Positive but variable effects of crop diversification on biodiversity and ecosystem services

The impacts of increasing the diversity of cultivated crop species or varieties in agroecosystems are still under scrutiny. The available empirical evidence is scattered in scope, agronomic and geographic contexts, and impacts on ecosystem services may depend on the type of diversification strategy used. To robustly assess the effects of crop diversification in agroecosystems, authors compiled the results of 95 meta-analyses integrating 5156 experiments conducted over 84 experimental years in 85 countries. Overall, their synthesis of experimental data from across the globe shows that crop diversification enhances not only crop production but also the associated biodiversity, and several supporting and regulating ecosystem services. However, there was substantial variability in the results for each individual ecosystem service between different diversification strategies such as agroforestry, intercropping, cover crops, crop rotation or variety mixtures. Their results highlight that while increasing the diversity of cultivated crop species or varieties in agroecosystems represents a very promising strategy for more sustainable land management, contributing to enhanced yields, enhanced biodiversity and ecosystem services, some crop diversification strategies are more effective than others in supporting key ecosystem services.