PDF(Pubmed)
Abstract：
Cassava (Manihot esculenta) is among the most important staple crops globally, with an imperative role in supporting the Sustainable Development Goal of \'Zero hunger\'. In sub-Saharan Africa, it is cultivated mainly by millions of subsistence farmers who depend directly on it for their socio-economic welfare. However, its yield in some regions has been threatened by several diseases, especially the cassava brown streak disease (CBSD). Changes in climatic conditions enhance the risk of the disease spreading to other planting regions. Here, we characterise the current and future distribution of cassava, CBSD and whitefly Bemisia tabaci species complex in Africa, using an ensemble of four species distribution models (SDMs): boosted regression trees, maximum entropy, generalised additive model, and multivariate adaptive regression splines, together with 28 environmental covariates. We collected 1,422 and 1,169 occurrence records for cassava and Bemisia tabaci species complex from the Global Biodiversity Information Facility and 750 CBSD occurrence records from published literature and systematic surveys in East Africa. Our results identified isothermality as having the highest contribution to the current distribution of cassava, while elevation was the top predictor of the current distribution of Bemisia tabaci species complex. Cassava harvested area and precipitation of the driest month contributed the most to explain the current distribution of CBSD outbreaks. The geographic distributions of these target species are also expected to shift under climate projection scenarios for two mid-century periods (2041-2060 and 2061-2080). Our results indicate that major cassava producers, like Cameron, Ivory Coast, Ghana, and Nigeria, are at greater risk of invasion of CBSD. These results highlight the need for firmer agricultural management and climate-change mitigation actions in Africa to combat new outbreaks and to contain the spread of CBSD.
摘要：
木薯（Manihotesculenta）是全球最重要的主要农作物之一，在支持“零饥饿”的可持续发展目标方面发挥了至关重要的作用。在撒哈拉以南非洲，它主要由数百万自给自足的农民种植，他们的社会经济福利直接依赖它。然而,它在一些地区的产量受到几种疾病的威胁，尤其是木薯褐条病（CBSD）。气候条件的变化增加了疾病传播到其他种植区的风险。这里,我们描述了木薯的当前和未来分布，非洲的CBSD和粉虱烟粉虱物种复合体，使用四个物种分布模型(SDM)的集合：增强回归树，最大熵,广义加法模型，和多元自适应回归样条，以及28个环境协变量。我们从全球生物多样性信息设施收集了木薯和烟粉虱物种复合体的1,422和1,169个发生记录，并从东非已发表的文献和系统调查中收集了750个CBSD发生记录。我们的结果确定等温性对木薯的当前分布贡献最大，而海拔是烟粉虱物种复合体当前分布的最高预测指标。木薯收获面积和最干旱月份的降水对解释CBSD暴发的当前分布贡献最大。在气候预测情景下，这些目标物种的地理分布也有望在两个世纪中期（2041-2060和2061-2080）发生变化。我们的结果表明，主要的木薯生产者，像卡梅隆一样,象牙海岸,加纳,尼日利亚,入侵CBSD的风险更大。这些结果突出表明，非洲需要加强农业管理和减缓气候变化行动，以应对新的疫情并遏制CBSD的蔓延。
