Communities are the result of species interactions for the resources. Plant species compete for the resources above and below the soil and ameliorate the environment for neighboring species. In this way superior competitors eliminate the inferior competitive species and affect the phytodiversity of an area. As a result those species sustain which are acclimatized to the prevailing environment. Hence, considering the relative influence of species interactions and an environment on the diversity, we expected variations in the diversity of plant species along the edaphic gradients. We investigated eastern, western and northern sites in the semi-arid area of District Bannu, Khyber Pakhtunkhwa, Pakistan, to identify the plant species diversity and its relation with the variation in the selected edaphic variables. We analyzed the soil samples of the three sites for the micro and macro-elements. We used quadrate method to collect the quantitative data of the plant species. Shanoon`s diversity index and similarities among the sites of the plant species was used to analyze the correlation between the diversity and the edaphic variables. Higher importance value index for tree species was computed as compared to shrubs and herbs. We have observed less diversity among the three sites in which western and northern sites have more similarities. We did not find a relationship in the edaphic variables for the macro-elements. However, few micro-elements have shown strong correlation with the diversity. We argue that less diversity may be the result of environmental filtering and anthropogenic activities prevailing in the area.
