The Lewisville Lake Environmental Learning Area (LLELA) is a wildlife management area with tallgrass prairie, an endangered ecosystem. Essential ecosystem processes, especially fire, are part of restoration. To support fire management efforts at LLELA and surrounding areas, this project evaluated and developed tools for fire restoration. The four primary prairie grasses respond favorably to burning. Fuel loads and fuel models vary by scale and survey method. One- and 10-hour fuel moisture can be predicted using a statistical model; 100- and 1,000-hour fuel moisture cannot. Historic weather data suggests that burning can occur when it is most effective. The production of ozone precursors produced by burning is comparable to those emitted every six minutes by regional automobiles.

Long term fire exclusion has been attempted in Catchment IX (CIX) at Cathedral Peak. Baseline vegetation of CIX was sampled in 1952, with follow-up surveys in 1973, 1986 and 2010. These took place at key times in terms of changes in fire history within the catchment. Complete fire exclusion was achieved between 1973 and 1986, but eight accidental fires burnt part of CIX thereafter. The woody component was resurveyed in 2010 after the latest of thirteen unintended fires had swept through CIX in 2007. This fire burnt about 90% of the catchment. The vegetation of the area not burnt was a distinct community and size structure indicating it had not been burnt by other accidental fires. Partial exclusion of fire over 58 years resulted in vegetation transforming from grassland to a grassland-fynbos-scrub forest mosaic. Erica evansii and Leucosidea sericea, a reseeder and resprouter respectively, were the two dominant species in CIX. These displayed expected responses to a single fire, resulting in dominance shifting from E. evansii (92% mortality) to L. sericea (1.6% mortality). The decrease in E. evansii individuals resulted in a relative increase in community contribution of species not affected by fire. Leucosidea sericea’s post-fire dominance in burnt plots was not apparent in fire-protected areas. A successional trend of colonisation of woody species, predominantly E. evansii and L. sericea, into grassland was observed. Despite occasional fires since 1986 vegetation did not revert to grassland. The emergent woody community was not homogenous. This was attributed to a combination of an irregular pattern of accidental burns and environmental variability within the catchment. The mosaic of distinct grassland, woodland, ecotonal and scrub forest communities are predicted to remain as such.

Thirty-eight oligotrophic lakes located around the Reservoir Gouin in central Quebec (48°N, 75°W) were sampled over three years to test the hypothesis that forest clearcutting and fires should be reflected in both higher nutrient export rates and ultimately in greater areal hypolimnetic oxygen deficit rates (AHOD). Significant differences in estimated total phosphorus export rates across treatments were found. However, no effect of clearcutting or forest fire on hypolimnetic oxygen consumption rates could be demonstrated as the result of a much greater and confounding variation in the effect of lake morphometry and the absence of information on the role of catchment-derived organic matter on the AHOD. Consequently, only lake morphometry (hypolimnetic volume to hypolimnetic surface area ratio) served as a predictor of the AHOD. Covariation of mean hypolimnetic water temperature with morphometric variables underlines the influence of lake morphometry on heat dynamics and hypolimnetic respiration rates in these lakes. / This research made considerable use of specialized data manipulation techniques involving a relational database management system, owing to the size of the dataset used (114 lake-years of data). The specific approach used in this thesis is presented in an appendix.

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Fires are the primary method of deforestation and agricultural management in the tropics, but associated emissions such as aerosols, ozone, and carbon monoxide can have negative impacts on ecosystems, climate, and public health. Recent advances in satellite monitoring of fire activity, including using thermal anomalies for active fire detections and burn scar mapping of post-fire effects, have offered an unprecedented level of detail in understanding the magnitude and extent of fire activity. This dissertation aims to quantify the human health impact across populations in tropical regions by determining which areas are the most susceptible to transported fire emissions and how this exposure varies over time. The following chapters can be used to highlight critical conservation regions, not only for conserving ecosystems for biodiversity and climate benefits, but also for protecting public health. To address how fire emissions can affect regional populations, satellite observations of fire activity are combined with models of how tropical fire emissions are transported in the atmosphere. Satellites provide two primary pieces of information for this approach: 1) measurements of the distribution and magnitude of fire activity, and 2) categorization of fire types (such as agricultural burning or deforestation) by overlaying observed fire patterns on land use maps. Atmospheric models perform the crucial step of simulating how emissions evolve and where they are transported after release into the atmosphere. The following dissertation chapters are linked through exploration of fire emissions impacts from continental to local scales, including implementing fire emissions inventories into atmospheric models, quantifying population exposure to fire activity in Equatorial Asia, and projecting fire emissions associated with various future land use scenarios in Sumatra. Model estimates of aerosol concentrations are more influenced than trace gases by using finer temporal resolution fire emissions, due to interactions between emissions and modeled meteorology and transport. This in turn can impact air quality estimates by permitting higher peak concentrations. In addition, model results show that population exposure to fire emissions in Equatorial Asia is highly variable over time depending on the phase of the El Niño cycle; strong El Niño years can have fire contributions to fine particulate matter of up to 200 µg/m³ near fire sources, corresponding to 200 additional days per year over the World Health Organization 50 µg/m³ 24-hour fine particulate matter air quality target. These risks are not confined to people living near fire sources, but expose broad regional populations due to the atmospheric transport of emissions. Health impacts also depend on underlying fuel characteristics, with the future magnitude of Equatorial Asian fire emissions estimated to be strongly dependent on the level of protection given to fuel-rich peatswamp forests (contributing 33-48% of future emissions in the absence of protection). Collectively, these chapters emphasize variability in how tropical fire emissions affect regional population exposures to outdoor air pollution, and the need to consider the dependence of this public health effect on different fuel types and year-to-year variations in climate. The results described in this dissertation quantify direct benefits of conservation for people living near fire areas.

In this study, I addressed how a large-scale wildfire affected a prairie arthropod community in southern Alberta, Canada. First, I looked at the general effects of disturbance on the arthropod community. Second, I addressed how processes such as competition and secondary succession may have affected diversity in this arthropod community. Third, I determined how the arthropod community trophic structure was regulated. Results showed that the effect of disturbance on arthropods varies greatly by taxa. Factors, such as site, year, distance from disturbance edge, as well as the disturbance itself, were important in determing the abudance, biomass, richness, and diversity of the arthropod community. There were strong year-to-year differences hat exceeded the disturbance effects. Results showed that the processess behind the intermediate disturbance hypothesis, succession and competition are not detectable in this arthropod community. This arthropod community was likely regulated in a bottom-up manner, in which herbivores ultimately control the abundance of predators and parasitoids. / x, 97 leaves : ill. ; 28 cm.

Fire is a major disturbance force that affects global ecosystems and associated biomes and plays a pivotal role in the determination of ecosystem structure, functionality and dynamics. Anthropogenic environmental disturbances have resulted in shifts in fire regimes and the biogeochemical processes of these ecosystems are thus unable to function as they have done in the past, impacting both floral and faunal species. Therefore there is a need for anthropogenic management. Prescribed burning is one of the few beneficial fire management options available to decrease the severity of wildfires, decrease the associated costs in suppressing these fires and restore fire-dominated ecosystems. The uKhahlamba Drakensberg Park World Heritage Site (UDP-WHS) is predominantly managed for water resource and nature conservation, and fire hazard reduction. It is divided into management compartments in which prescribed management burns are conducted, (i.e. manager’s burn by compartment). These compartments are subdivided by three altitudinal belts (alpine, sub-alpine and montane). Each of these belts contains different vegetation communities and therefore requires different fire regimes. However these compartments do not coincide with the natural contours and consequently, the altitudinal belts of the Park. This is problematic for management as a certain percentage per altitudinal belt is required to be burnt annually. When burning a compartment that falls within two or more belts, the total area of that compartment needs to be sub-divided into its respective altitudinal belts as a whole compartment can be prescribed to burn not a sub-division thereof. A fire management environmental decision support system (EDSS) was developed to achieve prescribed burning objectives in the UDP-WHS. The system is based on ecologically ideal fire regimes and fire management objectives of the heritage site, using GIS and associated graphs to visually display the required fire regimes. The EDSS data preparation, statistical analysis and modelling was completed using ESRI ArcGIS suite (ArcMap, Scene and Catalog). Its main components are two models, an excel spreadsheet and an ArcMap document. The spreadsheet contains the historical burning data of the management compartments based on the compartment codes, with each compartment being not burnt or having a burning treatment. Years Since Last Burnt (YSLB) was calculated from these data and joined to the management compartments in the ArcMap document. The Intermediate output model was developed to create numerous temporary outputs allowing decision makers to decide which compartments to treat with prescribed burning by re-running the model with required alterations. The second model (Final Output model) is then run to export the selected burning treatment in table format to update the original historical data, and consequently YSLB, in the excel and ArcMap document. The ArcMap document contains the user interface housing the graphs for each altitudinal belt showing the percentage area selected to be burnt per YSLB compared to the minimal, maximum and ideal fire regimes. The fire management EDSS for the UDP-WHS consists of an ArcMap document, geodatabase, excel document and folders, which are all housed in one single folder. The use of GIS and EDSSs in environmental management improves the efficiency and accuracy of the decision making process and provides the ability to validate outputs. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

This study provides an analysis of watershed response to climate change and forest fire impacts, to better understand the hydrologic budget and inform water management decisions for present and future needs. The study site is 2,365 km2, located in the upper Umatilla River Basin (URB) in northeastern Oregon. The Precipitation Runoff Modeling System, a distributed-parameter, physical-process watershed model, was used in this study. Model calibration yielded a Nash Sutcliffe Model Efficiency of 0.73 for both calibration (1995-2010) and validation (2010-2014) of daily streamflow. Ten Global Climate Models using Coupled Model Intercomparison Project Phase 5 experiments with Representative Concentration Pathways 4.5 and 8.5 (RCP), were used to observe hydrologic regime shifts in the 2020s, 2050s, and 2080s. Mean center timing of flow occurs earlier in the year in both pre- and post-fire conditions, where there are increased winter flows and decreased summer flows throughout the 21st century. Change in temperature and percent change in precipitation is more variable in the summer than winter increasing over time, with a slight decrease in winter precipitation in the 2080s in RCP 8.5. Temperature increases 1.6°C in RCP 4.5 and 3.3°C in RCP 8.5 by the end of the 21st century. The ratio of Snow Water Equivalent to Precipitation decreases 96% in the 2080s in RCP 8.5 before forest cover reduction, and decreases 90-99% after forest cover reduction. Potential basin recharge and the base-flow index are both sustained throughout the 21st century with slight declines before forest cover reduction, with an increase in basin recharge and increase in base-flows in the 2080s after fire-burns. However, the simulated sustained base-flows and area-weighted basin recharge in this study, do not take into account the complex geologic structure of the Columbia River Basalt Group (CRBG). A more robust characterization and simulation of URB aquifer recharge would involve coupling the PRMS model with a groundwater model in a future study. Although groundwater recharge in the CRBG in the URB is not well understood, the long-term decline of groundwater storage presents a serious environmental challenge for the Confederated Tribes of the Umatilla Indian Reservation and communities in the URB.

Forested watersheds in western North America are subject to significant change from natural and anthropogenic disturbance, including wildfire. Forest canopy changes have subsequent impacts on sub-canopy snow processes. A simple, process-based point energy balance model was developed to quantify differences in energy balance characteristics between a burned and a healthy forest stand. Potential model uncertainties were identified using sensitivity analyses. Simulated snowmelt accurately recreated measured snowmelt, providing confidence in the model’s ability to simulate energy balance processes in subcanopy environments where wind redistribution and sublimation are not major drivers of the local snowmelt energy balance. In the burned stand, sub-canopy snow accumulation was greater but melted more rapidly than in the healthy stand. The removal of forest canopy resulted in more energy available for snowmelt, including higher short-wave and lower long-wave radiation, and increased turbulent fluxes. Burned stands should be considered a separate land cover type in larger scale watershed models. / xii, 129 leaves : ill,, map ; 29 cm