A study in Germany found that over 40 years (1971-2011), populations of adults dropped rapidly in agricultural land, while dropping slightly less severely in native grasslands (although still decreasing by almost 83%). The article stated that fragmented habitat protection does a poor job of securing biodiversity and protecting many species that are in peril, as it does not account for many species that cannot seek extra fragmented breeding sites. Many species, including "Boloria selene", fail to find good nesting sites as they cannot pass through the human habitat that divides suitable fragments.