The role of phytochemical diversity in the management of agroecosystems

Biodiversity in ecosystems is crucial in providing ecosystem services and their stability and resilience. However, most studies supporting the benefits of biodiversity in crop health were studied at the cultivar scale, generally without specifying the resistance mechanisms involved in the resistance of crops to pests. Thus, it is unclear if phytochemical diversity is one of those resistance mechanisms and whether the ecosystem patterns and processes in which phytochemical diversity is involved can be replicated or adapted to the management of sustainable agroecosystems. Here, I review the roles of phytochemical diversity in natural ecosystems and determine if they can be helpful in the management of agroecosystems. I briefly review (a) the spatial and temporal structure of phytochemical diversity in ecosystems and its effect on plant consumers; (b) how that diversity is generated and maintained; and (c) the current or potential role of phytochemical diversity in agroecosystems. The α-, β-, and γ-phytochemical diversities are very high in ecosystems and landscapes; phytochemical diversity gets displayed in dynamic mosaics of mixtures of secondary metabolites that vary in their concentration and composition within and among individuals, populations, or species. Phytochemical diversity is fostered by evolutionary or coevolutionary processes, mainly under an arms-race scenario. The patterns and processes of phytochemical diversity are idiosyncratic depending on the identity of the interacting species and the local biotic and abiotic environment; thus, to copy them to industrial agroecosystems is hardly viable. However, five recommendations in which phytochemical diversity could be helpful in agroecosystem management are made.