Impact of Invasive Species from Different Land Use on Vegetation Structure and Soil Microbial Dynamics in Warwade, Sudan Savanna, Jigawa State, Nigeria
Abstract
This study assessed the vegetation structure which was classify into indigenous and exotic to determine invasive plant species and microbial population across ecological zones. Randon sampling using twenty quadrats across three ecological zones. Plant species encountered within each quadrat were identified, enumerated, and classified using Plant NET and iNATURALIST. Coordinates of invasive species were recorded using a Global Positioning System receiver to determine their spatial distribution. A total of 29 plant species, 256 individuals and 33 occurrences were recorded. Plantation had the highest species richness 14 and abundance 124 individuals, followed by Fallow 13 species, 82 individuals, while Agricultural landscape had the lowest 12 species, 64 individuals. Fabaceae 43.5% dominated plant families. Plantation recorded the highest diversity indices, indicating greater species evenness and reduced dominance. Exotic species 52.2% slightly outnumbered natives 47.8%, reflecting anthropogenic influence. Sorensen similarity indicated substantial species overlap among zones. Prosopis farcta, Portulaca oleracea, Physalis angulata, Euphorbia hirta, Setaria verticillata, Boerhavia erecta, Euphorbia heterophylla, Amaranthus spinosus, and Spigelia anthelmia were identified as invasive species. Forest Land recorded the highest bacterial count at 3.4×108 CFU/g, but differences were not significant. Bacillus sp. occurred in all land uses, while Klebsiella and Enterobacter indicated anthropogenic inputs. Five fungal genera were recorded, with Aspergillus, Penicillium, and Rhizopus present in all zones. Study area supports diverse plant community despite the occurrence of invasive exotic species. Continuous monitoring, early detection, and appropriate management strategies are recommended to minimize the spread of invasive species and conserve the indigenous flora of the plantation.