Abstract Enhancing agrobiodiversity offers a suite of functions key to the sustainability of low input agroecosystems. The pairing of shade trees in pan-tropical tree-crop systems represents one of the most common and widespread applications of agroecosystem diversification, yet given the vastly heterogeneous conditions in which shade tree selection is made, generalizable advances in the identification of suitably paired tree-crop and shade tree is essential for performance and adoption. Here, we determine the phylogenetic distance between 78 reported shade tree genera and the dominant tree-crop, Theobroma cacao L (cocoa), across four countries in sub-Sahara Africa. We hypothesize that shade trees classified as desirable will be phylogenetically distant from T. cacao, based on the well-established theory that disparate evolutionary histories confer niche differentiation. Our analyses confirm that shade tree taxa categorized as desirable by farmers and institutions present higher phylogenetic distance with T. cacao than shade trees taxa categorized as undesirable. These results demonstrate that shade tree evolutionary distance to the target crop could be a useful tool to predict a taxon’s a priori suitability in cocoa agroforests, as well as the ability of phylogenetic analyses in prescribing appropriate shade trees in other current and future agroforestry systems.

中文翻译：

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进化距离解释了农林业系统中遮荫树的选择

摘要 提高农业生物多样性为低投入农业生态系统的可持续性提供了一系列关键功能。泛热带树木作物系统中遮荫树的配对代表了农业生态系统多样化最常见和最广泛的应用之一，但考虑到进行遮荫树选择的巨大异质条件，在识别适当配对的树-作物和遮荫树对于性能和采用至关重要。在这里，我们确定了撒哈拉以南非洲四个国家中 78 个已报道的遮荫树属与优势树种可可树（可可）之间的系统发育距离。我们假设被归类为理想的遮荫树在系统发育上与可可树相距甚远，基于成熟的理论，即不同的进化历史赋予生态位分化。我们的分析证实，被农民和机构归类为理想的遮荫树分类群与 T. cacao 的系统发育距离高于被归类为不受欢迎的遮荫树分类群。这些结果表明，遮荫树与目标作物的进化距离可能是一个有用的工具，可以预测一个分类群在可可农林中的先验适用性，以及系统发育分析在其他当前和未来农林系统中开出合适的遮荫树的能力。