Background The European mink (Mustela lutreola) used to inhabit the courses and banks of rivers and wetlands in central and northern Europe, but now its distribution is reduced to two small sub-populations. The eastern one, in north-eastern Russia, is rapidly disappearing due to the introduction of a competitor, the American mink (M. vison). The western sub-population, is only found in the south-west of France and northern Spain, where in the last few decades its area of distribution has shrunk by some 70%. When the project began there were only about 800 adults left in an area of 40 000 km2. Experts believed then that without urgent action the European mink was to disappear over the next decade. The upper Ebro basin (Burgos, Soria, Alava, Rioja and Navarre) is the only region still sustaining a relatively healthy population of this species, chiefly due to the absence of its harmful competitor, the American mink. This project formed part of a coordinated Action Plan between various neighbouring regions, aimed at saving the European mink from extinction in the European Union. Objectives The project would address the main threats affecting the European mink population of Castilla-León, home to 12% of the Spanish population. As for the other two projects adopted that year under LIFE-Nature, measures were to be taken to control the spread of the American mink into the region and to limit the occurrence of diseases, the effects of pollutants and the genetic deterioration of the population. A programme of measures was also to be introduced to conserve and restore its natural habitats along the rivers. Finally, a long term conservation plan was to be drawn up to safeguard the future of the European mink and an information awareness campaign launched amongst the local population aimed at raising awareness over the need to conserve this unique animal. Results The expected results were successfully achieved. The following can be highlighted: The distribution area of the species was maintained and the global negative trends of the regional population (-47% between 1999 and 2004) of this scarcely known species seemed to had stabilized in the last 2 years of the project (even youngsters were found colonizing areas where the American mink had been eradicated). However, this cannot be fully ascertained as previous sampling methods were different and the population is very small. The successful measures for the control of the expansion of the American mink allowed to prevent this alien species entering the distribution area of the native one. A pSCI (“Riversides of the Tirón river sub-basin”) was enlarged in 36 ha. as a result of the project findings and other areas considered critical for the conservation of the species were detected. Sound monitoring and checking programmes were developed, which have allowed for a dramatic increase in the knowledge on the species –including population parameters, ecology, health status and incidence of diseases, namely the ADV, effects of pollutants, and genetic status of the populations– that clearly contributes to preserving its status. A better knowledge on this rare species was achieved and awareness on its biology and threats was raised through training campaigns among the regional nature wardens and information campaigns among school children and the general public. This species used to be a ‘phantom’ one, barely known in its biology, ecology, distribution and threats. This project and those coordinated with it enlarged critically the available knowledge about the species and set the bases for its conservation. As a result the National working group received a critical impulse, and a series of key documents for conservation were produced (including a national strategy for the conservation of the species, regulations and/or protocols for captive breeding, for eradication of competing species, for control of fur farms). Consequences of the enhanced knowledge and awareness about the species were the change of its consideration in the Habitats’ Directive to ‘priority’ and its listing as ‘endangered’ in the national legislation and relevant regional legislations. After 4 years, the species changed from being a ‘phantom’ species to be a ‘flag’ species. The National working group was reinforced thanks to the project. The Spanish Ministry of Environment assumed more readily the coordination role and as a result some important initiatives were brought to fruition: the species was listed as ‘endangered’ at the national level and a national plan for the eradication or control of the American mink was designed and adopted. The latter involved the national authority taking a leading role and compromised the funding of the works after the project’s implementation. Other neighbouring administrations with significant populations of mink started plans to preserve the species and provide a geographical continuity to the conservation programme. The Navarra region asked for LIFE funding in the 2005 round with the aim of protecting the species’ habitat; other regions such as Aragón or the Basque Country became more involved and aware of the species’ status. As mentioned above, the coordination of the nature conservation departments of the regions with LIFE projects dealing with the species was very fruitful and extended beyond the conservation of this single species. Other coordinated approaches regarding the protection of riparian habitats, the coherence of the Natura 2000 network or the action against common threats in the shared environments were adopted and the links will most probably be maintained after the end of the projects. Despite of all this global successes, by the end of the project the target species was still in a critical situation, especially in Castilla y León, and no clear improvement indicators had been observed. It was evident that more time was needed before the species reacted, given its critical status and the magnitude of the threats to it. In fact, one of the main foreseen outcomes was the approval of a regional Conservation Plan for the species, which would be the main tool to ensure the continuity of most of the actions undertaken within the project. Unfortunately, as this type of legal tools undergo long administrative processes, a definitive version was not officially approved by the project’s end. Benefits were also obtained for the Natura 2000 network: an outstanding habitat restoration in the river Tirón, one of the main areas for the species within the region, led to changes in the regional network, as the pSCI 'Riversides of the Tirón river sub-basin' was enlarged to protect the species and now covers the whole basin. Besides, the success of this restoration encouraged the beneficiary to extend this restoration scheme to other riparian habitats in the region. Innovation also resulted from the project as the external assistance that carried out the works checked, tested and invented some new methodologies to make the monitoring works more feasible and cheaper. For the first time, internal emitters were installed that allowed for a permanent and safe monitoring of the animals. Several techniques were also checked for collecting the data emitted by the specimens, and a new trap specifically designed for trapping American minks was tested and used. The project developed new techniques and devices for undertaking the fieldwork, namely the use of new tagging devices for small animals (used specifically for the females) and the design of a system for the automatic radio-location of the tagged animals, which would substitute the need to travel to the river stretches daily. The socio-economic effects of this project are rather limited, since the species does not interact much with any social or economic group or interest. However, the main economic interaction is with the development of infrastructure for providing electric energy through small power plants and some relevant steps are being taken in this regard for instance within the draft Conservation Plan -e.g. on the regulation of minimum flows in the Ebro’s tributaries and on the need of applying environmental impact assessment schemes for most works, namely small power plants. Still, there were some projects under development or executed during the project time duration that showed some shortcoming in the integration of the conservation requirements with the development of these activities. The power of the water management authorities, represented in Spain by the 'Confederaciones Hidrográficas', depending on the National Ministry of Environment, makes it very difficult for the regions to work efficiently in the rivers and riverbeds. The main decisions are finally taken by these organisms, which are not particularly aware of conservation issues.