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

Master of Science / Department of Animal Sciences and Industry / K C Olson / We evaluated effects of annual, prescribed burning on vigor of the noxious weed, sericea lespedeza (Lespedeza cuneata; SL) in native tallgrass prairie over a 4-yr period. We hypothesized that annual prescribed burning conducted during the growing season would selectively pressure SL, whereas locally-conventional, dormant-season prescribed burning would have no effect on SL. A 50-ha native tallgrass pasture infested with SL (initial basal frequency = 2 ± 1.3%, initial aerial frequency = 36 ± 3.4%) was used for our study. It was divided along watershed boundaries into 9 fire-management units (5 ± 2.6 ha) for this experiment. Burn units were assigned randomly to 1 of 3 prescribed-burning times (n = 3 / treatment): early spring (1 April; EARLY), mid-summer (1 August; MID), or late summer (1 September; LATE). Forage biomass, SL aerial frequency, SL stem length, SL seed production, soil cover, and plant species composition were measured along single, permanent 100-m transects in each burn unit. Treatment and measurement date influenced forage biomass and SL stem length (treatment × time). Forage biomass was not different (P ≥ 0.43) between treatments on 17 July; however, forage biomass was greater (P < 0.01) in EARLY than MID and greater in MID than LATE on 10 October. Maximum stem length of SL was less (P ≤ 0.02) in MID and LATE than in EARLY on 17 July and on 10 October. Aerial frequency of SL was least (main effect – P < 0.01) in LATE, intermediate in MID, and greatest in EARLY, whereas basal frequency of SL was less (P < 0.01) in MID and LATE compared with EARLY. Whole-plant dry weight and seed production of SL at dormancy were greatly diminished (P ≤ 0.02) in MID and LATE compared with EARLY. Occurrence of bare soil, litter cover, and total basal plant cover were not different (P ≥ 0.21) between treatments. Similarly, basal cover of grasses, forbs, and shrubs were not different (P ≥ 0.24) between treatments. We interpreted these data to indicate that annual prescribed burning during the growing season had strong suppressive effects on SL compared to locally-conventional, early-season prescribed burning and produced no apparent detrimental effects on soil cover or non-target plant species. Post-fire regrowth was sufficient to prevent erosion and soil-moisture loss during the subsequent dormant season and would have allowed light to moderate grazing during the ensuing winter. Key words: Lespedeza cuneata, prescribed fire, range improvement

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

Cheatgrass (Bromus tectorum) is an invasive annual grass common in several semiarid plant communities in the western U.S. B. tectorum presence increases fire frequency and size, reducing species diversity, and leading to annual species-dominated systems with inconsistent livestock forage potential and degraded wildlife habitat value. Most efforts to manage B. tectorum-dominated rangelands have focused on controlling the plant itself rather than addressing the causes of vegetation change. An alternative approach, ecologically-based invasive plant management (EBIPM), identifies treatments that can alter factors associated with the causes of succession, leading to a more desirable vegetation state. This study utilized the EBIPM framework to design a large-scale demonstration project, which implemented a series of manipulation treatments (mowing, prescribed fire, imazapic herbicide, and seeding with perennial species) to suppress B. tectorum and promote desirable species. The treatments were implemented at two semiarid shrubland sites in northwestern Utah. Treatments were evaluated by measuring resident vegetation cover, density, aboveground biomass, and litter and soil seed banks. Herbicide was most effective in reducing B. tectorum cover, density, and biomass, while fire was effective in reducing seed density in the litter seed bank. Treatment interactions were rarely significant; however, by combining fire and herbicide, increased B. tectorum control was achieved. Seedlings of seeded perennial grasses emerged in all treatments; however, establishment by the end of the first growing season was greatest in treatments involving fire. The results of this study indicate that using a decision-making framework to select a series of treatments that alter the causes of succession can improve the management of B. tectroum-dominated rangelands.

The Yellow Rail (Coturnicops noveboracensis) is a migratory nongame bird of high conservation priority throughout its entire range. The objectives of this study were: (1) assess Yellow Rail occupancy in the context of prescribed fire regime in pine savanna habitats of Mississippi and Alabama and (2) assess Yellow Rail habitat use in pine savanna habitats of coastal Mississippi. Yellow Rail occupancy decreased significantly with time since fire and increased with grassland patch size. Throughout the study area Yellow Rail maintained small (mean = 3.37 ha) home ranges aggregated within study areas, indicating suitable habitat may be limited. Yellow Rail used areas dominated by Aristida stricta and Carex spp. They used locations with lower woody percent cover, greater herbaceous height structure and lower frequency of trees than locations outside their home range. This research highlights the continued need to prioritize conservation and management of open grasslands and pine savanna habitats.

The global community is struggling with mitigating the effects of widespread habitat loss and degradation; the effects of which are being further magnified in the face of global climate change. Quality natural habitat is becoming increasingly limited and atmospheric carbon levels continue to rise. Therefore, land managers responsible for multiuse management are often faced with the dilemma of managing ecosystems for biodiversity, as well as optimizing ecosystem services such as carbon storage and sequestration. However, some management techniques used to meet these objectives may yield conflicting results, specifically, the management tool of prescribed fire. Fire is crucial in maintaining species composition and structure in many ecosystems, but also results in high carbon emissions. Thus, it is important for land mangers to achieve the most efficient prescribed fire management regime to both preserve plant and animal communities, and optimize carbon storage. A former ranchland at the Disney Wilderness Preserve, Central Florida, USA is being restored to native ecosystems and managed to preserve biodiversity and increase carbon storage. This study quantified the carbon stocks within the aboveground biomass, litter, and top 90 cm of soil in five ecosystems at the Disney Wilderness Preserve, all of which are managed with prescribed fire every two to three years. These carbon stocks were compared in ecosystems in different stages of restoration: bahia grass pasture, pasture in restoration for longleaf pine flatwoods, and restored longleaf pine flatwoods. The carbon stocks were also compared among three restored flatwoods communities: longleaf pine flatwoods, slash pine flatwoods, and scrubby flatwoods. To determine the effects of the current prescribed fire management, carbon stocks were quantified and compared in recently burned areas (burned 4 months prior) and areas burned two to three years prior, in all ecosystems. Soil carbon properties were assessed using ¹³C isotope analysis. Aboveground biomass and litter carbon stocks were found to increase with higher stage of restoration, and were significantly less in areas with recent fire management. The results of this study did not provide evidence that soil carbon stock was significantly different in different stages of restoration or at different times since fire, but soil carbon stock was found to be significantly different among the flatwoods communities. In un-restored pasture and pasture in restoration sites, the soil was found to be increasingly depleted in ¹³C with increasing soil depth. This pattern indicated that carbon in the upper, more labile soil carbon pool had been derived from current C4 pasture or native grasses, while carbon in the deeper, more stable carbon pool is a legacy of the historical C3 forest vegetation that existed prior to conversion to pasture. Additionally, a pattern of less depletion in ¹³C with increasing time since deforestation was noted, indicating an increasing loss of historic forest carbon with increasing pasture age. As the pastures in restoration for longleaf pine flatwoods mature, the isotopic composition of the soil profile in the restored longleaf pine flatwoods may serve as a reference value for the soil profiles of these sites. Overall, the mean carbon stock in the aboveground biomass, litter and top 90 cm of soil in the un-restored pasture was ~13.3 kg C/m², the carbon stock in the pasture in restoration was ~12.7 kg C/m², the longleaf pine flatwoods had the highest carbon stock at ~17.7 kg C/m², the scrubby flatwoods had the smallest carbon stock at ~7.7 kg C/m², and the slash pine flatwoods had a carbon stock of ~15.8 kg C/m².

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