Floristic composition and taxonomic distribution of plants in the dryland of Northwestern Nigeria
This study assessed floristic composition of plant species in the dryland of northwestern Nigeria with a view to understanding the inter-annual growth/decline in vegetation activity for sustainable management of species in the region. Quadrat sampling was conducted in nineteen study locations to inventory, identify and record plant species at 100m x 100m plots. Samples of species that were not directly identified in the field were collected on pressers and transported to herbarium of the Department of Biological Sciences of Bayero University Kano for identification. Results of this study revealed that a total of 50 plant species were encountered in the study area. These species fall into 22 families, 35 trees, 13 shrubs and 2 herbs. The families Caesalpiniaceae and Mimosaceae at 7% dominate the area with seven species while Sapotaceae, Mimosoideae, Meliceae, Malvaceae, Lamiceae, Euphorbiaceae, Burseraceae, Bombaceae, Balanitaceae, Ascelpiadaceae, Apocynaceae and Annonaceae are occasional with either one or two members. Analysis of abundance and rarity of species reveals that 10% and 90% of the encountered species were abundant and rare respectively in the study area. These finding poses serious ecological concerns in the study area, thus we recommended that rare species should be deliberately conserved by confronting the factors that increases rarity in the area. This may be achieved through targeted interventions aimed at reducing habitat loss and degradation.
Key words: floristic composition, taxonomic distribution, plants, northwestern Nigeria