Phylogenetic niche conservatism, phylogenetic signal and the relationship between phylogenetic relatedness and ecological similarity among species

TLDR

Ecologists increasingly view species relationships through an evolutionary lens, assuming that close phylogenetic relatedness predicts ecological similarity, but this requires distinguishing phylogenetic signal from true niche conservatism. The study cautions against assuming phylogenetic niche conservatism and urges empirical testing of its prevalence. A review of case studies shows that ecological and phylogenetic similarities are often unrelated, indicating that phylogenetic niche conservatism is not as common as previously thought.

Abstract

Ecologists are increasingly adopting an evolutionary perspective, and in recent years, the idea that closely related species are ecologically similar has become widespread. In this regard, phylogenetic signal must be distinguished from phylogenetic niche conservatism. Phylogenetic niche conservatism results when closely related species are more ecologically similar that would be expected based on their phylogenetic relationships; its occurrence suggests that some process is constraining divergence among closely related species. In contrast, phylogenetic signal refers to the situation in which ecological similarity between species is related to phylogenetic relatedness; this is the expected outcome of Brownian motion divergence and thus is necessary, but not sufficient, evidence for the existence of phylogenetic niche conservatism. Although many workers consider phylogenetic niche conservatism to be common, a review of case studies indicates that ecological and phylogenetic similarities often are not related. Consequently, ecologists should not assume that phylogenetic niche conservatism exists, but rather should empirically examine the extent to which it occurs.