Optimizing crop diversity across multiple spatial scales

Increasing crop diversity in agricultural landscapes can increase biodiversity but it is unclear how different diversification strategies affect crop diversity across spatial scales. Here we compared different diversification strategies for farmers along three dimensions of diversity: temporal, genetic, and spatial. We developed a framework that optimizes crop diversity for different spatial scales and applied it to a case study of 58 arable farms with 544 fields in the municipality of Lelystad, Netherlands. We showed that the scale at which crop diversity is assessed determines what the optimal crop diversification strategy is. At lower spatial scales, strategies that increase crop diversity along the spatial dimension increased crop diversity most. In contrast, at higher spatial scales, strategies that increase crop diversity along the temporal and genetic dimensions increased crop diversity most. These differences led to trade-offs between the optimal level of crop diversity at different spatial scales. With our modelling framework we can provide guidelines to efficiently allocate activities that aim to increase crop diversity across multiple spatial scales.