Evidence for a Cenozoic radiation of ferns in an angiosperm-dominated canopy
- 7 July 2009
- journal article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 106 (27), 11200-11205
- https://doi.org/10.1073/pnas.0811136106
Abstract
In today's angiosperm-dominated terrestrial ecosystems, leptosporangiate ferns are truly exceptional--accounting for 80% of the approximately 11,000 nonflowering vascular plant species. Recent studies have shown that this remarkable diversity is mostly the result of a major leptosporangiate radiation beginning in the Cretaceous, following the rise of angiosperms. This pattern is suggestive of an ecological opportunistic response, with the proliferation of flowering plants across the landscape resulting in the formation of many new niches--both on forest floors and within forest canopies--into which leptosporangiate ferns could diversify. At present, one-third of leptosporangiate species grow as epiphytes in the canopies of angiosperm-dominated tropical rain forests. However, we know too little about the evolutionary history of epiphytic ferns to assess whether or not their diversification was in fact linked to the establishment of these forests, as would be predicted by the ecological opportunistic response hypothesis. Here we provide new insight into leptosporangiate diversification and the evolution of epiphytism by integrating a 400-taxon molecular dataset with an expanded set of fossil age constraints. We find evidence for a burst of fern diversification in the Cenozoic, apparently driven by the evolution of epiphytism. Whether this explosive radiation was triggered simply by the establishment of modern angiosperm-dominated tropical rain forest canopies, or spurred on by some other large-scale extrinsic factor (e.g., climate change) remains to be determined. In either case, it is clear that in both the Cretaceous and Cenozoic, leptosporangiate ferns were adept at exploiting newly created niches in angiosperm-dominated ecosystems.Keywords
This publication has 48 references indexed in Scilit:
- Dating the origin of the Orchidaceae from a fossil orchid with its pollinatorNature, 2007
- RAxML-VI-HPC: maximum likelihood-based phylogenetic analyses with thousands of taxa and mixed modelsBioinformatics, 2006
- Exploring the evolution of humus collecting leaves in drynarioid ferns (Polypodiaceae, Polypodiidae) based on phylogenetic evidenceÖsterreichische botanische Zeitschrift, 2005
- South American palaeobotany and the origins of neotropical rainforestsPhilosophical Transactions Of The Royal Society B-Biological Sciences, 2004
- Responses of ferns to red light are mediated by an unconventional photoreceptorNature, 2003
- A Tropical Rainforest in Colorado 1.4 Million Years After the Cretaceous-Tertiary BoundaryScience, 2002
- A Revised Circumscription of the Genera of the Fern Family VittariaceaeSystematic Botany, 1997
- Contribution of Nontrees to Species Richness of a Tropical Rain ForestBiotropica, 1987
- Complex Paleozoic Filicales in the Evolutionary Radiation of FernsAmerican Journal of Botany, 1987
- Comparison of Fern and Flowering Plant Distributions with Some Evolutionary Interpretations for FernsBiotropica, 1972