Dissertations / Theses on the topic 'Land reclamation/restoration'

With the emergence of the new field of resource economics, one now has the ability to value and to include natural resources in decision making. This thesis aims to explore the valuation of natural resources by reviewing the economic values, techniques, methods and ecological aspects of restoration. Assegaaibos mountain catchment in the Western Cape Province has been used as a case-study example. A cost-benefit analysis of the restoration of the mountain catchment, in terms of the direct benefits of water and tourism, has been performed. The costs of restoration were observed to see whether they outweighed the benefits (income) derived (water and tourism). The results show that the water and tourism benefits did outweigh the costs of a basic restoration scenario. However, the basic restoration scenario did not fulfil the ecological requirements of the project. The results also illustrated that in the moderate restoration scenario, costs only outweighed the benefits when a three percent discount rate was applied. With the optimistic restoration scenario, costs outweighed benefits only when an eight percent discount rate was used. In the comprehensive restoration scenario, costs were shown to outweigh by far the water and tourism benefits over a thirty-year time frame. However, it should be noted that the deterioration of the environment (accelerated erosion, reinvasion, reduced water quality) was not factored into the costs of failure to rehabilitate.

A mineração é uma das atividades antrópicas mais impactantes aos recursos naturais, e que pode afetar profundamente a resiliência dos ecossistemas em função do elevado nível de degradação do solo e da paisagem. Diante disso, muitas áreas mineradas não são efetivamente recuperadas a ponto de restabelecer parte relevante da biodiversidade e dos serviços ambientais perdidos com a mineração. No entanto, novos métodos de restauração ecológica têm gerados resultados promissores mesmo em situações de degradação tão intensa como as de mineração, o que permitiria rever os níveis mínimos de qualidade ambiental exigidos de áreas que foram mineradas e que precisam passar por um processo de recuperação como forma de mitigação dos impactos causados e cumprimento de demandas legais de compensação ambiental. Assim, o objetivo geral desse estudo é avaliar a recuperação física, química e microbiológica do solo em áreas de mineração de bauxita em processo de recuperação ambiental. Avaliamos inicialmente a restauração do solo em minas de bauxita localizadas em Poços de Caldas-MG, tendo como objetivo contextualizar a melhoria do solo através de vários parâmetros químicos, físicos e microbiológicos em áreas recém-mineradas, em restauração de diferentes idades e remanescentes de floresta nativa. Encontramos que a restauração florestal foi eficiente em desencadear um processo de recuperação do solo, que resultou no restabelecimento, em poucos anos, de características químicas, físicas e microbiológicas já bem similares às do ecossistema de referência. Em seguida, avaliamos a recuperação dos teores de fósforo no solo pela restauração de florestas tropicais em minas de bauxita, e obtivemos como principais resultados a recuperação de importantes frações de P no solo, parte relevante da produção de serapilheira e da estrutura da floresta ao longo da trajetória sucessional nas jovens áreas restauradas após a mineração. A restauração ecológica mostrou-se capaz de restaurar rapidamente importantes atributos do solo, evidenciando o potencial da abordagem de restauração ecológica para mitigar os impactos ambientais negativos da mineração. Dessa maneira, destaca-se que políticas públicas voltadas para a mitigação de danos ambientais causados pela mineração podem exigir níveis mais elevados de qualidade ambiental em áreas de recuperação de minas, protegendo os interesses coletivos envolvidos na mediação de interesses entre empresas e sociedade.<br>Mining is one of the human activities with the highest impact in natural resources. It can profoundly affect the resilience of ecosystems due to the high level of soil degradation and landscape alteration. Thus, many mined areas are not effectively recovered enough to restore important part of biodiversity and ecosystem services lost. However, new ecological restoration methods showed promising results even in such intense degradation situations such as mining. Thus, it is needed to review the minimum levels of environmental quality required for areas that have been mined and need to recovered to mitigate the impacts and compliance with legal demands of environmental compensation. Thus, the general objective of this study is to evaluate the physical, chemical and microbiological soil in bauxite mining areas under ecological restoration. We initially evaluated soil restoration in bauxite mines located in the county of \"Poços de Caldas\", aiming to contextualize soil improvement through various chemical, physical and microbiological parameters in newly mined areas, restoration of different ages and remaining native forest. We found that forest restoration was effective in triggering a soil recovery process, which resulted in the recuperation, in a few years, of the chemical, physical and microbiological characteristics already very similar values to the references. We then evaluated the recovery of soil phosphorus for the restoration of tropical forests in bauxite mines, and obtained as main results the recovery of important fractions of soil P, litter production and forest structure along the successional trajectory in young restored areas after mining. Ecological restoration proved to be able to quickly restore important soil properties, showing the potential of ecological restoration approach to mitigate the negative environmental impacts of mining. Thus, it is emphasized that public policies to mitigate environmental damage caused by mining may require higher levels of environmental quality in mining recovery areas, protecting the collective interests involved in the mediation of interests between business and society.

Reclamation has been required since the mid-1970s in Florida and many other states that mine land for phosphate. While often controversial, land reclamation has involved a variety of technologies and regulations which often reflect the complexity of economical ecological and political forces involved in the decision-making process. Most often reclamation procedures are dictated by economic constraints and less often by environmental concerns. In 1982, Borden, inc. donated a 6.040 7 acre abandoned phosphate mine, located within Polk County In Central Florida, to the State of Florida. In 1989, the site was designated by the State of Florida as a state recreation area known today as Tenoroc State Recreation Area. The Area currently provides facilities for hiking, picnicking, and horseback riding with a particular emphasis on quality fishing within its manmade lakes. lt is the intent of the state to integrate land reclamation functions with the recreational potentials of the site thus providing a public use area that will generate support revenue (Scruggs 1992). The primary difference between the reclamation activities at Tenoroc and those reclamation activities of today is the lack of a conceptual plan. For the most part reclamation at Tenoroc has been planned as stand-alone projects with minimal foresight of the needs for future recreational uses, drainage patterns, or continuing reclamation activities. At this point a conceptual master plan is needed to integrate hydrological and land reclamation functions with the recreational potentials of the site into a framework for future management and development of Tenoroc. The goals and objectives of this study are as follows 1 To produce a plan for the restoration of Tenoroc State Recreation Area which will address the reclamation of natural systems with an emphasis on wildlife habitat and landscape diversity. 2 To provide for safety and recreation of visitors and staff, and 3. To develop a plan for a unique, educational and recreational experience that will fulfill the objectives of the Florida Department of Natural Resources. The process of reclamation starts the moment man begins to explore the earth for its minerals. Since mining is here to stay reclamation should be looked upon as a continuation of succession of the landscape, rather than repair of a damaged landscape. By approaching reclamation holistically, as just another step in the mining process; through proper planning, management and program, the strife for achieving a balance between our quality of life and our sustainability become that much more of a reality.<br>Master of Landscape Architecture

Coal mining has had profound impacts in the Appalachian region, initiating a need to understand the implications of traditional and current reclamation practices on wildlife. I evaluated wildlife use of reclaimed sites of varying ages and cover types in southwestern Virginia. I compared reclaimed sites to another form of anthropogenic disturbance (clearcut) and relatively undisturbed mature forest. Birds were surveyed during early mornings throughout the breeding season in 2007 and 2008 using the point count method. Amphibians were surveyed using artificial cover, constrained-time night searches, and auditory pond surveys. Microhabitat data were collected at each sampling point and were combined with landscape-level GIS information to relate habitat characteristics and wildlife patterns. <p>I observed 80 bird species using reclaimed areas, clearcuts, and mature forest. Pre-regulation sites (prior to the Surface Mining Control and Reclamation Act of 1977) supported the highest number of species overall. Cluster analysis identified 4 bird associations based on habitat characteristics. I developed site-specific, landscape-level, and mixed-scale logistic regression models to identify habitat characteristics that best predicted the presence of 27 species. For 18 species, mixed-scale models performed best, suggesting the importance of a multi-scale approach to habitat analysis. <p>Salamanders were generally not detected on reclaimed areas, possibly due to the lack of soil moisture, leaf litter, and woody debris on young sites. Frogs were present in all water bodies surveyed, suggesting the importance of managing ponds and wetlands on reclaimed sites. Identifying and focusing on important habitat characteristics will help managers enhance post-mining land for wildlife.<br>Master of Science

Coal surface-mining is often implicated for its negative impacts on native flora and fauna. However, some studies suggest that, in reclaiming land after mining, there may be potential to create early successional habitat needed by many avian species currently in decline throughout eastern North America. I evaluated nest-site selection and nest success for on reclaimed mine lands in southwest Virginia during the summers of 2010 and 2011. For this nest-site analysis, I focused on 2 bird species common to reclaimed mine lands in southwest Virginia: field sparrows (Spizella pusillia) and indigo buntings (Passerina cyanea). In addition, I assessed bird community attributes in relation to various surface-mine reclamation regimens over a 5-year period from 2007-2011. For both species, I found estimates of daily nest success to be higher than other estimates reported in the literature; however, empirical estimates of adult and juvenile survival are needed to provide better estimates of population status. For field sparrows, models of avian nest success support the hypothesis that a tradeoff exists between nest concealment and a view of the surroundings for field sparrows. For indigo buntings, year explained the most variation in nest success, with much lower estimates of daily nest survival in 2010, possibly as a result of increased precipitation. I also assessed avian community dynamics in relation to vegetation changes on reclaimed mine sites and observed a total of 96 species throughout the 4 years of sampling. Local species persistence and species turnover were comparable to another continental scale study conducted using breeding bird survey (BBS) data. Observed changes in community vital rates were likely a result of changes in certain habitat attributes over the 5-year period. Lastly, seven species were unique to certain cover types, suggesting the need to consider landscape level processes when developing restoration guidelines for reclaimed coal surface-mines.<br>Master of Science

Coal surface-mining is often implicated for its negative impacts on native flora and fauna. However, some studies suggest that, in reclaiming land after mining, there may be potential to create early successional habitat needed by many avian species currently in decline throughout eastern North America. I evaluated nest-site selection and nest success for on reclaimed mine lands in southwest Virginia during the summers of 2010 and 2011. For this nest-site analysis, I focused on 2 bird species common to reclaimed mine lands in southwest Virginia: field sparrows (Spizella pusillia) and indigo buntings (Passerina cyanea). In addition, I assessed bird community attributes in relation to various surface-mine reclamation regimens over a 5-year period from 2007-2011. For both species, I found estimates of daily nest success to be higher than other estimates reported in the literature; however, empirical estimates of adult and juvenile survival are needed to provide better estimates of population status. For field sparrows, models of avian nest success support the hypothesis that a tradeoff exists between nest concealment and a view of the surroundings for field sparrows. For indigo buntings, year explained the most variation in nest success, with much lower estimates of daily nest survival in 2010, possibly as a result of increased precipitation. I also assessed avian community dynamics in relation to vegetation changes on reclaimed mine sites and observed a total of 96 species throughout the 4 years of sampling. Local species persistence and species turnover were comparable to another continental scale study conducted using breeding bird survey (BBS) data. Observed changes in community vital rates were likely a result of changes in certain habitat attributes over the 5-year period. Lastly, seven species were unique to certain cover types, suggesting the need to consider landscape level processes when developing restoration guidelines for reclaimed coal surface-mines.<br>Master of Science

Mining has caused ecosystem losses worldwide, with surface mining disturbing >2.4 million hectares in the United States since 1930. The Appalachian region of the US is home to extensive temperate deciduous forests that provide many ecosystem services and economic benefits. However, >400,000 hectares of forest have been lost due to surface coal mining, with most not being restored back to native forests or other productive land uses. These areas are left fragmented, heavily modified, unmanaged, and densely invaded by non-native plants. Autumn olive (Elaeagnus umbellata) is one of the most prevalent invasive species on reclaimed mines in Appalachia and viewed as one of the main hindrances to the successful reclamation of mined land to restore native forests. In order to better assess the impact autumn olive can have on reclamation success, we characterize autumn olive's performance in various reclamation scenarios and also how the management of autumn olive affects hardwood tree establishment. We review how exotic species impact restoration outcomes, and advocate for a better understanding of how these species could contribute towards a more ecological understanding of reclamation. Reclamation goals are currently assessed after 5 years, prioritizing short-term goals (e.g. erosion control) instead of longer-term goals such as the return of ecosystem function. With a better understanding of plant function and ecological processes, we hope to continue to advance successful reclamation on surface mined lands.<br>Master of Science in Life Sciences

Approaching the ecological rehabilitation of an open-cast phosphate mine in the West Coast of South Africa during the post-operational phase presented some challenges. The area was extensively modified during the mining operations. Soils from different layers were mixed with topsoil being covered by subsoil, overburden dumps and tailing dams being constructed resulting in extensive cross-zoned soils. Large areas of subsoil areas were exposed on the mine floor with localized and small scale salinity being evident. The modified topography as well as the complex new surface material posed a challenge in terms of identifying suitable local species that could be used to rehabilitate the post-mining environment. The mine area was heavily infested with woody alien invasive plants, such as Acacia cyclops, established in an attempt to reduce the dust and little natural vegetation cover was present. In the arid west coast environment, the four-month-long winter growing season is followed by hot and windy dry summers (Chapter 2) presenting a challenge reestablishing local vegetation in modified soils. Moreover, little was known about the local vegetation in terms of their propagation and use in stabilization techniques as an alternative to exotic vegetation such as the A. cyclops, which had been more often used in revegetation projects. A study was conducted to determine the most efficient and cost-effective methods of vegetative rehabilitation of the Chemfos site (Chapter 1). A review of the literature available at the time as well as approaches that were successfully implemented in other Western Cape rehabilitation projects such as the Du Toitskloof Pass and the Sishen–Saldanha railway line (Chapter 3), were considered. Previous studies on the west coast dunes at Blaauwberg had shown using Marram grass as a dune stabilizer was most successful. Marram grass was tested in trials alongside local grasses, such as Chaetobromus dregeanus and Ehrharta villosa, that showed potential but had not been formally evaluated. The environmental context of Chemfos (Chapter 2) as well as the Conceptual Rehabilitation Plan that considered the modified environment, soils and closure objectives of the mine, were reviewed to determine the most pressing rehabilitationrelated questions that required answers. This led to the final experimental design that was implemented mid-winter in 1996 (Chapter 5). The trials were implemented in the areas perceived to be the most difficult to rehabilitate, namely the mobile sands in the tailings dam and the exposed subsoil or mine floor areas. The use of brushwood together with specific plants and seeds appropriate for the use in either sandy soil or subsoil were evaluated in a variety of combinations and application densities to determine the most effective treatment combination at the minimum effective density. The best initial cover of the tailings dam were recorded in the Ammophila arenaria trials but the use of the local grass species Ehrharta villosa, performed better from year two onwards and was much cheaper to establish. On the subsoil, the trials where a cover of topsoil was used performed better than the combination trials. This indicated that topsoil placement on post-operational phase shaped subsoils during the mining operation to be the most desirable treatment. Initial results of the trials were used as a basis for developing the rehabilitation techniques that were rolled out across the Chemfos landscape. The approaches were refined as indications of trial responses became evident. Lessons learned were incorporated in the adaptive management approach that was followed and the rehabilitation techniques (Chapter 6) were continually re-evaluated and adjusted. This resulted in a significant step towards achieving the overall research objective of finding cost-effective approaches to rehabilitation. Components such as refinement of the seed collection and processing techniques (Chapter 7) where the post-harvest processing cost was significantly reduced by introducing specially designed drying racks. Processing techniques were adjusted to suit the different species, and a variety of mechanical processing options were explored. The scale of the Chemfos project led to the development of new techniques of manufacturing a smoke-derived germination stimulant (Chapter 8) since commercial availability of these products was very limited. The development of FireGrow assisted in the overall aim of reducing cost by increasing germination of seed in the rehabilitation sites using a very cost-effective smoke concentrate. Socio-economical aspects were considered during the implementation as well as the post-closure phases of the rehabilitation and BHPBilliton invested through the agency of the SAMANCOR Trust. This led to the development of livelihoods of the staff that remained in the area and that lived in the mine village. The demography of the population has changed over time in the Green Village as well as the skills that the inhabitants have developed. Thus, the new economic opportunities that were pursued have brought a new lease on life beyond the lifespan of the mine (Chapter 9) once the closure certificate had been issued.

[Truncated abstract] Establishment of vegetation and ecosystem functioning is central to the mitigation of environmental impacts associated with mining operations. This study investigated the ecophysiological functioning of mature plants in natural vegetation and applied this knowledge to diagnose problems affecting plant health and causes of poor plant cover at a mine-rehabilitation site. Ecophysiological parameters, including plant water relations and mineral nutrition, were studied in conjunction with soil physical, hydraulic and chemical properties. The natural ecosystem at the study location in the Great Sandy Desert is characterised by sand dunes and interdunes with distinct plant communities on each. One of the most notable features of the vegetation is the presence of large Corymbia chippendalei trees high on the dunes and relatively small scattered shrubs in the interdunes. Triodia grasses (spinifex), dominate the vegetation in both habitats but different species occur in each; T. schinzii is restricted entirely to the dunes, and T. basedowii occurs only in the interdunes. It was hypothesised that the deep sandy dunes afford greater water availability but lower nutrient supply to plants in this habitat compared with those occurring in the lower landscape position of the interdunes. Water-relations parameters (leaf water potentials, stomatal conductance, d13C) revealed that dune plants, particularly woody species, displayed higher water status and water use than closely related and often congeneric plants in the interdunes. Nutrient concentrations in soils were significantly higher in the interdunes, but concentrations in foliage were similar for related species between habitats. It is concluded that the dunes provide a greater store of accessible water than the soil profile in the interdunes. ... Following an experimental wetting pulse equivalent to a summer cyclone event, A. ancistrocarpa plants displayed significant increases in stomatal conductance, leaf water potential and sap velocity in lateral roots within three days of irrigation at the natural site and two days at the rehabilitation site. Secondary sinker roots originating from distal sections of lateral roots were evidently supplying water to maintain hydraulic function in laterals, thus enabling a fast pulse response. This was accentuated at the rehabilitation site where roots were confined closer to the surface. These results indicate that plants at the rehabilitation site are more dependent on small pulses of water and have less access to deep reserves than plants at the natural site. It is concluded that high runoff losses and insufficient soil depth are major factors contributing to plant water stress, and combined with the direct impacts of erosion, are largely responsible for plant death and ultimately poor plant cover. These issues can be alleviated if cover soil depth is increased to more than 0.5 m and slope angles are reduced to <12o. This study demonstrates the value of an ecophysiological approach for diagnosing problems affecting plant establishment at mine-rehabilitation sites. Furthermore, it has provided recommendations that will improve the rehabilitation strategy and lead to the development of a well vegetated, resilient ecosystem on a stable and non-polluting land form.

Thesis (MScConsEcol(Conservation Ecology and Entomology)--University of Stellenbosch, 2006.<br>Anglo American Corporation’s Namakwa Sands heavy minerals mining and beneficiation operation has been strip-mining a heavy mineral deposit, rich in the commercially valuable minerals ilmenite, rutile and zircon, since September 1994. The mine is located in the vicinity of Brand-se-Baai on the west coast of South Africa, approximately 385 km north of Cape Town. Strip-mining causes total destruction of natural ecosystems through the removal of vegetation and soil in the area where mining is being undertaken. Namakwa Sands has been rehabilitating mined out areas as the mining front moves forward. Due to the difficulty of rehabilitating mined out areas as a result of harsh environmental factors, Namakwa Sands has initiated various research projects to gain an understanding of the baseline conditions and ecosystem function in order to increase plant cover and biodiversity on post-mined areas. This on-going research and the development of rehabilitation and mining techniques have resulted in the implementation of four rehabilitation techniques varying in investment of topsoil replacement, seeding and plant translocation. This study assesses the success and effectiveness of these techniques in terms of various vegetation and soil parameters. In addition, those parameters that are considered useful for monitoring are identified. This study indicated that topsoil replacement and plant translocation facilitate the return of similarity, species richness, species diversity and vegetation cover to post-mined areas. The rehabilitation site that had the greatest amount of biological input (topsoil replacement and plant translocation) appeared to be the most successful technique in facilitating vegetation recovery similar to reference sites. In comparison, the site that had the least amount of biological input performed the worst and requires adaptive management, e.g. reseeding and / or plant translocation. Namakwa Sands should continue to replace topsoil in all future rehabilitation efforts and, when possible (e.g. after sufficient winter rain), continue to translocate species in multi-species clumps. In terms of species selected for translocation, Othonna cylindrica, Ruschia versicolor and Lampranthus suavissimus should be considered for future large-scale translocation projects. Zygophyllum morgsana appears to be more difficult to re-establish under the current climatic conditions (below average rainfall). The long-term viability of rehabilitated Z. morgsana populations needs to be determined before considering this species for any future large-scale translocation purposes. No translocated Asparagus spp. individuals survived and should therefore not be considered for any further translocation purposes. The grass Ehrharta calycina, which is dominant in the site seeded, should continue to be considered for future seeding. Species and functional diversity appear to be the most limiting factors within all the rehabilitation sites and Namakwa Sands will not be able to meet their long-term objective of small-stock farming if diversity and the number of palatable species do not increase significantly. Adaptive management should seriously be considered in order to speed up this process. Alternatively, an appropriate grazing strategy, which is related to the Tetragonia fruticosa dominated vegetation within rehabilitation sites, would need to be determined and adopted.More time is needed to ameliorate the rehabilitated soil profiles to the same level as in reference sites, especially with regard to carbon, pH and sodium levels. In order to increase organic matter within rehabilitation areas, Namakwa Sands should consider creating clumps with cleared vegetation from the mining front. Since the long-term rehabilitation goal has not been achieved, Namakwa Sands will need to continue to monitor plant and soil changes until it has been achieved. The objectives of the current rehabilitation programme are limited and Namakwa Sands should develop additional objectives relating to the structure and function of the natural vegetation. This will give a better indication of whether rehabilitation sites are progressing towards the desired end point and if adaptive management is required. In addition, the current monitoring programme (vegetation survey) implemented at Namakwa Sands could be improved by increasing the vegetation parameters to be monitored. It is recommended that the following vegetation parameters be monitored as part of the long-term monitoring programme: species composition and similarity, species richness, species diversity, vegetation cover, species dominance, vertical structure and functional diversity of the vegetation (clumps and inter-clumps). It is also recommended that carbon, pH and sodium of soil profiles be monitored as part of the long-term monitoring programme. These parameters should not be seen as exhaustive as this study only considered various vegetation parameters and soil chemistry between rehabilitation and reference sites. The results of other studies on the fauna, mycorrhiza, insects, etc. should also be taken into consideration and the monitoring parameters expanded accordingly.

[Truncated abstract. Please see the pdf format for the complete text. Also, formulae and special characters can only be approximated here. Please see the pdf version for an accurate reproduction.] This thesis examines the water use, ecophysiology and hydraulic architecture of Eucalyptus marginata (jarrah) growing on bauxite mine rehabilitation sites in the jarrah forest of south-western Australia. The principal objective was to characterise the key environment and plant-based influences on tree water use, and to better understand the dynamics of water use over a range of spatial and temporal scales in this drought-prone ecosystem. A novel sap flow measurement system (based on the use of the heat pulse method) was developed so that a large number of trees could be monitored concurrently in the field. A validation experiment using potted jarrah saplings showed that rates of sap flow (transpiration) obtained using this system agreed with those obtained gravimetrically. Notably, diurnal patterns of transpiration were measured accurately and with precision using the newly developed heat ratio method. Field studies showed that water stress and water use by jarrah saplings on rehabilitation sites were strongly seasonal: being greatest in summer when it was warm and dry, and least in winter when it was cool and wet. At different times, water use was influenced by soil water availability, vapour pressure deficit (VPD) and plant hydraulic conductance. In some areas, there was evidence of a rapid decline in transpiration in response to dry soil conditions. At the end of summer, most saplings on rehabilitation sites were not water stressed, whereas water status in the forest was poor for small saplings but improved with increasing size. It has been recognised that mature jarrah trees avoid drought by having deep root systems, however, it appears that saplings on rehabilitation sites may have not yet developed functional deep roots, and as such, they may be heavily reliant on moisture stored in surface soil horizons. Simple predictive models of tree water use revealed that stand water use was 74 % of annual rainfall at a high density (leaf area index, LAI = 3.1), high rainfall (1200 mm yr-1) site, and 12 % of rainfall at a low density (LAI = 0.4), low rainfall (600 mm yr-1) site, and that water use increased with stand growth. A controlled field experiment confirmed that: (1) sapling transpiration was restricted as root-zone water availability declined, irrespective of VPD; (2) transpiration was correlated with VPD when water was abundant; and (3) transpiration was limited by soil-to-leaf hydraulic conductance when water was abundant and VPD was high (> 2 kPa). Specifically, transpiration was regulated by stomatal conductance. Large stomatal apertures could sustain high transpiration rates, but stomata were sensitive to hydraulic perturbations caused by soil water deficits and/or high evaporative demand. No other physiological mechanisms conferred immediate resistance to drought. Empirical observations were agreeably linked with a current theory suggesting that stomata regulate transpiration and plant water potential in order to prevent hydraulic dysfunction following a reduction in soil-to-leaf hydraulic conductance. Moreover, it was clear that plant hydraulic capacity determined the pattern and extent of stomatal regulation. Differences in hydraulic capacity across a gradient in water availability were a reflection of differences in root-to-leaf hydraulic conductance, and were possibly related to differences in xylem structure. Saplings on rehabilitation sites had greater hydraulic conductance (by 50 %) and greater leaf-specific rates of transpiration at the high rainfall site (1.5 kg m-2 day1) than at the low rainfall site (0.8 kg m-2 day1) under near optimal conditions. Also, rehabilitation-grown saplings had significantly greater leaf area, leaf area to sapwood area ratios and hydraulic conductance (by 30-50 %) compared to forest-grown saplings, a strong indication that soils in rehabilitation sites contained more water than soils in the forest. Results suggested that: (1) the hydraulic structure and function of saplings growing under the same climatic conditions was determined by soil water availability; (2) drought reduced stomatal conductance and transpiration by reducing whole-tree hydraulic conductance; and (3) saplings growing on open rehabilitation sites utilised more abundant water, light and nutrients than saplings growing in the forest understorey. These findings support a paradigm that trees evolve hydraulic equipment and physiological characteristics suited to the most efficient use of water from a particular spatial and temporal niche in the soil environment.

by Tsang Po-yan.<br>Thesis (M.Phil.)--Chinese University of Hong Kong, 1997.<br>Includes bibliographical references (leaves 173-191).<br>Abstract --- p.i<br>Acknowledgements --- p.iii<br>List of Tables --- p.iv<br>List of Figures --- p.v<br>List of Plates --- p.vi<br>List of Appendices --- p.vii<br>Chapter CHAPTER 1 --- INTRODUCTION<br>Introduction --- p.1<br>Chapter 1.2 --- Conceptual framework --- p.3<br>Chapter 1.3 --- Objectives --- p.15<br>Chapter 1.4 --- Significance and scope of study --- p.17<br>Chapter 1.5 --- Organization of the thesis --- p.18<br>Chapter CHAPTER 2 --- STUDY AREA<br>Chapter 2.1 --- Location --- p.20<br>Chapter 2.2 --- Climate --- p.23<br>Chapter 2.3 --- Geology --- p.25<br>Chapter 2.4 --- Soils --- p.26<br>Chapter 2.5 --- Vegetation --- p.27<br>Chapter 2.6 --- Restoration and floristic composition of the rehabilitated communities --- p.29<br>Chapter 2.7 --- Post-planting maintenance of the rehabilitated communities --- p.31<br>Chapter CHAPTER 3 --- RESTORATION OF SOIL CHEMICAL PROPERTIES<br>Chapter 3.1 --- Introduction --- p.33<br>Chapter 3.2 --- Methodology --- p.37<br>Chapter 3.2.1 --- Sampling --- p.37<br>Chapter 3.2.2 --- Soil reaction --- p.37<br>Chapter 3.2.3 --- Organic carbon --- p.37<br>Chapter 3.2.4 --- Total Kjeldahl nitrogen (TKN) --- p.38<br>Chapter 3.2.5 --- Mineral nitrogen (ammonium and nitrate nitrogen) --- p.38<br>Chapter 3.2.6 --- Total phosphorus --- p.39<br>Chapter 3.2.7 --- Available phosphorus --- p.39<br>Chapter 3.2.8 --- Exchangeable cations --- p.39<br>Chapter 3.2.9 --- Exchangeable A1 and H --- p.40<br>Chapter 3.2.10 --- Carbon : nitrogen ratio --- p.40<br>Chapter 3.3 --- Statistical analysis --- p.40<br>Chapter 3.4 --- Results --- p.41<br>Chapter 3.4.1 --- Chemical properties of the newly excavated soil --- p.41<br>Chapter 3.4.2 --- Effect of rehabilitated communities on soil chemical properties --- p.42<br>Chapter 3.4.2.1 --- Soil reaction and exchangeable acidity --- p.42<br>Chapter 3.4.2.2 --- Organic matter and C:N ratio --- p.43<br>Chapter 3.4.2.3 --- Total Kjeldahl N and mineral N --- p.43<br>Chapter 3.4.2.4 --- Total and available phosphorus --- p.44<br>Chapter 3.4.2.5 --- Nutrient cations --- p.44<br>Chapter 3.4.3 --- Intra-layer differences of soil properties --- p.44<br>Chapter 3.5 --- Discussion --- p.46<br>Chapter 3.5.1 --- Properties of granitic soils awaiting restoration --- p.46<br>Chapter 3.5.2 --- Effect of rehabilitated communities on soil acidity --- p.49<br>Chapter 3.5.3 --- "Effect of rehabilitated communities on SOM, N and P" --- p.51<br>Chapter 3.5.4 --- Changes in cation nutrients after rehabilitation --- p.57<br>Chapter 3.5.5 --- Comparison of ecosystem rehabilitation with other studies --- p.60<br>Chapter 3.6 --- Conclusion --- p.66<br>Chapter CHAPTER 4 --- NITROGEN MINERALIZATION<br>Chapter 4.1 --- Introduction --- p.68<br>Chapter 4.2 --- Methodology --- p.73<br>Chapter 4.2.1 --- In situ incubation --- p.73<br>Chapter 4.2.2 --- "Determination of N mineralization, uptake and leaching" --- p.75<br>Chapter 4.3 --- Statistical analysis --- p.76<br>Chapter 4.4 --- Results --- p.76<br>Chapter 4.4.1 --- Temporal variations of NH4-N and N03-N in the rehabilitated sites --- p.76<br>Chapter 4.4.2 --- "Net ammonification, nitrification and N mineralization in the rehabilitated sites" --- p.78<br>Chapter 4.4.3 --- Uptake of mineral N in the rehabilitated sites --- p.80<br>Chapter 4.4.4 --- Leaching loss of mineral N in the rehabilitated sites --- p.82<br>Chapter 4.5 --- Discussion --- p.84<br>Chapter 4.5.1 --- Nitrogen mineralization in the rehabilitated sites --- p.84<br>Chapter 4.5.2 --- Uptake of mineral nitrogen in the newly rehabilitated sites --- p.92<br>Chapter 4.5.3 --- Leaching loss of and mechanisms to conserve mineral nitrogen in newly rehabilitated sites --- p.96<br>Chapter 4.6 --- Conclusion --- p.98<br>Chapter CHAPTER 5 --- SOIL RESPIRATION IN NEWLY REHABILITATED BORROW AREA<br>Chapter 5.1 --- Introduction --- p.100<br>Chapter 5.2 --- Methodology --- p.105<br>Chapter 5.3 --- Statistical analysis --- p.107<br>Chapter 5.4 --- Results --- p.107<br>Chapter 5.5 --- Discussion --- p.109<br>Chapter 5.5.1 --- Inherent microbial activities of the newly excavated soil --- p.109<br>Chapter 5.5.2 --- Effects of young plantations on soil respiration --- p.110<br>Chapter 5.5.3 --- Comparison of soil respiration between the rehabilitated sites and secondary Pinus massoniana woodland --- p.114<br>Chapter 5.6 --- Conclusion --- p.116<br>Chapter CHAPTER 6 --- GROWTH PERFORMANCE AND FOLIAR COMPOSITION OF REHABILITATED VEGETATION<br>Chapter 6.1 --- Introduction --- p.118<br>Chapter 6.2 --- Methodology --- p.122<br>Chapter 6.2.1 --- Growth performance measurements --- p.122<br>Chapter 6.2.2 --- Chemical analysis --- p.123<br>Chapter 6.3 --- Statistical analysis --- p.124<br>Chapter 6.4 --- Results --- p.124<br>Chapter 6.4.1 --- Growth measurements --- p.124<br>Chapter 6.4.1.1 --- Height --- p.124<br>Chapter 6.4.1.2 --- Stem basal diameter (SBD) --- p.127<br>Chapter 6.4.1.3 --- Crown coverage --- p.130<br>Chapter 6.4.2 --- Foliar nutrient composition of rehabilitated vegetation --- p.133<br>Chapter 6.4.2.1 --- Total Kjeldahl nitrogen --- p.133<br>Chapter 6.4.2.2 --- Total phosphorus --- p.134<br>Chapter 6.4.2.3 --- Potassium --- p.136<br>Chapter 6.4.2.4 --- Sodium --- p.137<br>Chapter 6.4.2.5 --- Calcium --- p.138<br>Chapter 6.4.2.6 --- Magnesium --- p.140<br>Chapter 6.4.3 --- Element abundance among the rehabilitated species --- p.142<br>Chapter 6.5 --- Discussion --- p.142<br>Chapter 6.5.1 --- Species growth in the rehabilitated sites --- p.142<br>Chapter 6.5.2 --- Role of nitrogen fixers in rehabilitating the borrow area --- p.144<br>Chapter 6.5.3 --- Species selection in ecosystem restoration --- p.150<br>Chapter 6.6 --- Conclusion --- p.154<br>Chapter CHAPTER 7 --- CONCLUSION<br>Chapter 7.1 --- Summary of findings --- p.156<br>Chapter 7.2 --- Implications of the study --- p.161<br>Chapter 7.2.1 --- Ecosystem restoration strategy in Hong Kong --- p.161<br>Chapter 7.2.2 --- Can native species establish on degraded land? --- p.164<br>Chapter 7.2.3 --- Are the present findings transferable to other areas? --- p.167<br>Chapter 7.3 --- Limitations of the study --- p.169<br>Chapter 7.4 --- Suggestion for future studies --- p.171<br>REFERENCES --- p.173<br>APPENDICES --- p.192

Thesis (M.Sc.)--University of Alberta, 2010.<br>Title from PDF file main screen (viewed on Apr. 23, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science, Department of Renewable Resources, University of Alberta. Includes bibliographical references.

Soil erosion as a result of extensive overgrazing and the subsequent reduction in vegetation cover is seriously affecting the long term ecological and economic sustainability of the grazing industry. Where this occurs on saline-sodic soils, the loss of the Ai horizon and consequent exposure of the silty A2 horizon, results in the creation of an impervious crust over the clayey B horizon. The resultant scald is an extremely hostile environment for plants. Currently 10%, or the semi-arid rangelands of western NSW is affected by scalding. A lack of water in the soil profile is the primary factor restricting plant reestablishment on scalds. Although the A2 is thin, it reduces infiltration rates dramatically, so that water is quickly lost from the scald surface by runoff and evaporation. Waterponding, whereby U-shaped banks are formed on the scald surface to create shallow ponds approximately 0.5ha in area, is arguably the most effective method of scald reclamation. These ponds trap rain, allowing greater opportunity for infiltration and thus leaching of salts from the upper soil profile. The leaching reduces the structural stability of the upper soil profile and encourages shrink-swell processes to occur, with the subsequent formation of cracks. These cracks enable water to by pass the crust, thereby improving the water availability and likelihood of reestablishment of vegetation on the pond. This study was undertaken to investigate the role of spatial and temporal factors on the above soil processes and vegetation characteristics. The study area, covering approximately 1 800 km^, is located on the Bogan River/Marra Creek/Macquarie River flood plain, approximately 100 km north of Nyngan, NSW. Between September 1995 and March 1996, soil and vegetation data were collected at 9 sites from both ponds and their adjacent scalds. The ponds range in age from 6 months to 31 years. Changes in soil and vegetation properties after these different periods of waterponding were measured. The success of reclamation was assessed in terms of vegetation and soil response to ponding.

Land degradation has been a global agenda. It has been affecting both developed and developing nations (including Ethiopia). The overall objective of the study was to assess the impact of landscape restoration (including area closure) on the environment and farmers‘ livelihood in Hita-Borkena watershed, northeastern Ethiopia. Three Landsat images (1986, 2001 and 2015) were used to detect land cover dynamics. Laboratory analysis of selected soil physico-chemical properties were made to compare the soil properties of closed/restored and open grazing areas. Household questionnaire was administered to investigate environmental problems before and after landscape restoration, the role of area closure and different conservation measures, and the impact of the restoration on farmers‘ livelihood. A total of 255 household heads were selected randomly for the questionnaire survey. This survey was also substantiated by interviewing agricultural experts, observation and reviewing reports prepared by Kalu District Agriculture Office. Both descriptive and inferential statistics were employed to analyze quantitative data. Besides, qualitative approach was implemented in order to analyze qualitative data. The study found out that forestlands and shrublands shrunk through 1986 – 2015, grasslands expanded mainly due to the implementation of area closure under MERET project since 2001. The study revealed that better organic matter, total nitrogen, clay and silt contents, CEC and total porosity were recorded under area closure than under open grazing land. However, both available P and K were found minimum under the former land use type. This may be due to the reason that such nutrients exist more in unavailable form or it may be because of the fact that large amount of those nutrients are extracted by the restored vegetation. The study showed that rates of soil erosion, overgrazing and illegal cutting of trees were relatively higher before landscape restoration. The respondents also appreciated the positive role of land restoration in improving the fertility of the soils of the study watershed and then the positive impact to their livelihood. Based on the results of the study, it is recommended that similar restoration activities shall be implemented in similar environments in Ethiopia to improve both the environment and farmers‘ livelihood<br>Geography<br>Ph. D. (Geography)

This thesis brings new information about development of five chosen snad-pits in CHKO Třeboňsko. It represents future state of this sand-pits with different rate of near ? natural restoration used during the reclamation. The results are accompanied by comparison of surface temperature of each category of land cover.

The new science of restoration ecology offers those who work towards ecological restoration an evaluative framework for measuring success. This research project considers the restoration work carried out on four mined sites in the Box and Ironbark Forest Ecosystem of North Central Victoria. To measure success, vegetation cover and height, along with thirteen environmental variables and three site characteristics, were recorded in four mine sites and compared to nearby forest controls. It was found that mined sites had fewer native species than the control sites, and soil fertility and litter cover were less. Five floristic communities were described from the mined areas and controls, two of which are restricted to mined areas. Global Non-parametric Multi Dimensional Scaling of the vegetation data and vector fitting of the environmental and site variables also showed that strong floristic differences exist between mined and control areas at most sites. As restoration attempts were similar at each site, ecosystem resilience was considered as the main contributing factor to the different degrees of success. It was found that mined areas with prolonged disturbance regimes shared less in common with their control. Weed cover was not found to be significantly different between the controls and mined areas. This study serves as baseline data for long term research and recommends that clear goals and objectives need to be implemented in determining successful mine site restoration in the Box and Ironbark Ecosystem.

The aim of this thesis is detailed description of solved reclamation in the selected location Cep II after gravel extraction. The part of thesis solves property settlements on the parcels concerned. The literary review outlines generally issue of mining and its impact on the landscape and ways of deal with these negative impacts. Besides the classical methods of reclamation (agricultural, forestry and hydrological reclamation) is described a method of using spontaneous restoration. There is also particularised the possibility of incorporating suitably reclaimed parcels into territorial system of ecological stability in terms of land adjustment.

M.Sc.<br>The decommissioning of mines and mining-related activities brings about the onset of rehabilitation. A legacy that most coal mines must address is the rehabilitation of the coal discard dumps that are generated by the beneficiation process of the raw coal. Rehabilitation involves the shaping and covering with a topsoil layer of these coal discard dumps. The topsoil layer is then revegetated to provide a stable form of protection against erosion. Considerations taken into account regarding the rehabilitation of coal discard dumps include the final slope angle, physical constraints i.e. railways or rivers, a source of topsoil and the grass species to be sown. Once the dump has been shaped, capped and seeded, regular applications of fertilizer take place for a defined period of time. This is to accelerate the growth of the grasses, as well as to stabilise the nutrient levels in the topsoil capping. Ingwe Mine Closure Operations (MCO), part of Ingwe Collieries Limited, is the business unit entrusted with the management and successful rehabilitation of Ingwe’s defunct operations. All of the coal discard dumps sampled in this study are found on such defunct operations. These coal discard dumps have been rehabilitated to a very high standard by MCO, and in most cases exceed the minimum requirements stipulated by law and guideline documents. This study and the results obtained from it reflect this. This study investigated, in terms of defined types of cover, whether or not there is a statistically significant difference between the: • six coal discard dumps from which data were collected; • five different defined slope aspects; • two groups of slope angles; and • slope angle and slope aspect in terms of cover. The data collected was analysed statistically, so as to determine whether significant differences (95 percentile confidence level), in terms of cover, exist. The purpose of this was to determine whether or not a preferred slope aspect or slope angle group could be identified for the six coal discard dumps sampled. By identifying a preferred slope aspect or slope angle group, companies could alter the design of operational or defunct dumps so as to maximise these. This would make the rehabilitation of the dump more sustainable and could possibly reduce aftercare costs. Through statistical analysis of the data collected it was determined that: • of the six coal discard dumps sampled, significant differences did exist between some of the dumps regarding basal cover, plant litter cover and bare ground. As each dump is different with its own specific micro-climate, this can be expected. The age of the dumps could also have played a role in terms of development; • of the five different defined slope aspects analysed, no significant differences existed between any of them; • of the two groups of slope angles analysed, no significant difference existed between them; and • no relationship between slope angle and slope aspect, in terms of cover, could be established. The analysis of the data collected was done by means of ANOVA one-way tests, coupled with Post Hoc Tests and Contrast Tables. The results of the statistical analysis were evaluated by the STATCON Department of the Rand Afrikaans University for accuracy. The data and the statistical analysis thereof were found to be satisfactory and correct. Various other statistical analyses were conducted on the data, but the results obtained from these tests were all the same as that of the original data analysis. These analyses included the Univariate Analysis of Variance, T-tests and Mann-Whitney tests.

Reclaimed oil sands landscapes are perceived to be low in plant diversity compared with naturally occurring plant communities. Approximately 66 Carex species inhabit the oil sand region. This thesis is unique and represents the first large scale study of Carex establishment on reclaimed oil sands landscapes. Research compared diversity and habitat variables between natural ecosystems and reclaimed landscapes, and examined the colonization mechanism for Carex establishment on reclaimed landscapes (i.e., ingress from adjacent natural ecosystems or emergence from the soil seed bank). Low positive associations between the presence of Carex in natural and reclaimed landscapes, and the presence of species on reclaimed landscapes not accounted for in either the forest or edge plots, suggests Carex established from the soil seed bank and less so from natural ingress. Carex share the same seed dispersal mechanisms as many plants, so the implications may apply to a broader range of plant species.