Impact of Alligator Weed ( <i>Alternanthera philoxeroides</i> ) Invasion on Floral Composition and Soil Microbiota

Plant invasion modifies the aboveground and belowground biota directly or indirectly via allelopathic effect. This study aimed to ascertain if the invasive species <i>Alternanthera philoxeroides</i> impacts plant diversity, plant composition, and soil microbes or not. The soil microbial activity (CO₂ release) and soil pH were also recorded. The plant communities invaded and uninvaded with <i>Alternanthera philoxeroides</i> were examined using the quadrat method. Soil samples were collected from 0 to 10 cm depth, and the culture method was used for soil microbial analysis. The plant species richness and soil fungi were found to be reduced at <i>A. philoxeroides</i> invaded plots than at uninvaded plots. The IVI of all common species such as <i>Cynodon dactylon</i>, <i>Bidens pilosa,</i> and <i>Trifolium repens</i> was highly suppressed in the invaded zone. The parameters like plant diversity indices, colony count of soil microbes, soil microbial activity (CO₂ release), and soil pH were found to be reduced at invaded sites than at uninvaded sites. The results indicated that the invasive <i>A. philoxeroides</i> modifies the plant community composition, and the underlying mechanism for the change is possibly by altering the soil microbiota, microbial respiration, and soil pH with their successful invasion.