Limited Effect of Management on Apple Pollination: A Case Study from an Oceanic Island.

Paulo A. V. Borges,Adara Pardo,Natalia Fierro,David H. Lopes

doi:10.3390/insects11060351

Paulo A. V. Borges, Adara Pardo + Show 2 more

Open Access

https://doi.org/10.3390/insects11060351

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Journal: Insects	Publication Date: Jun 4, 2020
Citations: 7	License type: CC BY 4.0

Affiliation: University of the Azores, University of Extremadura

Abstract

Intensive agricultural practices leading to habitat degradation represent a major threat to pollinators. Diverse management practices are expected to influence wild pollinator abundance and richness on farms, although their effect in perennial crops is still unclear. In this study, we assessed the impact of management on apple (Malus domestica) pollination on an oceanic island, by comparing conventional (with and without herbicide application) and organic apple orchards. Pollinator visitation and pan trap surveys were carried out in six apple orchards in Terceira Island (Azores) and the landscape composition surrounding orchards was characterized. We also quantified fruit set, seed set and apple weight. We found no significant effect of management on insect visitation rates, whereas there was a negative association with increasing surrounding agricultural land. In contrast, management had an effect on species abundance, richness and diversity at the orchard level. Conventional orchards without herbicides showed higher abundance than the rest, but lower richness and diversity than conventional orchards with herbicides. Management had an effect on fruit set, but not on seed set or fruit weight. Our results suggest that management alone is insufficient for the overall improvement of apple pollination on an oceanic island, while landscape composition may play a relevant role.

Highlights

Pollination is widely recognized as an essential ecosystem service and a vital process to sustain food security [1,2]
We sampled a total of 38 insect species and morphospecies visiting apple orchards, belonging to four arthropod orders, namely, spiders (Arachnidae: Araneae), and insects (Hexapoda: Coleoptera, Diptera and Hymenoptera) (Table S3)
The most common species collected in pan traps were Halictus morio (Hymenoptera: Halictidae) (58.3%) and Sepsis sp. (Diptera: Sepsidae)

Summary

Introduction

Pollination is widely recognized as an essential ecosystem service and a vital process to sustain food security [1,2]. The impact of biodiversity erosion drivers, namely habitat loss and degradation, climate change, or the intensification of agriculture in the past half-century, has triggered a decline in wild and managed bees and other pollinating insects in several regions of the world [3,4,5,6,7,8]. Agriculture poses many threats to insect pollinators, including changes in land use, loss, fragmentation and degradation of habitat, introduction of exotic organisms, modern agricultural practices, and pesticide use [9,10]. Diverse agricultural management practices are expected to influence wild bee abundance and richness on farms [12]. For instance, can improve bee abundance, richness and productivity [13,14,15], as long as sufficient habitat exists to maintain source populations [16,17]

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