Arthropod Communities in Urban Agricultural Production Systems under Different Irrigation Sources in the Northern Region of Ghana

Louis Amprako; Kathrin Stenchly; Martin Wiehle; George Nyarko; Andreas Buerkert

doi:10.3390/insects11080488

Arthropod Communities in Urban Agricultural Production Systems under Different Irrigation Sources in the Northern Region of Ghana

Insects. 2020 Aug 1;11(8):488. doi: 10.3390/insects11080488.

Authors

Louis Amprako¹, Kathrin Stenchly^{1

2

3}, Martin Wiehle^{1

4

5}, George Nyarko⁶, Andreas Buerkert¹

Affiliations

¹ Organic Plant Production and Agroecosystems Research in the Tropics and Subtropics (OPATS), University of Kassel, Steinstrasse 19, D-37213 Witzenhausen, Germany.
² Competence Centre for Climate Change Mitigation and Adaptation (CliMA), University of Kassel, Kurt-Schumacher-Straße 25, D-34117 Kassel, Germany.
³ Grassland Science and Renewable Plant Resources (GNR), University of Kassel, Steinstrasse 19, D-37213 Witzenhausen, Germany.
⁴ Tropenzentrum-Centre for International Rural Development, University of Kassel, Steinstrasse 19, D-37213 Witzenhausen, Germany.
⁵ International Center for Development and Decent Work, University of Kassel, Kleine Rosenstrasse 1-3, D-34109 Kassel, Germany.
⁶ Department of Horticulture, Faculty of Agriculture, University for Development Studies (UDS), P.O. Box TL 1882, Tamale, Ghana.

Abstract

Urban and peri-urban agricultural (UPA) production systems in West African countries do not only mitigate food and financial insecurity, they may also foster biodiversity of arthropods and partly compensate for structural losses of natural environments. However, management practices in UPA systems like irrigation may also contribute to disturbances in arthropod ecology. To fill knowledge gaps in the relationships between UPA management and arthropod populations, we compared arthropods species across different irrigation sources in Tamale. During a 72-h sampling period, 14,226 arthropods were caught with pitfall traps and pan traps from 36 fields. These specimens comprised 13 orders, 103 families, 264 genera, and 329 taxa (243 identified species, 86 unidentified species) and categorized into five feeding guilds (carnivores, decomposers, herbivores, omnivores, and pollinators). Species richness, species accumulation curves, and diversity functions (richness, evenness, and dispersion) were calculated to characterize the arthropod community. Non-metric multidimensional scaling was applied to examine structural similarity of arthropod communities among sites. To account for the effects of soil-related data, we furthermore applied a redundancy analysis. Arthropods grouped according to the irrigation water source, whereby the dipterans were most dominant under wastewater conditions. Here, particularly the eye gnat, Hippelates pusio, a disease-causing vector for humans, accounted for the dipterans. The occurrence of three alien ant species suggested community shifts through invasive species, while the occurrence of seven ant species (at least one ant species occurred under each water source) that form mutualistic relationships with aphids highlighted future risks of aphid pest outbreak. Future studies on these taxa should specifically target their ecological and economic effects and potential countermeasures.

Keywords: NMDS; RDA; Sub-Sahara Africa; agrobiodiversity; ecosystem service; feeding guild; insects; species function; urban agriculture.

Abstract

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