biological diversity and tropical forests in tunisia - PART

B. Fauna
-- Mamnals. Although there is a dlversity of vegetatioc types alocg the
coast, the most common associatiocs are of halophile species. Halophile
associations provide adequate cover for small to mid-sized mamnals, such
as jerboa Jaculus oriectalia, gerbil Cerbillus campestrls, sacd rat
Psammomys obesus, haw's jrird, brow. hare, Algeriac hedgehog and the
Egyptiac mongoose, red fox and jackals that prey or them. Uplacd areas
also harbor many of the above mamnala, but cultivatioc, overgrazicg and
other forms of disturbance limit the habitat value.
- Birds. Vac Dijk (1986) reported that "it would appear that the C~lf
of Cabes is the major area in the Kediterraceac for wictericg waders acd
some waterfowl species". This conclusioc was based oc co~cts made of
wintericg waterfowl and waders over 380 km of shorelice (765 of the Gulf
of Cabes total) ic Jac~ary - March 1984.
The Cilf of Gabes is the most importact wictericg erea ic the
1,lediterraceac for cormoracts acd spoocbills. At least 3 threateced
species also occ;r there. Niceteec wader acd waterfowl specles vere
detormjced to wicter ic the Gulf of Cabes ir combers greater thac :% of
their total flyway or biogeographical populations. Those species are
noted ir. the list of Golf of Cabes bird species (fiezre 4).
Marice Faoca. The mocotocy of sedjmects, the homogecejty, acd the
abse~ce of rocky substrates ic the golf resslts ic a vast extecsioc acd
low dlvfrsjty of marjce faica (~zouz 1975). Doniract specjes of the
sootheast coast are:
Ceodea sp. Picctada albida (cot foo~d to the north)
Spatacgus porpureus Hacelia attecuata (sab-tropical)
Cectrostephac~s locgi spir.;s "
Altho~gh species diversity is low, prodoctior js very high. Almost
all of the sponges, 75: of the shrimp and 605 of the ber.thjc fish
harvested in Txisia come from the Ciilf of Gabes (!he-0thnac :973).
Extecstive lists of harvested fish species are giver by Ber-Cthmac (:973)
acd Na jai acd Zaarah (1 981 1.
A total of 500 mollusc species have beec reported for th Gulf of Gabes
(~osso 7979, Searat 1924 acd 1929, as cited ic Vac Dijk 1986); however,
only a few species are important ic terms of biomass acd decsity. Average
dry weight per square meter of macrobenthos fauca from the ictertidal
flats near Kneiss island is 26.0 erams (~ac Dijk 1986). The taxonomic
groups represected in that weight are: Castropodia (4951, Bivalvia (36),
Polychaeta (:O%), Crustacea (I&) and other groups only comprised 15 of