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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

Efeito da expansão do cultivo de cana-de-açúcar na composição da paisagem do estado de São Paulo / Effects of the sugarcane expansion on the landscape composition in São Paulo state

Thaís Nícia Azevedo 08 August 2013 (has links)
As mudanças de uso e cobertura do solo causam uma série de impactos no ambiente. No Brasil, o primeiro cultivo que deu início à mudança de uso e cobertura do solo foi o de cana-de-açúcar. Desde sua introdução, o cultivo de cana-de-açúcar vem alterando a paisagem em que está inserido. Atualmente, o estado de São Paulo é o maior produtor de cana-de-açúcar do país, tendo sofrido alterações na paisagem com maior intensidade desde a implantação do Proálcool, em 1975. O histórico de mudança de uso e cobertura do solo nos permite compreender como a expansão do cultivo de cana-de-açúcar afetou essas paisagens. Neste estudo, avaliamos como a expansão do cultivo de cana-de-açúcar afetou a composição da paisagem de 1965 a 2010. Para isso, mapeamos nove unidades amostrais representativas da dinâmica do cultivo da cana-de-açúcar no estado de São Paulo durante o Proálcool em quatro datas: 1965, 1980, 1995 e 2010. Analisamos a dinâmica das paisagens e elaboramos matrizes de transição para as unidades estudadas nos três intervalos de tempo: 1965-1980, 1980-1995 e 1995-2010. Avaliamos se a ocupação das Áreas de Preservação Permanente (APPs) difere das áreas fora de APPs com relação à preferência por conversão de terras, regeneração e perda de vegetação natural. A expansão da cana-de-açúcar foi caracterizada pela perda de cobertura natural, especialmente campo cerrado e cerradão, quando estes existiam e pela substituição da pastagem, classe que mais cedeu espaço para a cana-de-açúcar. No entanto, fora das APPs, não houve uma preferência para a conversão do uso do solo durante a expansão da cana-de-açúcar, ou seja, a cana-de-açúcar expandiu mais sobre a pastagem por essa ser a classe mais dominante da paisagem. Já nas APPs, houve um direcionamento da expansão da cana-de-açúcar, principalmente no último período analisado, em que a conversão de cobertura natural para cana-de-açúcar foi evitada. A regeneração dentro das APPs foi maior do que nas áreas fora de APPs. Todavia a perda de vegetação natural ocorreu independentemente da localização. Em todos os períodos, o percentual de cobertura natural foi inferior a 20% quando a cana-de-açúcar foi a matriz da paisagem. Esses dados atestam que a expansão da cana-de-açúcar durante o Proálcool ocorreu desrespeitando a legislação ambiental, tanto dentro quanto fora das APPs. Concluímos que a expansão do cultivo de cana-de-açúcar alterou a composição da paisagem, reduzindo significativamente as áreas naturais e as pastagens. Apesar da ligeira tendência recente de recuperação das áreas naturais em APPs, é necessário estimular essa regeneração, seja através da certificação ambiental ou da aplicação efetiva do novo Código Florestal. Estas ações poderiam auxiliar na manutenção de áreas naturais e no cumprimento das áreas de preservação, visando paisagens mais favoráveis à conservação da biodiversidade e dos serviços ecossistêmicos. / Land use and land cover change causes a series of impacts on the environment. In Brazil, the first crop that started the land use land cover change was sugarcane. Since its introduction, the cultivation of sugarcane is changing the landscape in which it is inserted. Presently, the state of São Paulo is the biggest producer of sugarcane in the country, and had its landscape modified with greater intensity since deploying Proálcool in 1975. The history of land use and land cover change allows us to understand how the sugarcane expansion affects these landscapes. In this study, we evaluate how the sugarcane expansion affects the composition of the landscape from 1965 to 2010. For this, we mapped nine sampling units which represented the sugarcane dynamics in São Paulo during Proálcool for four dates: 1965, 1980, 1995 and 2010. We analyze the landscape dynamics and elaborate transition matrices for the units studied in three intervals: 1965-1980, 1980-1995 and 1995-2010. We assessed whether the occupation of Permanent Preservation Areas (PPAs) differs from areas outside of PPAs regarding preference for land conversion, regeneration and deforestation. The sugarcane expansion was characterized by loss of natural cover, especially in campo cerrado and cerradão, when they exist, and the substitution of pasture, class that more relented space to sugarcane. However, outside of PPAs, there was no preference for conversion of land use during the expansion of sugarcane, in other words, the sugarcane expanded more over pasture because this was the most dominant class in the landscape. In PPAs, there was a direction of the sugarcane expansion, especially in the last analyzed period in which the conversion of natural cover for sugarcane was avoided. The regeneration in the PPAs was higher than in areas outside of PPAs. Nevertheless the loss of natural vegetation occurred regardless of location. In all periods, the percentage of natural cover was less than 20% when sugarcane was the matrix of the landscape. These data confirm that the expansion of sugarcane during the Proálcool occurred disrespecting environmental legislation, both inside and outside of the PPAs. We conclude that the sugarcane expansion changed the landscape composition, significantly reducing natural areas and pastures. Despite the recent trend of slight recovery of natural areas in PPAs, it is necessary to stimulate this regeneration, either through environmental certification or effective implementation of the new Forest Code. These actions could help maintain natural areas and carrying out the conservation areas, seeking more favorable landscapes for biodiversity conservation and ecosystem services.
122

A curva de Kuznets ambiental (CKA) para o bioma caatinga no estado de Pernambuco

SALES, Vilane Gonçalves 10 February 2015 (has links)
Submitted by (edna.saturno@ufrpe.br) on 2016-06-10T11:55:53Z No. of bitstreams: 1 Vilane Goncalves Sales.pdf: 2983831 bytes, checksum: f4d92a82d9e60512ba543ee1bf1c317e (MD5) / Made available in DSpace on 2016-06-10T11:55:53Z (GMT). No. of bitstreams: 1 Vilane Goncalves Sales.pdf: 2983831 bytes, checksum: f4d92a82d9e60512ba543ee1bf1c317e (MD5) Previous issue date: 2015-02-10 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Environmental problems happen when it interferes with any part or phase of an ecosystem by changing it. In Brazil, deforestation caused by hot spots makes the country a major emitter of carbon dioxide, one of the gases causing the greenhouse effect. There is a concern that, with the progress of development, the pressure on the environment increases. When looking at the Caatinga biome, one realizes that it is endemic and the importance it is given by presenting a diverse flora and fauna and their degradation causes, and the loss of biodiversity, defragmentation of the formation of the region. Within this context, this study investigated the hypothesis of the Environmental Kuznets Curve (EKC) for the Caatinga biome, in the municipalities of the state of Pernambuco, that is, if there is a relationship in the form of inverted "U" between environmental degradation index (deforested area in hectares) and economic growth (indicated by GDP), at the municipal level, in the period 2002-2008 using a model for panel data. The econometric results indicate the presence of unobserved effects and are more suitable for estimating fixed effects. A further issue addressed was the impact of environmental public policies for the economic growth of the studied biome. The basic model and with the insertion of dummy environmental policy have the EKC relationship as "N" inverted, indicating that the annual deforested area is larger for low levels of GDP per capita, and decreasing as the GDP increases, then to grow back, and higher income levels, it is decreasing. Public policy variable was not considered significant at 5%. Thus, it is necessary to institute specific environmental policies to the biome, so that strengthen coexistence practices. In addition, the results show different relationships between deforestation and municipal GDP, as well as different relations of deforestation with other explanatory variables, notifying the presence of heterogeneous spatial effects. / Os problemas ambientais acontecem quando se interfere em qualquer parte ou fase de um ecossistema, alterando-o. No Brasil, o desmatamento provocado por focos de calor torna o país um grande emissor mundial de dióxido de carbono, um dos gases causadores do efeito estufa. Há a preocupação de que, com o avanço do desenvolvimento, a pressão sobre o meio ambiente aumente. Ao observar o bioma Caatinga, percebe-se que o mesmo é endêmico e a importância dele é dada por apresentar uma fauna e flora diversificada e que a sua degradação ocasiona, além da perda da biodiversidade, a desfragmentação da história da formação da região. Dentro deste contexto, esse trabalho investigou a hipótese da Curva de Kuznets Ambiental (CKA) para o bioma Caatinga, nos municípios do estado de Pernambuco, isto é, se existe uma relação na forma de "U" invertido entre um índice de degradação ambiental (área desmatada em hectares) e o crescimento econômico (indicado pelo PIB), em nível municipal, no período 2002- 2008, utilizando um modelo para dados em painel. Os resultados econométricos indicam a presença de efeitos não observados, sendo mais adequada a estimação por efeitos fixos. Uma questão adicional abordada foi o impacto das políticas públicas ambientais para o crescimento econômico do Bioma estudado. O modelo básico e o com a inserção da dummy política ambiental apresentam a relação CKA na forma de "N" invertido, indicando que a área desmatada anual é maior para baixos níveis de PIB per capita, sendo decrescente à medida que o PIB aumenta, depois volta a crescer, e para níveis de renda mais elevados, torna-se decrescente. A variável política pública não foi considerada significativa em 5%. Dessa forma, é preciso que se instituam políticas ambientais específicas ao bioma, de tal forma que fortaleçam as práticas de convivência. Além disso, os resultados mostram diferentes relações entre desmatamento e PIB municipal, assim como diferentes relações do desmatamento com as demais variáveis explicativas, notificando a presença de efeitos espaciais heterogêneos.
123

Efeitos da conversão de florestas em áreas agrícola sobre assembleias de peixes das cabeceiras do Rio Xingu / Effects of forest conversion into agricultural areas on fish assemblages in the headwaters of the Xingu River

Paulo Ricardo Ilha Jiquiriçá 29 June 2015 (has links)
A expansão da fronteira agrícola amazônica representa possivelmente a mais extensa e profunda mudança no uso da terra do mundo contemporâneo. Estima-se que a Bacia Amazônica já teve 20% de sua área desmatada e seus ecossistemas aquáticos, que abrigam a maior diversidade de peixes de água doce do planeta, também vem enfrentando inúmeras outras pressões, entre elas a construção de barragens. O desmatamento e a construção de barragens causam profundas alterações nas características bióticas e abióticas dos ecossistemas lóticos, incluindo o aquecimento da água e mudanças na composição e estrutura das assembleias de peixes. Existem inúmeras evidências de que o aumento da temperatura afeta negativamente o tamanho corporal dos organismos, e aquecimentos provocados por mudanças climáticas já foram relacionados com reduções no tamanho corporal de peixes. Contudo, faltam estudos que demonstrem que processos locais e regionais de grande relevância como as mudanças no uso da terra, também podem causar o mesmo resultado. Com foco geográfico no arco do desmatamento amazônico nas cabeceiras do Rio Xingu, os objetivos desta tese foram, (i) investigar os efeitos do desmatamento e da construção de barragens sobre características ambientais, e sobre a composição e estrutura das assembleias de peixes em riachos de primeira ordem; e (ii) testar as hipóteses de que a conversão de florestas em áreas agrícolas está associada a um aquecimento dos riachos e a uma redução no tamanho corporal dos peixes, e que esta redução no tamanho corporal é resultado de alterações na crescimento dos peixes, seja por mecanismos de adaptação e/ou por plasticidade fenotípica, promovidas pelo aquecimento do ambiente. No primeiro capítulo desta tese, demonstramos que o desmatamento e a construção de barragens provocam alterações em características ambientais dos riachos de primeira ordem que afetam a disponibilidade de hábitat para os peixes. Isto resultou em alterações na composição e estrutura das assembleias, de forma que riachos de área agrícola apresentaram maior abundância e biomassa de peixes que riachos de floresta. Trechos represados apresentaram menor riqueza de espécies que trechos lóticos tanto em ambientes florestados como desmatados, sugerindo que a construção de barragens constitui uma ameaça significativa para a conservação da biodiversidade de peixes. No segundo capítulo, combinamos amostragem em campo e experimentos em laboratório e campo para demonstrar que a conversão de florestas em áreas agrícolas aqueceos riachos de cabeceira e reduz o tamanho corporal dos peixes através de alterações nas taxas de crescimento individual Os aquecimentos e reduções de tamanho que observamos foram consideravelmente maiores que os reportados na literatura para os efeitos observados e previstos do aquecimento global. Este é o primeiro estudo, até onde nós sabemos, que investigou os efeitos do aquecimento provocado pelo desmatamento no tamanho corporal de peixes. É possível que reduções no tamanho corporal de peixes mediadas pelo aquecimento estejam ocorrendo ao longo de todo o arco do desmatamento, onde riachos de primeira ordem coletivamente contribuem com grande fração da biodiversidade de espécies amazônicas, muitas delas endêmicas. / The expansion of the Amazonian agricultural frontier possibly represents the most extensive and profound land use change in the contemporary world. Deforestation, dam construction, and numerous other pressures have serious impacts on its aquatic ecosystems, that collectively hold the greatest diversity of freshwater fish on the planet. Deforestation and dam construction cause profound changes in biotic and abiotic characteristics of stream ecosystems, including water heating and changes in the composition and structure of fish assemblages. There are many evidences that the increase in temperature negatively affect organisms body size, and warming caused by climate changes have already been associated with reductions in fish body size. However, there are no studies showing that local and regional processes of major relevance, such land use changes, can also cause the same result. With a geographic focus on the Amazonian arc of deforestation in the headwaters of the Xingu River, the objectives of this thesis were: (i) to investigate the effects of deforestation and dam construction on environmental characteristics, and on the composition and structure of fish assemblages in first order streams; and (ii) to test the hypothesis that the conversion of forests into agricultural areas is associated with stream warming and reductions in fish body size, and that this reduction in body size is a result of changes in individual growth caused by adaptation and/or phenotypic plasticity, promoted by environmental warming. In the first chapter of this thesis, we show that deforestation and the construction of dams cause changes in environmental characteristics of first-order streams that affect the habitat availability for fish. This resulted in changes in the composition and structure of assemblages, so that agricultural area streams showed higher abundance and biomass of fish that forest streams. Reservoirs had lower species richness than lotic stretches both in forested and deforested streams, suggesting that the construction of dams poses a significant threat to the conservation of fish biodiversity. In the second chapter, we combine field sampling and laboratory and field experiments to demonstrate that the conversion of forests into agricultural areas warms headwater streams and reduces fish body size through changes in individual growth rates. Warming and size reductions we observed were considerably higher than those reported in the literature for the observed and predicted effects of global warming. This is the first study as far as we know, that investigated the effects of warming caused by deforestation in fish body size. It is possible that a broad scale fish body size reduction due to warming is occurring throughout the arc of deforestation, in streams that collectively account for a large fraction of Amazonian fish biodiversity.
124

Fractured reflections : rainforests, plantations and the Malaysian nation-state

Sioh, Maureen Kim Lian 05 1900 (has links)
This study examines how deforestation in Malaysia is framed as an economic issue fought out in the political arena using cultural codes as an entry point to examining the political tensions of contemporary Malaysia. Three themes recur throughout this work. The first theme concerns the centrality of resources in Malaysia's colonial and post-colonial political economy. The second theme concerns the displacement of the anxieties of national and cultural survival onto the contests over economic rights. And the third theme is the way collective memories 'flesh out' contemporary contests between the state and civil society. In the sense that the three themes are inter-related, this study traces the twinned construction, and opposition, of the two central ideas: of 'nature' in the form of the rainforest and 'race' in the guise of nation. In keeping with the role of memory in present-day social and political engagements, this study weaves both archival and contemporary material to trace the construction of the history, imagery and vocabulary that have been mapped onto the physical space of the rainforest. I explore the production of the cultural codes through this mapping process that are then used to articulate the contests over the rainforest. These codes are the consequence of negotiations that reflect the unstable alliances and inconsistent identities of contemporary Malaysia, and they are the legacies, albeit translated, of colonialism. In retracing the contests over and about the forests, I hope to shed some light on why Malaysians made, and continue to make, decisions that appear to work against them. The decisions affecting the fate of the rainforest reflects choices made about the kind of society Malaysians live with. Hence, the three core chapters of this study examine military, political/cultural and economic contests and negotiations surrounding the birth of the Malayan/Malaysian nation-state through their impacts on the rainforest. By acknowledging how much of Malaysia's contemporary politics is its colonial legacy, I hope to highlight the trade-off we have made between limited political engagement and development. To accept that we cannot protect basic rights as the price of economic success is to continue to live within the racist framework of colonialism that human rights are only for some humans. / Arts, Faculty of / Geography, Department of / Graduate
125

Different perspectives of deforestation in the Peruvian Amazon : An interview study based in Cusco and Pilcopata in the Cusco region

Wåtz, Teresa, Eriksson, Emma January 2019 (has links)
The Amazon rainforest constitutes a quarter of the global biodiversity and is responsible for 15% of the terrestrial photosynthesis. It is important to protect the forest and limit the deforestation to not release more greenhouse gases, which aggravate climate change. There is a big problem today with deforestation, especially in the Peruvian Amazon. In Peru is the main driver to deforestation human activity, such as road infrastructure, markets and agriculture. It is most common with small-scale agriculture, especially in the Cusco region where this study is conducted. How the deforestation should be managed or if current instruments are working is there different perspectives on. In this essay are the different perspectives regarding the exploitation of the Amazon and its impacts being analyzed. The essay has an interview method and the interviews are carried out on members of non-governmental organizations and Cusco regional government. Our analysis shows that the different perspectives show similarities regarding the main drivers for the deforestation, the information and knowledge-gap regarding the impacts of deforestation. There is, however, a difference in the perspectives regarding funds. One perspective from the non-governmental members is that there is not enough funding to receive as well as that the funds that do exist go to people and projects that do not do the work properly. / Amazonas regnskog utgör en fjärdedel av den globala biologiska mångfalden och ansvarar för 15% av den markbundna fotosyntesen. Det är viktigt att skydda skogen och begränsa avskogningen att inte släppa ut mer växthusgaser, vilket förvärrar klimatförändringar. Det finns ett stort problem idag med avskogning, särskilt i Peruanska Amazonas. I Peru är den viktigaste drivkraften att avskogningen mänsklig aktivitet, såsom väginfrastruktur, marknader och jordbruk. Det är mest vanligt med småskaligt jordbruk, särskilt i Cusco-regionen där denna undersökning genomförs. Hur avskogningen ska hanteras eller om nuvarande instrument fungerar finns det olika perspektiv kring. I denna uppsats beskrivs olika perspektiv på utnyttjandet av Amazonas och dess konsekvenser. Uppsatsen har en intervjumetod och intervjuerna utförs på medlemmar i icke-statliga organisationer och Cuscos regionala regering. Vår analys visar att de olika perspektiven har likheter angående de viktigaste drivkrafterna för avskogningen och informations- och kunskapsklyftan om avskogningens effekter. Det finns dock en skillnad i perspektivet kring finansiering. Ett perspektiv från de icke-statliga medlemmarna är att det inte finns tillräckligt med finansiering att få och att de ekonomiska medel som finns går till personer och projekt som inte gör jobbet korrekt.
126

Sezónní vývoj makrozoobentosu, jeho dlouhodobé změny a vliv mimořádných událostí na acidifikovaných tocích pramenné části povodí Litavky v Brdech / Seasonal development, long-term changes and effect of extreme events on macrozoobenthos of acidified brooks in headwater catchments of Litavka, the Brdy Mountains

Beneš, Filip January 2013 (has links)
This Master thesis was focused on seasonal development of macrozoobenthos for season 2009-2010, its long-term changes and effects of extreme events on acidified brooks in headwater catchments of the Litavka river in the Brdy Mountains (the Czech Republic). The extreme events are considered: drought, floods and deforestation. Changes in composition of macrozoobenthos were compared with the previous research, which was provided there for season 1999-2000. Headwater catchment of the Litavka river consist of two streams: strongly acidified Litavka-krmelec (LK) and slightly acidified Litavka-hlavní (LH), which is taken as a reference stream. Measured pH levels of LK were in range of 4,00-4,22 (with median 4,10) and concentration of reactive aluminium (R-Al) were in range of 1381-2187 µg.L-1 (with median 1692 µg.L-1 ). Measured pH levels of LH were in range of 4,74-6,22 (with median 5,62) and concentration of reactive aluminium (R-Al) were in range of 8-400 µg.L-1 (with median 33 µg.L-1 ). Concentrations of R-Al are observed due to toxic forms of Al3+ ions on aquatic organisms. The significant differences in composition of macrozoobenthos were also observed. On strongly acidified study site LK were not present acidosensitive groups, such as mayflies, molluscs and some species of caddisflies. All of these...
127

Run forest run! - A cross-national study on the effect of property rights and liberty on deforestation

Hansen, Emma January 2020 (has links)
This thesis examines the effect of property rights and democracy on deforestation. The aim of the study is to test the two hypotheses; (1.a.) Well-defined property rights will lower deforestation and (1.b.) Higher levels of liberty will decrease deforestation. Furthermore, the test will be constructed by an extensive cross-country study of 193 countries by the method of fixed effect regressions. A contribution is made in the form of investigating the two explanatory factors, property rights and liberty, on deforestation in the scope of one study. Which there is (to the best of my knowledge) a lack of within this research area. The results gained no support for hypothesis (1.a.) meanwhile hypothesis (1.b.) found support. On the other hand, the thesis shows that property rights and liberty can affect the deforestation rate. Finally, this thesis underlines the association between the two explanatory factors under the scope, and by thus, motivates further research on the matter to fill a vital gap within the studies of deforestation.
128

Effects of American Colonial Settlement and Deforestation on Lacustrine Redox Conditions: Longterm Insights from Martin Lake, Indiana

Henke, Alyssa Nicole 11 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Colonial settlement of Indiana changed the environment in significant ways; the aim of this study is to quantify the impacts of settlement through the use of geochemical proxies including: % lithics; the carbon (δ13C), nitrogen (δ15N), and sulfur (δ34S) isotope composition of organic matter; the elemental composition of carbon (TOC) and nitrogen (Ntot) in organic matter and their ratio (C/N); the δ34S of mineral sulfides (pyrite and acid volatile sulfides); and iron redox proxies. Lakes are a great recorder of aquatic-terrestrial linkages on both local and global scales. Martin lake’s watershed, in northeastern Indiana, was settled in 1840 by Euro-Americans, and since then clear shifts in lake chemistry are recorded in its sediments. A core spanning roughly the last 300 years taken from Martin Lake is the basis of this study. The impacts of settlement can be seen through the lenses of all the proxies that were used in this study. 1) Post-settlement deforestation increased erosion in Martin Lake’s watershed, increasing sedimentation rates and % lithics. 2) δ13C of organic matter reveals a pattern of deforestation and partial regrowth and agricultural use of land. 3) A pronounced increase in δ15N timed with the change in population at the time of settlement is consistent with the increased input of human or animal waste into Martin Lake. 4) TOC and C/N show an overall increase in the amount of organic matter within the lake caused by deforestation, and that the increased nutrient supply may have stimulated more in-lake productivity. 5) δ34S of mineral sulfides show that deforestation lead to an increase in the available sulfate pool of Martin Lake, which in combination with 6) an increase in FeHR created redox conditions in which pyrite formation was more favorable. These factors culminated in a transition in Martin Lake chemistry and redox cycling within the sediments.
129

Response of three semi-arid savannas on contrasting soils to the removal of the woody component

Scholes, Robert John 24 February 2012 (has links)
Ph.D., Faculty of Science, University of the Witwatersrand, 1987
130

Response of three semi-arid savannas on contrasting soils to the removal of the woody component

Scholes, Robert John 11 September 2015 (has links)
A thesis submitted to the Faculty of Science University of the Witwatersrand, Johannesburg for the Degree or Doctor or Philosophy October 1987 / A t h r e e - y e a r study was un dertaken in the semi-arid (500mm p a . ) n o rth -eastern lowland area of South Afric a. All the woody plants were removed from one -hectare savanna plots on three d i f f e r e n t soil types , and key hydrological and biological changes were monitored relative to adjacent controls. Runoff increased initially, but decreased once the grass cover increased. Deep drainage and lateral subsurface flow increased on the sandiest site. Evaporation from the soil surface increased on the heavier t e x t u r e d soils. The duration of plant - available water in the soil increased on all cleared p l o t s . & The p re - c l e a r in g woody plant abo veground biomass was in the range of of which 0 . 6 6 to 0 . 8 0 t ha was 5.6 to 11.2 t ha -1 leaf biomass. The annual herbaceous production was stron gly rainfal' dep endent, averaging 1 to 1.5 t ha -1 , and increased by 0 . 4 - 0 6 t .ha -1 except on the most f erti le site ( 0 . 6 - 2 0 t ha ) . Total available forage increased with c l e a ring, but so did its variability The observed changes in herbaceous layer palatability could not be a t trib u t e d to clearing. Woody plants and grasses wore shown to have w a te r- u s e niche separation in both rooting depth and time of water use. Simulation over forty years of wetting patterns indicated 75 to 85 % niche overlap, w t h separation on the depth axis more important in sandy sites, and on the time axis in clayey sites. Competition between woody plants and grasses was strongly asymmetrical in favour of woody plants. w >

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