biological diversity and tropical forests in tunisia - PART

North.of Sfax the vegetation associations are ueually dominated by
halophile groups and :
Artemisia herba alba Zizyphus lotus (sub/assn .)
Asparagus albus Atractylie serratuloides "
Trigonella anguina
Lygeum spartum
or a group of
Solanum sodomaeum (variant)
South of Sfax the halophile groups are interspersed with associations of:
Pituranthos tortuosa Erodium glaucophyllum (da)
Halophyllum vermicularire
and
Rhantherium suaveolens Lygeum spartum (~/8)
Artemisia campestris Atractylis serratuloidas "
South of Kceiss the vegetation is joined by an association of:
Zygophyllum album Anarrhinum brevifolium
acd a gypso-halophilo association of:
Nitraria retusa
Suaeda vermiculata
Salsola sieberi var. vesceritensis
On the Zarzis peninsula is an association of
Artemisia herba alba Gymnocarpos decander (sub.)
Arthrophytum scoparium
Intertidal mudflats are often covered by dense Zostera nolti (van Dijk
1986), and cear Mahares sea lettuce sp. grows on the sea bottom.
Close to the shore at Kneiss, Spartina sp. and Halocnemum strobilaceum
grow. Where inundation is less frequent and of shorter duration Halimone
portulacoides, Limonium cf. , . Limoniastrum rnonope talum and Suaeda
sp. appear. On the shore and small dunes Arthrocnemum cf. fruticosum,
perene, Zygophyllum album, Thmelaea hirsuta and Haloxylon articulatum
replace the more salt tolerant species.
Marine Flora. Near Kerkennah island at the north end of the Gulf of
Gabes, Posidonea oceanica comprises 95% of the marine fauna at depths less
than 30 m. Between 30 - 45 m depth, Canlerpa sp. and Vidalia volubilis
(green algae) dominate. At depths greater than 50 m, the red calcareous
algae Lithophyllum racemus is found (~ajai and Zaarah 1981 ).