Biodiversity for multifunctional grasslands: equal productivity in high-diversity low-input and low-diversity high-input systems

• Main Authors: A. Weigelt, W. W. Weisser, N. Buchmann, M. Scherer-Lorenzen
• Format: Article
• Language: English
• Published: Copernicus Publications 2009-08-01
• Series: Biogeosciences
• Online Access: http://www.biogeosciences.net/6/1695/2009/bg-6-1695-2009.pdf
• ISSN: 1726-4170; 1726-4189

Modern grassland management seeks to provide many ecosystem services and experimental studies in resource-poor grasslands have shown a positive relationship between plant species richness and a variety of ecosystem functions. Thus, increasing species richness might help to enhance multifunctionality in managed grasslands if the relationship between species richness and ecosystem functioning is equally valid in high-input grassland systems. <br><br> We tested the relative effects of low-input to high-input management intensities and low to high plant species richness. Using a combination of mowing frequencies (1, 2 or 4 cuts per season) and fertilisation levels (0, 100 and 200 kg N ha<sup>−1</sup> a<sup>−1</sup>), we studied the productivity of 78 experimental grassland communities of increasing plant species richness (1, 2, 4, 8 or 16 species with 1 to 4 functional groups) in two successive years. <br><br> Our results showed that in both years higher diversity was more effective in increasing productivity than higher management intensity: the 16-species mixtures had a surplus of 449 g m<sup>−2</sup> y<sup>−1</sup> in 2006 and 492 g m<sup>−2</sup> y<sup>−1</sup> in 2007 over the monoculture yields whereas the high-input management resulted in only 315 g m<sup>−2</sup> y<sup>−1</sup> higher productivity in 2006 and 440 g m<sup>−2</sup> y<sup>−1</sup> in 2007 than the low-input management. In addition, high-diversity low-input grassland communities had similar productivity as low-diversity high-input communities. The slopes of the biodiversity – productivity relationships significantly increased with increasing levels of management intensity in both years. <br><br> We conclude that the biological mechanisms leading to enhanced biomass production in diverse grassland communities are as effective for productivity as a combination of several agricultural measures. Our results demonstrate that high-diversity low-input grassland communities provide not only a high diversity of plants and other organisms, but also ensure high forage yields, thus granting the basis for multifunctional managed grasslands.