Smaller fields support more butterflies: comparing two neighbouring European countries with different socioeconomic heritage

Changing landscape configuration, a component of landscape heterogeneity, due to varying arable field size represents an attribute of farmland intensification with potentially grave consequences for biodiversity. We recorded butterflies in an intensively farmed region along the border of two European countries with contrasting socioeconomic heritage, one with small farms (Poland), the other with huge farmed units (Czech Republic). Although only the most common generalist species occurred in our records, we observed 2.3x more individuals and 1.9x more species in Poland, and the differences withstood robust statistical controls. Different socioeconomic heritage-in this case, different policies of two communist regimes, one tolerating small family farms and the other expropriating them-influence biodiversity long after the policies that shaped the respective landscapes had been abandoned.