Department of Agricultural and Biological Engineering, University of Florida, Gainesville, Florida, United States of America.
Department of Geography, University of Florida, Gainesville, Florida, United States of America.
PLoS One. 2020 May 14;15(5):e0232681. doi: 10.1371/journal.pone.0232681. eCollection 2020.
In West Africa, long and complex livestock value chains connect producers mostly in the Sahel with consumption basins in urban areas and the coast. Regional livestock trade is highly informal and, despite recent efforts to understand animal movement patterns in the region, remains largely unrecorded. Using CILSS' database on intraregional livestock trade, we built yearly and overall weighted networks of animal movements between markets. We mapped and characterized the trade networks, identified market communities, key markets and their roles. Additionally, we compared the observed network properties with null-model generated ensembles. Most movements corresponded to cattle, were made by vehicle, and originated in Burkina Faso. We found that live animals in the central and eastern trade basins flow through well-defined, long distance trade corridors where markets tend to trade in a disassortive way with others in their proximity. Modularity-based communities indicated that both national and cross-border trade groups exist. The network's degree and link distributions followed a log-normal or a power-law distribution, and key markets located primarily in urban centers and near borders serve as hubs that give peripheral markets access to the regional network. The null model ensembles could not reproduce the observed higher-level properties, particularly the propinquity and highly negative assortativity, suggesting that other possibly spatial factors shape the structure of regional live animal trade. Our findings support eliminating cross-border impediments and improving the condition of the regional road network, which limit intraregional trade of and contribute to the high prices of food products in West Africa. Although with limitations, our study sheds light on the abstruse structure of regional livestock trade, and the role of trade communities and markets in West Africa.
在西非，长长的、复杂的牲畜价值链将生产者（主要在萨赫勒地区）与城市地区和沿海地区的消费地联系起来。区域牲畜贸易高度非正规，尽管最近努力了解该地区的动物流动模式，但仍在很大程度上未被记录。我们利用萨赫勒和撒哈拉抗旱办事处（CILSS）的区域内牲畜贸易数据库，建立了市场之间动物流动的年度和总体加权网络。我们绘制并描述了贸易网络，确定了市场群落、关键市场及其作用。此外，我们将观察到的网络属性与基于 null 模型生成的集合进行了比较。大多数动物流动与牛有关，通过车辆进行，起源于布基纳法索。我们发现，中部和东部贸易区的活体动物通过明确界定的长途贸易走廊流动，这些市场倾向于与附近的其他市场进行非关联交易。基于模块的群落表明，既存在国家内部贸易群组，也存在跨境贸易群组。网络的度数和链接分布遵循对数正态分布或幂律分布，主要位于城市中心和边境附近的关键市场充当枢纽，使外围市场能够进入区域网络。null 模型集合无法再现观察到的更高层次的属性，特别是接近度和高度负关联性，这表明其他可能的空间因素影响了区域活体动物贸易的结构。我们的研究结果支持消除跨境障碍和改善区域道路网络的状况，这限制了区域内的贸易，导致西非食品价格居高不下。尽管存在局限性，但我们的研究揭示了区域牲畜贸易的深奥结构，以及贸易群落和市场在西非的作用。
