Diversity of Wild Vegetation Along the Aridity Gradient Habitat of Dera Ghazi Khan

Abstract

The investigation was carried out of wild vegetation along aridity gradient from Sakhi Sarwar to Ghazi Ghat in Dera Ghazi Khan Landscape. Presence/absence data were collected from 13 sampling sites. We used classification as well as ordination methods to analyze the data structure. The main emphasis was on classification, ordination being used in part to check whether the classification results reflect in an adequate way the main floristically gradients in the data set, and also to detect relations between some environmental factors and the composition and structure of natural vegetation. The major axes brought by the ordination were related to soil characteristics. The application of multivariate statistic {detrended correspondence analysis (DCA) and cluster analysis} allowed an interpretation of weed species spatial distribution and assemblage. From the results of classification (cluster analysis) samples from fields could be divided into distinct plant associations based on floristic composition. We have shown that there is a clear relation between physical
and chemical features of the substrate and the association defined by numerical analysis. In this respect, soil texture and
organic matter seems particularly important in shaping the natural communities .