• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2
  • 1
  • 1
  • Tagged with
  • 4
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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.
1

Restauração florestal versus referência ecológica: utilização de indicadores ecológicos em ambientes ciliares na Floresta Ombrófila Mista / Forest restoration versus ecological reference: use of ecological indicators in riparian environments in Araucaria Forest

Stedille, Lilian Iara Bet 18 July 2016 (has links)
Submitted by Claudia Rocha (claudia.rocha@udesc.br) on 2017-12-08T12:33:43Z No. of bitstreams: 1 PGEF16MA062.pdf: 2473191 bytes, checksum: cbe6e188be2f3f4cf384e50b2938078b (MD5) / Made available in DSpace on 2017-12-08T12:33:43Z (GMT). No. of bitstreams: 1 PGEF16MA062.pdf: 2473191 bytes, checksum: cbe6e188be2f3f4cf384e50b2938078b (MD5) Previous issue date: 2016-07-18 / PROMOP / The forest succession is a way to restore disturbed forest. Measure taken to to the of permanent preservation areas (PPA’s) adequacy, mainly riparian, wood-producing farms in the Santa Catarina Plateau South region. Since the need for monitoring of these environments the main objective of this study was to investigate the passive restoration in riparian forest on Poço Grande and Campo de Dentro farms, with the main focus for the survey of the tree composition. Only on the Poço Grande farm has further study, envolvento environmental compartmentalization in forest "reference" ecological formed by fragments into more advanced successional stage and locations in passive "restoration". Where it was included natural regeneration, seed bank, the presence of grasses (Ocellochloa rudis (Nees) Zuloaga & Morrone and Merostachys multiramea Hack), soil and canopy. The results of the first chapter indicates that compartmentalization on the farm Poço Grande showed that the sites in "restoration" have lower density values, basal area, evenness among arboreal, and greater participation of pioneers and autocóricos individuals. In the second chapter between 23 variables, the existence of an ecological gradient of diversity (Shannon index of tree) standing out among the other variables involved. The second gradient formed is related to the presence of O. rudis and higher soil pH and effective cation exchange capacity, even without a relationship with a sector, may influence the formation of a dense layer of biomass. The tree composition of Poço Grande and Campo de Dentro farms for years of assessment 2011 and 2016, has among the species most phytosociologic position. Between evaluated the sampled species follow the same pattern of ecological groups and dispersal syndromes, with high participation of zoochorous. Since the Poço Grande farm, a decrease in the share of late side individuals and increase climax individuals. Inside the Campo de Dentro farm was an 15 16 increase in the proportion of pioneering individuals and decrease among individuals climax. In both farms there was an increase of individuals with syndrome zoochoric dispersion and a decrease of anemochorous and autocóricos. The methodology of passive restoration proved to be a promising alternative in locations with favorable landscape. Indicates continuing the monitoring / A sucessão florestal é uma maneira de restaurar florestas alteradas. Medida adotada para para a adequação de áreas de preservação permanente (APP), principalmente ciliares, em fazendas produtoras de madeira na região do Planalto Sul Catarinense. Visto a necessidade de monitoramento destes ambientes o objetivo principal deste trabalho foi investigar a restauração passiva nas áreas ciliares das fazendas Poço Grande e Campo de Dentro, com enfoque principal para o levantamento da composição arbórea. Apenas na fazenda Poço Grande tem-se um estudo mais aprofundado, envolvento a setorização ambiental, em floresta de “referência” ecológica formada por fragmentos em estádio sucessional mais avançado e, locais em “restauração” passiva. Onde incluiu-se o levantamento da regeneração natural, banco de sementes, presença de gramíneas (Ocellochloa rudis (Nees) Zuloaga & Morrone e Merostachys multiramea Hack), solos e dossel. Os resultados do primeiro capítulo indicam que a setorização na fazenda Poço Grande evidenciou que os locais em “restauração” apresentam menores valores de densidade, área basal, equabilidade entre adultos, e maior participação de indivíduos pioneiros e autocóricos. No segundo capítulo entre 23 variáveis analisadas, a existência de um gradiente ecológico de diversidade (índice de Shannon de árboreas) sobressaindo-se entre as demais variáveis envolvidas. O segundo gradiente formado está relacionado a presença de O. rudis, com maiores valores de pH do solo e capacidade de troca catiônica efetiva, que mesmo sem uma relação com algum setor, pode influênciar pela formação de uma densa camada de biomassa. Ao avaliar a composição arbórea das fazendas Poço Grande e Campo de Dentro, para os anos de avaliação 2011 e 2016, tem-se a manutenção das espécies de maiores valores de importância. Entre os anos avaliados as espécies seguem o mesmo padrão de grupos ecológicos e síndromes de dispersão, com elevada participação de zoocó 11 12 ricas. Sendo que na fazenda Poço Grande, ocorreu diminuição na participação dos indivíduos secundários tardios e, aumento de indivíduos clímax. Na fazenda Campo de Dentro ocorreu aumento na proporção de indivíduos pioneiro e diminuição entre os indivíduos clímax. Em ambas fazendas se verificou um aumento de indivíduos com síndrome de dispersão zoocórica e, uma diminuição de anemocóricos e autocóricos. A metodologia da restauração passiva mostrou-se como uma alternativa promissora em locais com paisagem favorável. Indica-se dar continuidade ao monitoramento
2

Impacts des caractéristiques du peuplement et des cloisonnements sur la biodiversité floristique en forêt de plaine / Effects of stand attributes and skid trails on ground flora diversity in lowland forests

Wei, Liping 26 September 2014 (has links)
Le maintien ou l'amélioration de la biodiversité est un des objectifs importants de la gestion forestière durable. La flore du sous-bois, qui représente la partie la plus diversifiée de la flore dans les forêts tempérées, joue des rôles écologiques importants. Pourtant, elle pourrait être impactée par l'augmentation de la mécanisation de la gestion forestière. A l'échelle de la parcelle, nous avons étudié en forêt de Montargis les effets simples et combinés de caractéristiques du peuplement et de la surface en cloisonnement sur la diversité floristique du sous-bois (richesse et abondance). Les caractéristiques du peuplement (type de peuplement ou surface terrière des essences à étaient les meilleurs indicateurs de la diversité du sous-bois. La surface des cloisonnements avait un effet négligeable. A plus petite échelle – à l’intérieur du cloisonnement – nous avons étudié la réponse statistique de la diversité du sous-bois à la position dans ou hors du cloisonnement, à des facteurs micro-environnementaux (humidité du sol, compaction du sol, lumière) et aux caractéristiques du peuplement. A cette échelle, les meilleurs modèles incluaient pour les groupes écologiques la position par rapport au cloisonnement, l’humidité du sol et/ou la compaction du sol, selon le groupe écologique considéré. Au niveau espèce, la position par rapport au cloisonnement était le facteur dominant. Globalement, les cloisonnements avaient soit pas d’effet soit un impact positif sur la diversité floristique de sous-bois. Ces résultats ont dépendants du contexte écologique et historique de la forêt de Montargis. L’utilisation d’engins plus lourds ou des passages répétés sur une plus longue période pourraient changer ces conclusions. / Maintaining or improving biodiversity is an important goal of sustainable forest management.Ground flora, which is responsible for most floristic diversity in temperate forests, plays multiple important roles in biodiversity but may be impacted by the increasing mechanisation of forest practices. At stand scale, we investigated in Montargis forest the individual and combined effects of tree stand attributes and skid trail area on ground flora diversity. Tree stand attributes (stand type or basal area) were the best indicators of ground flora diversity, depending on the successional traits or light preference of the species group. The effects of skid trail area were negligible. At finer scale, we studied plant response to skid trail disturbance (represented by subplot on and off skid trails), micro-environmental factors (soil moisture, soil compaction, light) and stand attribute (stand type, basal area). The best models for ecological groups included subplot location, soil moisture or soil compaction, depending on which ecological groups (classified by life form, seed bank persistence, light and moisture requirements) the species belonged to. Stand type as a covariate played a significantly important role in fine-scale diversity pattern. Subplot location was the dominant factor at species level. In conclusion, skid trails had either no impact or a positive impact on ground flora diversity. These results are dependent on the context of Montargis forest (ecological and historical), especially that mechanized harvesting is relatively recent. The employment of heavier machines and increased number of passages is likely to happen. This might induce greater soil compaction and negative effects on plant.
3

Methodological investigations on vegetation typology and phytogeography of rain forests of tropical Africa

Senterre, Bruno B.M.L. 17 June 2005 (has links)
I. An original methodological discussion is proposed on the problem of the typology of tropical rain forest’s plant communities, based on the study of forest types across gradients of continentality and elevation, within Atlantic central Africa. These investigations were based on the statement that the main problems in forest typology are related to the non-zonal or zonal character of the different vegetation types and to non considering the relations and differences between forest strata. II. Field data consisted in phytosociological homogeneous sample plots localized within different recognized phytogeographical entities, in a region of tropical Africa where these entities are known to be well conserved. A total of 37 such plots were inventoried in the region extending from the littoral forests of Ndoté, Equatorial Guinea, which are wet evergreen forests, to the continental forests of the Dja, Cameroon, known as evergreen seasonal forests. The studied region also included the oriental Atlantic forests of Equatorial Guinea, known as moist evergreen forests or caesalp forests. In various parts of this continentality gradient, some plots were localized within climax non-zonal formations, namely the submontane rain forests. The emphasis was put on the vegetation of the Monte Alén National Park. The sampling methodology was willing to be as "complete ", including all strata, "quantitative ", enumerating all individuals, and "representative ", within each stratum, as possible. These multi-layers plots were realised using nested sub-plots, with a sampling size of 100 individuals for every ligneous stratum recognized (dominant trees, dominated trees and shrubs) and a sampling size of 200m² for the herbaceous and suffrutex stratum. Forest types were defined independently for each stratum and the differences were analysed. A method was proposed for the simultaneous analysis of all floristic data, converting and standardizing the values from ligneous strata, on the one hand, and from understorey strata, on the other hand. III. Ten forest types were described using IndVal and discussed in the general context of the guineo-congolian region, from a syntaxonomic view point (agglomerative classification) and from a phytogeographical view point (divisive classification). Homologies between these two approaches are described. The proposed phytogeographical system is based on an "open " conception of hierarchical classifications, combining advantages of agglomerative and divisive classifications. In concrete terms, the non-zonal criteria, for example the submontane variants, are categorised separately and in analogy with the zonal criteria, related to the usual phytochoria. Analysis of ecological relationships for the 10 communities showed that the main variables related to the floristic variability in our mainland rain forests are elevation, rainfall, hygrometry (estimated using bryophytes cover levels) and distance to the ocean. The two extremes on the vertical microclimatic gradient, dominant trees stratum and herbaceous stratum, give similar typologies, however canonical analysis showed that for the herbaceous layer, non-zonal variables (hygrometry and elevation) were gaining more importance when the influence of the two zonal variables was attenuated. In every case, spatial autocorrelation was less important than the environment in explaining floristic variability but its role increased in the spatial arrangement of understorey species, whose dispersal capacity is generally lower than canopy trees. The phytosociological, phytogeographical and ecological description of forest types is accompanied by a physiognomical description using biological types spectrum, as well as architectural models, leaf sizes, etc. With regard to diversity, we have demonstrated that species richness was higher from upper to lower strata because of the accumulation in lower strata of species from various strata. On the other hand, the proper stratum diversity, i.e. the structural set, decreased from dominant trees to shrubs. The proper diversity of the herb layer showed relatively high figures mainly due to the higher individual density in relation to the existence of microstrata. Within the 37 sample plots, 1,050 taxa have been identified to species or morpho-species levels, for a total of 25,750 individuals. These taxa represent 442 genus among 104 families. The richest forest type is found on the foothills of the Niefang range, on the windward side. This forest type is also characterised by a high number of oligotypic genus and by species belonging to functional types indicators of glacial refuges. These functional types are defined on the basis of the dispersal capacity and on kind of stand needed for effective germination. We formulated the hypothesis that this kind of "foothills refuge ", characterised by his zonal nature, could have been one of the rare refuges for species from mainland rain forests, while montane and fluvial refuges would mainly have preserved species from non-zonal forest types: (sub)montane and riverine. Based on indicator species of submontane forests, a potential distribution map of this forest type has been realised at the Atlantic central African scale. More than 400 submontane forest localities have been mapped. These forests begin at 400m of altitude near the ocean, and progressively at higher altitude for increasing distance to the ocean. Many lowland localities also comprised submontane species, which could indicate the existence of ecological transgressions. These transgressions would allow migratory tracks for submontane species between isolated mountain ranges, not only during glacial periods, through heights at the northern and southern borders of the congo basin, but also contemporarily through the lowland riverine forest network, in the centre of this basin. Finally, a special attention has been attributed to littoral forests and to some cases of choroecological transgressions, coupled to the ecological equalization phenomenon.
4

Recherches méthodologiques pour la typologie de la végétation et la phytogéographie des forêts denses d'Afrique tropicale

Senterre, Bruno 17 June 2005 (has links)
I. An original methodological discussion is proposed on the problem of the typology of tropical rain forest’s plant communities, based on the study of forest types across gradients of continentality and elevation, within Atlantic central Africa. These investigations were based on the statement that the main problems in forest typology are related to the non-zonal or zonal character of the different vegetation types and to non considering the relations and differences between forest strata.<p><p>II. Field data consisted in phytosociological homogeneous sample plots localized within different recognized phytogeographical entities, in a region of tropical Africa where these entities are known to be well conserved. A total of 37 such plots were inventoried in the region extending from the littoral forests of Ndoté, Equatorial Guinea, which are wet evergreen forests, to the continental forests of the Dja, Cameroon, known as evergreen seasonal forests. The studied region also included the oriental Atlantic forests of Equatorial Guinea, known as moist evergreen forests or caesalp forests. In various parts of this continentality gradient, some plots were localized within climax non-zonal formations, namely the submontane rain forests. The emphasis was put on the vegetation of the Monte Alén National Park.<p><p>The sampling methodology was willing to be as "complete ", including all strata, "quantitative ", enumerating all individuals, and "representative ", within each stratum, as possible. These multi-layers plots were realised using nested sub-plots, with a sampling size of 100 individuals for every ligneous stratum recognized (dominant trees, dominated trees and shrubs) and a sampling size of 200m² for the herbaceous and suffrutex stratum.<p><p>Forest types were defined independently for each stratum and the differences were analysed. A method was proposed for the simultaneous analysis of all floristic data, converting and standardizing the values from ligneous strata, on the one hand, and from understorey strata, on the other hand.<p><p>III. Ten forest types were described using IndVal and discussed in the general context of the guineo-congolian region, from a syntaxonomic view point (agglomerative classification) and from a phytogeographical view point (divisive classification). Homologies between these two approaches are described. The proposed phytogeographical system is based on an "open " conception of hierarchical classifications, combining advantages of agglomerative and divisive classifications. In concrete terms, the non-zonal criteria, for example the submontane variants, are categorised separately and in analogy with the zonal criteria, related to the usual phytochoria.<p><p>Analysis of ecological relationships for the 10 communities showed that the main variables related to the floristic variability in our mainland rain forests are elevation, rainfall, hygrometry (estimated using bryophytes cover levels) and distance to the ocean. The two extremes on the vertical microclimatic gradient, dominant trees stratum and herbaceous stratum, give similar typologies, however canonical analysis showed that for the herbaceous layer, non-zonal variables (hygrometry and elevation) were gaining more importance when the influence of the two zonal variables was attenuated. In every case, spatial autocorrelation was less important than the environment in explaining floristic variability but its role increased in the spatial arrangement of understorey species, whose dispersal capacity is generally lower than canopy trees. The phytosociological, phytogeographical and ecological description of forest types is accompanied by a physiognomical description using biological types spectrum, as well as architectural models, leaf sizes, etc.<p><p>With regard to diversity, we have demonstrated that species richness was higher from upper to lower strata because of the accumulation in lower strata of species from various strata. On the other hand, the proper stratum diversity, i.e. the structural set, decreased from dominant trees to shrubs. The proper diversity of the herb layer showed relatively high figures mainly due to the higher individual density in relation to the existence of microstrata. Within the 37 sample plots, 1,050 taxa have been identified to species or morpho-species levels, for a total of 25,750 individuals. These taxa represent 442 genus among 104 families. The richest forest type is found on the foothills of the Niefang range, on the windward side. This forest type is also characterised by a high number of oligotypic genus and by species belonging to functional types indicators of glacial refuges. These functional types are defined on the basis of the dispersal capacity and on kind of stand needed for effective germination. We formulated the hypothesis that this kind of "foothills refuge ", characterised by his zonal nature, could have been one of the rare refuges for species from mainland rain forests, while montane and fluvial refuges would mainly have preserved species from non-zonal forest types: (sub)montane and riverine.<p><p>Based on indicator species of submontane forests, a potential distribution map of this forest type has been realised at the Atlantic central African scale. More than 400 submontane forest localities have been mapped. These forests begin at 400m of altitude near the ocean, and progressively at higher altitude for increasing distance to the ocean. Many lowland localities also comprised submontane species, which could indicate the existence of ecological transgressions. These transgressions would allow migratory tracks for submontane species between isolated mountain ranges, not only during glacial periods, through heights at the northern and southern borders of the congo basin, but also contemporarily through the lowland riverine forest network, in the centre of this basin. Finally, a special attention has been attributed to littoral forests and to some cases of choroecological transgressions, coupled to the ecological equalization phenomenon.<p> / Doctorat en sciences agronomiques et ingénierie biologique / info:eu-repo/semantics/nonPublished

Page generated in 0.0636 seconds