Grasslands are globally distributed and naturally occurring; however, in Europe, most grasslands are anthropogenically created or altered by livestock grazing or mowing. Low‐intensity use and management have led to species‐rich communities in European grasslands. The intensification of crop production and livestock farming with stabling throughout the year has led to an abandonment of grasslands that are no longer economically profitable. In this study, we looked at the influence of grassland abandonment on biodiversity. We hypothesized that abandonment of grasslands decreases the overall biodiversity, but has different effects depending on the focal taxonomic group (i.e., vascular plants, insects, or birds). We also hypothesized that the type of management before abandonment, the type of grassland, and the time after abandonment would influence grassland biodiversity. We conducted a Web of Science search, with pre‐defined terms, to find articles that compared biodiversity of managed and abandoned grasslands in Europe. We screened the articles and included 39 studies in a subsequent meta‐analysis. We found that overall biodiversity was reduced after abandonment; however, the biodiversity reduction in the grasslands differed among taxonomic groups. Plant species diversity was significantly lower after abandonment (plant summary effect size: −0.25 [−0.34; −0.16]), whereas the diversity of insects and birds showed no significant trend, but a visual trend toward an increase. None of the other environmental variables (type of management, type of grassland, or the time after abandonment) had a significant influence on the biodiversity of the grasslands. We conclude that maintaining grassland management is crucial to support biodiversity conservation in European grasslands.

Mass-flowering crops, such as Oilseed Rape (OSR), provide resources for pollinators and benefit from pollination services. Studies that observe the community of interactions between plants and pollinators are critical to understanding the resource needs of pollinators. We observed pollinators on OSR and wild plants in adjacent semi-natural areas in Sachsen-Anhalt, Germany to quantify (1) the co-flowering plants that share pollinators with OSR, (2) the identity and functional traits of plants and pollinators in the network module of OSR, and (3) the identity of the plants and pollinators that act as network connectors and hubs. We found that four common plants share a high percentage of their pollinators with OSR. OSR and these plants all attract abundant pollinators in the community, and the patterns of sharing were not more than would be expected by chance sampling. OSR acts as a module hub, and primarily influences the other plants in its module that have similar functional traits. However, the plants that most influence the pollination of OSR have different functional traits and are part of different modules. Our study demonstrates that supporting the pollination of OSR requires the presence of semi-natural areas with plants that can support a high abundances of generalist pollinators.

Conserving biodiversity, especially in agricultural landscapes, is a major societal challenge. Broad scientific evidence exists on the impacts of single drivers on biodiversity, such as the intensification of agriculture. However, halting biodiversity decline requires a systemic understanding of the interactions between multiple drivers, which has hardly been achieved so far. Selecting Germany as a case study, the goal of our analysis is (i) to understand how various socio‐economic drivers of biodiversity in agricultural landscapes interact at the national scale, (ii) to identify plausible pathways that most likely will lead to an improvement of biodiversity in agricultural landscapes and (iii) to discuss guiding principles for policy‐making based on the pathways. We applied the expert‐based Cross‐Impact‐Balance (CIB) methodology to the German agri‐food system (target year 2030). Seven descriptors that represent the most relevant socio‐economic drivers of biodiversity (here, we focus on species richness) in agricultural landscapes in Germany were defined. In three workshops with different groups of experts, we assessed all the interactions and impacts between these descriptors. From the workshops, seven overlapping scenarios were identified and aggregated into four main future pathways for enhancing biodiversity in agricultural landscapes. These pathways are: (1) ‘Innovation and stricter legislation’, (2) ‘Major change in protein production and CAP shift’, (3) ‘Major change in protein production and national legislation’ and (4) ‘Major social changes compensate for a lack of innovation in food production’. Socio‐economic drivers interact to varying degrees. Societal values have a strong active influence on the system, e. g. agricultural policy, whereas the orientation and objectives of agriculture, e. g. focus on public goods, are rather passively determined. Conserving biodiversity thus depends upon the evolution of societal values, European and national nature conservation and agricultural policies, innovations in plant and protein production as well as on global commodity markets. A key message for policymakers is that there are generally different, complementary options for achieving the objective of improving biodiversity. This is important when specific drivers such as the CAP cannot be steered in a particular desired direction. Read the free Plain Language Summary for this article on the Journal blog.