The conservation of the Cranberry Fritillary Boloria aquilonaris across space and over time : study of a boreo-montane butterfly from distribution to demography

Biodiversity is in crisis and its conservation requires the implementation of preservation and management actions. These should be defined based on the understanding of the interactions of species with their environment. Patterns and processes in ecology, as well as the importance of the environmental factors affecting them, are known to be scale-dependent. Hence, the conservation of species would clearly benefit from research conducted at multiple spatial and temporal scales. My global objective was to understand how the Cranberry Fritillary Boloria aquilonaris, a boreo-montane butterfly of conservation concern in many parts of Europe, responds to environmental conditions across space and over time, from patterns of genetic diversity over the distributional range to variation in local demographic parameters. My aim was to derive conservation guidelines from information collected at multiple scales and integrate the results in a conservation framework as comprehensive as possible. The genetic structure at the distributional range scale is the result of a range expansion from one single glacial refugium, followed by a range contraction that happened within the last 2,000 years. At least four genetic lineages exist in Europe, and might serve as conservation units. Valleys are important features facilitating effective dispersal at the regional scale. Several life stages are sensitive to climatic conditions at the local scale, with consequences for individual survival and population growth rate. A population viability analysis showed that a temperature increase superior to 3°C would largely affect the species persistence.