Linkage between crop diversity and agro-ecosystem resilience: Nonmonotonic agricultural response under alternate regimes

- We examine the linkage between crop diversity and the agro-ecosystem resilience.
- We incorporate the regime shifts of the agro-ecosystem into a time-varying transition probability Markov switching model.
- Crop diversity enhances the agro-ecosystem resilience.
- Crop diversity gives different effects on agricultural production depending on the regimes of agro-ecosystem.

This study investigates the dynamic linkage between crop diversity and agro-ecosystem resilience. The analysis estimates a panel data of rice farming in Japan using a time-varying transition probability Markov switching model, capturing (i) the alternate regimes of agro-ecosystems, (ii) the controlling factors affecting the regime shifts of agro-ecosystems, and (iii) the nonmonotonic response of agricultural production under alternate regimes. Results show that the effect of crop diversity on agro-ecosystem productivity differs depending on its regimes. Crop diversity increases productivity during normal periods, a normal regime, while it decreases the productivity during periods exposed to disturbances such as extreme weather events and disease and insect damage, an adverse regime. Further, we find that crop diversity enhances the agro-ecosystem resilience. Thus, it increases the likelihood of the agro-ecosystem remaining in a normal regime and staving off an adverse regime. The crop diversity loss has gradually increased in agro-ecosystems without sufficient understanding about the linkage between crop diversity and agro-ecosystem resilience. Our findings suggest the possibility that the agro-ecosystem resilience would be a key driver of sustainable agriculture under increasing uncertainties. This study gives useful insights on this issue by empirically demonstrating the effects of crop diversity on the agro-ecosystem resilience.