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Regeneration ecology of anemochorous tree species Qualea grandiflora (Mart.) and Aspidosperma tomentosum (Mart.) of the cerrado Aguara Ñu located in the Mbaracayú Nature Forest Reserve (MNFR), ParaguayDa Ponte Canova, Giovanna 14 February 2019 (has links)
Understanding of the diverse aspects affecting the regeneration ecology of species is crucial to make decisions regarding management and conservation strategies, especially in highly fragile and threatened ecosystem as the Neotropical savanna (cerrado) formations. Available knowledge of regeneration ecology of cerrado species is too limited to attain optimal or suitable management actions. The objectives of the present study were: i) analysis of the characteristic parameters of the anemochorous seed dispersal of study species Q. grandiflora, (ii) determine the spatial distribution of tree species Q. grandiflora for growth stages (seedlings to juveniles) and interrelations between the stages, and (iii) determining variables of the spatial distribution of recruitment of tree species A. tomentosum.
The present study was conducted in the cerrado Aguara Ñu of the Mbaracayú Nature Forest Reserve located in the northeast of Paraguay. The cerrado Aguara Ñu is part of the Mbaracayú Biosphere Reserve and represents one of the most important ecoregions in the world, the cerrado ecosystem. The cerrado biome encompasses areas from northeastern to southwestern Brazil, eastern Bolivia, and northern Paraguay. It is characterized by the presence of high plant and animal biodiversity and also high endemism (Myers et al., 2000). Tree species Q. grandiflora and A. tomentosum are typical species of the cerrado formation.
Based on the selected investigated regeneration cycle stages of study tree species Q. grandiflora and A. tomentosum, the present thesis describes the spatial analysis of recruitment of both study species and the anemochorous diaspore dispersal of tree species Q. grandiflora. The purpose of the present investigation is to address regeneration aspects not attained so far as certain seed dispersal aspects, such as seed densities and distances from conspecific adult trees and spatial arrangements of seedlings of species A. tomentosum. Results of the present study aim to contribute to existing information and at the same time provide new knowledge on ecological aspects so far not investigated.
Research results on seed dispersal of tree species Q. grandiflora revealed that dispersal can be modeled by inverse modelling considering isotropy and lognormal density function presenting mean dispersal distances of 10.69 to 62.48 m. Estimations of the fruit production of a seed tree yielded a total 50671 to 70632 (DBH = 70 cm). Results of spatial arrangement of seedlings and juveniles revealed a significant distance effect to conspecific adult trees. Moreover, results also showed: (i) highest densities or intensities (m2) of seedlings (heights <50 cm) close to the conspecific adult trees and (ii) a shift of intensity of seedlings with increase of growth stage or size for tree species Q. grandiflora. Additionally, seedlings (up to 200 cm height) of study species Q. grandiflora indicated gradual decreasing clumping patterns and juveniles (200 – 500 cm height) presented clumping patterns.
Modelling results of spatial patterns of seedlings (heights ≤ 200 cm) of study tree species A. tomentosum revealed aggregation patterns. Moreover, shade effect resulted to be a statistical significant factor for the establishment of seedlings of tree species A. tomentosum (p-value = 0.0266), whereas distance effect to seed tree resulted not significant (p-value= 0.4936).
Considering the findings of seed dispersal and spatial patterns analysis of tree species Q. grandiflora and A. tomentosum some management aspects to be attained for conservation purposes are avoiding fragmentation of the ecosystem, management of the spatial and time fire frequency and maintain minimum amount of seed trees per unit area in order to guarantee successful recruitment.:1. Introduction 1
References 8
2. Materials and Methods 13
2.1 Characterization of the cerrado biome 13
2.2 Description of the study area and study sites 15
2.3 Characterization of the study tree species 23
2.3.1 Qualea grandiflora (Mart.) 23
2.3.2 Aspidosperma tomentosum (Mart.) 24
2.4 Principles and selection criteria 25
2.5 Data collection 26
2.5.1 Seed dispersal 26
2.5.2 Spatial patterns of plants 27
2.6 Data analysis 28
2.6.1 Statistical analysis of data 28
2.6.2 General statistical procedures of data analysis 30
2.6.3 Spatial point process analysis – Inverse modelling and spatial point patterns 31
2.6.4 Spatial point patterns analysis procedure 33
2.6.4.1 Descriptive statistics in spatial point patterns 36
2.6.4.1.1 Distance effect of seedlings from seed trees (rhohat function) 36
2.6.4.1.2 Pair correlation function (pcf) 36
2.6.4.2 Point process modelling 38
References 43
3. Seed dispersal of Qualea grandiflora (Mart.) 49
3.1 Introduction 49
3.2 Methodology 51
3.2.1 Data collection and seed trap design 51
3.2.1 Data analysis – inverse modelling 53
3.3 Results 58
3.3.1 Seed density 58
3.3.2 Inverse modelling results – seed production, dispersal and distances 60
3.3.2.1 Isotropic modelling 61
3.3.2.2 Anisotropic modelling 63
3.3.2.3 Statistical comparison isotropy vs. anisotropy 66
3.4 Discussion 67
3.4.1 Applied methodology for seed dispersal – trap design and inverse modelling 67
3.4.2 Seed dispersal modelling 69
3.5 Conclusion 74
References 75
4. Spatial analysis of Qualea grandiflora (Mart.) 80
4.1 Introduction 80
4.2 Methodology 82
4.2.1 Data collection – Field sampling 82
4.2.2 Data analysis 85
4.2.2.1 Spatial point pattern – Explorative analysis 85
4.2.2.2 Point process modelling (Poisson and Gibbs models) 87
4.2.3 Results 89
4.2.3.1 Spatial distribution of individuals of study species 89
4.2.3.2 Modelling distance effect of recruitment to adult trees 95
4.2.4 Discussion 102
4.2.4.1 Applied methodology for spatial analysis of study species 102
4.2.4.2 Spatial arrangement of study species 103
4.2.5 Conclusion 109
References 109
5. Spatial analysis of Aspidosperma tomentosum (Mart.)115
5.1 Introduction 115
5.2 Methodology 117
5.2.1 Data collection – Field sampling 117
5.2.2 Data analysis 120
5.2.2.1 Spatial point pattern – Explorative analysis 120
5.2.2.2 Point process modelling – Replicated point patterns 120
5.3 Results 123
5.3.1 Spatial distribution of natural regeneration of study species 123
5.3.2 Modelling shade and distance to seed tree effect on natural regeneration of study species 130
5.4 Discussion 133
5.4.1 Applied methodology for data collection and analysis 133
5.4.2 Spatial distribution of natural regeneration of study species 134
5.5 Conclusion 139
References 140
5. Concluding discussion and summary 146
6.1 Regeneration ecology of Qualea grandiflora and Aspidosperma tomentosum 146
6.1.1 Inferences on relation of seed dispersal and spatial distribution of recruitment of Qualea grandiflora 146
6.1.2 Inferences on spatial patterns of recruitment of Aspidoserma tomentosum 149
6.2 Management implications for Qualea grandiflora Aspidosperma tomentosum 150
6.3 Future research 153
6.4 Concluding summary 154
References 155
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The ecology of large herbivores native to the coastal lowlands of the fynbos biome in the Western Cape, South AfricaRadloff, Frans Gustav Theodor 12 1900 (has links)
Thesis (DSc (Botany and Zoology))—-Stellenbosch University, 2008. / The south-western Cape is a unique region of southern Africa with regards to generally low
soil nutrient status, winter rainfall and unusually species-rich temperate vegetation. This
region supported a diverse large herbivore (> 20 kg) assemblage at the time of permanent
European settlement (1652). The lowlands to the west and east of the Kogelberg supported
populations of African elephant, black rhino, hippopotamus, eland, Cape mountain and plain
zebra, ostrich, red hartebeest, and grey rhebuck. The eastern lowlands also supported three
additional ruminant grazer species - the African buffalo, bontebok, and blue antelope. The
fate of these herbivores changed rapidly after European settlement. Today the few remaining
species are restricted to a few reserves scattered across the lowlands. This is, however,
changing with a rapid growth in the wildlife industry that is accompanied by the
reintroduction of wild animals into endangered and fragmented lowland areas. These
reintroductions, together with the realisation that we have limited knowledge of the
functional role of native large herbivores in the fynbos ecosystem, provided the rationale for
this study. Questions on large herbivore ecology were addressed at three different spatial
scales.
At the biome level, the reason for the absence of three ruminant grazers from the western
lowlands was investigated. It was hypothesised that the absence of adequate high quality
fodder in the form of C4-grass during the hot and dry summers made it impossible for
buffalo, blue antelope, and bontebok to survive on the western lowlands. The results from
carbon isotope analysis of late prehistoric, historic and contemporary large herbivore remains
were consistent to this Summer Nutritional Stress Hypothesis. I found that eland, elephant,
grey rhebuck, ostrich, and red hartebeest (all species that historically occurred in both coastal
lowlands) can survive with very little (< 15%) C4 grass in their diet. In contrast, bontebok
utilized at least 43% C4 grass biomass in what was considered their natural habitats.
At a regional level, I tested the hypothesis that the large herbivores avoid nutrient-poor
sandstone, sand, and limestone fynbos shrublands in favour of the more nutrient-rich shale
renosterveld habitats. Support for this Renosterveld Preference Hypothesis was found by
means of dung count surveys, which showed that both eland and bontebok readily utilize
renosterveld, but avoid sandstone and limestone fynbos. In the latter they only utilize grassy
microhabitats such as karstic sinkhole depressions. The same hypothesis was addressed in a
novel way by using strontium isotope analysis and concluded that the technique needs more
refinement for it to produce reliable results.
At a landscape level, interactions between fire and grazing by native large herbivores in
relation to renosterveld vegetation dynamics were addressed. I conclude that the
disappearance of the native herbivores probably had little bearing on the putative structural
changes in renosterveld (grassland-shrubland dynamics). Support was found for the notion
that a high fire frequency followed by intense grazing by livestock could have converted
original renosterveld grasslands to unpalatable shrublands. Herbivory by native
grazers/browsers, or the release from it, cannot by itself bring about the vegetation-state
(structural) changes in renosterveld patches which had already been altered to herbivoretolerant
plant communities. However, in combination with fire, the presence or absence of
large herbivores can change the trajectory of the system among the alternative structural
states.
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The forest and the mainframe : the dynamics of modeling and field study in the Coniferous Forest Biome, 1969-1980Long, Tulley A. 28 July 2005 (has links)
In an initial research proposal of December 1969, the scientists of the Coniferous Forest Biome (CFB), an ecosystem study centered in the Pacific Northwest and part of the larger International Biological Programme (IBP),
expressed optimism that computer simulations and systems modeling could transform empirical knowledge of the carbon, water, and nutrient flows turned into viable forest management practice. The CFB's strategy aimed to use projections of the computer simulations and data from field study to constantly check and direct each other, resulting in a flexible, refined, and accurate understanding of forest ecosystems, as well as a reliable guide to forest management. To what extent did the CFB's research program, centered on a total system model, complete its cycle of field study, modeling, and validation? Despite the innovative strategies of the CFB modelers, ecosystem modeling lost its preeminent status among the goals of the CFB, due to different interpretations of the purpose and philosophy of ecosystem modeling and the practical limitations of administering a large research
program. Instead, small field-based studies during the CFB yielded a number of
ground-breaking discoveries. Although they diverged from the modeling objectives, these areas of fieldwork emerged from questions the forest's functions and cycling processes that the modeling efforts of the CFB required. Focusing on the work of CFB participants from Oregon State University and the USDA Forest Service in the H. J. Andrews Experimental Forest, this thesis addresses the relationship between the marginalization of the modeling objectives and the rising centrality of field-based forest studies in the CFB from 1969 to 1980. Given the ongoing legacy of CFB research at the Andrews Long-Term Ecological Research (LTER) site and the later implications of CFB findings in debates over forest policy and management, this thesis also seeks to evaluate the Coniferous Forest Biome as a whole and discuss the role of modeling and field work within large ecological research endeavors
more generally. / Graduation date: 2006
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Estimativas de variáveis biofísicas de vegetação campestre sob manejo pastoril por meio de sensoriamento remotoGuerini Filho, Marildo January 2018 (has links)
O Bioma Pampa representa aproximadamente 63% do território do Estado do Rio Grande do Sul - Brasil caracteriza-se pela alta biodiversidade de espécies vegetais e por sua formação predominantemente campestre. Em função da contínua incorporação de espécies exóticas, monoculturas e a práticas por vezes inadequadas de manejo pastoril para produção pecuária, os campos do Bioma Pampa estão rapidamente sendo degradados, fragmentados e descaracterizados. A Biomassa é uma das variáveis biofísicas estratégicas de interesse em estudos de controle, monitoramento e estimativas da vegetação campestre. O objetivo principal deste estudo é contribuir no desenvolvimento de novas estratégias de manejo e monitoramento adequados da vegetação campestre e inferir regressão linear multivariada para estimar a biomassa dos campos nativos a partir de dados remotos e dados de campo. As avaliações foram realizadas em área pertencente à Universidade Federal de Santa Maria, localizada na região central do Rio Grande do Sul. Os manejos pastoris correspondem a duas somas térmicas acumuladas, em dias, de 375 e 750 graus-dias (GD), que determinaram os intervalos entre pastoreio. Os dados remotos utilizados foram oriundos de imagem MSI do Satélite Sentinel-2 e dados de espectrorradiômetro com amplitude de 350-2500 nm. Verificou-se que as duas técnicas apresentaram resultados satisfatórios, em que inferiu-se regressões com r²ajustado = 0.65 para estimar biomassa verde e regressões com r²ajustado = 0.61 para biomassa total e biomassa senescente. Desta forma, o estudo verificou que é possível minimizar os esforços de campo para auxiliar no monitoramento, organização e conservação dos campos nativos do Bioma Pampa utilizando dados de sensoriamento remoto como ferramenta de manejo buscando a sustentabilidade destes complexos ambientes naturais. / The Pampa Biome represents approximately 63% of the territory in the State of Rio Grande do Sul - Brazil, characterized by the high biodiversity of plant species and its predominantly rural formation. As a result of the continuous incorporation of exotic species, monocultures and excessive cattle production, the Pampa Biome fields are rapidly being degraded, fragmented and decharacterized. Biomass is one of the strategic biophysical variables of interest in studies of prevention, monitoring and estimates of the country vegetation. The main objective of this study is to contribute to the development of new strategies for the proper management and monitoring of the country vegetation and to infer multivariate linear regression to estimate the biomass of the natural grassland in native fields from remote data and field data. The evaluations were carried out in an area belonging to the Federal University of Santa Maria, located in the central region of Rio Grande do Sul. Pastoral management correspond to two accumulated thermal sums in days of 375 and 750 degrees-days (GD), which determined the intervals between grazing. The remote data used came from MSI image of Sentinel-2 Satellite and spectroradiometer data with amplitude of 350-2500 nm. It was verified that the two techniques presented satisfactory results, in which regressions with adjusted r² of 0.65 were estimated to estimate green biomass and regressions with adjusted r²> 0.61 for total biomass and dry biomass. In this way, the study verified that it is possible to minimize the field efforts to assist in the monitoring, organization and conservation of the natural grassland in native fields of the Pampa Biome using remote sensing data as a management tool seeking the sustainability of these complex natural environments.
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Influência da monocultura de eucalipto sobre a vegetação campestre em área de Pampa no sul do BrasilHübel, Ingo 29 May 2009 (has links)
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Previous issue date: 2009-05-29 / Aracruz Celulose S/A / A implantação de monoculturas de eucalipto é muito criticada e tratada como responsável pela degradação do solo e por importantes mudanças biológicas. No Rio Grande do Sul a conservação dos campos se limita basicamente às Áreas de Preservação Permanente – APP, que prevêem a preservação de uma faixa de 30 m de vegetação ciliar a partir dos cursos d’água e também de áreas de reserva legal. Este estudo investiga as possíveis mudanças na diversidade, composição e abundância de espécies vegetais campestres em função da proximidade com plantações de eucalipto. O estudo foi realizado na fazenda Formosa, situada no município de São Gabriel, RS. Foram escolhidas três áreas com interface entre monocultura de eucalipto e campo e três áreas de campo sem plantio de eucalipto (controle). Um total de 120 parcelas fixas de 1 m x 1 m foi aleatorizado em transecções lineares a 5 e 30 m a partir da borda do eucalipto e do limite da APP nas áreas controle. Com auxílio de um quadro gradeado de 10 em 10 cm foi feito o levantamento da cobertura-abundância de todas as espécies vasculares presentes, além do levantamento de fatores de ambiente. No inventário foram encontradas 145 espécies vegetais campestres. A riqueza e diversidade de espécies apresentaram o mesmo padrão para as áreas com eucalipto, sendo que na monocultura a riqueza foi maior na borda e menor no interior em relação à APP adjacente, que apresentou riqueza intermediária e não diferiu entre si nas distâncias a partir da borda. Esse gradiente não é observado para áreas sem eucalipto. Em conjunto estes resultados sugerem um efeito da monocultura sobre a diversidade de espécies adjacente. A composição e abundância-cobertura de espécies variaram significativamente entre os ambientes avaliados. Fatores de ambiente como umidade relativa, compactação do solo e inclinação do terreno foram importantes na determinação da composição e abundância-cobertura de espécies nas APPs. Os resultados deste trabalho demonstram que apenas a manutenção de APPs com áreas de vegetação campestre não garante a manutenção da integridade biológica dos campos. / The establishment of monocultures of eucalyptus is criticized and regarded as responsible for soil degradation and significant biological changes. In Rio Grande do Sul, south Brazil, the conservation of grasslands is confined to areas of permanent preservation - APP's, defined by current legislation as the riparian vegetation extending 30 m from both sides of watercourses. This study investigates the possible changes induced by eucalyptus plantations on adjacent grassland APPs. The study was conducted in Formosa ranch, located in the municipality of São Gabriel, RS. Three areas with the interface between eucalyptus plantations and grassland APPs, and three other areas without eucalyptus plantations (control areas) were chosen for the study. A total of 120 1 m2 plots were randomized along linear transects established at 5 and 30 m from the edge of the APP both to the APP itself and towards the plantation interior (in areas with plantations) or towards grasslands outside APPs (in control areas). A grid of 10 by 10 cm was used to assess the cover-abundance of all vascular species present at each plot revealing a total of 145 plant species. The richness and diversity of species showed the same trend for areas with eucalyptus: inside plantations species richness was greater in the edge, while in the adjacent APP species richness did not present a clear distance gradient. Such a distinction between APPs and areas distant from APPs was not detected in control areas. In conjunction these results suggest a possible effect of the plantation upon the species richness of adjacent APPs. The composition and coverage-abundance varied significantly among the areas studied . Environmental factors such as soil humidity and compaction, and relief slope were important in determining the composition and abundance of species in APPs. This study shows that the maintenance of APPs do not suffice to preserve the integrity of grassland vegetation.
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Do desbravar ao cuidar : interdependências trabalho-educação no/do campo e a Amazônia Mato-GrossenseSouza, Maria Ivonete de January 2014 (has links)
A presente tese de doutorado é resultado de uma pesquisa realizada na Escola do Campo Florestam Fernandes, localizada no Projeto de Assentamento 12 de Outubro, Município de Cláudia, entrada do Bioma Amazônia mato-grossense. O trabalho de pesquisa tem como perspectiva analisar como se dá o fluxo entre as orientações do Movimento Camponês, da proposta de Educação do Campo e o Currículo desenvolvido pela Escola Estadual Florestan Fernandes, num contexto em que o bioma Amazônia Mato-grossense é devastado de forma avassaladora desde os anos 1970 quando os planos militaristas para essa região instituíram o processo colonizatório. Prioritariamente, o projeto militar, através da mercantilização dos territórios sob o álibi de integração e segurança nacional, “Ocupar para não Entregar”, interpôs o aniquilamento da floresta/biodiversidade, empreendido pela expansão do metabolismo social do capital na região. Num contexto macrocósmico, esse processo vem assolando tanto as possibilidades do Bem-Viver quanto nutrindo o modo de produção hegemônico. E por isso, concomitante ao desmatamento na região, um dos maiores do País, avançam os índices de desigualdade social. O mito do desbravamento e do progresso sedimenta-se na atualidade pelo modus operandi do agronegócio. Na vivência de lutas pelas condições vitais o sujeito histórico camponês se vê diante do grande desafio histórico de se aproximar da natureza, seu corpo inorgânico, como forma de sobreviver. Para isto, faz-se necessário romper com os ranços da Revolução Verde e o mito do desbravamento, ainda fortemente impregnados nas práticas sociais. À formação desse camponês convicto do seu trabalho interdependente à floresta/biodiversidade a Educação do Campo é convocada, prioritariamente, pelo Movimento Camponês, mas também, por todas as pessoas que, de uma forma ou de outra, entendem que a transformação social é urgente e nela perpassa, também, a construção de outra relação do gênero humano com a natureza. O aporte teórico metodológico utilizado neste trabalho funda-se no materialismo histórico e dialético como meio de contribuir, através da investigação científica, com a luta social para transformação da realidade socioambiental e educacional estudada. Para sustentação desta pesquisa estabeleceu- se um contínuo diálogo com autores de diversas teorias críticas, como: Triviños, Mészáros, Charlot, Taffarel, Ribeiro, Apple, e com os educadores-estudantes-camponeses. Essa trajetória densa e intensa de investigação conduziu-me à compreensão de que, embora os migrantes, base do campesinato local, possuam pouco conhecimento do Bioma Amazônia, e a luta pela terra-floresta não seja antagônica às lutas socioambientais, esse tema não integrou o currículo da escola estudada. O mito do desbravamento tem sido muito forte, dificultando uma práxis proximal camponês-floresta/biodiversidade, fazendo com que a floresta seja vista como selvagem e perigosa ao humano civilizado. Mesmo que o Movimento dos Trabalhadores Sem Terra (MST) e a Educação do Campo na região tenham contribuído para uma formação omnilateral do sujeito histórico camponês, a perspectiva de se constituírem em “cuidadores da floresta” ainda é uma construção incipiente diante da hegemonia do agronegócio da soja. Faz-se necessário, então, que sejam integrados nos currículos escolares os estudos sobre a agroecologia e suas práticas a fim de que possam corroborar com a compreensão dos Sistemas Agroflorestais, uma modalidade produtiva importante para manutenção da floresta em pé. / The present thesis is the outcome of a research carried out at Escola de Campo Florestam Fernandes, located in Settlement Project 12 de Outubro, Municipality of Claudia, gateway to the Mato Grosso Amazonian Biome. The research perspective has been to analyze how the flow between the orientations of the Peasant Movement of the proposed Field Education and Curriculum developed by the State School Florestan Fernandes, in a context where the Mato Grosso Amazonian biome has been overwhelmingly devastated since the 1970s when the militaristic government policies for the region begun the colonization process. Ultimately, the military project through the commodification of territories under the alibi of integration and national security, "Occupy not surrender" brought the destruction of the forest / biodiversity undertaken by the expansion of social metabolism of capital in the region. In a macrocosm context, this process has been sweeping both the possibilities of Good Living and has been nursing the hegemonic production way. Therefore, along with deforestation in the region, one of the largest in the country comes the advance of social inequality. The myth of progress by clearing and settles has its basis on the current modus operandi of agribusiness. Rural workers have been now struggling for vital living conditions where the historical peasant subject has presently been facing the historical challenge of approaching nature, its inorganic body, as a way to survive. For such, it is necessary to break with the stuffiness of the Green Revolution and the myth of the clearing, still strongly impregnated in social practices. The formation of this peasant convinced of his work interdependently to the forest / biodiversity Field Education is convened primarily by Peasant Movement, but also for all the people who in one way or another, understand that social change is urgent and it also pervades the construction of another relationship of humanity with nature. The methodological theoretical approach in this work is based on the historical and dialectical materialism as a means to contribute, through research, to fight for social and environmental transformation of the educational reality studied. To support this research we have established a continuous dialogue with authors of various critical theories: Triviños; Meszaros; Charlot; Taffarel; Ribeiro; Apple; and students-teachers-peasants.This dense and intense trajectory of research has led me to the realization that, although migrants as base of local peasantry, have little knowledge of the Amazonian Biome, and the struggle for forest-land is not antagonistic to environmental struggles, this topic has not integrated the curriculum of the school studied. The myth of the clearing has been very strong; making it difficult to peasant-forest/biodiversity proximal praxis, leading the forest to be seen as wild and dangerous to civilized humans. Even if the Movement of Landless and the Rural Education and in the region have contributed to unilateral formation of peasant historical subject, the perspective of getting themselves established as "caretakers of the forest" is still a fledgling construction in front of the hegemony of soy agribusiness. Therefore, it has been necessary the inclusion of a school curricula on agro-ecology study and its practices so that they can corroborate to the understanding of agroforestry systems, an important modality for the maintenance of productive forest.
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Influência da silvicultura na composição e diversidade de aves florestais no bioma pampaPezda, Angelo Marcon January 2015 (has links)
A perda e degradação de habitats são os principais fatores que geram diminuição da biodiversidade. A silvicultura é um dos maiores agentes de distúrbio ambiental para aves. Mudanças na diversidade de espécies entre ambientes podem ser geradas por dois mecanismos: aninhamento e/ou substituição (turnover) de espécies. As comunidades animais variam em relação às mudanças na composição dos ambientes, onde a distribuição das espécies responde aos arranjos espaciais dos elementos da paisagem. Assim, os objetivos deste trabalho foram: 1) descrever a assembleia de aves em talhões de Eucalyptus sp. 2) avaliar a composição da assembleia durante o ciclo silvicultural e a relação com a composição das assembleias de aves das matas ripárias nativas, distinguindo entre aninhamento e turnover e 3) verificar a influência do tipo de uso do solo adjacente aos plantios na riqueza das assembleias de aves. O estudo foi realizado em talhões de Eucalyptus sp. em diferentes estágios de desenvolvimento e em porções de florestas ripárias no Bioma Pampa, sendo coletado informações sobre riqueza e composição das assembleias de aves, através de pontos de contagem. Para a composição de espécies, foram realizadas análises de diversidade beta, distinguindo entre aninhamento e turnover, mostrando que a maior semelhança da composição das assembleias de aves ocorreu entre os diferentes estágios do plantio do que destes com a floresta ripária, e que a semelhança da assembleia de aves dos plantios com a assembleia da floresta nativa é menor em estágios avançados de desenvolvimento. Para as variáveis do entorno, foram feitas regressões múltiplas, indicando que a presença de ambiente florestal nativo, influencia na riqueza de espécies de aves dos plantios de Eucalyptus sp., apesar de poucas espécies de interior de floresta contribuírem para composição da assembleia de aves deste ambiente antrópico. / Habitat loss and degradation are the major factors driving biodiversity loss. Silviculture is a relevant environmental disruption agent to birds. Changes in species diversity among environments can be generated by two mechanisms: nestedness and/or turnover. Animal communities vary in relation to changes of environment composition, where the species distribution respond to spatial arrangements of landscape elements. The goals of this study were: 1) describe the birds assembly in Eucalyptus sp. stands, 2) avaluate the assembly composition during the silvicultural cycle, relating to the composition of birds in the native riparian forests, distinguishing between nestedness and turnover, and 3) verify the influence of adjacent land use, on the birds assembly richness. The study took place in stands of Eucalyptus sp. in different development stages and in riparian forests portions in the Pampa Biome, and was collected information about richness and birds assembly composition by counting points. For species composition, were carried out beta diversity analyzes, distinguishing between nestedness and turnover, showing that the greatest similarity of the birds assembly composition was between the differents plantation stages than those compared to riparian forest, and the similarity of the composition of plantations birds assembly between the native forest assembly, it is smaller in Eucalyptus sp. advanced development stages. For the environmental variables, multiple regression analysis was made, indicating that the presence of surrounding native forest environments hold the richness of bird species in Eucalyptus sp. plantations, despite a few of forest interior species contribute to the man-made environmental birds assembly composition.
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Padrões de diversidade e estruturação das comunidades de anfíbios anuros no Parque Estadual do Mirador-MA / e. Diversity patterns and structure of anuran communities in the Parque Estadual do Mirador-MAANDRADE, Etielle Barroso de 13 June 2017 (has links)
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Previous issue date: 2017-06-13 / FAPEMA / This study aimed to evaluate the diversity patterns and structure of anuran’s communities in the
Cerrado remnants of the Parque Estadual do Mirado-PEM, correlating environmental variables
with distribution patterns of the species and identifying factors that determine the conservation
status of the park. Although the PEM is located an area of great ecological importance, few
studies were conducted on the biological communities, especially of amphibians. Thus, we
perform a survey about the amphibian’s species describing the richness and composition of
anuran fauna and analyzing the influence of different vegetation types in their formation. The
sampling was carried out through active search and survey on breeding sites in different water
bodies in the PEM, which resulted in the registration of 31 species belonging to five families:
Leptodactylidae, Hylidae, Bufonidae, Microhylidae and Phyllomedusidae. Species richness in
the PEM was greater than that recorded by several other authors in different regions of Brazil,
being formed by typical Cerrado species and by species strongly associated with other biomes.
The replacement of the species among the different water bodies was considered high in all
combination pairs tested, even among the nearest water bodies. The results revealed a different
use in vocalization sites, forming different groups with varying degrees of overlap, with
environmental heterogeneity being the best criterion to explain the high diversity and spatial
and temporal distribution of the species. Structurally complex environments have greater
availability of resources and the composition of communities is regulated by the degree of
overlap in the use of available microenvironments. The PEM is an important corridor
bioregional conservation and understand the factors that act on the ecological and
biogeographic processes of species are useful in the implementation of the management plan
of the park and essential for the conservation of amphibians of the Maranhão state. / O presente trabalho teve por objetivo avaliar os padrões de diversidade e estruturação das
comunidades de anfíbios anuros em remanescentes de Cerrado do Parque Estadual do MiradorPEM,
correlacionando as variáveis ambientais com os padrões de distribuição das espécies e
identificando fatores que determinem o estado de conservação do parque. Apesar do PEM se
encontrar numa área de grande importância ecológica, poucos foram os trabalhos realizados
sobre as comunidades biológicas, especialmente a de anfíbios. Assim, foi realizado um
levantamento das espécies de anfíbios, de modo a descrever a riqueza e a composição da
anurofauna, analisando a influência dos diferentes tipos vegetacionais na sua formação. As
amostras foram realizadas através de procura ativa e o levantamento em sítios reprodutivos em
diferentes corpos d’água no parque que resultou no registro de 31 espécies, pertencentes à cinco
famílias: Leptodactylidae, Hylidae, Bufonidae, Microhylidae e Phyllomedusidae. A riqueza de
espécies no PEM foi maior que a registrada por vários outros autores em diferentes regiões do
Brasil, sendo formada por espécies típicas de Cerrado e por espécies fortemente associadas a
outros biomas. A substituição das espécies entre os diferentes corpos d’água amostrados foi
considerada elevada em todos os pares de combinação testados, mesmo entre os corpos d’água
mais próximos. Os resultados revelaram o uso diferenciado nos sítios de vocalização, formando
diferentes grupos com graus variados de sobreposição, sendo a heterogeneidade ambiental o
melhor critério para explica a elevada diversidade e a distribuição espaço-temporal das
espécies. Ambientes estruturalmente complexos apresentam maior disponibilidade de recursos
e a composição das comunidades é regulada pelo grau de sobreposição no uso dos
microambientes disponíveis. O PEM é um importante corredor biorregional de conservação e
entender os fatores que agem sobre os processos ecológicos e biogeográficos das espécies são
úteis na implantação do plano de manejo do parque e fundamental para a conservação das
espécies de anfíbios anuros do Maranhão.
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Plant traits as predictors of ecosystem change and function in a warming tundra biomeThomas, Haydn John David January 2018 (has links)
The tundra is currently warming twice as rapidly as the rest of planet Earth, which is thought to be leading to widespread vegetation change. Understanding the drivers, patterns, and impacts of vegetation change will be critical to predicting the future state of tundra ecosystems and estimating potential feedbacks to the global climate system. In this thesis, I used plant traits - the characteristics of individuals and species - to investigate the fundamental structure of tundra plant communities and to link vegetation change to decomposition across the tundra biome. Plant traits are increasingly used to predict how communities will respond to environmental change. However, existing global trait relationships have largely been formulated using data from tropical and temperature environments. It is thus unknown whether these trait relationships extend to the cold extremes of the tundra biome. Furthermore, it is unclear whether approaches that simplify trait variation, such as the categorization of species into functional groups, capture variation across multiple traits. Using the Tundra Trait Team database - the largest tundra trait database ever compiled - I found that tundra plants revealed remarkable consistency in the range of resource acquisition traits, but not size traits, compared to global trait distributions, and that global trait relationships were maintained in the tundra biome. However, trait variation was largely expressed at the level of individual species, and thus the use of functional groups to describe trait variation may obscure important patterns and mechanisms of vegetation change. Secondly, plant traits are related to several key ecosystem functions, and thus offer an approach to predicting the impacts of vegetation change. Notably, understanding the links between vegetation change and decomposition is a critical research priority as high latitude ecosystems contain more than 50% of global soil carbon, and have historically formed a long-term carbon sink due to low decomposition rates and frozen soils. However, it is unclear to what extent vegetation change, and thus changes to the quality and quantity of litter inputs, drives decomposition compared to environmental controls. I used two common substrates (tea), buried at 248 sites, to quantify the relative importance of temperature, moisture and litter quality on litter decomposition across the tundra biome. I found strong linear relationships between decomposition, soil temperature and soil moisture, but found that litter quality had the greatest effect on decomposition, outweighing the effects of environment across the tundra biome. Finally, I investigated whether tundra plant communities are undergoing directional shifts in litter quality as a result of climate warming. Given the importance of litter quality for decomposition, a shift towards more or less decomposable plant litter could act as a feedback to climate change by altering decomposition rates and litter carbon storage. I combined a litter decomposition experiment with tundra plant trait data and three decades of biome-wide vegetation monitoring to quantify change in community decomposability over space, over time and with warming. I found that community decomposability increased with temperature and soil moisture over biogeographic gradients. However, I found no significant change in decomposability over time, primarily due to low species turnover, which drives the majority of trait differences among sites. Together, my thesis findings indicate that the incorporation of plant trait data into ecological analyses can improve our understanding of tundra vegetation change. Firstly, trait-based approaches capture variation in plant responses to environmental change, and enable prediction of vegetation change and ecosystem function at large scales and under future growing conditions. Secondly, my findings offer insight into the potential direction, rate and magnitude of vegetation change, indicating that despite rapid shifts in some traits, the majority of community-level trait change will be dependent upon the slower processes of migration and species turnover. Finally, my findings demonstrate that the impact of warming on both tundra vegetation change and ecosystem processes will be strongly mediated by soil moisture and trait differences among vegetation communities. Overall, my thesis demonstrates that the use of plant traits can improve climate change predictions for the tundra biome, and informs the fundamental rules that determine plant community structure and change at the global scale.
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As mudanças climáticas globais e as ONGs socioambiental brasileiras: novas estratégias de conservação para a Amazônia / The global climate change and the Brazilian social environmental NGOs: new strategies to the Amazon conservation.Couto, Gabriela de Azevedo 17 January 2012 (has links)
A emergência das mudanças climáticas globais como problemática socioambiental central dos tempos atuais impõe-se como um desafio não só porque exige da sociedade medidas para minimizar os impactos e buscar novos modos de vida em um planeta em transformação, mas principalmente porque demanda um melhor entendimento sobre como as alterações no clima são percebidas e interpretadas pela sociedade, assim como sobre a propensão de determinados grupos sociais para intervir no tema. Este estudo tem como objetivo compreender uma parte deste processo, investigando, a partir da emergência e posicionamento do tema Mudanças Climáticas Globais na agenda internacional, como as estratégias e ações de ONGs ambientalistas brasileiras para conservação da Amazônia são influenciadas. Isso porque o desmatamento da floresta Amazônica se apresenta como o maior responsável pelos altos índices de emissões brasileiras de Gases de Efeito Estufa, mas também porque a floresta amazônica é considerada um importante sumidouro de carbono. Além disso, este estudo apresenta elementos que mostram a importância da atuação de ONGs ambientalistas brasileiras, uma vez que influenciam os processos de tomada de decisão relativos às mudanças climáticas no âmbito nacional e internacionalmente. Esta pesquisa concentra-se em compreender o papel desempenhado por um grupo específico de organizações não-governamentais ambientalistas brasileiras no processo social que contribui para o debate relativo à problemática estabelecida. São organizações que vêm se articulando com diferentes parceiros, desenvolvendo novos projetos, inovando em suas estratégias de atuação social e política, transitando da escala local à global e ampliando e diversificando seu universo de ações e relações, sem que para isso tenham que modificar sua missão. A principal ideia da dissertação é que estas organizações não devem ser consideradas meras oportunistas por lidarem com um tema da moda, nem tampouco reféns de financiadores que impõem a elas suas prioridades; ao contrário, são organizações que contribuem para a construção de novas agendas e constroem novas oportunidades de financiamento a fim de continuarem cumprindo com sua missão. / The emergence of global climate change is a unique social and environmental problematic. Climate change is a challenge, not only because it requires societal measures to minimize impacts and to search for new ways of life in a transforming world, but especially because it demands a better understanding of how climate change is perceived and interpreted by different societies, and of the willingness of social groups to act in response to these challenges. The objective of this study is to understand one part of this process, evaluating how the strategies and actions of Brazilian environmental NGOs advocating the conservation of the Amazon are influenced by the emergence and positioning of the Global Climate Change issue on the international agenda. This connection is important, both because the deforestation of the Amazon is the main contributor to high Brazilian greenhouse gas emissions, and because the forest is an important carbon stock for the world. This study presents evidence that demonstrates the importance of some Brazilian environmental NGOs, which exert influence on decision-making processes at national and international climate change talks. Moreover, the research is focused on understanding the role played by a specific group of Brazilian environmental NGOs in the bottom-up social processes that contribute to the climate change debate. These organizations articulate among different partners, develop new projects and innovate in their strategies for social and political action. They transit from the local to the global scale, amplifying and diversifying their range of activities and relationships, all of this without the need for change in their institutional missions. The central thesis of this dissertation, then, is that these organizations not be considered as mere opportunists because they are now dealing with a fashionable issue, or as hostages of international donors that impose new priorities. Rather, they are argued to be organizations that contribute to the development of new agendas and the building of new financing opportunities, in order to continue striving toward the achievement of their institutional missions.
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