I find this discussion very interesting. I am not a scientist, but have been looking for management studies that directly compare grazing, fire, and combinations of the two. My friend, paleoecologist Guy Robinson, was coauthor of a paper published in Science on changing conditions at the end of the pleistocene in North American. A consistent find all around the world seems to be that fire frequencies shoot up dramatically with the die-off of megafauna and the arrival of humans. Which leads me to wonder how many of the species we now consider fire dependent were also adapted to impacts of large animals? I see so many management prescriptions for fire in prairies and savannas, but fewer studies of impacts of various grazing regimes. Based on historic and ongoing conservation conflicts with agriculture one suspects a bias towards fire and against grazing.
David Burg On Sun, Oct 7, 2012 at 3:28 PM, Thomas J. Givnish <[email protected] > wrote: > The list goes on and on and on. Bulbostylis in Venezuelan savannas flowers > within a few days after fires; several orchids in Australian woodlands > obligately depend on fires to trigger flowering; many other plants in other > systems flower profusely a year or two after fires (e.g., Xanthorrhoea, > Xerophyllum, Lilium). Several species in Mediterranean scrub in sw > Australia, sw South Africa, and s California germinate in response to > compounds released in smoke. Hundreds of species in many genera (e.g., > Pinus, Cupressus, Eucalyptus, Hakea, Banksia, Protea) release their seeds > promptly from serotinous cones, follicles, etc. only in response to fire. > Many carnivorous or nitrogen-fixing plants are facilitated by fire. A suite > of ca. 17 federally endangered species endemic to the Lake Wales Ridge in > south-central Florida are almost surely facilitated by the extraordinarily > high frequency of lightning strikes there. Long-term studies at Konza > Prairie and Cedar Creek show that different plant species are favored by > different long-term fire frequencies. The Karner Blue Butterfly has no life > stages resistant to fire, but depends on fire to renew its habitat and > maintain an abundance of Lupinus perennis, the sole larval food plant. > > -- > Thomas J. Givnish > Henry Allan Gleason Professor of Botany > University of Wisconsin > > [email protected] > http://botany.wisc.edu/givnish/Givnish/Welcome.html > > > > > > On 10/07/12, "David L. McNeely" wrote: > > I apologize. I left off the list of references I compiled for this post. > Here it is: > > > > > http://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1010&context=barkbeetles > > > > http://www.gffp.org/pine/ecology.htm > > > > http://www.esa.org/education_diversity/pdfDocs/fireecology.pdf > > > > http://www.fs.fed.us/database/feis/plants/tree/pinconl/all.html > > > > http://fireecology.org/docs/Journal/pdf/Volume08/Issue02/107.pdf > > > > http://www.na.fs.fed.us/pubs/silvics_manual/Volume_1/pinus/contorta.htm > > > > http://www.firescience.gov/projects/briefs/01B-3-1-01_FSBrief30.pdf > > > > http://www.fws.gov/southeastfire/what/ecology.html > > > > http://cee.unc.edu/people/graduate-students/theses/Kaplan_MA.pdf > > > > > > ---- "David L. McNeely" <[email protected]> wrote: > > > Wayne, I have heard this "fire dependent" terminology in reference to > both community types and specific plants. However, most often it has been > in reference to community types that included dominant fire adapted > species. I also have heard more convincingly that lodgepole pine, _Pinus > contorta_, was fire dependent due to serotinous cones. I accepted this > without judgement. However, one of these references suggests that though > serotinous, under warm enough conditions 45 - 50 C soil surface > temperature) the cones may open without fire. I wonder if soils in the > northern portions and higher elevations of the range get that hot, but I > don't know. > > > > > > I have also heard the term applied to Longleaf Pine, _Pinus palustris_ > , and the communities that it dominated prior to extensive exploitation of > the SE U.S. forests. My understanding has always been that in that case, > more shade tolerant species that have seeds that can reach the soil surface > despite dense grassy understory replace the longleaf pine when fire is > absent from an area for extensive time. > > > > > > Here are some references, some of them secondary, that discuss these > phenomena. > > > > > > I am definitely not a forest or fire ecologist. > > > > > > David McNeely > > > > > > ---- Wayne Tyson <[email protected]> wrote: > > > > Ecolog: > > > > > > > > I just caught a video production on TV done by a major governmental > fire authority. It contained a mixture of truth and superstition, as well > as some questionable assumptions that y'all can help me clear up. > > > > > > > > 1. A uniformed fire official claimed that some plants are DEPENDENT > upon fire for their survival. He did not say that some plants are ADAPTED > to fire, he said "dependent." > > > > > > > > Please share your knowledge and references, please. > > > > > > > > Thanks, > > > > > > > > WT > > > > > > -- > > > David McNeely > > > > -- > > David McNeely >
