(Uploaded by Plazi for the IPBES Invasive Alien Species Assessment) Impacts of invasion of a ligneous weed, Prosopis juliflora, in plant communities of reserve forests, protected forests, unprotected forests and open grazing lands in Jamnagar district in arid coastal areas of Gujarat state of India were assessed. Sites invaded by P. juliflora had different ligneous plant composition with lower order seral species being dominant. In all landuses, Prosopis-invaded sites had more species richness, diversity, and evenness. However, increase in species richness was due to occurrence of more weedy species along with Prosopis juliflora. Even amongst the protected and undisturbed sites, dominance of late successional species, e.g., Acacia senegal, Maytenus emarginata, Ziziphus nummularia and Acacia nilotica, was less at sites with Prosopis juliflora than at sites without it. Density of Commiphora wightii, an endangered species, decreased with increasing density of P. juliflora. Invasion of P. juliflora has thus demonstrable adverse impacts on plant communities in arid grazing lands.