Monitoring invasive alien plants dynamics: application in restored areas

In environmental restoration, evaluating the effect of control actions on alien species is essential for a correct assessment of the success of the restoration. A simple method for the evaluation of the dynamics of alien plants after manual and mechanical control in restored areas is proposed in this work. This method is based on the cover-abundance of alien plants, the size of the inventoried area and subsequently corrected with the degree of invasiveness based on national catalogues. Alien plants data abundances are obtained from floristic relevés retrieved from the restoration actions, carried out in the Eo River (Spain) during the LIFE Fluvial project (2018–2021). The Invasive Alien Plants Index (IAPI) was calculated, before and after the control actions for three ecological units (fluvio-estuarine, riverbank and lake). In all cases, index decreases after the control actions and it is sensitive to the changes that may occurs as recolonization by new alien species. As a whole, in the Eo River, a decrease of 53% of the IAPI has been obtained from 2018 to 2021, which estimate the effect of alien plants control. This indicator is applicable to any type of habitat, ecosystem or region and is adapted to different administrative areas that have published an official list of invasive species.