Conserving structural and compositional diversity in Fescue Prairie requires reintroducing natural disturbances according to their historic regime. Fire is an important natural process that may be a source of spatial heterogeneity in Fescue Prairies. The effects of burning in all months of the year except January and February were evaluated in a Fescue Prairie in central Saskatchewan for 6 years following burning on 2 sites that had not been previously burned and 2 sites that had been burned 5 years earlier. Except for burning in March, burning reduced cover of litter (P<0.01) and <i>Festuca hallii </i> (Vasey) Piper (P=0.01) while increasing bare soil (P<0.01) for 1 to 5 years. Cover of <i>Elymus lanceolatus </i>(Scribn. & J.G. Sm.) Gould (P<0.01), graminoids (P=0.02), and species evenness (P=0.01) increased with burning frequency. Burning in late-summer reduced cover of graminoids (P=0.03), plants other than the dominant grasses (P=0.03), and total plant cover (P=0.02). Burning increased the spatial variance (s2) in litter cover (P<0.01) and bare soil (P<0.01) for 1 to 3 years. Aside from burning in early spring, burning reduced s2 in total standing crop (P=0.02) and <i>F. hallii</i> (P=0.01). Variability in the cover of <i>E. lanceolatus </i>(P<0.01) and graminoids (P=0.04) increased with burning frequency. Canonical correspondence analysis (CCA) indicated that pre-burn history had a dominant effect on plant community composition, explaining 13% of the variation (P<0.01). The cumulative effects of repeated burning, annual variability in weather, and exposure to temperature extremes may have caused a shift in the composition of the plant community. The first 4 ordination axes explained 22% of the variation in plant community composition after burning, indicating that many other environmental or site variables controlled community composition. A range of burning dates and frequencies should be reintroduced or maintained in Fescue Prairie to create a mosaic of plant communities in various stages of recovery after burning. A mosaic will increase the structural and compositional diversity in remnant Fescue Prairies.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:SSU.etd-06052005-132651 |
| Date | 06 June 2005 |
| Creators | Gross, Dale |
| Contributors | Romo, James T., Pennock, Dan J., Hughes, Geoffrey R., Bai, Yuguang, Archibold, O. W. (Bill) |
| Publisher | University of Saskatchewan |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://library.usask.ca/theses/available/etd-06052005-132651/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Saskatchewan or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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