Evolution of the climatic niche in scaly tree ferns (Cyatheaceae, Polypodiopsida)
ancestral characters, biogeography, climatic envelopes, maximum likelihood, niche conservatism, niche divergence, ordination
Although climatic niche conservatism has been assumed by a large number of studies focused on climatic niche evolution, there are examples of climatic niche diversiﬁcation and adaptation to changing climates. In this article, we reconstruct a climatic niche of scaly tree ferns (Cyatheaceae) using a rigorous analytical procedure which combines climatic niche modelling with reconstruction of continuous characters given a phylogenetic hypothesis. To estimate the limits to climatic niches of species, we used climate envelope modelling and ordination. Ancestral climatic niches of species were reconstructed by maximum likelihood and least-squares analyses. We observed a trend towards niche conservatism with occasional events of niche transformations in scaly tree ferns. We discuss the implications of our study with respect to the potential and limitations for applications of niche modelling to evolutionary studies. We suggest that future studies of evolution of climatic niches could be considerably improved by employing approaches enabling reconstruction of continuous response to climatic gradients. Further progress may also be achieved by exploring models of character evolution other than the Brownian motion model.