Seed availability in hay meadows: Land-use intensification promotes seed rain but not the persistent seed bank

• Published in: Agriculture, ecosystems & environment ecosystems & environment, 2013-05, Vol.171, p.55-62
• Main Authors: Zeiter, Michaela, Preukschas, Juliane, Stampfli, Andreas
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Amplification; Biological and medical sciences; cold; cutting; Density; ecosystems; Fundamental and applied biological sciences. Psychology; General agroecology; General agroecology. Agricultural and farming systems. Agricultural development. Rural area planning. Landscaping; General agronomy. Plant production; Generalities. Agricultural and farming systems. Agricultural development; Grasslands; Hay; Land use; Management; meadows; plant establishment; Productivity; Rain; seed dispersal; Seed longevity; Seed production; Seed size; Seeds; Semi-natural grassland; sowing; Species diversity; spring; topsoil
• ISSN: 0167-8809; 1873-2305
• DOI: 10.1016/j.agee.2013.03.009

•In Swiss hay meadows productivity reflects land-use intensification.•The density and species diversity of the seed rain increase with productivity.•The mean seed size in the seed rain diminishes with productivity.•The proportion of persistent seeds and the proportion of species with persistent seeds in the topsoil decline with productivity. Intensification of land use in semi-natural hay meadows has resulted in a decrease in species diversity. This is often thought to be caused by the reduced establishment of plant species due to high competition for light under conditions of increased productivity. Sowing experiments in grasslands have found reliable evidence that diversity can also be constrained by seed availability, implying that processes influencing the production and persistence of seeds may be important for the functioning of ecosystems. So far, the effects of land-use intensification on the seed rain and the persistence of seeds in the soil have been unclear. We selected six pairs of extensively managed (Festuco-Brometea) and intensively managed (Arrhenatheretalia) grassland with traditional late cutting regimes across Switzerland and covering an annual productivity gradient in the range 176–1211gm−2. In each grassland community, we estimated seed rain and seed bank using eight pooled seed-trap or topsoil samples of 89cm2 in each of six plots representing an area of c. 150m2. The seed traps were established in spring 2010 and collected simultaneously with soil cores after an exposure of c. three months. We applied the emergence method in a cold frame over eight months to estimate density of viable seeds. With community productivity reflecting land-use intensification, the density and species richness in the seed rain increased, while mean seed size diminished and the proportions of persistent seeds and of species with persistent seeds in the topsoil declined. Stronger limitation of seeds in extensively managed semi-natural grasslands can explain the fact that such grasslands are not always richer in species than more intensively managed ones.