SummaryThe elemental composition of plants (the elementome) is a reliable indicator of their functional traits and the ecological strategies that they follow, and thus represents a good predictor of how ecosystems work. Biodiversity and, especially, functional diversity are also widely recognized as important drivers of ecosystem functioning, mainly because of niche partitioning amongst different species. Here, I review evidence indicating that plant elementomes relate to their ecological niches and how plant elemental concentrations may shift in response to abiotic and biotic drivers. I propose the use of ecosystem elementome diversity as a universal metric to compare ecosystems and investigate diversity–ecosystem functioning relationships. Future research using this promising novel approach will bring together elementomes, diversity, and ecosystem functioning.