Vegetation and species altitudinal distribution in Al-Jabal Al-Akhdar landscape,Libya

Cyrenaica is the largest phytogeographical region in libya. the region holds al-jabal al-akhdar (the green mountain) landscape with the richest vegetation and highest species diversity in the country. field study of the vegetation was carried out in the different habitat types representing the mountainous landscape. data were analyzed by detrended correspondence analysis (dca) and canonical correspondence analysis (cca) against the environmental variables. vegetation and species richness varied with altitude from the sea level,through mid elevation slope vegetation in wadis,to herbaceous and lowshrub- vegetation towards the mountain top. vegetation is classified into three major groups: (1) coastal and low altitude vegetation dominated by shrubs and trees which constitute about 60% of the plant life forms; (2) mid altitude and wadi vegetation with the highest species richness and dominated by shrubs and trees which constitute over 60% of the plant life forms; and (3) mountain top vegetation dominated by herbs and few low shrubs constituting up to 90% of the plant life forms. the altitude,aspect and soil parameters do not explain the majority of variance in the obtained data which reveal that other diverse local conditions and habitat types seem to be the main determinant of vegetation variation in al-jabal al-akhdar landscape.