Exploring ecosystem multifunctionality of restored temperate grasslands

Ecological restoration can help bending the curve of biodiversity loss and thus securing ecosystem functioning. Due to trade-offs among ecosystem functions and services, ecosystem multifunctionality (EMF) is hard to achieve when restoring degraded ecosystems, even in well-researched systems such as temperate grasslands. As different methods with varying levels of intensity are applied to restore grasslands, analysing how restoration measures affect EMF helps identifying and dealing with these trade-offs. In three regions across Germany, we sampled 121 restored grasslands that cover a wide gradient of soil moisture and restoration methods, i.e., management adaptation, sowing of cultivars or regional seed mixtures, or transfer of directly harvested material. The restored grasslands were compared with ancient grasslands as negative or positive reference sites. We characterised grassland EMF using twelve indicators of ecosystem functions and services, and analysed the effect of different restoration methods on individual indicators as well as EMF, using the averaging approach and Hill-Chao numbers. Comparison of the averaging approach and the Hill-Chao numbers consistently led to the same result, i.e. EMF were highest when high-quality restoration methods such as the sowing of regional seed mixtures or direct harvested material were applied, and no trade-off between biomass production and target plant species richness was detected. As restoration of target plant species richness is a main driver of EMF in grasslands, our results indicate that restoration practitioners should implement high-quality restoration methods that lead to diverse plant communities. Then restored grasslands can provide both, sustainable fodder production and biodiversity conservation.