Hierarchization of species and prioritization of conservation actions: towards a conservation strategy for flora, from biogeographical to regional level

The Maritime and Ligurian Alps, located at the interface between the Alps Mountains and the Mediterranean region, constitute one of the regional biodiversity hotspots of the Mediterranean basin. Biodiversity hotspots are areas where exceptional concentrations of endemic species undergo exceptional loss of habitat. In fact, with the population increase and tourism boom, many low altitude species are critically threatened of extinction. Refuge areas, containing a great biodiversity, are also threatened by human impacts because they are submitted to important pressures. Many of these endemic species have very restricted distribution areas shared between two countries, France and Italy. Most conservation actions are funded at the national or regional level; however, in most cases this doesn\u2019t match species distribution. Moreover, resources are usually limited and it is not possible to implement conservation actions for all species. This is why a hierarchisation of species and a prioritisation of their conservation actions are required, at both cross-border (or biogeographical) and administrative scales. The considered strategy can be synthesised in four steps: (1) list and hierarchise species; (2) list the different management projects; (3) prioritise management projects; and (4) choose a set of projects to implement. A hierarchisation of species was carried out according to three criteria: biogeographical rarity, local rarity and threats. This last criterion included two sub-criteria, habitat vulnerability and artificialisation. This hierarchisation enabled us to classify species into four conservation concerns: very high, high, medium and low. Then for each very high or high conservation concern species, a management project is assigned according to several criteria. Each project is then assessed in terms of costs, benefits and likelihood of success; which produce the project efficiency. Finally we choose a set of projects to implement, according to their efficiency, but also according to available financial and human resources, legislation, and other contextual factors. This strategy should enable us to head resources towards species which need them the most and towards projects with a high success probabilit