Friends of the Cawthra Bush
Greater Mississauga Area
Pages of Special Interest;
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copy, if there are errors, please e-mail me with corrections:
Department of Environment and Resource Studies
Faculty of Environmental Studies University of Waterloo
519 888-4567 or 519-885-1211 200 University Aveune West
Fax 519-746-0292 Waterloo, Ontario, Canada N2L 3GI
June 9, 1998
Mr. Donald Barber
Dear Mr. Barber,
Thank you for your fax of 3 June 1998. The problems you described are indeed widespread and under documented. My own study is still in the stages of being prepared for a submission to an academic journal. I provide a synopsis for you:
In eastern Ontario forests, increased fragmentation has caused edge effects to increase in severity. This means that the micro-climate around the forest edge is altered and the interior of the forest also is subjected to environmental conditions that normally would be associated with edge habitat. These edge effects tend to self perpetuate because they allow invasive species to colonize sites, out-compete species that prefer shady, moist, and wind-free habitats, and thereby kill off regeneration of tree seedlings or understorey herbs (for example). This frees up more habitat suitable for the invasives and they advance further into the forest. Simultaneously, the changes in micro-climate and habitat structure indirectly affect organisms such as insects that pollinate plants. My study focused on a beetle that pollinated sharp-lobed hepatica. The larvae of this beetle cannot survive in a dry, sunny area and die when edge effects alter the micro-climate. When this happens, the hepaticas lose their sole pollinator and resort to selfing (inbreeding) that eventually can cause severe mutations and eliminate local populations. The problem ran be serious as hepatica is not as vulnerable as other species that are not as proficient or adapted to selfing or clonal replication; this means other species may be in greater peril. This concept holds for most organisms, especially plants and animals (as opposed to protozoans, for example).
I do have an extensive list of papers that describe similar situations (albeit couched in more scientific than management language). I list these at the end of this letter; I have copies of all of them and we could arrange to get you copies as well.
I probably can drop by at some point to take a look at your site and also could see if one of my students would be interested in helping you with whatever you may need (e.g. you seem to indicate species surveys and micro-climatological studies are needed). I have a graduate student who is doing similar work in York Region and I'll see if she would like to come by as well. We could explore these possibilities further in a couple of weeks (once my field research season tapers off for awhile).
Please do not hesitate to contact me by phone, fax, or e-mail in the coming weeks if you think our assistance can be of use. I am usually in the office Tuesday and Wednesday afternoons and occasionally Thursdays during the summer (during the rest of the year, I'm usually there every day except Fridays).
A (relatively) short list of relevant papers (the first # is the accession # from my electronic database):
Palik, B. J., and P. G. Murphy. 1990.
Matlack, G. R. 1993.
Matlack, G. R. 1993.
Brothers, T. S., and A. Spingam. 1992.
Laurence, W. F., and E. Yensen. 1991.
Weaver, M., and M. Kellman. 1981.
Harris, L. D. 1988.
Yalmer, R. H. 1988.
Whitney, G. G., and J. R. Runkle. 1981.
Knappen, J. P., M. Scheffer, and B. Hanns. 1992.
Taylor, P. D., L. Fahrig, K. Henein, and G. Merriam. 1993.
VIhitney, G. G., and W, J. Someriot. 1985.
Riley, J. L., and P. Mohr. 1994.
Matlack, G. R. 1994.
Murcia, C. 1995.
Murphy, S. D., and C. J. Swanton. 1995.
Murphy, S. D., and L. Vasseur. 1995.
Poser, S. F., W. J. Crins, and T. J. Beechey. 1993.
Riley, J.L. (ed.). 1989.
With best wishes. Stephen D. Murphy, B.Sc. (Hons.), Ph.D. Assistant Professor phone extension: 5616; e-mail: firstname.lastname@example.org
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