Open Journal of Ecology, 2018, 8, pg. (483-494)Although the relationship between invasive alien species (IAS) and plant com- munity structure has attracted considerable interest, the impacts of IAS on abun- dance and diversity of resident plant communities in species rich-ecosystems, such as tropical wetlands are poorly understood. Consequently, this has im- peded development of improved management strategies and successful res- toration of invaded tropical wetlands. Therefore, data on vegetation were col- lected from 60 plots of 20 × 50 m to study the impacts of alien invasive grass Echinochloa colona (L.) Link abundance on plant community abundance, richness, evenness and diversity of resident plant species within grasslands of the Kilombero Valley wetland, Tanzania. Moreover, the impacts of abun- dance of E . colona on plant functional groups ( i.e. graminoids, forbs and shrubs) richness were also explored. Generalized linear models showed that community richness, evenness, diversity and abundance of resident species were negatively related to the E. colona abundance. There was a negative rela- tionship between richness of graminoids and shrubs and the abundance of E. colona . Similarly, the abundance of graminoids, forbs and shrubs is related negatively to the abundance of E. colona . Given that most of the community and functional group attributes of resident plants is related negatively to E . colona abundance, improved management strategies should be developed to minimize the abundance and further spread of E . colona to restore and con- serve wetland biodiversity.