Amprako Louis, Stenchly Kathrin, Wiehle Martin, Nyarko George, Buerkert Andreas
Organic Plant Production and Agroecosystems Research in the Tropics and Subtropics (OPATS), University of Kassel, Steinstrasse 19, D-37213 Witzenhausen, Germany.
Competence Centre for Climate Change Mitigation and Adaptation (CliMA), University of Kassel, Kurt-Schumacher-Straße 25, D-34117 Kassel, Germany.
Insects. 2020 Aug 1;11(8):488. doi: 10.3390/insects11080488.
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, , 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.
西非国家的城市及城郊农业（UPA）生产系统不仅能缓解粮食和金融不安全状况，还可能促进节肢动物的生物多样性，并部分弥补自然环境的结构性损失。然而，UPA系统中的管理措施（如灌溉）也可能导致节肢动物生态的紊乱。为填补UPA管理与节肢动物种群之间关系的知识空白，我们比较了塔马利不同灌溉水源地的节肢动物物种。在72小时的采样期内，用陷阱诱捕器和盘式诱捕器从36块田地中捕获了14226只节肢动物。这些标本包括13个目、103个科、264个属和329个分类单元（243个已鉴定物种，86个未鉴定物种），并分为五个取食类群（食肉动物、分解者、食草动物、杂食动物和传粉者）。计算物种丰富度、物种积累曲线和多样性函数（丰富度、均匀度和离散度）来表征节肢动物群落。应用非度量多维标度法来检验各地点节肢动物群落的结构相似性。为考虑土壤相关数据的影响，我们还应用了冗余分析。节肢动物根据灌溉水源进行分组，其中双翅目昆虫在废水灌溉条件下最为占优势。在这里，特别是眼蠓，一种人类致病媒介，占双翅目的大部分。三种外来蚂蚁物种的出现表明入侵物种导致群落发生变化，而七种与蚜虫形成互利关系的蚂蚁物种（每种水源下至少出现一种蚂蚁物种）的出现突出了未来蚜虫虫害爆发的风险。未来对这些分类单元的研究应特别针对它们的生态和经济影响以及潜在的应对措施。
