The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on October 16, 2009). Thesis advisor: Dr. Richard P. Guyette. Includes bibliographical references.

Thesis (doctoral)--Universität zu Göttingen, 2003. / Includes bibliographical references (p. 139-155).

Thesis (M.S.)--West Virginia University, 2005. / Title from document title page. Document formatted into pages; contains xi, 278 p. : ill. (some col.), maps (some col.). Vita. Includes abstract. Includes bibliographical references (p. 85-108).

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 146-153). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 50-58). Also available on the World Wide Web.

Thesis (M.S.)--Baylor University, 2009. / Includes bibliographical references (p. 65-71).

As disturbance frequencies, intensities, and types have changed and continue to change in response to changing climate and land-use patterns, coastal communities undergo shifts in both species composition and dominant vegetation type. Over the past 100 years, fire suppression throughout the Northern Gulf of Mexico coast has resulted in shifts towards woody species dominance at the expense of marsh cover. Over the next 100 years, sea levels will rise and tropical storm activity is projected to increase; resultant changes in salinity could reduce cover of salt-intolerant fresh marsh species. Together, the effects of fire suppression upslope and rising salinities downslope could "squeeze" fresh marsh species, reducing cover and potentially threatening persistence. To mitigate the effects of fire suppression, the use of prescribed fire as a management tool to mimic historic conditions is becoming increasingly widespread and will likely gain further popularity during the 21st century. Ecological shifts that will result from changing disturbance regimes are unknown. It was hypothesized that two recent hurricanes, Ivan and Katrina in 2004 and 2005, respectively, and a prescribed fire, in 2010, differentially affected species along the estuarine gradient and drove overall shifts away from woody dominance. Overall community composition did not change significantly in the intermediate and fresh marsh zones. However, significant changes occurred in the salt and brackish marshes and in the woody-dominated fresh marsh-scrub ecotone zones. Relative to 2004, woody species abundance decreased significantly in all zones in 2006, following Hurricanes Ivan and Katrina, and 2012, following the hurricanes and fire, though woody species regeneration in the marsh-scrub ecotone had begun to occur by 2012. It is hypothesized that interacting changes in fire and tropical storm regimes could release upslope areas from coastal squeezing.

Conventional knowledge of fynbos fire ecology is based on the summer-autumn fire regimes of the western Cape Floral Kingdom (CFK) where the climate is Mediterranean. However, the climate in the eastern coastal-CFK is milder and rainfall occurs year-round, with presumed effects on fire regimes. The Garden Route National Park (GRNP) has recently been established in the region, in a landscape where indigenous forests, fire-prone fynbos shrublands and fire-sensitive plantations of invasive alien trees are interspersed. The park faces considerable challenges related to the management of fire, including significant pressure from the adjacent plantation industry to reduce wildfire hazard by burning fynbos at short intervals, and high levels of invasion by alien trees (largely Pinus species originating from plantations). This study sought to improve understanding of fire regimes in eastern coastal fynbos shrublands, and to provide guidelines for ecologically sound management of fire in the area. My approach entailed (i) an assessment of the context within which fire management was practiced during the past century; (ii) characterisation of the recent fire history and fire regime (1900–2010); (iii) characterisation of the seasonality of fire weather and lightning; (iv) estimation of minimum fire return intervals (FRIs) from juvenile periods and post-fire recruitment success of overstorey proteoids (non-sprouting, slow-maturing, serotinous Proteaceae); and (v) determination of the ecologically appropriate fire season from post-fire recruitment seasonality of proteoids. I established that historically, plantation protection enjoyed priority over fynbos conservation in the area that is now the GRNP. Fynbos close to plantations has most likely been compromised by frequent and low-intensity burning in the past, as well as by invasion by alien trees. In terms of area burnt (1900–2010), natural (lightning-ignited) fires dominated the fire regime, particularly in the east, whereas prescribed burning was relatively unimportant. Typical fire return intervals (FRIs; 8–26 years; 1980–2010) were comparable to those in other fynbos protected areas and appeared to be shorter in the eastern Tsitsikamma than in the western Outeniqua halves of the study area. Proteaceae juvenile periods (4–9 years) and post-fire recruitment success (following fires in ≥7 year-old vegetation) suggested that for biodiversity conservation purposes, FRIs should be no less than nine years in moist, productive fynbos. Increases in the total area burnt annually (since 1980) were correlated with long-term increases in average fire danger weather, suggesting that fire regime changes may be related to global change. Collectively, findings on the seasonality of actual fires and the seasonality of fire danger weather, lightning, and post-fire proteoid recruitment suggested that fires in eastern coastal fynbos are not limited to any particular season, and for this reason managers do not need to be concerned if fires occur in any season. The ecological requirements for higher fire intensity may nonetheless be constrained by a need for safety. I articulated these findings into ecological thresholds pertaining to the different elements of the fire regime in eastern coastal fynbos, to guide adaptive management of fire in the Garden Route National Park. I also recommended a fire management strategy for the park to address the aforementioned operational considerations within the constraints posed by ecological thresholds. Finally, I highlighted further research and monitoring needs.

This study was initiated in 1985 to assess the response of seven key forage and browse species to prescribed burning for wildlife habitat and range improvement in the East Kootenay region of British Columbia. The species studied were Agropyron spicatum (bluebunch wheatgrass), Amelanchier alnifolia (saskatoon), Ceanothus velutinus (snowbrush), Festuca scabrella (rough fescue), Purshia tridentata (bitterbrush), Stipa occidentalis (stiff needlegrass), and Symphoricarpos albus (common snowberry). The primary objective of the study was to determine how these species respond to burning in terms of percent cover and current annual growth. There were two approaches to this study. First, experimentally burned plots were established on two sites. Spring and fall burning were carried out on one site and fall burning on a second site. Second, five previously operationally burned areas were compared with immediately adjacent unburned areas to assess differences in the percent cover of all the species and in the sprouting response of bitterbrush. Three of the sites were sampled in the first postburn growing season, one site was sampled in the second postburn growing season, and one site was sampled in the fourth postburn growing season. The total preburn fuel load on these sites ranged from 1.2 to 2.0 kg/m². Total fuel consumption varied from 53 to 91% on the experimentally burned plots. The variability of each fuel load component was high. In the first growing season following fall and spring burning, and the second growing season following fall burning, there were no significant differences in the percent cover of all species except bitterbrush and stiff needlegrass between burned and unburned plots. There was significantly less bitterbrush following both spring and fall burning. By the second growing season, bitterbrush had recovered slightly following fall burning. There was significantly more (33%) percent cover of stiff needlegrass on the fall burned plots both in the first and second growing season following burning. The only species for which there was a significant difference in the current annual growth on fall burned plots compared with control plots, were bitterbrush and saskatoon. There was 71% less current annual growth of bitterbrush the first growing season following fall burning. Saskatoon had 48% less current annual growth on the fall burned plots compared with the control plots. The results for percent cover were similar on the operationally burned areas. At all but the four-year-old operationally burned site, there was significantly less percent cover of bitterbrush on the burned plots compared with unburned plots. The percent decrease varied from 76 to 90%. At a two-year-old operationally burned site, there was 58% less snowberry on burned plots compared with unburned plots. At the same site there was less rough fescue (94%) but this represented only a 2% decrease in the percent cover. There was 58% more percent cover of stiff needlegrass on one of the one-year-old operationally burned sites. On these sites the postfire survival adaptation of all these species was by resprouting from either buds at the surface or the base of the plant, or from underground rhizomes. Some graminoid species seeded in from off-site seed sources. This study shows that where bitterbrush is the focus of enhancement, prescribed burning may have initial detrimental effects regardless of the timing of burning. The effects appear to be more variable and less dramatic for the other species studied. The implications of the response of these forage species to current prescribed burning practices are discussed and recommendations on future research are made. / Forestry, Faculty of / Graduate

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