Reprint of 鈥淪eed availability in hay meadows: Land-use intensification promotes seed rain but not the persistent seed bank鈥?/span>

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• 作者：Michaela Zeiter ; Juliane Preukschas ; Andreas Stampfli
• 关键词：Semi-natural grassland ; Management ; Seed size ; Seed longevity ; Seed production ; Species diversity
• 刊名：Agriculture, Ecosystems & Environment
• 出版年：1 January, 2014
• 年：2014
• 卷：182
• 期：Complete
• 页码：88-95
• 全文大小：663 K

文摘

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 176-1211 gm^鈭?. In each grassland community, we estimated seed rain and seed bank using eight pooled seed-trap or topsoil samples of 89 cm² in each of six plots representing an area of c. 150 m². 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.