This study assessed the phytodiversity distribution pattern and community composition with respect to the altitudinal gradient in three vegetation zones, like the riparian (30°03^/22^// N, 70°64^/44^// E), piedmont zone (29°54^/00^// N, 69°58^/00^// E) and upper rocky slopes (29°54^/00^// N, 69°58^/00^// E) of the Kohe Suleman Mountain range of district Dera Ghazi Khan, Pakistan with 104 to 1972 m above sea level (a.s.l) range of altitude. During the field surveys from the three sites, a total of 40 stands were employed for vegetation analysis using the normal cluster analysis (NCA) and the presence or absence of data were taken as indicators to classify and ordinate both the sites and species. Spearman’s rank correlation coefficient (SRCC) was used to assess the relationship between environmental factors and species distribution. Results of the normal cluster analysis displayed overall three vegetation groups from the studied sites including Chloris barbata-Eragrostis minor community (group A), Nerium oleander-Leptadenia pyrotechnica community (group B) and Bothriosperum tenellum - Acacia jacquemontii community (group c) which were clearly separated along the first two axes of the DCA. Results of the Spearman’s rank correlation coefficient indicated that the species richness and diversity (SR = 19.70+3.38, 14.30+1.97, 9.30+1.316; F & P = 54.92***) were decreased with respect to elevation (r =-0.712***) and a highly negative significant values of soil anions and cations with axis II confirmed the decline of nutrients with altitudinal gradients. It could be concluded that the distribution patterns of the species are strongly associated with elevation, concomitant variations in climatic regime as well as the edaphic factors of the region.

Index Terms- Altitudinal gradient, Dera Ghazi Khan, Koh-Suleman Mountain, phytodiversity, species distribution, vegetation zone