title: Flammable biomes dominated by eucalypts originated at the Cretaceous-Palaeogene boundary.
abstract: Fire is a major modifier of communities, but the evolutionary origins of its prevalent role in shaping current biomes are uncertain. Australia is among the most fire-prone continents, with most of the landmass occupied by the fire-dependent sclerophyll and savanna biomes. In contrast to biomes with similar climates in other continents, Australia has a tree flora dominated by a single genus, Eucalyptus, and related Myrtaceae. A unique mechanism in Myrtaceae for enduring and recovering from fire damage likely resulted in this dominance. Here, we find a conserved phylogenetic relationship between post-fire resprouting (epicormic) anatomy and biome evolution, dating from 60 to 62 Ma, in the earliest Palaeogene. Thus, fire-dependent communities likely existed 50 million years earlier than previously thought. We predict that epicormic resprouting could make eucalypt forests and woodlands an excellent long-term carbon bank for reducing atmospheric CO(2) compared with biomes with similar fire regimes in other continents.
authors.affiliation: Division of Evolution, Ecology and Genetics, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory 0200, Australia. mike.crisp@anu.edu.au
authors.forename: Michael D
authors.initials: MD
authors.lastname: Crisp
authors.forename: Geoffrey E
authors.initials: GE
authors.lastname: Burrows
authors.forename: Lyn G
authors.initials: LG
authors.lastname: Cook
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Thornhill
authors.forename: David M J S
authors.initials: DM
authors.lastname: Bowman
mesh_terms: D001483:Base Sequence; D001499:Bayes Theorem; D005075:Biological Evolution; D019295:Computational Biology; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D017753:Ecosystem; D005390:Fires; D008957:Models, Genetic; D027822:Myrtaceae / Q000033:anatomy & histology / Q000235:genetics / Q000502:physiology*; D010163:Paleontology; D010802:Phylogeny; D018547:Plant Stems / Q000033:anatomy & histology / Q000254:growth & development; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D021903:DNA, Ribosomal Spacer