Community recomposition caused by species extinction in the colonization-competition trade-off model for vegetation

Abstract

Species extinction and the resulting impact on the community composition is a pervasive threat to vegetation ecosystems today. Understanding how the extinction of one or more species affects and threatens biodiversity is challenging. Here, we study the scenario of a sudden species extinction in the colonization-competition trade-off model by assuming that a disturbance eliminates a species on a fleeting time scale. The system then returns to equilibrium, but the equilibrial abundances have changed for all inferior competitors. We use numerical and analytical calculations to show that the sudden extinction of one species results in a large increase in abundance of the next inferior competitor and subsequent additional extinction of the next-but-one inferior species. We present the changes in community composition and diversity using rank abundance distributions and the Shannon index, respectively. In addition to theoretical parameterizations, we use data for grasslands, which are exponentially distributed, where additional species extinctions occur.