Dissertations / Theses on the topic 'Clearing of land'

[Truncated abstract] Land clearing is known to increase runoff, and in many dryland landscapes is also associated with rising saline watertables, causing increased stream salinity and degrading riparian vegetation. The limited understanding of how river morphology responds to these changes and the potential for vegetation-based strategies to offer river management options under these conditions, has prompted this research. In southwestern Australia the severity of salinity and recent nature of land clearing provides an appropriate setting to investigate river response. A data-based, multidisciplinary methodology was applied to determine how land clearing and landscape salinisation has altered landscape sensitivity through changes in erosive potential, system connectivity and material threshold mechanisms, and how these affect patterns of river response. The study investigated the responses of morphologically similar reaches across fifty two study sites in the Kent River and Dalyup River catchments, in the south coastal rivers region of Western Australia. Land clearing was found to have significantly altered the hydrologic regime and erosive potential in both frequency and magnitude, with flow becoming more perennial, and increased annual discharge, flood peaks and bankfull flow frequency. While sediment transport rates have also increased since land clearing, they remain low on a global scale. Human response to a reduced rainfall regime and related water security pressures has caused large hillslope areas to be decoupled from the main channels by bank and farm dam construction, and have reduced downstream transmission of change. ... By contrast, steeper-sloped mid-catchment areas with minimal vegetation degradation caused by salinity are associated with higher erosive potential. A more erosive response is observed in these reaches where floodplains have been cleared for agricultural purposes. A conceptual model of vegetation growth across the salinity gradient observed in the study catchments was developed, and applied to selected river styles to assess the potential that vegetation-based strategies offer for river management. This work identifies the unsuitability of river restoration strategies, but the potential for river restoration or remediation in a saline landscape. Hydraulic modelling demonstrated that river rehabilitation strategies such as improving the vegetation condition of the riparian buffer using native or commercial species on areas elevated above saline flow can stabilise reaches. For river styles in wide and flat valleys, there is limited potential for vegetation-based river rehabilitation under the current salinity gradient. Field observation and modelling suggest that river remediation may offer geomorphic management options in salt-affected reaches through channelisation to lower watertables, and further research on this is warranted. This work found a consistent response for river styles across the two study catchments. Based on the understanding of river response and the potential for vegetation-based river management for each style, this research offers a regional-scale tool for river management in a saline landscape.

This research develops eight recommendations for amendments to key Ontario legislation affecting Brownfield redevelopment that, if implemented, will reduce the liability and risk associated with the development of contaminated land and benefit stakeholders, such as, municipalities and developers. Utilizing the methodology of law and economics, this research examines the legal landscape in Ontario and expands the dialogue regarding the risks of developing contaminated land. Through this examination, this research uncovers the origins of the risks of Brownfield redevelopment and extrapolates recommendations for amendments to legislation and policy that balance the liability of Brownfield redevelopment with the protection of the environment. Recent developments in environmental law appear to increase environmental protection, but actually limit Brownfield redevelopment in Ontario by increasing liability and costs. The polluter pays principle that has been entrenched in Canadian law has governed the law in respect of contaminated lands for decades. However, as society evolves, the common law is forced to re-evaluate environmental protection in the face of contaminated lands. This evolution of the law is an attempt to intervene to correct a market failure that exists with respect to contaminated lands. The increased liability associated with Brownfield redevelopment translates into heightened costs to redevelop the land, which also severely threatens environmental justice in Ontario. The recommendations in this research will benefit stakeholders, the public, and the environment. With respect to stakeholders, it will be of assistance to municipalities, cities, developers, corporations, secured lenders, mortgage insurers and the government. The risks associated with Brownfield redevelopment can be offset by the recommended corrections to legislation regarding liability and stronger policies that create accessible programs and incentives to promote just, innovative, and sustainable redevelopment.

Terrestrial catchments adjacent to the Great Barrier Reef have undergone extensive anthropogenic modification over the last 150 years, including substantial land clearing and land use change. From 1996 to 2006, rates of land clearing in Queensland were among the highest in the world. More than 60% of this clearing occurred within the Brigalow Belt bioregion, which includes 98% of the Fitzroy Basin and 46% of the Burdekin Basin, both of which drain directly into the Great Barrier Reef lagoon. This land clearing and land use change has led to increased pollutant loads of nutrients, sediment and pesticides entering the Great Barrier Reef, which adversely impact the survival of this precious ecosystem. Agricultural land use is currently the largest contributor to pollutant loads. The effects of land clearing and land use change on runoff in the Brigalow Belt bioregion are well documented. Long-term research has shown clearing of virgin brigalow scrub for cropping or grazed pasture has doubled runoff irrespective of land use. Peak runoff rates doubled when land was cleared for cropping and increased by 50% when cleared for grazed pasture. The short-term effects of land clearing and land use change on land resources such as soil fertility were also documented, but the long-term implications were not. It was unclear how these changes in hydrology and soil fertility as a result of land clearing and land use change impacted water quality. Contemporary water quality investigations seeking to address this question are confounded by multiple issues. For example, climatic variability in central Queensland is large, so long-term monitoring is essential to develop true systems understanding. Short-term, three-to-five-year monitoring programs often fail to capture extremes in climate, so findings may not translate temporally. Broad-scale land clearing in the Brigalow Belt bioregion of central Queensland commenced in the 1960s and was generally considered to have ceased in 2006. As such, contemporary water quality data sets, while reflective of current catchment condition, likely provide little insight into the magnitude of change in water quality immediately post clearing due to multi-decadal lags between clearing and monitoring. Larger catchment scale water quality studies can be further confounded by mixed land use within a catchment and mixed land management within a single land use. Both scenarios make it difficult to separate land use effects on water quality from land management effects on water quality, with one likely to mask the effects of the other. When broad-scale land clearing in the Brigalow Belt bioregion of central Queensland commenced in the 1960s, changes in hydrology and soil fertility were anticipated. In order to determine the effects of this land clearing and land use change on hydrology, soil fertility and productivity, the Brigalow Catchment Study was initiated in 1965. The subsequent data collected from this long-term paired, calibrated catchment study provided an opportunity to determine the impacts of land clearing and land use change on water quality. The use of long-term data from paired catchments of a single land use, that have been monitored for hydrological and soil fertility change since prior to clearing, resolves many of the confounding factors common to contemporary water quality studies. This study of the effects of land clearing and land use change on water quality had four objectives as follows: 1) To determine the impact of changing land use from virgin brigalow scrub into a crop or pasture system on runoff water quality; 2) To evaluate whether clearing of brigalow scrub for cropping or grazing would alter the dynamics of soil organic carbon, nitrogen, phosphorus, sulfur and potassium over time; 3) To determine the impact on water quality of managing grazing land by varying stocking rate; and 4) To determine the impact of managing grazing land with tebuthiuron, a herbicide used for broad-scale woody weed control in grazing systems, on water quality. All four of these objectives were priority knowledge gaps of the Reef 2050 Water Quality Improvement Plan 2017-2022, the 2017 Scientific Consensus Statement and their predecessors. Long-term water quality modelling indicated that changing land use from virgin brigalow scrub to cropping or grazing increased loads of total suspended solids, total and dissolved inorganic phosphorus, and ammonium nitrogen. The well-managed (unfertilised) pasture system had less nitrogen in runoff compared to runoff from virgin brigalow scrub. In years when runoff occurred from the agricultural catchments, but no runoff occurred from the virgin brigalow scrub, water quality loads were entirely anthropogenic and totally attributable to land use change. These changes in water quality were modelled by extrapolating data collected at least 17 years after land clearing and land use change. During this 17-year period, significant nutrient fluxes occurred within the surface 0.1 m of the soil profile associated with clearing, burning and subsequent agricultural production. These fluxes, in particular the nine-fold increase in ammonium-nitrogen, the eight-fold increase in nitrate-nitrogen and the two to three-fold increase in bicarbonate- and acid-extractable phosphorus immediately after clearing likely resulted in extremes in water quality loads and pollutant concentrations compared to that observed in later years. The effect of managing grazing land by varying stocking rate was greater than that of changing land use from virgin brigalow scrub to conservatively grazed pasture. Heavy grazing of improved pasture more than tripled runoff, peak runoff rate and total suspended solids loss compared to conservatively grazed pasture. Loads of total suspended solids, nitrogen and phosphorus in runoff were also greater from heavy than conservative grazing. The effect of land management on water quality was most easily determined where the input to the system was entirely anthropogenic, such as broad-scale application of herbicide. Unlike nutrients, with no confounding natural input, herbicide loss in runoff was entirely contingent on herbicide use. Tebuthiuron loss in runoff was primarily in the dissolved phase with no correlation to total suspended solids. Concentrations of tebuthiuron in runoff declined exponentially with time, cumulative rainfall and cumulative runoff. The new knowledge of the effects of land clearing, land use change and land management on soil fertility and runoff water quality generated in addressing the four objectives of this thesis has been extended, both spatially and temporally, by its inclusion in models for Great Barrier Reef catchments. This modelling estimates the effects of land management on water quality from catchments such as the Fitzroy Basin. Specifically, the research presented in this thesis has underpinned the design, calibration and validation of models at both the paddock and catchment scales as part of the Reef 2050 Water Quality Improvement Plan 2017-2022. This new body of knowledge has also been used to guide the development of regulations for protection of the Great Barrier Reef. These regulations were the focus of a 2020 senate inquiry, during which new knowledge from this thesis was presented in both written submissions and given as evidence.<br>Thesis (PhD Doctorate)<br>Doctor of Philosophy (PhD)<br>School of Eng & Built Env<br>Science, Environment, Engineering and Technology<br>Full Text

This case study of the debate around broad-scale land-clearing in Queensland adds to knowledge about the place of news media in resolving public policy issues. It includes an historical account of the issue, and from the evidence of newspaper contents, observes that some parties in such debates are likely to only conditionally accept policy outcomes, such as enacted legislation. Focusing on the regulation of broad-scale land-clearing between 1998 and 2006, the study identifies, analyses, and compares relevant, evidence-based arguments from policy stakeholders published in two Queensland newspapers: a metropolitan daily and a rural industry weekly.

Engelmann spruce-subalpine fir [Picea engelmannii Parry ex Engelm.-Abies lasiocarpa (Hook.) Nutt.] (ESSF) forests occupy large portions of western North America, and of British Columbia (B.C.) in particular. These areas represent a harsh environment for plant growth. The ESSF forests of B.C. have presented serious problems of regeneration following harvesting; several factors stimulated speculation as to whether N supply limitations were involved. This study was intended to highlight the post-harvest N dynamics of an ESSF forest, and the implications of the latter for silvicultural practices. Its general objectives included characterization of the post-harvest assart effect, and investigation of the N status and growth of advance regeneration. These were achieved by means of a comparative study of an age sequence of harvested sites. The assart effect lasted for at least eight years after harvesting, with a peak of change between years three and six. There were no major physical changes in the forest floor. Low C/N ratios between 19 and 32 were believed to have contributed to increased N availability. ESSF forests may have a generally higher level of N availability than previously supposed. The advance regeneration benefited from the assart effect. Nutrient uptake appeared to increase generally from at least three years after harvesting; increases of up to 78% were noted for N. There appeared to be no general macronutrient or micronutrient limitation to growth. However, evidence of S deficiencies was encountered in some trees. Moreover, the critical levels used for N may be in need of revision. A revised critical level of 1.40% for foliar N concentrations is proposed for subalpine fir advance regeneration. If this is accurate, regeneration may have been at least temporarily N-limited from year eight after harvesting. A more rigorous investigation of these possibilities is needed. The cutting method applied to the sites approximated a one-cut shelterwood method. The method as encountered in this study should not be considered a viable silvicultural option for similar ESSF forests. Its successful application would involve some degree of forest floor manipulation to improve seedbed conditions and soil microclimatic regimes. The findings of this study demonstrate that the environmental and biological characteristics of ESSF forests make high levels of planning and care a prerequisite for the success of silvicultural practices. The question of what comprises realistic growth and yield expectations of second-rotation stands in the ESSF zone needs to be addressed urgently.<br>Forestry, Faculty of<br>Graduate

The main objective of this study was to examine the abundance and diversity of ants in suburban sites following vegetation removal or modification for development. This research examines the capacity of suburban sites to support ant diversity, which is dependent on the site characteristics and their surrounding environment. The study focused on 29 suburban garden and 3 suburban reserve sites on the Gold Coast, Queensland, Australia. This region, through continuing land development, undergoes ongoing habitat disturbance and modification. Ground-dwelling ants were collected by pitfall trapping in study sites over three summers between 1997 and 1999. In total, 28,512 ants from 60 species in 31 genera were collected. Garden sites that maintain vegetation structural diversity were found to be most similar to reserve sites in terms of ant community composition. These sites were highest in ant richness and diversity and contained particularly high proportions of specialized ant species. Sites in close proximity to remnants of native vegetation contained higher species diversity and a greater proportion of specialized ant species. The introduced tramp ant, Pheidole megacephala was found in 28 of the 32 sites and was found to significantly reduce ant species richness and diversity and displace the dominant ant Iridomyrmex sp. 1 in suburban environments. This ant poses a serious threat to the recovery of a diverse ant fauna to suburban environments. Ant community composition was shown to vary significantly among suburban sites. The ant functional groups commonly found in disturbed sites were abundant in open sites with little canopy cover in this study. Sites that provided vegetation structural diversity and areas of closed canopy supported similar functional groups to natural vegetation remnants. These results indicate that ant communities in suburban environments respond to disturbance in a similar manner to ant communities in tropical forests and rainforests. The dominance by functional groups and presence of specialized species may therefore be used as an indicator of disturbance and the restoration of suitable habitat in suburban sites. The presence of specialized species of ants in suburban garden sites and their clear preference for particular site characteristics indicate that these species utilize resources available in the suburban matrix. These results indicate that residential suburban sites are of value in the enhancement of ant diversity in fragmented landscapes and that they may provide supportive habitat to, and act as corridors between, vegetation fragments. In order to preserve biodiversity within suburban environments, landowners should be advised to retain as much existing vegetation within a site as possible. Clearing should be limited to that necessary to allow construction of dwellings and for safety. In addition, landowners should be encouraged to establish or maintain structurally diverse vegetation layers within sites in order to provide diverse microenvironments for fauna habitat.

The main objective of this study was to examine the abundance and diversity of ants in suburban sites following vegetation removal or modification for development. This research examines the capacity of suburban sites to support ant diversity, which is dependent on the site characteristics and their surrounding environment. The study focused on 29 suburban garden and 3 suburban reserve sites on the Gold Coast, Queensland, Australia. This region, through continuing land development, undergoes ongoing habitat disturbance and modification. Ground-dwelling ants were collected by pitfall trapping in study sites over three summers between 1997 and 1999. In total, 28,512 ants from 60 species in 31 genera were collected. Garden sites that maintain vegetation structural diversity were found to be most similar to reserve sites in terms of ant community composition. These sites were highest in ant richness and diversity and contained particularly high proportions of specialized ant species. Sites in close proximity to remnants of native vegetation contained higher species diversity and a greater proportion of specialized ant species. The introduced tramp ant, Pheidole megacephala was found in 28 of the 32 sites and was found to significantly reduce ant species richness and diversity and displace the dominant ant Iridomyrmex sp. 1 in suburban environments. This ant poses a serious threat to the recovery of a diverse ant fauna to suburban environments. Ant community composition was shown to vary significantly among suburban sites. The ant functional groups commonly found in disturbed sites were abundant in open sites with little canopy cover in this study. Sites that provided vegetation structural diversity and areas of closed canopy supported similar functional groups to natural vegetation remnants. These results indicate that ant communities in suburban environments respond to disturbance in a similar manner to ant communities in tropical forests and rainforests. The dominance by functional groups and presence of specialized species may therefore be used as an indicator of disturbance and the restoration of suitable habitat in suburban sites. The presence of specialized species of ants in suburban garden sites and their clear preference for particular site characteristics indicate that these species utilize resources available in the suburban matrix. These results indicate that residential suburban sites are of value in the enhancement of ant diversity in fragmented landscapes and that they may provide supportive habitat to, and act as corridors between, vegetation fragments. In order to preserve biodiversity within suburban environments, landowners should be advised to retain as much existing vegetation within a site as possible. Clearing should be limited to that necessary to allow construction of dwellings and for safety. In addition, landowners should be encouraged to establish or maintain structurally diverse vegetation layers within sites in order to provide diverse microenvironments for fauna habitat.<br>Thesis (Masters)<br>Master of Philosophy (MPhil)<br>School of Environmental and Applied Science<br>Full Text

Thesis (M.S.)--University of Toledo, 2010.<br>Typescript. "Submitted to the Graduate Faculty as partial fulfillment of the requirements for the degree of Master of Science in Biology (Ecology track)." "A thesis entitled"--at head of title. Title from title page of PDF document. Bibliography: p. 38-42 and 51.

<p>The clearing of woodland to eradicate the tsetse fly in the Babati district, Tanzania, was a governmental initiative. The clearings were mainly carried out in the mid 20^th century and managed to reduce the tsetse fly by a great amount. The clearings opened up remote areas and made it possible to access areas that had previously been unavailable for humans. The clearing also had an enormous impact on the environment. This is a case study on five different areas in the Babati district that have all been subjected to tsetse clearings. The studied areas are Bonga, Kiru Erri Kiru Valley, Magugu and Mamire.</p><p>The fieldwork consisted of semi-structured interviews and transect walks. The purpose was to study if the clearings have had any influence over the spreading of agriculture land that were not cultivated before and to inquire into the most significant environmental impact that the clearings had.</p><p>Different outcome in agriculture land spreading due to the clearings could be seen in the five studied areas. In Bonga and Kiru Valley no agriculture started after the clearings, but in Kiru Erri, Magugu and Mamire some of cleared land is nowadays used for agriculture. The result of the fieldwork indicates that the clearings have had noticeable influence over the spreading of agriculture land but there were also other important driving forces. These were increase in population, land degradation, land shortages and the politic agenda. The most important negative environmental impact due to the clearings was erosion.</p>

Cette étude concerne essentiellement des sols ferrallitiques argileux (du Congo, du Brésil et de la Martinique). Les formes de matière organique (MO) susceptibles de variations importantes avec le mode de gestion de terres et la stabilité de l'agrégation ont été étudiées par différentes approches : par fractionnement granulométrique du sol et par extraction du sol à l'eau chaude. La stabilité structurale est estimée par le taux de macroagregats stables à l'eau (AS) avant et après traitement à l'eau chaude (ASE). La diminution importante des teneurs en C total dans les horizons de surface des sols cultivés après défrichement de la végétation naturelle a été généralement confirmée. Le fractionnement granulométrique de la MO montre que : (I) tous échantillons confondus, les contenus en C augmentent des fractions sableuses aux fractions argileuses, (II) toutes les fractions sont concernées par les variations des contenus en C, mais avec des amplitudes variables selon la fraction, le type de sol et le mode de gestion. Toutefois, les variations de la fraction sableuse sont les plus importantes. La mise en culture intensive induit aussi une diminution des teneurs en C soluble à l'eau chaude (CS) et en sucres totaux (CST) des sols. Les relations entre MO des sols et AS ont été étudiées pour les MO solubles à l'eau chaude et pourles fractions granulométriques de la MO. On a pu montrer, comme d'autres auteurs, l'existence de relations hautement significatives entre teneur en CS et AS. Pourtant l'étude de l'effet direct de ces MO solubles ne met pas en évidence un effet agrégeant de ces MO. Quant au contenu en C des fractions granulométriques des sols, seules les MO associées aux fractions sableuses (débris végétaux) montrent une corrélation significative avec AS. Compte-tenu des observations ci-dessus, on ne peut toutefois conclure à un effet réel et direct de cette fraction sur l'agrégation. En conclusion, ce travail n'aura pas permis d'identifier avec certitude une fraction organique agrégeante dans ces sols. Il aura toutefois conduit à montrer que les MO solubles à l'eau chaude ne le sont probablement pas, et que, dans ces sols A argile 1 : 1 ou le processus de désagrégation est dominé par le phénomène d'éclatement, les MO associées aux fractions sableuses pourraient éventuellement jouer un rôle important dans la stabilité structurale.

Etudier un phénomène écologique requiert de le considérer dans sa globalité afin d’appréhender l’ensemble de ses causes et ses conséquences. Dans la plaine de la Crau, écosystème pseudo-steppique du sud est de la France, la fragmentation des habitats, la perte de biodiversité et les changements d’usage ont favorisé l’envahissement de fragments relictuels de steppe par Rubus ulmifolius Schott. Par une approche multiscalaire, les objectifs de cette thèse sont de mettre en évidence les facteurs responsables de cet envahissement, d’appréhender ses conséquences sur la communauté végétale et de tester d’éventuelles techniques de restauration écologique en évaluant leurs effets à l’échelle de la communauté et de la population de ronces. La présence de fortes proportions de zones irriguées et de parcelles anciennement cultivées dans la matrice paysagère proche des zones envahies correspond à des taux de recouvrements parcellaires en ronciers plus élevés. A l’échelle de la communauté végétale, les infiltrations hydriques ont également des effets importants sur la végétation steppique en permettant le développement d’une espèce herbacée compétitrice : Brachypodium phoenicoïdes (L.) Roem. &amp; Schult. Aucun des différents régimes de perturbation (débroussaillage et/ou pâturage) testés, croisés au drainage ou non du sol ne permet de restaurer à court terme (trois années) l’intégrité de la steppe de référence. Seule une augmentation significative de la richesse et de la diversité spécifique est mesurée dans le cas d’un débroussaillage et d’un pâturage annuel des placettes. A l’échelle des ronces, les effets des différents traitements varient selon l’année, la saison ou la période de la journée considérée. Les régimes de perturbation (débroussaillage et/ou pâturage) ont cependant plus d'influence sur les traits éco-physiologiques et morphologiques de la ronce que la limitation des ressources en eau. Nos résultats soulignent ainsi la difficulté de contrôler à court terme la dynamique d’une espèce envahissante. Ils ouvrent également le débat sur les objectifs de conservation et/ou de restauration des parcelles qui peuvent alors être considérées comme des écosystèmes dégradés ou comme de « nouveaux écosystèmes » dont les potentiels patrimoniaux sont encore inconnus<br>Studying an ecological phenomenon require to consider it in its entirety in order to apprehend all the causes and consequences. In the Plain of La Crau, a sub-steppic ecosystem in southeastern France, habitat fragmentation, loss of biodiversity and land-uses changes have fostered the encroachment by a species of brambles Rubus ulmifolius Schott of the original steppic patches. Using a multiscale analysis, the aims of the thesis are to highlight the main drivers, to assess the consequences on the plant community and to test restoration techniques by evaluating their effects on plant community and on bramble population. The presence of high proportions of irrigated habitats and formely fallows around invaded plots correspond to the largest cover rates of brambles. At community scale, water infiltrations have also a great impact on the steppe plant community by favoring the dynamic of an herbaceous competitor species: Brachypodium phoenicoïdes (L.) Roem. &amp; Schult. Among the different disturbance regimes tested (scrub-clearing and / or grazing), crossed with the presence or the absence of sol draining, none could restore in the short-term (3 years), the integrity of the steppe reference. A significant increase in species richness and diversity was only measured for drained, scrub-cleared and annually grazed plots. At bramble population scale, the effects of the different treatments change depending on the year, the season and the time of the day. However, disturbance regimes (clearing and / or grazing) have more impact on eco-physiological and morphological traits of the bramble than the water resources limitation. Our results highlight the difficulty controlling short-term dynamics of an invasive species. They question the objectives of conservation and / or restoration of plots which can then be considered as degraded ecosystems or as "novel ecosystems" whose potential patrimonial values are still unknown

Land clearing services are quickly spreading, mostly due to legal requirements imposed on field owners to force them to clean their terrains in order to prevent the spread of eventual wildfi res. These land clearing services are traditionally made with the help of machinery or chemicals, which is costly and heavy on the environment. An alternative is a process which is not a novelty in itself - bringing grazing animals, usually sheep, to the terrain, and have them eat the unwanted weeds. This is a cheaper and more environmental-friendly way of conducting a land clearing service. In order to increase the eficiency of this process, the SheepIT project was created, which brought the possibility of exerting a better control over the animals with the use of smart devices, which also enable valuable data collection. This dissertation is built on top of the SheepIT project and aims at being the bridge between owners of fields who intend on paying for these services, and the owners of sheep acting as service providers and looking to nd clients. The goal is to create a platform where they can publicize their intents, contractualize services and manage them. Blockchain technology was then used in order to guarantee the provenance and integrity of important data Flowing through the system, in order to generate trust between all the users of the platform.<br>Os serviços de limpeza de terreno estão rapidamente a ganhar popularidade, principalmente devido a requisitos legais impostos a donos de terrenos, que têm como objetivo a prevenção de eventuais fogos florestais. Estes serviços de limpeza são tradicionalmente feitos com recurso a maquinaria ou produtos químicos, o que acaba por ser um processo custoso e com impacto no ambiente. Uma solução alternativa é um processo que não é uma novidade por si só - o uso de animais de pastagem para a remoção das espécies vegetais indesejáveis. Esta é uma alternativa com um custo monetário e ambiental reduzido. Para aumentar a eficiência deste processo, o projeto SheepIT foi criado, e trouxe a possibilidade de exercer um melhor controlo sobre os animais através do uso de aparelhos eletrónicos, que simultaneamente permitem uma coleção de dados importantes. Esta dissertação acresce ao trabalho desenvolvido no projeto SheepIT, e tem como objetivo tornar-se uma ponte entre donos de terrenos que tencionam pagar por serviços de limpeza de terreno, e donos de rebanhos que atuam como prestadores desse serviço e estão à procura de clientes. O objetivo final é criar uma plataforma onde os utilizadores possam publicitar as suas intenções, contratualizar serviços de pastagem, e gerir os mesmos. A tecnologia blockchain é então usada para garantir a proveniência e integridade de dados importantes que passam pelo sistema, com o intuito de fomentar confiança entre os utilizadores da plataforma<br>Mestrado em Engenharia de Computadores e Telemática

Habitat fragmentation involves the break-up of continuous native vegetation into remnant patches that are set in a matrix of altered habitat. The consequences of habitat fragmentation include the loss of original habitat which is followed by reductions in remnant size that increase edge effects and reduce habitat quality, and also increase the isolation of remnants from one another. Habitat fragmentation is an international environmental concern that also effects Australia. Over the last ten years Queensland has been responsible for some ninety percent of the clearing occurring in Australia, and as a result recorded some of the highest vegetation clearing rates in the world.<br>thesis (PhDEnvironmentalManagement)--University of South Australia, 2004.

The overall effect of tree clearing on pasture, litter production and major soil parameters were analysed using multivariate analysis.. "Tree clearing is practised for greater beef production and hence monetary gains from grazing systems of central Queensland. The high rates of clearing in the past and even recently (577, 000 ha/yr during 1999-2001) were mainly to develop land for pastures. The sustainability of cleared pasture systems over the long-term is questioned. Three major types of tree communities i.e. Eucalyptus populnea F. Muell., E. melanophloia F. Muell. and Acacia harpophylla F. Muell. ex. Benth. were selected on one property in central Queensland to quantify the impacts of clearing on pasture production and composition, and soil properties. The impacts were measured over time-since-clearing (recent (<5 years), medium (11-13years) and old (>30 years)) in unreplicated cleared pastures in comparison to their replicated uncleared/intact woodland pastures of each tree community. Measures of pasture above-ground biomass production on a single property over time-sinceclearing in cleared systems showed that gains were not sustained over the long-term. The difference in response to clearing between tree communities was evident and important to support the future policy decisions. The impact of clearing on soil properties (physicochemical and biological) was confirmed, and explained the lesser availability of nutrients with time of clearing in cleared pastures. The changes in some soil properties underscored the associated risks and changes in ecosystem functions due to clearing. Less litter was produced at cleared than uncleared pastures, but nutrient release was faster at cleared compared to uncleared systems. The overall effect of clearing in terms of pasture and litter production, and major soil parameters were analysed using multivariate analyses. -- abstract