# Impact of Alligator Weed (Alternanthera philoxeroides) Invasion on Floral Composition and Soil Microbiota

## TL;DR

This study shows that the invasive alligator weed reduces plant diversity and soil microbial activity, likely by altering soil conditions and microbiota.

## Contribution

The study demonstrates how alligator weed invasion affects both plant communities and soil microbiota through allelopathic mechanisms.

## Key findings

- Invasive alligator weed reduces plant species richness and soil fungi in invaded plots.
- Soil microbial activity and pH are lower in areas invaded by alligator weed.
- Common plant species show suppressed abundance in invaded zones.

## Abstract

Plant invasion modifies the aboveground and belowground biota directly or indirectly via allelopathic effect. This study aimed to ascertain if the invasive species Alternanthera philoxeroides 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 Alternanthera philoxeroides 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 A. philoxeroides invaded plots than at uninvaded plots. The IVI of all common species such as Cynodon dactylon, Bidens pilosa, and Trifolium repens 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 A. philoxeroides 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.