Extirpation‐resistant species do not always compensate for the decline in ecosystem processes associated with biodiversity loss

Summary Accelerating rates of biodiversity loss may result in a rapid decline in important ecosystem processes such as carbon capture. Whether extirpation‐resistant species compensate for the decline in ecosystem processes associated with the loss of extirpation‐prone species is poorly understood. We apply a novel approach to answer this question using an assemblage of salt marsh plants. First, manipulations were performed to simulate a realistic sequence of species loss, based on observed sensitivity to disturbance. Then, changes in biomass and primary production of extirpation‐resistant species were monitored over three consecutive growing seasons. Extirpation‐resistant species did not compensate for the loss of either biomass or primary production associated with the removal of extirpation‐prone species. Factors that determine the potential for compensation within ecosystems are discussed. These include resource‐regulated compensation rates, the level of functional redundancy within an assemblage and the extirpation resistance of species which possess good compensation traits. Synthesis . These results suggest that we cannot assume extirpation‐resistant species will compensate for the decline in ecosystem processes associated with biodiversity loss across all ecosystems. Understanding those factors that influence the ability of ecosystems to compensate for declines in ecosystem processes associated with biodiversity loss constitutes a significant challenge.