An article found on BBC news world, written by Mark Kinver, a reporter for the Science and Environment branch of BBC News World attempts to summarize findings of William J. Bond and Andrew C. Scott in their recently published paper “Fire and the spread of flowering plants in the Cretaceous”. Kinver has the daunting task of condensing seventeen pages of scientific data and research into one and a half pages that are interesting and informative to BBC’s general audience and yet doesn’t stray too far from the actual points that have been put forward in the original paper. But summarizing and watering down the research for general consumption doesn’t come without sacrifice. Kinver does lose some of the key points from Bond and Scott’s paper but maintains most of the paper’s stands on claims made.

Nothing is ever proved in science, research either rejects a hypothesis or fails to reject it, never proves it. This has been an idea imposed on science students at the University of Guelph in Biology, Chemistry, Environmental Science and Physics and yet this idea of perpetual uncertainty is something that I for one, had never thought of before now and the general public may not have known either. In the original paper Bond and Scott make it clear that the study has not proven anything but only found arguments that “suggest” or “support the idea” of a novel fire regime being the main cause for the spread of angiosperms in the Cretaceous. Kinver tries to avoid making any of his own conclusions from the data by using quotes from interviews of both the authors of the primary source and takes quotes directly from the original study.

“One of the aims of the paper, which he co-authored with Professor Will Bond of the University of Cape Town, was to point out "that fire had not really been considered as an element in the success of flowering plants during this period" (Kinver 2010) The main point of the primary article as seen in the above quote was to explore the possibility that the evolution of angiosperms and the natural fire regime of the time along with other key factors such as oxygen levels and characteristics of the dominate gymnosperms all came together at the right time to help create the perfect setting for the spread and dominance of the angiosperms. One thing that the secondary BBC article fails to properly explain is the importance of the angiosperms to be able to regenerate quickly after fires providing new fuel for another fire in a relatively short time. The article states that “"They can also quickly provide fuel ready to be burnt; this means that they have quite a good competitive advantage over other plants.” (Kinver 2010) and later states that this creates a positive feedback cycle. This cycle is never fully explained and could be cause for the spread of misinformation. The surface fires, one would assume to be detrimental to the spread and diversification of “weedy” angiosperms of the time but as outlined in Bond and Scott’s paper the fire would kill the slow growing conifers that would if allowed to reach maturity would block sunlight from the low growing angiosperms. The second part of the explanation involves a trait which is found even some of today’s angiosperms, the germination trigger of smoke. “Butenolide is a constituent of smoke. Many plants in crown fire systems, such as chaparral and fynbos, have smoke-stimulated seed germination (Keeley & Fotheringham, 2000). However, the butenolide response of seeds is very widespread among angiosperms” (Bond and Scott 2010)

This ability provides the full picture to the positive feedback cycle. The quick and reoccurring fire is fuelled by the newly evolved angiosperms and kills off competition as well as allows for the new generation of angiosperms to germinate and take hold of the newly cleared fire zones.

Example of surface level fire in Australia (Taylor 2009).

The only other notable difference between the primary article and the secondary article was the lack of a few other key points on angiosperm genetics like “recent advances in the ecophysiological understanding of plant hydraulics have revealed the basis for the high productivity of Cretaceous angiosperms and the environmental context in which it is most likely to be expressed. There are strong similarities to the evolution of the C₄ photosynthetic pathway and the spread of C₄ grasses in the late Miocene (c. 8 Ma).” (Bond and Scott 2010) as well as providing the reader with information as to how this research effects the present day fire cycles and location of forests and plains. Bond and Scott use their data to extrapolate that “Major changes in vegetation did indeed occur from the Palaeocene into the Eocene with the widespread expansion of forest, including tropical rainforests” (Bond and Scott) which in turn would have affected the location of today’s forests and plains.

In conclusion, while it can be assumed that secondary sources are not always accurate in terms of representing the findings of a scientific study credit has to be given to Mark Kinver of BBC News for writing an article that may have had a few flaws but is nothing compared the disaster many news articles turn into in terms of misrepresentation of stats and data. I am sure that many of my peers on this blog can attest to this fact.

Reference list:

1. Bond, W. J. and Scott, A. C. , Fire and the spread of flowering plants in the Cretaceous. New Phytologist, no. doi: 10.1111/j.1469-8137.2010.03418.x

2. Kinver, M. (2010, September 17). Spread of early flowering plants 'aided by fire'. Retrieved from http://www.bbc.co.uk/news/science-environment-11298978

3. Taylor, D. (Photographer). (2009). Prescribed burn. [Web]. Retrieved from http://www.kinrm.sa.gov.au/TakingAction/Managingbiodiversity.aspx

ENVS1020 Fall 2010 KO

Thursday, September 23, 2010

Fire Regimes and the Spread and Diversification of Flowering Plants

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