A recent paper by Beaumelle, L., Auriol, A., et al., published in the online journal Ecological Solutions and Evidence, examines how the benefits of increased cover crop diversity for predators and biological pest control depend on the landscape context.

In agricultural areas, increasing plant diversity is a powerful method to strike the balance between food production and biodiversity preservation. Increased plant diversity at the local scale could assist biological pest management. Such favorable effects, on the other hand, are frequently dependent on the landscape context, which determines the available pool of natural enemy species and their capacity to colonize newly formed habitats. However, it is still unknown how the landscape context influences the local impact of plant diversity on natural enemies and pest management services.

The researchers experimented with cover crop diversity (two versus twenty plant species) in nine pairs of vineyards positioned along a landscape gradient ranging from 20 to 60% semi-natural habitats. In European vineyards, the ecologists investigated the predation rate of a significant moth pest by sampling natural enemy groups in the soil and foliage (Lobesia botrana).

Across the experiment, diverse cover crops increased the quantity of natural enemies by 140 percent while maintaining their taxonomic richness and composition. We also discovered that cover crops have a distance-decay influence on natural enemy abundance across cover crop kinds.

The research reveals the advantages of increasing plant variety at the local scale in vineyard agroecosystems to increase the richness of natural enemies and the level of biological pest control services. In simplified landscapes, diverse cover crops primarily benefit natural enemies and biological pest control, demonstrating that the performance of local agroecological strategies in promoting biodiversity and ecosystem services is dependent on the landscape context. To optimise favourable effects on biodiversity and ecosystem services, the researchers believe that a deliberate spatial organisation of farming methods that increases local plant diversity is required.

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Photo: Cover of the Ecological Solutions and Evidence Volume 2, Issue 3.