Disentangling the Benefits of Organic Farming for Beetle Communities (Insecta: Coleoptera) in Traditional Fruit Orchards

Abstract

The conversion of traditional land-use systems into more intensive agriculture forms plays a main role in biodiversity loss. Within this framework, organic management has received widespread attention since it is assumed to enhance multiple taxa, including different groups of insects and plants. However, its contribution to the promotion of organism diversity is still controversial. We developed a study in traditional cherry orchards from the Jerte Valley (western Spain) to examine how coleopteran and plant assemblages are driven by farming system (organic vs. conventional), topographic features, and seasonality. The coleopteran community was examined on the basis of its taxonomic and trophic guild response. Organic orchards supported a higher number of beetle families and a greater plant species richness. Additionally, beetle and plant communities were highly correlated; conventional orchards were more homogeneous in terms of both plant and beetle composition, while organic orchards were more heterogeneous, their composition being also shaped by the hillside aspect. From a more functional approach, the different coleopteran trophic guilds exhibited varying responses to the factors analyzed. The benefits of organic farming were notable even when working in traditional systems: highly valuable habitats for overall biodiversity. Therefore, we highlight the potential of organic orchards for conservation purposes.