Background The project targeted one of the few remnants of the priority species European mink (Mustela lutreola) and its riparian habitats in the Aragón and Arga River systems. The project sites host one of the largest remnant populations of European mink in Europe, and 10% of the Spanish population. Other animal and bird species of European importance found in the area include the European pond turtle (Emys orbicularis), otter (Lutra lutra), French nase (Chondrostoma miegii), escalo roach (Rutilus arcasii), purple heron (Ardea purpurea) and night heron (Nycticorax nycticorax). Riparian galleries with willow (Salix alba) and poplars (Populus alba) cover a large part of the sites and these represent one of the favoured habitats of the European mink. Habitat degradation and fragmentation, and competition with the American mink (Mustela vison) were thought to be the main threats to a viable European mink population. Fragmentation of habitats has also led to the genetic isolation of populations, which is now threatening the genetic viability of the remaining European mink. The project area included two habitats of community interest (92A0 and 92D0). Objectives The project aimed to restore and secure European mink habitats at a proposed Site of Community Interest (pSCI) in Spain’s Navarra region. The objective was to ensure a viable population of European mink in the area and to provide the species with possibilities for expansion. Riparian habitats in the Aragón and Arga River systems were restored in order to improve the habitat connectivity. To decrease competition from the American mink (Mustela vison), actions were implemented to control its presence in the project area. An information campaign and guidance to recreational users, particularly anglers, aimed to increase the knowledge and understanding about the European mink and its habitats among the local and general public. Results The project was a success and achieved its desired objectives. The restoration works made important improvements to the European mink habitats which included creation of new biotopes as well as improving the connectivity of existing ones. New habitat features such as gullies (24.03 ha), meanders (30.30 ha), wetlands (5.9 ha) and breeding areas (1.7 ha) were created, while alterations to dykes and ripraps helped to facilitate beneficial fluvial dynamics and an enhanced floodplain. Some 33 black spots in the road network and on irrigated lands were eliminated to reduce mink mortality rates. Furthermore, a dump site of 1 250 m3 was sealed and rehabilitated to boost desired habitat cover. In total, 13.04 ha of riparian galleries forest habitats (92A0 and 92D0) were restored and 70.52 ha experienced improved quality. Outcomes from this combined package of practical conservation work are judged to have helped increase the habitats’ carrying capacity for European minks. Project staff generated a great deal of useful data during the LIFE project regarding European mink population dynamics. This confirmed the absence of American minks in the target area as well as verified the fact that Aleutian Disease has little relevance in the Navarre population of European mink. Information determining a slight genetic variability in western populations of the species was also collated. Local communities and other stakeholders were actively involved throughout the project and this succeeded in engendering support for the new riparian zone management activities. Long term sustainability of the project actions has been assisted by a 45% enlargement of the SCI ‘Tramos bajos de los ríos Arga y Aragón’. A new management plan agreement for the SCI is anticipated to be completed by the end of 2008 and this will strengthen legal protection for the mink habitats. This project has been selected as one of the 26 "Best" LIFE Nature projects in 2007-2008.