Vegetation and plant diversity pattern study of Central Eastern Niger grasslands

Abstract

Vegetation and plant diversity patterns of Central Eastern Niger grasslands were investigated following phytosociological methods. Vegetation data collected on 76 plots by using the Braun-Blanquet’s (1932) coverabundance scale were analyzed through five multivariate analyses (TWINSPAN, NMS, DCA, ISA and MRPP) in order to distinguish and to describe plant communities. Alpha diversity (H’, E and R) was also used to describe these communities. A total of 162 species belonging to 37 families and 104 genera were identified. Dominant families were the Poaceae (18%), Leguminosae-Papilionoideae (8%), Convolvulaceae (7%) and Leguminosae-Caesalpinioideae (4%). Life forms were dominated by Therophytes (59%) and Phanerophytes (27%), whereas the most prominent geoelements were of the Soudano-zambesians-saharo-sindians (33%), Soudano-zambesians (25%) and Guineo-congolian-soudano-zambesians (25%) types. In total, five plant communities were identified on the basis of environmental gradients and species composition. The environmental parameters that favorably influence these plant distributions are topography, moisture, texture and land use (fallow, pasture). Importantly, each of these communities seems to correspond to a particular wildlife habitat. These habitats shelter their own species that may be seen as a keystone species.

Keywords: Multivariate analysis, vegetation communities, characteristic species, Central East grassland, Niger