S15 - Session O1 - Biodiversity in apple orchards - an assessment towards increased sustainability and resilience

Authors: Hannah Jaenicke *, Andreé Hamm

In order to increase the accompanying biodiversity in apple orchards, managed under the "controlled-integrated" production system in Germany, measures including flower strips, bee and bird nesting blocks and flowering shrubs were introduced to four pilot farms in the Rhineland region. Assessments of the diversity and abundance of wild bees, hover flies, bugs, spiders, ground beetles as well as birds and bats were carried out using a variety of catching methods. For flying insects, nets and Malaise traps were used, ground beetles and spiders were caught in ground (Barber-) traps, bats were identified acoustically using a Bat detector and birds were visually observed through transect walks in Winter and nest mapping during the brood period in Spring. Early results indicate a substantial diversity in the plantations, including records of several species on the German Red List of endangered species. A minimum of 74 species of ground beetles, 113 wild bee species, 93 spider species and 54 hover fly species were documented in addition to five bat species and 37 bird species. The assessment of total arthropod biodiversity using the meta-barcoding analysis from 24-hour-Malaise trap catches in 2018 and 2019 documented nearly 700 taxa. While flower strips had a clear positive effect on nectar and pollen collecting insects, ground beetles were neither negatively nor positively affected. Many ground beetles as well as bats and birds are attracted by the availability of insects as a food source and can be seen as indicators for a functioning ecosystem. Further measures to support the sustainability and hence resilience of the plantations are recommended.