Background Alder forests (Alnus glutinosa) commonly grow on the banks of rivers with permanent water flows. This habitat is at its optimum in the middle of river courses. Past human activity has led to a reduction of many alder forests and much of this habitat is now limited to thin rows of trees located in single lines directly at the riparian edge. Objectives This project is targeting the conservation of alder alluvial forests in two Portuguese rivers, in order to increase the populations of three species of dragonfly (Oxygastra curtisii, Gomphus graslinii and Macromia splendens). The project also sets out to improve the conservation status of two species of water pearl mussels (Margaritifera margaritifera and Unio crassus). It will achieve its objectives by conceiving, implementing and evaluating active management methodologies targeting improvements to alluvial forests supporting alder and ash (Fraxinus excelsior). Forest management methodologies will be tailored to support the conservation status of endangered water pearl mussel populations. Several ex-situ reproduction techniques will be used to increase the mussel populations and to reinforce the populations of fish that are host to these species. Expected results: Project activities will take place along a continuous 12 km stretch of riparian zone on the River Paiva and 5 km on the Torgal stream. This will result in the restoration of some 15 ha of the priority habitat, Alluvial forests with Alnus glutinosa and Fraxinus excelsior, consisting of 11 ha on the “Rio Paiva” Natura 2000 site and 4 ha on “Costa Sudoeste” Natura 2000 site. An additional 5 ha of the target habitat will be created by the project. Conservation work will involve: Planting some 10 000 trees and shrubs to enhance the alder forest’s natural floristic composition; Increasing dragonfly populations through the settlement of aquatic plants by reconnecting 5 ha of old waterbeds and improving 2 ha of new areas; Reinforcing the population nucleus of M. Margaritifera by adding 4 500 juvenile individuals to the estimated 500 adults thought to exist in the area; Reinforcing the population nucleus of U. crassus by adding 400 juvenile individuals to the estimated 100 adults thought to exist on the area; Undertaking two actions targeting fish repopulation; Creating and enhancing two areas for concession sports fishing; Producing dissemination materials (including leaflets, posters, videos and an exhibition on riparian alder forests).