In a groundbreaking study that sheds light on the impact of land consolidation on biodiversity, researchers from the UK, Netherlands, and China have discovered that the removal of hedgerows and field margins covered by wild grass and flowers significantly decreases the diversity and abundance of arthropods in rice fields. The study, published in the Journal of Applied Ecology, monitored 20 rice fields in China over a six-year period to assess how the changing agricultural landscape affects the natural enemies of rice pests, as well as rice yield.
Traditional Chinese smallholder fields, characterized by their irregular shapes and separation by hedgerows, wild grass, and flowers, are rapidly being transformed as farmers consolidate land to improve agricultural operation efficiency. However, the grassy margins and flowering vegetation between these fields provide a crucial habitat for the natural enemies of rice pests, such as spiders and ground beetles. Dr. Yi Zou from XJTLU, the corresponding author of the study, emphasizes that removing these habitats during land consolidation negatively impacts arthropod communities.
The research team collected an impressive 141,587 individual arthropods representing 80 taxonomic families. Their findings revealed that traditional farmland supported a significantly higher abundance and diversity of rice pests' natural enemies compared to consolidated land. Interestingly, there were no significant differences in the number of rice pests or rice yield between the two types of farmland.
The study also investigated the effects of insecticide application, with half of each field being sprayed. The results showed that insecticide use decreased the diversity and abundance of both pests and natural enemies in consolidated and traditional fields. However, in fields where insecticide was not applied, a 10.8% decrease in rice yield was observed.
The findings of this study provide support for the implementation of agri-environmental measures, such as using flowering plants in field margins, to increase farmland biodiversity and mitigate the negative impact of land consolidation. While AEM has been widely implemented in Europe, it is rarely used in China. Dr. Zou recommends the implementation of AEM or re-establishing field margin vegetation during the consolidation process to mitigate the potential negative effects on rice arthropod biodiversity.
Dr. Jenny Hodgson from the University of Liverpool, a co-author of the study, highlights the quality of the data and the breadth of influential factors investigated, which allowed the researchers to disentangle the effects of farmland consolidation, pesticide application, and seminatural habitat beyond the farm.
The researchers acknowledge that biodiversity is not the only concern for farmers, and there is a trade-off between biodiversity improvements, labor efficiency, yield, and pest control. Dr. Shanxing Gong, the lead author of the study, emphasizes the need for further investigation into the effectiveness of natural enemies in biological pest control before implementing AEM strategies.
The study, which includes researchers from various institutions in China, the Netherlands, and the UK, provides valuable insights into the impact of land consolidation on biodiversity and the potential of AEM to mitigate these effects. As agricultural landscapes continue to evolve, it is crucial to consider the balance between biodiversity, productivity, and profitability to ensure sustainable farming practices that benefit both the environment and the farmers.
