This file contains the data used in the paper titled: "Competitive outcomes change across environments to maintain species coexistence." Abstract. Plant competitive outcomes, driven by niche and fitness differences, have not been explored across simultaneous changes in abiotic and biotic conditions, such as soil properties, mutualisms and natural enemies. Here, we combined coexistence theory with detailed field observations in an annual grassland over two consecutive years and in-silico simulations to assess changes in competitive outcomes, from coexistence to competitive exclusion, and from exclusion to priority effects. Changes in the studied conditions promoted local competitive exclusion but with marked changes in the identity of the superior competitor. Coexistence was rarely predicted in our system although promoted by herbivore abundance, and priority effects were mostly observed in the absence of a deterministic driver. Our results show that coexistence theory predicts little coexistence at the local scale of plant interactions, and suggest that species diversity under complex natural conditions is maintained by changes in the superior competitor´s identity across larger scales.