Fire and evolution: Cretaceous fires and the spread of angiosperms
Recently we have highlighted the importance of wildfires in the evolution of plants in many ecosystems worldwide [1 | previous post]. In this line, a recent paper by Bond & Scott suggest that the spread of angiosperms in the Cretaceous (145-65 Ma) was promoted by the development of novel fire regimes linked to the evolution of novel, highly productive (and flammable) plants. They suggest that Creatceous angiosperms were similar to current ruderal (weedy) species, i.e., short, with high maximum photosynthetic rates, rapid reproduction and small seeds. This fast-growing angiosperms would not only compete with regenerating gymnosperms, but would also rapidly accumulate fuel. More fuel would promote more frequent fires, which would help to maintain open habitats in which rapid growth traits of angiosperms would be most favoured, promoting rapid fuel accumulation. The authors emphasize the similitude of this "angiosperm–fire cycle" with the grass fire-cycle that helped to spread C4 grasses in the Miocene (c. 8 Ma)  and with the grass fire-cycle replacing forests by invasive grasses in the modern world . This would also imply that forest was slow to develop until the Eocene, when fire activity dropped to very low levels. This hypothesis could also help to explain the ancient origin of some fire traits like resprouting and the abundance and phylogenetically widespread examples of species with smoke-stimulated germination [1, 5]. In conclusion I think this is a nice and stimulating contribution to the evolution of angiosperms.
 Bond, W. J. and Scott, A. C. 2010. Fire and the spread of flowering plants in the Cretaceous. New Phytol. 188: 1137–1150 [doi]
 Keeley, J. E. and Rundel, P. W. 2005. Fire and the Miocene expansion of C4 grasslands. Ecol. Lett. 8: 1-8.
 D'Antonio, C. M. and Vitousek, P. M. 1992. Biological invasions by exotic grasses, the grass/fire cycle and global change. Annu. Rev. Ecol. Syst. 23: 63-87.