Data from: Species colonisation, not competitive exclusion, drives community overdispersion over long-term succession

Ecological communities often transition from phylogenetic and functional
clustering to overdispersion over succession as judged by space-for-time
substitution studies. Such a pattern has been generally attributed to the
increase in competitive exclusion of closely related species with similar
traits through time, although colonisation and extinction have rarely been
examined. Using 44 years of uninterrupted old-field succession in New
Jersey, USA, we confirmed that phylogenetic and functional clustering
decreased as succession unfolded, but the transition was largely driven by
colonisation. Early colonists were closely related and functionally
similar to residents, while later colonists became less similar to the
species present. Extirpated species were generally more distantly related
to residents than by chance, or exhibited random phylogenetic/functional
patterns, and their relatedness to residents was not associated with time.
These results provide direct evidence that the colonisation of distant
relatives, rather than extinction of close relatives, drives phylogenetic
and functional overdispersion over succession.