Skip to main content
Dryad

Biodiversity effects on grape quality depend on variety and management intensity

Steiner, Magdalena1; Grace, James Benjamin2; Bacher, Sven3

Published Jul 19, 2021 on Dryad. https://doi.org/10.5061/dryad.z8w9ghx83

Data files

Jul 19, 2021 version files 13.38 KB

Abstract

Interactions between plants can be beneficial, detrimental or neutral. In agricultural systems competition between crop and spontaneous vegetation is a major concern. We evaluated the relative support for three non-exclusive ecological hypotheses about interactions between crop and spontaneous plants based on competition, complementarity or facilitation.

The study was conducted in Swiss vineyards with different vegetation management intensities. Thirty-three vineyards planted with two different grape varieties were studied over 3 years to determine whether low-intensity vegetation management might provide benefits for grape quality parameters. Management intensity varied with the degree of control of spontaneous inter-row vegetation. Features of spontaneous vegetation measured included total cover, total species richness and abundance of nitrogen fixing plants. Grape quality parameters of known importance to wine-making (yeast assimilable nitrogen, sugars, tartric acid, and malic acid) were determined by Fourier-transform infrared spectroscopy (FTIR). Using structural equation modeling, we evaluated hypotheses about the multivariate responses of grape quality parameters as well as the direct and indirect (plant-mediated) effects of management. 

Observed effects of management differed between grape varieties. Management intensity and abundance of N-fixing plants significantly influenced grape quality parameters, while total richness of spontaneous plants did not have detectable effects. Abundance of N-fixing plants was enhanced by low-intensity management resulting in increased N content in the red grape variety (Pinot noir), potentially enhancing grape quality, while measured soil N content did not explain the increase.

Synthesis: Our study shows that crop quality can be enhanced by spontaneous plants, in this case by the abundance of a key functional group (N-fixers), most likely through plant-plant or plant-microbe facilitation. However, beneficial interactions may have a high specificity in terms of facilitation partners and may have contrasting effects at low taxonomic resolutions such as crop varieties. Generally increasing plant biodiversity in agricultural systems may increase competition with crops. Thus, the identification of suitable interaction partners and a careful balance between crop variety and spontaneous plant species may be necessary to utilize beneficial interactions and to reduce the trade-off between agricultural production and biodiversity to achieve a sustainable ecological benefit in agricultural systems.