Abandoning grassland management negatively influences plant but not bird or insect biodiversity in Europe

Abstract

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.