Assessing crop diversity across scales using high-resolution remote sensing over the European Union: first insights for agro-environmental policies

Understanding crop diversity is crucial for resilience in farming, ecosystem services, and effective agro-environmental policies. We utilize a novel EU-wide satellite product (2018, 10 m resolution) to assess crop diversity across different scales. We define local crop diversity ($\alpha$-diversity) at 1 km scale, which in the EU is proportional to the area covered by large farms or clusters of small-to-medium sized farms. We also compute $\gamma$-diversity, covering landscape, regional, and national levels crop diversity. $\beta$-diversity ($\gamma$/$\alpha$) provides a measure of between agroecosystems diversity. National $\alpha$, $\gamma$, and $\beta$ diversity varies greatly ($\alpha$: 2.1-3.9, $\gamma$: 3.5-7.5, $\beta$: 1.22-2.27). EU-wide $\gamma$-diversity increases logarithmically with spatial aggregation (1 km: 2.85, 100 km: 4.27). We categorize EU Member States (MS) into four groups for crop diversification policy recommendations. Compared to the USA, the EU exhibits higher diversity related to differences in farm structure and practices. High local $\alpha$-diversity is only found for MS with small farms (<25 ha), but their presence doesn't always guarantee high local diversity. This study aids CAP implementation in the EU, with potential for annual continental Copernicus crop type maps and ecosystem co-variates exploration for a deeper understanding of agro-ecosystem services.