||Aim: To describe spatial patterns of Mediterranean butterfly species richness by functional groups, analyze their main landscape and climatic drivers, test the existence of extinction debt effects, and predict past species richness distributions using past climatic and landscape data. Location: A transect of 186 1-km2 quadrats in the Montseny region and surrounding plains in the area of Catalonia (NE Spain), located between the Mediterranean Sea and the Pyrenees mountains. Methods: From 2003 to 2010 we systematically recorded the presence of butterfly species in each quadrat for a total 123 different butterfly species. Times series data were analyzed for average monthly temperature and average monthly precipitation to determine significant trends in climate. Proportions of landscape types per quadrat were calculated for years 1956, 1993 and 2005. Using these geographic, climatic and landscape data for each quadrat, a generalized linear model was built to determine the significant factors affecting butterfly species richness patterns. Results: Butterfly species richness followed a hump-shaped pattern along the altitudinal gradient. The highest species richness occurred at an average elevation range between 600 and 800 m. Of the landscape and climatic data, species richness was best explained by the interaction of temperature and precipitation (quadratic effect) as well as the amount of artificial unproductive land (negative effect), natural unproductive land (positive effect), and meadows and pastures present (positive effect). No extinction debt was found using past climatic and landscape data from the 1950s and 1990s. Main conclusions: Significant increases in temperature and large increases in artificial unproductive land may be attributable for the change in the predicted distribution of species from 1956 to 2005. These effects could also be filtering out certain functional groups, selecting for species most suited to higher temperatures and urbanized areas (i. e. species with high temperature preference, high dispersal ability and most generalist in habitat specialization), particularly at lower elevations.