hirsutus
and there is a vegetation group indicated by:
Spergula diandra Solanum sodomaeum
Scolymus hispanicus
A common association along the Gulf of Hammamet and the Gulf of Gabes is
the littoral sand group indicated by:
Ammophila arenaria
Agropyrum junceum
Cakile maritima
Medicago marina .
Two importact associations that occur along the entire coast acd ic the
steppes are found on saline soils, especially around sebkhets. The first
association consists of slightly to moderately halophile placts, iccluding
several species each of
Suaeda
Salsola
Frankenia
Limocium
Atriplex