biological diversity and tropical forests in tunisia - PART

To summarize, the general factors to which the island ecosystems are
sensitivp include:
3.2.1. Galite
Erosion causing activities:
Vegetation removal - especially on steep slopes
Disturbance of surface soil
Shoreline degradation - especially on the smaller islands
Activities that reduce flora and fauna species and numbers:
Water pollution
Water exploitation ( i. e . over-exploitation)
Human activity - especially during the nesting season
Egg collection or destruction
Erosion above nesting ledges - destroys nests and birds
Animal species over-population - can damage vegetation
Under-populatioc - gene pools below critical levels
Poaching
Coral collecting (~alite)
The Galite archipelago is 40 krn from the north coast of Tunisia, 45 km
northwast of Cap Serrat acd 64 krn northeast of Tabarka. The archipelago
is domirated by the "T" shaped main island of Galite, which is 5.4 km long
and c.950 m across at the carrowest point and 2.5 km at the widest part of
the "T". The planirnetric surface area of the island is 650 ha, which is
ir. reality increased by the sloping topography, culminating at 391 m ASL.
Aboiit 2.5 krn to the southwest of Galite is the islet of la Fauchelle,
14 ha ir area axd fairly low in altitude. The islet of Galitor. is only 50
meters to the west of la Fauchelle, has an area of 27 ha and is topped by
a lighthoase. A trio of small islets, the Isles de Chiens ("~og
~slands") lie 1.6 km north of Galite, the largest of which is less than 9
ha, but has ac altituds of 119 rn (~aulthier 1978). Thus the total
planimetric land aria of the archipelago is about 700 ha.
The Galite archipelago is the only granitic formation in Tunisia (IUCN
1987). Soils are thin, of granitic origin, and some of the smaller islets
and parts of the larger ones are scoured by the wind and waves to the
point that there is little soil or vegetation cover. On the main island
there are some valleys and plateaus with deep soils, and in many locations
the soil is thick enough to have been cultivated to vinyards and gardens.
Caves with above water or underwater entrances have been carved into
many places by the action of the sea (~osser 1978). Relatively shallow
water (cornpared to the rest of the "Coral coast") with a rocky bottom
surrounds the isla~ds. Around the archipelago the water depth is scarcely
over 100 n (~aalthiir 1978) and it is much less betweer. the islets.