We studied population sizes and mobility of Erebia epiphron and Erebia sudetica, two high mountain butterflies forming endemic subspecies in the Hrubý Jeseník Mountains, Czech Republic. E. epiphron formed two continuous populations containing ≈100,000 and ≈4,500 individuals on alpine grasslands. The butterflies moved freely within their habitats, but movements between the two populations were highly unlikely. E. sudetica formed a system of colonies at timberline sites on valley headwalls and in forest clearings. Two such colonies studied in detail contained ≈4,500 and ≈450 adults and were interconnected by limited dispersal. The negative exponential function and the sigmoid function (this assumes flat decrease of movements over short distances) were superior to the inverse power function in fitting mobility data for both species. For E. sudetica, the functions describing movements within a habitat differed significantly from total movements, suggesting different behaviours of dispersing individuals. The habitats of E. epiphron are uniform and highly isolated, favouring free within‐habitat mobility but prohibiting leaving their boundaries. The habitats of E. sudetica are diverse and disturbance‐dependent; leaving such habitats is less risky, and a source‐sink model may explain the persistence of the species in the mountains.

Aim To assess the effectiveness of protected areas in preventing biodiversity decline. We first test whether species richness of butterfly assemblages is higher within European Natura 2000 (N2000) sites than in their surroundings. We then assess temporal trends in butterfly richness and test whether these trends differ inside and outside the N2000 network. Location Germany, Europe. Methods We utilized generalized linear mixed‐effects models (GLMM) to analyse an 11‐year data series on species richness of butterfly assemblages collected on 245 transects across Germany, located inside and outside N2000 sites, and comprising a total of 122 butterfly species. Results Butterfly species richness was highest inside N2000 protected areas, while outside it constantly declined with increasing distance from N2000 sites. We found an overall decline in species richness by 10% within 11 years. This decline neither differed between transects located inside or outside the N2000 network nor varied with distance from N2000 sites. Main conclusions The higher species richness inside the N2000 network underlines their proper designation and their potential for the conservation of biodiversity. However, the current negative trend in butterfly species richness across Germany is not mitigated by the N2000 network, and we assume insufficient management or measures targeted at other organisms than butterflies as potential reasons.

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