The importance of species identity and interactions on multifunctionality depends on how ecosystem functions are valued

Studies investigating how biodiversity affects ecosystem functioning increasingly focus on multiple functions measured simultaneously (‘multifunctionality’). However, few such studies assess the role of species interactions, particularly under alternative environmental scenarios, despite interactions being key to ecosystem functioning. Here we address five questions of central importance to ecosystem multifunctionality using a terrestrial animal system: 1) Does the contribution of individual species differ for different ecosystem functions?; 2) Do inter-species interactions affect the delivery of single functions and multiple functions?; 3) Does the community composition which maximises individual functions also maximise multifunctionality?; 4) Is the functional role of individual species, and the effect of interspecific interactions, modified by changing environmental conditions?; and 5) How do these roles and interactions change under varying scenarios where ecosystem services are wei...