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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Vliv požáru na vegetaci vřesovišť na dopadových plochách v CHKO Brdy / Influence of fire disturbance on the heathland vegetation in the Protected Landscape Area Brdy.

Pánková, Karolína January 2019 (has links)
of the thesis Heathlands are an unique semi-natural element of European landscape, which historically evolved under continuous man land-use pressure. In conditions of our country, this biotope is relatively rare in occurrence and small in area. In the former military training zone Brdy, Protected landscape area nowadays, there are heathlands of great extent developed due to deforestration and history of fires and mechanical disturbances of the soil surface and vegetation, which used to accompany military trainings. After the termination of military use of the locality, there is a risk of gradual degradation of the biotope caused by tree encroachment, litter accumulation which inhibits generative regeneration of the heath, and degeneration of the heath itself. This thesis aism to entangle influence of the fire on the heathland vegetation in the area with special attention given to vitality and structure of heath stands. The fieldwork was focused on the dynamics and species composition of the vegetation, including bryophytes and lichens, separately on the long-term scale (up to 80 years) and the short-term scale (permanent plots in the recently burnt vegetation). Experimental part of the thesis tested germination of the seeds from Brdy area under the conditions of fire and with presence of different...
72

The influence of repeated prescribed burning and forest conversion on soil fungal communities

Bastias, Brigitte A., University of Western Sydney, College of Health and Science, Centre for Plant and Food Science January 2007 (has links)
Fungi are key components in forest ecosystems, being involved in decomposition of plant biomass and the cycling of nutrients in forest soils. Despite their importance little is understood about the influence forest management practices, such as long-term prescribed burning and forest conversion are having on soil fungal communities. Part of the work described in this thesis investigated the effects of long-term repeated prescribed burning on the total soil fungal community, the diversity of mycelial communities of ectomycorrhizal fungi and the influence of biennial prescribed burning on the cellulolytic soil fungal community using stable isotope probing techniques. The influence of long-term repeated prescribed burning on soil fungal communities was investigated through a series of studies conducted at Peachester State Forest, Queensland, Australia. This site has been the centre of a long-term repeated prescribed burning experiment, established since 1972, consisting of plots subjected to biennial, quadrennial or no burning. Denaturing gradient gel electrophoresis (DGGE) was used to show that long-term prescribed burning significantly altered the total fungal community structure in the top 10 cm of soil, when compared with unburned plots. Hyphal ingrowth bags, used to target ectomycorrhizal (ECM) mycelia in soil, along with DGGE analysis, indicated that profiles of the soil fungal community from 2 yr burn plots significantly differed from those of the 4 yr burn and unburned plots. Following analysis of clone assemblages from the different burn regimes, results indicated that this difference reflected an altered ECM fungal community composition. 13C stable isotope probing (SIP), following the incubation of soil with 13C labelled cellulose, and DGGE analysis was found to significantly alter the active fungal community in the upper 10cm of soil at Peachester State Forest. Fewer active fungi in the 2 yr burn plots were found to have incorporated 13C compared to the unburned plots, strongly suggesting that the activities of cellulolytic fungi were negatively affected by the 2 yr burning treatment. The thesis also incorporated work that assessed the effect of forest conversion from native eucalypt to Pinus elliottii plantation on the soil fungal community at Beerburrum State Forest, Queensland, Australia. ITS and 18S RNA and DNA were used, along with terminal restriction fragment length polymorphism (T-RFLP) and DGGE analysis, indicating that total and active fungal communities differed significantly between the native eucalypt forest and first rotation P. elliottii plantation. This suggested that the conversion from native eucalypt forest to P. elliotti plantation significantly altered the soil fungal community at the Beerburrum site. / Doctor of Philosophy (PhD)
73

Monitoring changes in plant community composition and landscape structure as a result of prescribed burning at Big Oaks National Wildlife Refuge

Basey, Gary L. 03 June 2011 (has links)
A vegetation monitoring program was initiated at Big Oaks National Wildlife Refuge (Big Oaks NWR) to help understand the effects of fire management on critical wildlife habitat. The objectives of this study were to produce a baseline description of plant community structure and composition and to describe the landscape-level impacts of fire management within the refuge. These grassland communities are important for managing rare grassland wildlife species, especially Henslow's sparrows. Permanent plots were established in three managed grassland communities. Information on plant community species composition and structure was collected during 2000-2001. Andropogon viginiana and Solidago juncea were the dominant plant species in the permanent plots. Rhus copallinum and Liquidamber styraciflua were the dominant woody species. Changes in landscape structure were determined using aerial photographs and a geographic information system (GIS). Vegetation data layers were created for 1995 and 1998 with vegetation patches classified using the National Vegetation Classification System (NVCS). Field data was collected during 2000 and 2001 to validate the data layers. Changes in composition and structure of nine vegetation classes were compared between burned and unburned areas. Percent cover of grassland area increased while sparse woodland and shrubland decreased during the study period. The amount of total patches and total edge declined in the burn areas. Mean grassland patch size increased while the number of grassland patches and grassland edge decreased in the burn areas. Therefore, the grassland areas within the burn units were more homogeneous in 1998. The results of this study were related to Henslow's sparrow population estimates in the fire management units.
74

Characterization and source apportionment of PM2.5 in the Southeastern United States

Lee, Sangil 07 November 2006 (has links)
Fine particulate matter (PM2.5) affects the environment in a variety of ways, including of human health, visibility impairment, acid deposition, and climate change. As of March, 2006, 47 counties are designated as non-attainment areas in terms of PM2.5 in the southeastern United States. State agencies with PM2.5 non-attainment counties must develop plans that demonstrate how they will achieve attainment status. State agencies also have to address emission sources of visibility impairment and develop strategies to improve visibility. It is essential to understand PM2.5 composition and sources in order to develop effective control strategies to reduce PM2.5. In this thesis, actual prescribed burning emissions were characterized for better estimation of their impacts on air quality. Chemical mass balance (CMB) modeling, a receptor-oriented source apportionment technique, was applied to understand regional characteristics of PM2.5 source impacts in the Southeast. Uncertainty issues in the CMB source apportionment results due to both poor spatial representativeness and measurement errors was addressed for better understanding and estimation of the uncertainties. Possible future research is recommended based on the findings in this thesis.
75

Spatio-temporal distribution of white-tailed deer (Odocoileus virginianus) relative to prescribed burns on rangeland in South Texas

Meek, Michael Glenn 15 May 2009 (has links)
Overgrazing and fire suppression has left much rangeland in poor condition for various wildlife species. Prescribed fire is one range improvement practice used to restore degraded wildlife habitat. I determined the effect of prescribed fire on whitetailed deer (Odocoileus virginianus) spatial and temporal distribution, in the presence of cattle grazing. Three 40 ha patches, constituting 10% and 6% of the land area in the lesser and greater Yellow Bluff pasture, respectively, were burned in September 2005. To determine habitat use and distribution of deer relative to these burns 3 bucks and 3 does were netted from a helicopter and fitted with Global Positioning System (GPS) telemetry collars (Lotek™ GPS_3300S) for a period of 30 days during each season. For estimation of spatial distribution of deer, the collars were programmed to take a position fix every hour to reduce problems associated with spatial autocorrelation. For 12 days within this period the collars recorded animal location every 5 minutes to compare habitat use with 6–9 GPS collars (GPS_3300LR) placed on cattle. This allowed me to examine fine-scale movements of deer relative to cattle. Trials were conducted prior to the burn and in each season for one year after the burn. Areas to be burned were not favored by deer. A month after the burn in Fall 2005 there was an increase in use of the burned areas by deer. Deer preference for burned areas fell in Spring and Summer 2006, but in Fall 2006 females dramatically increased their use of the burns. This is possibly an artifact of small sample size and the random selection of individuals. Interaction between deer and cattle was minimal, as they inhabited different areas. When cattle moved within approximately 50 m of a stationary deer the deer was likely to move away. Vegetation measurements showed no significant change in shrub cover and density and a decline in available herbaceous forage on both treatment and control sites in the second year. The lack of vegetative response because of drought conditions was likely the cause of the lack of response by the deer to the burns.
76

First-year changes in oak regeneration, understory competitors, and resource levels in response to two overstory treatments and prescribed burning at Chuck Swan State Forest

Jackson, Samuel Wayne, January 2002 (has links) (PDF)
Thesis (M.S.)--University of Tennessee, Knoxville, 2002. / Title from title page screen (viewed Sept. 4, 2002). Thesis advisor: David S. Buckley. Document formatted into pages (xi, 112 p.). Vita. Includes bibliographical references (p. 104-111).
77

Prescribed fire in a ponderosa pine stand in the Blue Mountains, Oregon : relationships among post-fire scolytidae incidence, delayed tree mortality, snag decay dynamics, and woodpecker snag use /

Kangas, Michael. January 2002 (has links)
Thesis (M.S.)--Oregon State University, 2003. / Typescript (photocopy). Includes bibliographical references (leaves 85-92). Also available online.
78

FERTILIZATION AND BURNING EFFECTS ON USE OF DESERT GRASSLAND BY CATTLE

Bryant, David Arley January 1971 (has links)
No description available.
79

THE EFFECTS OF CONTROLLED BURNING ON A SOUTHWESTERN PONDEROSA PINE UNDERSTORY: A FACTOR ANALYSIS

Eakle, T. W. (Thomas William), 1945- January 1976 (has links)
No description available.
80

Effects of forest site preparation methods on carabid beetle (Coleoptera:Carabidae) diversity

Beaudry, Suzanne January 1995 (has links)
The objective was to analyze the effects of logging and prescribed burning on carabid beetles (Coleoptera: Carabidae) at a jack pine stand and white spruce plantations in order to assess short-term impacts of these forestry practices on the diversity of this beetle group. In addition, soil scarification was also included at the jack pine stand. Based on previous reports on forest disturbance influences on carabids, it is hypothesized that short-term effects of studied forestry practices do not reduce carabids' diversity. Four carabid assemblage characteristics were compared: (a) number of catches; (b) dry mass; (c) species richness; and, (d) diversity index. Species responses and dry mass distributions were also investigated. Treatments either increased or maintained studied variables compared with control sites. Diversity indices were highest in burnt-over areas. Similar response patterns of species or groups of species were observed in both forest types. The presence of regenerating sites among the natural landscape increased carabid diversity.

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