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A decrease in habitat amount and connectivity causes immediate or delayed species extinctions in transformed landscapes due to reduced functional connections among populations and altered environmental conditions. We assessed the effects of present and historical grassland amount and connectivity as well as local habitat factors typical of the present landscape on the current species richness of grassland specialist and generalist plants and arthropods in grassland fragments. We surveyed herbaceous plants, ants, orthopterans, true bugs and rove beetles in 60 dry grassland fragments in Hungary. We recorded the area of the focal grassland, the slope and the cover of woody vegetation. By using habitat maps of the present and historical landscape, we calculated grassland amount and connectivity for four time periods covering 158 years (1858–2016). We found evidence for an unpaid extinction debt in specialist plants, suggesting that they have not come to equilibrium with the grassland amount and connectivity of the present landscape yet. This localised and typically long-lived group responded slowly to the landscape changes. Specialist arthropod taxa with short generation times responded much faster to habitat loss than plants and did not show an extinction debt. Generalist plants and animals adapted to a wide range of habitats were affected by the landscape-scale decline of grassland habitats. Despite decreased habitat connectivity, grassland fragments with dry environmental conditions and high environmental heterogeneity can sustain specialist plants in transformed landscapes. Unpaid extinction debt should be considered an early warning signal: Restoration of grassland connectivity is necessary to halt ongoing extinction processes. [ABSTRACT FROM AUTHOR]

Abstract: Conservation of grassland biodiversity is a key issue in the EU agro-biodiversity policy. We assessed the effects of yearly mowing on target forb biomass in years with contrasting precipitation (2006–2007) in mountain fen and dry-mesophilous hay meadows in NE-Hungary. We hypothesised: (i) Species richness and biomass of target forbs is higher in mown than in abandoned stands. (ii) Mowing has more an effect on the biomass of target forbs, graminoids and litter than precipitation. Mowing increased the species richness of forbs and target forbs. The biomass of forbs and target forbs was not affected by mowing because of the specific responses of certain forbs. The majority of target species were supported, but tall forbs (Succisa pratensis; Lathyrus pratensis) were suppressed by mowing. Precipitation affected only the amount of litter in dry-mesophilous meadows and forb biomass in fen meadows. In the dry year, the biomass of target forbs decreased but the proportion of the species did not change. Our results showed that mowing is necessary to maintain overall plant biodiversity in hay meadows by removal of graminoid biomass and litter, but not all target forbs were favoured by regular yearly mowing. Decreased mowing frequency (mowing in every second or third year) on the entire meadow or temporarily changing mosaics of mown and unmown stripes might be the most suitable management option for maintaining the highest biodiversity of forbs. [Copyright &y& Elsevier]