A complex monitoring of biodiversity of organic apple orchards could uncover the impact of agro-management strategies.
This complex study investigates causal relationships between biodiversity of insect indicator-insects in soil, on land surface and on trees, and agro-management practices in organic apple orchard in the region of Plovdiv, Bulgaria. In 2013-2015, indicator-insects density and biodiversity were higher in organic than in conventional orchard which was attributed to practices facilitating improved activity of beneficial insects in keeping pest population below threshold levels. Regression analysis showed a positive but mild correlation (at polynomial model) between agricultural intensification (AI)index and biodiversity indices (of Shannon and Simpson) of soil insects and land-surface insects, and a strong correlation (at linear model) between the indices on the organic trees. The AI index should however reflect other important factors impacting biodiversity, i.e. climate and soil conditions or agro-management (e.g. time of mowing, irrigation regime or time of pesticide applications).