Long-term monitoring of Menorcan butterfly populations reveals widespread insular biogeographical patterns and negative trends

A number of studies analysing the structure of butterfly communities on Mediterranean islands have confirmed the well-established pattern of a current decrease in species richness in island communities. However, these studies generally lack quantitative data on butterfly population densities across habitats and over time. This precludes testing the hypotheses of ecological release, niche expansion and density compensation in island populations...