Natural enemies and pollinators in traditional cherry orchards: Functionally important taxa respond differently to farming system

Natalia Rosas-Ramos, Laura Baños-Picón, José Tormos, Josep D.Asís

Departamento de Biología Animal, Facultad de Biología, Universidad de Salamanca, Campus Miguel de Unamuno s/n, 37007, Salamanca, Spain.

Abstract

Some of the negative effects of agricultural intensification on biodiversity can be counteracted by the implementation of practices typically associated with organic farming. The efficiency of key ecosystem services, such as natural pest control or pollination, depends on biodiversity and could determine agricultural productivity and food security. In terrestrial ecosystems, both land use and topographic features are important filters in shaping taxa distribution. It is essential to identify which factors significantly drive changes in populations in order to maximize the abundance and richness of beneficial arthropods and to support the underlying services they provide across agroecosystems. Although traditional orchards are high nature value farming systems that maintain high levels of biodiversity, there is a lack of information on how organic farming affects these systems. We examined beneficial arthropod communities to disentangle the extent to which predators, parasitoids, and pollinators are shaped by local field management (organic vs. conventional management) and topographic features (hillside aspect, i.e. the orientation of the slope). In traditional cherry orchards in western Spain, beneficial arthropod communities were assessed by using a combination of different sampling methods. Our results show that communities differed between farming systems. Overall, dominant or most representative parasitoid and pollinator taxa benefited from organic management, whereas predators showed a more heterogeneous pattern in their abundances probably due to their varying responses to habitat characteristics. Topographic features, although being a factor for some of the studied groups, did not strongly affect beneficial arthropod communities. Our results indicate that, in traditional orchards, the effects of farming system on beneficial arthropods are not easily predictable. Due to the variability in habitat preferences found among different functionally important taxa, we highlight the importance of continuing to unravel the specific responses of beneficial arthropods to local management practices.

Keywords: Organic farming, Hillside aspect, Traditional orchards, Predators, Parasitoids, Pollinators.