Phylogenetic density dependence and environmental filtering predict seedling mortality in a tropical forest

Citation

Paine CET, Norden N, Chave J, Forget P, Fortunel C, Dexter KG & Baraloto C (2012) Phylogenetic density dependence and environmental filtering predict seedling mortality in a tropical forest. Ecology Letters, 15 (1), pp. 34-41. https://doi.org/10.1111/j.1461-0248.2011.01705.x

Abstract
Negative density dependence (NDD) and environmental filtering (EF) shape community assembly, but their relative importance is poorly understood. Recent studies have shown that seedling's mortality risk is positively related to the phylogenetic relatedness of neighbours. However, natural enemies, whose depredations often cause NDD, respond to functional traits of hosts rather than phylogenetic relatedness per se. To understand the roles of NDD and EF in community assembly, we assessed the effects on seedling mortality of functional similarity, phylogenetic relatedness and stem density of neighbouring seedlings and adults in a species-rich tropical forest. Mortality risks increased for common species when their functional traits departed substantially from the neighbourhood mean, and for all species when surrounded by close relatives. This indicates that NDD affects community assembly more broadly than does EF, and leads to the tentative conclusion that natural enemies respond to phylogenetically correlated traits. Our results affirm the prominence of NDD in structuring species-rich communities.

Keywords
Community assembly; density dependence; French Guiana; generalised linear mixed models; Janzen-Connell hypothesis; seedling recruitment; species coexistence; survival

Journal
Ecology Letters: Volume 15, Issue 1