After the hotspots are gone: Land use history and grassland plant species diversity in a strongly transformed agricultural landscape

Question: We asked how landscape configuration and present management influence plant species richness and abundance of habitat specialists in grasslands in a ‘‘modern’’ (much exploited and transformed) agricultural Swedish landscape.Location: Selaöön, south-eastern Sweden (59°°24′′ N, 17°°10′′ E).Methods: Present and past (150 and 50 years ago) landscape pattern was analysed in a 25 km² area. Species richness was investigated in 63 different grassland patches; grazed and abandoned semi-natural grasslands, and grazed ex-arable fields. Influence of landscape variables; area, past and present grassland connectivity, present management on total species richness, density and abundance of 25 grassland specialists was analysed.Results: Semi-natural grasslands (permanent unfertilised pastures or meadows formed by traditional agricultural methods) had declined from 60%% 150 years ago to 5%% today. There was a significant decline in species richness and density in abandoned semi-natural grasslands. Total species richness was influenced by present management, size and connectivity to present and past grassland pattern. Landscape variables did not influence species density in grazed semi-natural grassland suggesting that maintained grazing management makes grassland patches independent of landscape context. The abundance of 16 grassland specialists was mainly influenced by management and to some extent also by landscape variables.Conclusion: Although species richness pattern reflect management and to some extent landscape variables, the response of individual species may be idiosyncratic. The historical signal from past landscapes is weak on present-day species richness in highly transformed, agricultural landscapes. Generalizations of historical legacies on species diversity in grasslands should consider also highly transformed landscapes and not only landscapes with a high amount of diversity hotspots left.Nomenclature: Lid & Lid (2005).