Thesis (MScBosb)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: The characteristics and total fuel load of the forest floor (FF) and harvest residue (HR) are needed to develop tools that can be used for fuel load management, fire risk analysis and fire behaviour prediction for P. patula grown in the summer rainfall area of South Africa (SA). Forest floor depth, mass and ash-free mass were measured and there was generally a greater range in depth under sawtimber (ST) stands than under pulpwood (PLP) stands. Forest floor loads, prior to ashing, ranged from 21 - 168 t ha-1 and 27 - 72 t ha-1, for ST and PLP stands, respectively and loads increased linearly with stand age. Sawtimber and PLP stands were analysed together, which resulted in a significant correlation between depth and mass (r2 = 0.78, n = 31). A loss on ignition procedure carried out on sub-samples of the FF improved the relationship between the FF depth and the ash-free mass for the different stands, and provided a more accurate model for the prediction of mass from depth. A multiple regression analysis revealed that age, altitude and mean annual precipitation (MAP) provided the best subset and accounted for 72% of the variation in the FF mass observed. The effect of increasing FF load and increasing moisture content on the fireline intensity (FLI) was examined using the fire behaviour prediction programme, BehavePlus. Harvest residue was quantified and characterised in terms of fuel size classes, under current silvicultural regimes for ST and PLP, for the development of fuel models for this species over its planted range in SA. An investigation into the proportion (by mass) of the 1- (0.0 - 0.6 cm), 10- (0.6 – 2.5 cm), 100- (2.5 – 7.6 cm) and 1000-hr (> 7.6 cm diameter) fuel classes of the total HR mass indicated that there was a significant difference between the mass of the 1-, 10- and 1000-hr fuel classes of the two silvicultural regimes, and no significant difference for the 100-hr fuel class. Two fuel models for P. patula HR and two models for standing timber were developed using the new model (NEWMDL) programme of BEHAVE and tested in BehavePlus. Nutrient concentrations were used with FF layer and HR size class load data to estimate the quantities of nutrients held in the fuel and to describe nutrient distributions in the fuel complex. Significant differences in the nutrient concentration of the FF layers and fuel components were observed which has important implications for fuel management. The concentration of N determined in this study, relative to that determined in other similar studies on P. patula was low. Forest floor loads were predicted and nutrient pools calculated for typical ST and PLP stands at both low and high altitude to provide insight into the nutrient distributions within the fuel complex. / AFRIKAANSE OPSOMMING: Die karaktereienskappe en totale brandstoflading van die bosvloer (FF) en kaalkap oorskot (HR) word benodig om instrumente te ontwikkel wat gebruik kan word vir brandstoflading bestuur, brandgevaar ontleding en brandgedrag voorspelling vir P. patula, wat in die somer reënvalgebied van Suid-Afrika groei. Die bosvloer diepte, massa en asvrye massa is gemeet en daar was oor die algemeen ‘n groter variasie in diepte onder saaghout (ST) opstande as onder pulphout (PLP) opstande. Die bosvloerladings, voor verassing, het varieer van 21 – 168 t ha-1 en 27 – 72 t ha-1 vir ST en PLP opstande respektiwelik. Ladings het linieêr vermeerder met opstand ouderdom. Saaghout en PLP opstande is saam geanaliseer en het tot ‘n betekenisvolle korrelasie gelei tussen diepte en massa (r2 = 0.78, n = 31). ‘n Verliestydens- ontbranding prosedure is uitgevoer op die FF monsters en het die verhouding tussen FF diepte en die asvrye massa van die verskillende opstande verbeter. Dit het ook gelei tot akkurater model vir die voorspelling van massa vanaf diepte. ‘n Veelvoudige regressie analise het aan die lig gebring dat ouderdom, hoogte en gemiddelde jaarlikse reënval (MAP) die beste sub-groep verskaf, en het 72% van die variasie in die FF massa verklaar. Ondersoek is ingestel op die effek van toenemende FF lading en toenemende voginhoud op die brandlyn intensiteit (FLI) deur die brandgedrag program, BehavePlus, toe te pas. Die kaalkap oorskot is gekwantifiseer en gekarakteriseer volgens brandstof grootteklasse, onder die huidige boskultuurstelsels vir ST en PLP, vir die ontwikkeling van brandstofmodelle vir hierdie spesie oor die betrokke groeistreek in SA. ‘n Ondersoek in die verhouding (volgens massa) van die 1- (0.0 – 0.6 cm), 10- (0.6 – 2.5 cm), 100- (2.5 – 7.6 cm) en 1000-uur (> 7.6 cm deursnee) brandstofklasse van die totale HR massa het aangedui dat daar ‘n betekenisvolle verskil is tussen die massas van die 1-, 10- en 1000-uur brandstofklasse van die twee boskultuurstelsels, en geen betekenisvolle verskil vir die 100- uur brandstofklas nie. Twee brandstofmodelle is ontwikkel vir P. patula HR en twee modelle vir staande hout deur gebruik te maak van die nuwe model (NEWMDL) program van BEHAVE en getoets in BehavePlus. Voedingstof konsentrasies is gebruik, tesame met die FF laag en HR klasgrootte ladingdata, om die voedingstof inhoud van die brandstof te skat en om die voedingstof verspreiding te beskryf in die brandstofkompleks. Betekenisvolle verskille is waargeneem in die voedingstof konsentrasies van die FF lae en brandstof komponente wat belangrike implikasies inhou vir brandstofbestuur. Die konsentrasie wat vir N in hierdie studie bepaal is, was laag relatief tot ander soortgelyke studies vir P. patula. Die bosvloer ladings is voorspel en voedingstofpoele bereken vir tipiese ST en PLP opstande vir beide lae en hoë hoogtes om insig te verkry, sodat insig verkry kon word in die voedingstof verspreidings binne die brandstofkompleks.

Thesis (MSc (Geography and Environmental Studies))--University of Stellenbosch, 2007. / The Agulhas Plain, an area rich in fynbos, was monitored within six months after the February 2006 fire. The potential of using medium resolution imagery, specifically from the Moderate Resolution Imaging Spectroradiometer (MODIS) in determining the re-growth rates of indigenous and alien vegetation types after fire was explored. Pixels representing dense areas of each vegetation type were selected. There was a significant difference in the pixels selected for each vegetation type. A time series of Normalized Difference Vegetation Index (NDVI) data was derived and fitted to functions, such as Double Logistics and Asymmetric Gaussian as implemented in the TIMESAT software. The results show that alien vegetation grows faster after a fire occurrence than in its absence. Within the specified months of monitoring, it was observed that fynbos grew faster than the alien vegetation. Also, the re-growth rates of vegetation on the coastal soils were higher than those of vegetation on the inland soils. The determination of the re-growth rate was necessary to assist resource managers determine the appropriate time for follow-up of clearing invaded sites after fire.

Food webs consist of a combination of bottom-up (resource-driven) and top-down (predator-driven) effects. The strength of these effects depends on the context in which they occur. I investigated food web (trophic) relationships between wolf (Canis lupus) predation, elk (Cervus elaphus) herbivory, aspen (Populus tremuloides Michaux) recruitment, and fire. The study setting, in the central portion of the Crown of the Continent Ecosystem, spans the US/Canada border and encompasses Glacier National Park (GNP), Montana and Waterton Lakes National Park (WLNP), Alberta. I stratified my observations across three spatially distinct areas, the North Fork Valley, in the western portion of GNP; the Waterton Valley, in the eastern portion of WLNP; and the Saint Mary Valley, in the eastern portion of GNP. All valleys are elk winter range (low-lying grasslands with patches of aspen). The valleys have three different observed wolf population levels (Saint Mary: low; Waterton: moderate; North Fork: high), which represent three levels of long-term predation risk (the probability of an elk encountering a wolf). Ecological characteristics (e.g., climate, soils, elevation, plant associations) are comparable among valleys. Fire has occurred in 90% of the North Fork. My objective was to examine the relative influence of bottom-up (fire) and top-down (predation risk) factors and the context-dependence of these relationships via data gathered during a three-year time span. I found complex elk responses to bottom-up and top-down factors that could influence habitat use by elk. Pellet transect data demonstrated that elk exhibited the same risk reduction behavior at all wolf population levels, even at very low levels. Predation risk variables that provided impediments to detecting or escaping wolves had a similar and negative influence on occurrence of elk (pellet piles), regardless of wolf population density. Fire had a negative effect on elk density and a positive effect on wolf density (per scat piles) in aspen communities where a high wolf population existed. Aspen cover, which may be riskier than open grassland, also had a negative effect on elk density, except at very high wolf levels without fire. The risk of wolf predation alone did not drive elk behavior. Conversely, focal animal (elk vigilance behavior) data suggested a positive relationship between wolf population and elk vigilance. However, when I deconstructed vigilance, elk demonstrated complex, context-dependent adaptive behavior in response to the long-term risk of predation by wolves. Commonly identified drivers of elk vigilance (group size, impediments to wolf detection and escape) appeared to be important drivers at an intermediate level of long-term predation risk (e.g., Waterton). These drivers ceased to function in this manner when the long-term predation risk level increased (The North Fork). At high levels of long-term predation risk, vigilance was high, but not driven by these common factors. In some cases, the relationship between vigilance and risk factors was reversed (e.g., group size). And at a low level of long-term predation risk (Saint Mary), elk did not respond to these drivers of vigilance. When I measured aspen demography (browse, recruitment), browse was lower in the North Fork, where there was a high wolf population, suggesting a top-down effect. However, I found low aspen recruitment in the absence of fire in all valleys, which indicates a bottom-up effect in that aspen is highly fire-dependent. Top-down predictors of aspen recruitment (e.g., plot position and stand size, which are related to predation risk) had no effect on browse levels regardless of wolf population level. In sum, the risk of wolf predation alone did not drive the food web relationships I observed. Bottom-up and top-down forces worked together in valleys that contained well-established wolf populations, and to a lesser degree in a valley with a low wolf population. Commonly used measures of predation risk responses (e.g., vigilance) reversed their relationship as the wolf population increased. Low aspen recruitment in the absence of fire demonstrates the importance of bottom-up effects. Bottom-up and top-down effects may be important joint engineers of aspen communities. My findings invite deeper inquiry into the interaction between bottom-up and top-down effects in large mammal systems. / Graduation date: 2012

Thesis (MSc) -- University of Stellenbosch, 2002. / ENGLISH ABSTRACT: The fires, which occurred during January 2000 on the Southern Cape Peninsula, Cape Province, South Africa, focused attention on the importance of sound, informed management of exotic plant invaders in fynbos, especially at the urban interface. The fires also highlighted the relative lack of knowledge about the combined impacts of fire, exotic plants and the exotic-clearing programme on soil seed banks and regeneration. This study examines soil borne seed banks, regeneration, soil chemistry and micro biota in different postfire environments, focusing on three components of exotic plant management: The post-fire effects of standing invasive exotic plants; stacks of slashed exotic plant material which were deliberately burnt and stacks reduced to heat scars by a wildfire. The primary hypothesis addressed is that post-fire vegetation regeneration patterns, seed bank diversity and seed bank abundance are linked to pre-fire vegetation characteristics and, in particular, to the treatment of exotic plant species. It is also hypothesised that soil microbe population sizes are linked to pre-fire vegetation and soil chemical composition. Differences in soil seed banks, soil micro biota and vegetation regeneration patterns occur in different post-fire environments. High volumes of (live or dead) woody exotic biomass negatively impact upon postfire indigenous species diversity and abundance, both above and below-ground. Soil seed banks and above-ground regeneration decline with increasing fire intensity, wildfire burnt stack treatments showing the largest declines followed by wildfire burnt standing exotics, control burnt stacks, wildfire burnt cleared areas and wildfire burnt Mountain Fynbos treatments. Persistent indigenous seed banks are found under some exotic dominated stands. Heat damage, associated with high woody exotic biomass, affects seeds of all species into deep soil layers. Depth of burial is a more important determinant of seed survival during fires than seed size. Soil microbial populations are variably affected by exotic plants, their management and increases in fire intensity. The most drastic microbial population changes are in post-fire treatments of high exotic plant biomass. Soil chemistry affects microbial population sizes as does seasonal climatic changes. In this thesis vegetation, seed bank and microbial responses to various exotic plant management practices are shown and management recommendations are made. Keywords: exotic plants, fire, Fynbos Siome, microbes, post-fire succession, soil seed banks. / AFRIKAANSE OPSOMMING: Die Januarie 2000 vure op die Suid Kaapse Skiereiland het fokus gerig op die belangrikheid van goeie, ingeligte bestuur van uitheemse indringerplante in fynbos, veral naby stedelike gebiede. Die vure het ook 'n relatiewe .gebrek aan kennis aangaande die gekombineerde impakte van vuur, uitheemse plantegroei en indringer plant beheer programme op grond saadbanke en die hergroei van plante na 'n vuur aan die lig gebring. Hierdie projek bestudeer die invloed van vuur op grond saadbanke, hergroei van plante, grond chemie en mikro-organismes. Die klem lê op drie komponente van uitheemse plant bestuur: waar staande uitheemse plante voorkom; waar skoongekapte uitheemse plante in hope gestapel is en gekontraleerd gebrand is en waar soortgelyke hope in 'n onbeplande weghol vuur gebrand is. Die primêre hipotese is dat plant herstelpatrone, saadbank diversiteit en grootte gekoppel is aan veldtoestande voordat daar gebrand is, en veral aan die bestuur van uitheemse plantspesies. Nog 'n sentrale hipotese is dat die grootte van grond mikrobiale populasies gekoppel is aan veld toestande voor die brand en aan grond chemiese samestelling. Hierdie studie dui verskille aan in grond saadbanke, mikro-organismes en plant hergroeipatrone onder verskeie toestande na vuur. Die brand van hoë volumes (lewende of dooie) houtagtige uitheemse plant biomassa benadeel inheemse plant spesie diversiteit en getalle (bo en onder die grond oppervlak). Grond saadbanke neem af met vehogings in vuur intensiteit. Die grootste afnames is in wegholvuur gebrande gestapelde uitheemse plantmateriaal gevolg deur wegholvuur gebrande staande uitheemse plante, opsetlik gebrande hope uitheemse plante, gebrande skoongekapte areas en wegholvuur gebrande Berg Fynbos. Ou inheemse saadbanke is gevind onder sommige areas wat voor die vuur oorheers was deur uitheemse plantegroei. Hitteskade, geassosieer met hoë volumes houtagtige uitheemse biomassa, affekteer sade van alle spesies tot diep in die grond. Saad oorlewing tydens brande is meer geaffekteer deur diepte van begrawing in die grond as deur saad grootte. Grond mikro-organisme populasies is geaffekteer deur uitheemse indringer plante, die bestuur van uitheemse plante en vuur intensiteit. Die grootste veranderinge is waar die biomassa van uitheemse plantegroei baie hoog is. Grond chemiese samestelling en seisoenale veranderinge in weerspatrone affekteer die grootte van mikrobiale bevolkings. In hierdie tesis word verskille in plantegroei, saad store en grond mikrobes, soos geaffekteer deur uitheemse plant beheer programme uitgewys en voorstelle vir toekomstige bestuur gemaak. Sleutelwoorde: Fynbos Bioom, grond saad stoor, mikrobes, plant hergroei, uitheemse plante, vuur.

Thesis (MPhil (Sociology and Social Anthropology))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: This study examines the issue of informal settlement fires, specifically in Kayamandi a township of Stellenbosch in the Western Cape province of South Africa. The study aims to identify the relevant role-players involved in addressing the issue and to understand the unique dynamics involved in this type of fires at the local level context. The study illuminates the main contextual factors that contribute to the perpetuation of informal settlement sprawl in South Africa and that relates to the risk and vulnerability experienced by informal settlement dwellers. A qualitative research approach was followed and a triangulation of data collection methods was used, combined with a relatively broad literature study to capture the complexity of the related issues. The contextual focus includes the macro-economic factors that contribute to the environment in which informal settlement fires occur, and furthermore, developmental, economic, political and social aspects and the related experience of poverty, urbanisation and unemployment. It was found that the theoretical underpinning of both the fields of Disaster Management and Community Development are relevant for analysis and addressing the research questions. Furthermore, that a relationship exists between the Disaster Management, Development and Community Development fields. This is particularly evident in Disaster Management policy and planning as related to prevention, mitigation, and public participation, such as community involvement in Community-Based Risk Assessments. Key findings suggest that local government in the demarcated study area has great influence on how the problem of informal settlement fires is addressed. From national to local municipality level, the State plays the largest role in addressing the issue and takes the responsibility for addressing informal settlement fires as part of disaster management mandates prescribed in legislation. The local government agenda as influenced by Disaster Management legislation include efforts related to awareness, education and training focused on Kayamandi as an informal settlement community and can be considered community development initiatives. This further relates to the view taken in the thesis that informal settlement fires are a social issue and not only an operational issue. Therefore the broad social, economic and political context and history were included and it was shown that the ‘problem’ of informal settlement fires is part of a greater developmental context and related processes. A variety of community development theories were chosen as a useful framework for analysis in this study and to approach issues of risk and vulnerability on a community level. It also presents a conceptual framework for including both non-governmental stake-holders and the affected community as role-players. / AFRIKAANSE OPSOMMING: Hierdie studie ondersoek die kwessie van vure in informele nedersettings en spesifiek in Kayamandi, ‘n informele nedersetting van Stellenbosch in die Wes-Kaap provinsie van Suid- Afrika. Die doel van die studie is om die relevante rolspelers te identifiseer wat betrokke is by die aanspreek van die kwessie en om die unieke dinamika van vure in hierdie plaaslike konteks te verstaan. Hierdie studie beklemtoon die belangrikste kontekstuele faktore wat bydra tot die uitbreiding van informele nedersettings in Suid-Afrika en wat verband hou met die risiko en kwesbaarheid van inwoners van informele nedersettings. ‘n Kwalitatiewe navorsingsbenadering is gevolg en ‘n triangulasie van dataversamelingsmetodes is in hierdie studie gebruik. Dit is met ‘n relatief breë literatuur-studie gekombineer om die kompleksiteit van die verwante kwessies weer te gee. Die konteksuele fokus sluit in makro-ekonomiese faktore wat bydrae tot ‘n omgewing waarin informele nedersettingsbrande voorkom, en voorts, ontwikkelings-, ekonomiese-, politieke- en sosiale aspekte, sowel as die verwante ervaring van armoede, verstedeliking en werkloosheid. Daar is bevind dat die teoretiese begronding van beide die velde van Rampbestuur en Gemeenskapsontwikkeling relevant is vir ontleding en om die navorsingsvrae te kan beantwoord en dat daar ‘n verhouding tussen Rampbestuur, Ontwikkeling en meer spesifiek Gemeenskapsontwikkeling bestaan. Dit kom veral na vore in Rampbestuurbeleid en - beplanning soos van toepassing op voorkoming, mitigasie en publieke deelname. Van die belangrikste bevindinge suggereer dat die plaaslike regering in die gegewe studie die grootste invloed het oor hoe die probleem van brande in informele nedersettings aangespreek word. Van nasionale tot plaaslike vlakke neem die Staat die verantwoordelikheid vir die aanspreek van informele nedersettingsbrande, soos vervat in mandate wat deur rampbestuur wetgewing bepaal word. Die plaaslike regering se agenda soos bepaal deur Rampbestuur wetgewing bevat gemeenskapsontwikkelingsidees oor deelname en inklusiewe beplanning, bewusmaking, opvoeding en spesifieke opleidingsinitiatiewe wat op Kayamandi afgestem is. Dit sluit verder aan by die siening, soos geneem in die tesis, dat informele nedersettingsbrande meer as net ‘n operasionele kwessie is, maar ook ‘n sosiale dimensie insluit. Om hierdie rede word die breër sosiale, ekonomiese, politieke en historiese konteks in die studie ingesluit, soos wat dit op die ‘probleem’ van informele nedersettingsbrande as deel van die groter ontwikkelingskonteks en prosesse dui. ‘n Verskeidenheid van gemeenskapontwikkelingsteorieë is as ‘n bruikbare raamwerk geselekteer vir ontleding en as ‘n benadering om risiko en kwesbaarheid op gemeenskapsvlak aan te spreek. Dit bied ook ‘n konsepsuele raamwerk om beide nie-regeringsrolspelers en die geaffekteerde gemeenskap ook as rolspelers in te kan sluit.

Abstract not available

Prior to European settlement, native prairie dominated the landscape of the Willamette Valley. Today, due to urbanization, agriculture, and the cessation of burning, only isolated remnants of these grasslands still exist. In response to conservation concerns, there has been a move to restore the remaining prairies in the Willamette Valley, and prescribed burning and sowing native seed are often top candidates for grassland restoration. However, the effects of burning on native seedling establishment and the spread of weedy exotics are largely unknown. In this study, I investigated how prescribed burning affects native and exotic species seedling establishment on three upland prairie vegetation types in the Willamette Valley. The general approach was to sow a known number of seeds from several native and exotic grassland species into experimentally manipulated plots, designed to separate the effects of litter removal from the other effects of burning, and to monitor seedling densities. Germinability and dormancy characteristics of the sowed seeds were also addressed. An additional study focused on the fire temperatures at soil surface in three grassland vegetation types and two burn sizes. Burning increased the establishment of most or all of the sown native species in the two low quality, exotic grass sites. Exotic seedling establishment also tended to increase, but did not differ significantly from unburned plots for most species tested. On the higher quality, native bunchgrass site, burning did not significantly improve native species establishment, but did significantly increase the establishment of short-lived exotic species over those in unburned plots. The germination and dormancy characteristics of the native and exotic species tested indicate that grasses, both native and exotic, are more likely than forbs to be non-dormant in the autumn following dispersal. Forbs, especially native forbs tend to require cold-stratification for maximum germinability. During grassland fire, temperatures at soil surface were relatively cool. Fire temperature intensity was highest in the higher quality native bunchgrass vegetation. These burns reached higher temperatures significantly closer to the soil surface than the plot burns in lower quality sites dominated by annual or perennial exotic grasses. Average temperatures in a two hectare broadcast burn and in replicated 2m x 2.5m plot bums in an annual exotic grassland were very similar. Prescribed burning can be an excellent tool for the restoration of low-quality upland prairies when combined with sowing native seeds in the fall. However, on high-quality prairie, prescribed burning may be a poor restoration choice for promoting native seedlings, as burning promoted weedy species without enhancing native seedling establishment. / Graduation date: 1997

In the canyon grasslands of Garden Creek Ranch Preserve in Idaho, where the threatened plant Silene spaldingii occurs and invasion by the exotic species Centaurea solstitialis and Bromus tectorum is proceeding rapidly, I examined environmental and community patterns of site invasion, and evaluated the apparent influence of invasion on Silene population vigor. In addition, two separate lightning fires at the preserve presented the opportunity to examine the short-term influence of late-season fire on this species and its associated bunchgrass plant community. I found that Silene-supporting sites most often invaded by exotics were on relatively gentle slopes that received more incident radiation. This pattern may relate, in part, to light requirements of Centaurea solstitialis. Invaded sites were also typically at higher elevations, which may indicate they were moister and therefore more productive. The plant communities in invaded Silene-supporting sites were similar to plant communities in uninvaded sites, although invaded sites tended to have greater legume and exotic annual grass cover. Exotic species invasion did not appear to influence negatively the vigor of Silene populations, as indicated by similar plant height and comparable levels of flowering, fruit and seed set in invaded and uninvaded populations. The similarity in Silene vigor between invaded and uninvaded sites may reflect a moderating influence of site productivity in invaded populations, or may indicate that mature Silene plants and the exotic species partition space or resources differently, potentially reducing competition between them. However, Silene recruitment may be limited by competition from weeds; my data did not allow a rigorous test of this possibility. Fire apparently decreased cover of Festuca idahoensis and increased cover of Lupinus sericeus in the first year after burning, while cover of Pseudoroegneria spicata, exotic grasses, and most other forb species did not differ between burned and unburned areas. Silene cover and abundance within populations were similar before and after fire. Burning did not appear to influence levels of flowering, change the number of flowers or capsules produced per stem, or alter the number of seeds per capsule. Burning decreased plant size slightly, and decreased the proportion of flowers that matured to seed-filled capsules. Silene and the plant communities that support this species appear well suited to late season fire, however the response to burning in other seasons or at higher frequencies remains unknown in this study area. / Graduation date: 2003

A series of trials and investigations were implemented to address concerns surrounding the dynamics of the fire-climax wooded/edaphic grasslands within the iSimangaliso Wetland Park, northern KwaZulu-Natal, South Africa. The research problem surrounded inadequate historical evaluations of changes in vegetation structure, grasslands progressing to a woody dominated composition, and increases in Helichrysum kraussii (Curry bush). These were addressed as follows: Firstly, the recovery of vegetation in response to different periods of fire exclusion in different communities along a topographical gradient of a coastal dune area, was assessed over a two year period. Secondly, the regeneration after wildfire of the persistent, stress tolerant shrub H. kraussii, was studied on different catenal positions with differing fire exclusion periods and with and without defoliation of surrounding plant biomass in the coastal edaphic grasslands north of Manzengwenya, South Africa. Thirdly, aerial photography from 1937, 1975, and 2000 was georectified, digitised and analysed using a Geographic Information System to examine broad vegetation changes in response to different management regimes for a site on the Eastern Shores of Lake St Lucia and a site within the Tewate Wilderness Area. In the absence of fire, the coastal edaphic grasslands progressed to a closed canopied scrub forest within six years. An increase in fire exclusion period resulted in a decrease in species abundance, an increase in woody height, and a decrease in plant density. Richness increased initially but declined marginally with increased fire exclusion period. Higher lying east and west facing sites had a better veld condition index compared with bottom sites and had an increased response (vigour) to defoliation but were far more likely to succeed through to woody scrub forest. Woody plant biomass vigour was greater for west facing sites. Ordination of species composition across sites in response to fire exclusion and catenal position revealed greater similarities within exclusion periods than between. Bottom sites were more similar with similarity decreasing for east and west facing sites. Fire exclusion resulted in an initial increase in woody species and a subsequent increase in herbaceous species. iii Growth response of H. kraussii was unaffected by catenal position and fire exclusion period, whereas defoliation of surrounding grass tended to increase in size (P<0.05). Density and height for this species however increased with increasing fire exclusion. An increase in soil moisture negatively affected H. kraussii growth indicating susceptibility to high water tables. The number of other woody species establishing beneath H. kraussii may be due to changes in the transmission of light through the canopy where an increase in canopy diameter resulted in an increase of photosynthetically active radiation at the soil surface. The effects of fire on landscape change were investigated for the Eastern Shores and Tewate Wilderness Area, iSimangaliso Wetland Park, South Africa using aerial photography. Changes to historical disturbance regimes largely through active exclusion of fire resulted in the majority of the higher lying coastal grasslands changing to savanna scrub or closed canopied forest within 63 years on the Eastern Shores. The degree of fragmentation of these grasslands was greatly reduced within the Tewate Wilderness Area where disturbance regimes included greater frequencies of fire. Hygrophilous grasslands remained largely unaffected by woody encroachment but did not preclude woody species establishment indicating possible susceptibility during long drier periods. Frequent fires result in the maintained distribution of the higher grasslands. This vegetation type is a system which becomes resilient in response to fire, whereas in the absence of fire readily progresses to Dune Forest. The coastal grasslands above the high water table are therefore highly unstable and transformed easily in the absence of regular disturbance. It would appear that a threshold of approximately six years exists, after which substantial management intervention may be required to reverse the succession back to grassland. The growth of H. kraussii was unaffected by fire and remained persistent irrespective of fire exclusion period. An ability to attain size (height and canopy diameter) was limited with increased soil moisture but density was reduced through regular burning. Frequent fires are necessary to reduce density of H. kraussii and reduce the competitive advantage gained with age. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2007.

Bushfires are an integral part of the Australian environment, and consequently Australian fire fighters are regularly confronted with the challenge of bushfire fighting activities. Bushfires can be extensive and long-lasting, and as a result fire fighters can be exposed to bushfire smoke for long periods without respite. Anecdotal evidence suggests that bushfire smoke exposure can lead to respiratory symptoms such as coughing, wheezing, and shortness of breath. In an optimal environment, fire fighters are equipped with respirators and protective filters to prevent the inhalation of the air toxics in bushfire smoke. Yet, reports from the fire ground indicate that the protective filters are not effective in preventing the inhalation of bushfire smoke. As a result, fire fighters have increasingly expressed concern about the ineffective equipment and the resultant respiratory symptoms during and after bushfire fighting. This research aims to establish a scientific data base to support the anecdotal evidence. The objectives of the research were: (1) to identify and quantify the air toxics in Western Australian bushfire smoke; (2) to profile the acute respiratory health effects associated with bushfire smoke exposure; (3) to assess the effectiveness of three different types of filters under controlled conditions in a smoke chamber, and in the field during fuel reduction burn-off; (4) to formulate recommendations for reducing fire fighters' exposure to bushfire smoke; and (5) to inform policy decision makers about the most effective form of respiratory protective equipment for bushfire fighting. Exposure trials were conducted in an experimental setting utilising bushfire smoke conditions in a smoke chamber and during prescribed burn-offs. Repeated measurements of respiratory symptoms, pulmonary function and oximetry were undertaken before and after bushfire smoke exposure. In addition, personal air sampling inside the respirators was undertaken to quantify and compare the levels of filtered air toxics. The analysis of the collected data demonstrated that, of those compared, the particulate/organic vapour formaldehyde filter was most effective in protecting fire fighters' respiratory health during the smoke exposure period of maximally 120 minutes. Further research would be useful to determine the v effectiveness of the filters under more realistic conditions during bushfire fighting activities. The findings of this research have resulted in a policy review in Western Australia. In 2006, the Fire and Emergency Services Authority of Western Australia (FESA) reviewed its Bush Fire Smoke Exposure Standard Operational Procedures 51, and now issues the recommended particulate/organic vapour/formaldehyde filters to the 1,000 FESA career fire fighters. The use of protective equipment for bushfire fighters is inadequately regulated worldwide and the recommendation implemented by FESA can be seen as proactive and in advance of national and international best practice. In conclusion, this project was instrumental in the translation of public health research into best practice that protects occupational health, without the need for the lengthy process of legislative reform. Fire fighter organisations in other countries with high frequencies of bushfires could learn from this example, and move to review their policies and introduce adequate personal protection for fire fighters.