Riparian forests host many endangered plant and animal species, which are restricted to this type of habitat along rivers. Most of riparian forests has been transformed into fields and settlements, especially in the semiarid region of south-eastern Kenya. In this study we compare the impact of human disturbance on riparian vegetation structure (species composition, regeneration and the impact of species invasion by exotic plant taxa). We compare the vegetation structure of a highly disturbed riparian forest along Nzeeu River, with a still intact riparian forest north-east of Kitui, along the Mwita-Syano stream. Plant diversity is assessed along these two rivers. Diameter at breast height (dbh) and height of woody species (dbh > 5cm) are recorded along transects (50m length and 10m width), laid out perpendicular to the river on both sides, at 300m intervals. The distance of each plant individual from the river bank and the corresponding land cover is noted, considering the following land cover classes: indigenous vegetation, mixed vegetation (indigenous and invasive plants), invasive thickets (dominated by Lantana camara), agriculture, grazing and woodlots. Vegetation assessments has been conducted by Christine Schmitt and members of her group (see our fieldwork activity in 2016), and by our Kenyan forest expert Danson Maseka Kioko in 2019.