Positive developments in low-intensive, protected grasslands in Switzerland suggest successful conservation measures

Conservation measures in protected areas are important for conserving global biodiversity. Despite the importance of assessing the effectiveness of protected areas and whether they develop toward their conservation goals, targeted monitoring programs in protected areas at the national level are rare. In Switzerland, a long-term program was launched in 2011 to systematically monitor changes in biodiversity and habitat quality in protected areas of national importance. Here, we focused on protected grasslands (0.7 % of Switzerland's surface area) and examined the status and changes of plot-level indicators over six years using a probability sample of 441 grassland sites (2149 vegetation plots) across Switzerland. We analyzed changes in vascular plant species richness, the proportions of threatened, specialized and neophyte species, environmental conditions (by means of ecological indicator values) and area of target vegetation types, and the factors associated with these indicators. Within six years, we detected a decreasing mean indicator value for nitrogen, an increasing proportion of specialist species and a significant decrease in area of non-target vegetation that developed toward the target vegetation, namely positive trends from a nature conservation perspective. However, thermophilization indicates climate-warming driven vegetation shifts. Our findings highlight the importance of well-replicated and standardized data in monitoring programs to evaluate temporal changes, which in our case enabled us to detect trends within a rather short period. The positive developments reflect successful nature conservation management by the federal and cantonal (= regional) authorities, which were implemented by farmers and nature conservation organizations by maintaining and promoting low-intensive land-use regimes. • Mostly positive developments of vegetation and habitat quality over six years • Consistently decreasing mean nitrogen indicator value and non-target habitat area • Increasing proportion of specialist and Red List species species • Climate-warming driven thermophilization at middle elevation • Positive developments reflect successful grassland conservation management.