Abstract The topography of the Milešov part of the České středohoří Mts represents a suitable model for study of spatial distribution of diversity and the effects of ecological factors on species diversity and composition. Near-natural forest vegetation was sampled at eleven hills by stratified-randomly sited relevés. Soil samples were collected in relevés at nine hills also. The soil samples were used for maximal capillary capability, pH, carbon and nitrogen volume analyses. These ecological factors, as well as tree cover, altitude and heat load index, were used for examination of the correlation of ecological factors with diversity, species richness and species composition. Positive relationship between species richness and heat load index and soil reaction was identified. Species diversity (Shannon index) positively correlates with soil reaction also. After partialling out geographic components in the samples, a significant correlation between the heat load index, tree cover and altitude and species composition of the herb and shrub layer was found. Values of alpha and beta components were rated using partitioning of diversity to alpha and beta components at four levels (relevé - aspect - hill - landscape). The beta component at the aspect level and the beta component at the hill level were...

Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2018-07-06T13:25:22Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) thais_ribeiro_costa.pdf: 3235496 bytes, checksum: 6f8cdc08809043df5efea75372782e92 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2018-07-18T13:13:10Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) thais_ribeiro_costa.pdf: 3235496 bytes, checksum: 6f8cdc08809043df5efea75372782e92 (MD5) / Made available in DSpace on 2018-07-18T13:13:10Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) thais_ribeiro_costa.pdf: 3235496 bytes, checksum: 6f8cdc08809043df5efea75372782e92 (MD5) Previous issue date: 2017 / Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Este estudo teve como objetivo conhecer a composi??o flor?stica da comunidade arb?rea e sua rela??o com o ambiente, bem como avaliar a diversidade, estrutura e as fun??es ecol?gicas das esp?cies de dezoito fragmentos de mata de galeria inund?vel. Al?m disso, se prop?s a caracterizar a vegeta??o da matriz de entorno de nove fragmentos de mata e galeria, bem como verificar se vari?veis ambientais atuam na transi??o entre as duas fitofisionomias, com ?nfase nas propriedades qu?micas do solo. O estudo foi conduzido no Parque Nacional das Sempre-Vivas, na Serra do Espinha?o, Minas Gerais. Foram inventariadas 5% da ?rea total de cada fragmento, instalando-se parcelas permanentes de 100 m? (totalizando 0,72 ha de amostragem), onde foram amostrados todos os indiv?duos arb?reos com di?metro ? altura do peito igual ou superior a 5 cm (DAP ? 5 cm). Para amostragem da cobertura vegetacional da matriz de entorno, foi utilizado o m?todo dos pontos, totalizando 12 pontos por fragmento, distribu?dos nas dist?ncias de 10, 20 e 30 m no sentido borda-campo. Em cada parcela e em cada ponto, foi mensurada a umidade do solo e coletadas amostras de solo, para posteriores an?lises qu?micas. Para os fragmentos foram mensurados qualitivamente a cobertura do dossel, altura de crestamento e impactos ambientais. Foram amostrados 1265 indiv?duos arb?reos, distribu?dos em 76 esp?cies, 55 g?neros e 32 fam?lias. A comunidade em geral, apresentou valores de diversidade e equabilidade compativeis com outras matas de galeria inund?veis do pa?s. As esp?cies amostradas foram agrupadas em seis grupos funcionais distintos. A maioria dos fragmentos apresentou uma tend?ncia de est?gio seral mais avan?ado, com esp?cies predominantemente secund?rias iniciais e tardias, zooc?ricas, zoo?filas, densidade m?dia da madeira, sementes recalcitrantes e pl?ntulas do tipo faneroep?geo-foli?ceo. A distribui??o por classes diam?tricas dos indiv?duos da comunidade arb?rea e para as principais popula??es obteve uma tend?ncia de J-invertido, indicando bom potencial regenerativo. As vari?veis ambientais que se correlacionaram com a varia??o da composi??o de esp?cies foram ? disponibilidade de ?gua e condi??es de acidez. O baixo percentual de explica??o das vari?veis ambientais e espaciais ressaltam que as esp?cies nos fragmentos de mata de galeria distribuem-se de maneira estoc?stica. O fogo constituiu o impacto mais frequente no interior dos fragmentos, o que ressalta a necessidade de t?cnicas de manejo nessas ?reas. Os campos ?midos ao entorno dos fragmentos apresentaram-se com elevada cobertura de herb?ceas, mesmo ap?s o manejo do fogo. Para as caracter?sticas ed?ficas avaliadas observaram-se os maiores valores de umidade, pot?ssio, soma de bases, capacidade de troca cati?nica total e mat?ria org?nica nos solos sob floresta. Portanto, a defini??o dos limites entre as duas fitocenoses estudadas parece ser primariamente relacionada com o gradiente de fertilidade e umidade do solo. Permite-se aqui chamar a aten??o para a import?ncia de estudos de pequenos fragmentos vegetacionais para a amplia??o do conhecimento sobre a diversidade ambiental local e regional, e seus principais determinantes, e poss?veis consequ?ncias para a din?mica da vegeta??o dos ecossistemas. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Ci?ncia Florestal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2017. / This study aimed to know the floristic composition of the tree community and its relationship with the environment, as well as to evaluate the diversity, structure and ecological functions of the species of eighteen fragments of forest of flooded gallery. In addition, it was proposed to characterize the vegetation of the surrounding matrix of nine forest fragments and gallery, as well as to verify if environmental variables act in the transition between the two phytophysiognomies, with emphasis on the chemical properties of the soil. The study was conducted in the Sempre-Vivas National Park, in the Serra do Espinha?o, Minas Gerais. 5% of the total area of each fragment were inventoried, and permanent plots of 100 m? (totaling 0.72 ha of sampling) were sampled, where all arboreal individuals with a breast height diameter equal to or greater than 5 cm were sampled (DAP ? 5 cm). In order to sample the vegetative cover of the environment matrix, the points method was used, totaling 12 points per fragment, distributed at distances of 10, 20 and 30 m in the edge-field direction. In each plot and at each point, soil moisture was measured and soil samples were collected for further chemical analysis. For the fragments, the canopy cover, height of crust and environmental impacts were measured. A total of 1265 arboreal individuals were sampled, distributed in 76 species, 55 genera and 32 families. The community in general presented values of diversity and equability compatible with other floodplain gallery forests in the country. The species sampled were grouped into six distinct functional groups. Most of the fragments presented a trend of more advanced seral stage, with predominantly early and late secondary species, zoocoric, zoo-philological, mean wood density, recalcitrant seeds, and phaneroege-foliaceous-type seedlings. The distribution by diameter classes of the individuals of the tree community and for the main populations obtained a tendency of J-inverted, indicating good regenerative potential. The environmental variables that correlated with the variation of the species composition were the availability of water and acidity conditions. The low percentage of explanation of the environmental and spatial variables emphasize that the species in the fragments of gallery forest distribute stochastic way. Fire was the most frequent impact within the fragments, which highlights the need for management techniques in these areas. The wetlands surrounding the fragments presented high herbaceous cover, even after fire management. The highest values of moisture, potassium, sum of bases, total cation exchange capacity and organic matter in soils under forest were observed for edaphic characteristics evaluated. Therefore, the definition of the boundaries between the two phytochenoses studied seems to be primarily related to the fertility and soil moisture gradients. It is worth noting here the importance of studies of small vegetation fragments to increase knowledge about local and regional environmental diversity and their main determinants and possible consequences for the dynamics of ecosystem vegetation.

Soil microbial communities are affected extensively by addition of amendments to their environment. Of particular concern is the addition of poultry litter, which contains a substantial C, energy, and nutrient supply, but also antibiotic resistance genes (ARG), antimicrobials, and a multitude of microbial species. This project seeks to primarily assess if there is a change in bacterial community structure in response to poultry litter amendments to pasture land across geographically independent land across northern Georgia. It may be that changes in the relative abundance of bacterial communities also result in alteration in ARGs, and the community resistance to antibiotics (“resistome”) which in turn increases the potential threat of antibiotic resistance genes. While another part of this study will determine changes in integrons and specific ARGs, this project will focus on changes in bacterial communities and the potential functional changes in the community, which in turn have consequences for ARG levels and its horizontal transfer to various members of the soil community. Addition of waste from livestock is a historical method for increasing nutrients needed in the soil for the cultivation of crops, and in turn causes pronounced shifts in soil microbial communities due to the addition of large amounts of carbon, nutrients, foreign microbes, and other material. This study is unique because it utilizes a novel and relatively large landscape-scale to determine if there are discernable and repeatable patterns of bacterial community structure change in response to amendment regardless of exact soil type or source of chicken litter amendment. In the future, these data can also provide insight into the changes in the relative abundance antibiotic related genes associated with community change. / M.S. / Soil is complicated, both in terms of its physical makeup and the organisms that live inside of it. Predicting changes in soil based on the addition of foreign material such as chemicals or biological waste is not an easy process, and whether or not it is even possible to reliably predict those changes is a matter of some dispute. This study is designed to illustrate that such changes can in fact be reliably and consistently predicted even with regard to the addition of complicated materials to the soil. In this study, specifically, the material in question is chicken litter. A mix of the bedding and waste produced by chickens, litter is commonly handled by composting and is added to soil in farms as a fertilizer rich in organic matter. It is possible to point at specific elements of the soil such as the chemistry and bacteria and see how it is changed with the addition of chicken litter, which allows us to determine the nature and extent of the change that chicken litter has on soil. This study is conducted on a larger scale than similar experiments conducted in the past, making it apparent that these relationships exist on a repeated basis. It is the object of this study to pave the way and make it easier for scientists in the future to determine these relationships in other unique contexts.

No description available.

The savanna woodlands of Southern Africa, colloquially termed the miombo, are poorly described in terms of biodiversity compared to other biomes. They have therefore been underrepresented in the wider understanding of how land use intensification is shaping global biodiversity. Land use change is known to reduce biodiversity and disrupt intactness of ecological communities with consequences for ecosystem functioning, resilience, and services. Miombo woodlands are described as biodiversity hotspots due to a high endemism of species and the presence of megafauna. At the same time, they are also considered dynamic socio-ecological systems shaped by disturbances and the land use activities of people. The patterns of biodiversity change in these tropical ecosystems may, therefore, have their own unique contexts, understanding of which will be essential for biodiversity and land use management in these ecosystems. In this thesis, I identified the patterns of biodiversity change in response to the two major land use practices in the two dominant woodland types in southern African woodlands: the selective logging due to charcoal production in the mopane woodlands, and agricultural expansion in the miombo. I also examined the impact of two main disturbance agents, humans and elephants, on habitat structure and biodiversity in mopane woodlands. Across all chapters in this thesis, I investigated the effects of land use change and habitat modification on biodiversity empirically using chronosequences. To understand biodiversity change, I employed a hierarchical multilevel modelling approach making inferences at the three levels of ecological communities: species, community, and meta-community (set of ecological communities at different sites). I selected six villages in the charcoal production hotspot of southern Mozambique and carried out field surveys for three taxonomic groups: trees, mammals and ground beetles. I modelled the counts of trees and beetles and incidence of mammals using meta-community occurrence models in a Bayesian framework with the intensity class of the villages, above-ground biomass and land cover type as predictors. The results suggested that the species richness of trees and mammals declined by 12 and 8.5 % respectively while that of beetles increased by 3.5%, albeit non-significantly. In addition, the beta diversity of trees decreased while that of mammals increased. The results show that while both trees and mammals reduced in richness, they responded differently to charcoal production in terms of community organisation. The trees underwent subtractive homogenisation (decrease in alpha and beta diversities) primarily because of deterministic processes induced by selective harvesting of tree stems for charcoal. Mammal communities, on the other hand, showed subtractive heterogenization (decrease in alpha, but increase in beta diversity) mainly due to random extinctions. In the agriculture frontier of miombo-dominated northern Mozambique, I investigated the effects of fragmentation and habitat loss caused by agricultural expansion on diversity and composition of trees and mammals. I modelled the occurrences of trees and mammals using occupancy models with the fragmentation and quantity of woodland cover as predictors. The model showed that most tree species (n=10), mainly the timber and firewood species, linearly declined in population size as fragmentation increased. Mammals, on the other hand, showed a nonlinear response. Seven mammal species increased at the lower levels of fragmentation. However, at the higher levels, none of the mammal species increased while two declined. Similarly, the species richness of trees linearly declined, while that of mammals increased up to a fragmentation level of 55-65% and declined above this limit. The beta diversity of trees increased with fragmentation while that of mammals decreased. The results suggest that, although fragmentation reduces species richness of both trees and mammals, it affects their species compositions in different ways. Trees undergo subtractive heterogenization due to random species losses while mammals experience subtractive homogenisation mainly due to the combined effects of fragmentation-led habitat loss and intensified hunting. Finally, this study concludes that, above 75% fragmentation or below 26% habitat quantity, both taxonomic groups endure biodiversity loss. The threshold results here corroborate similar habitat quantity thresholds (20-30%) observed elsewhere in different ecosystems. However, they differ with the widespread notion that above 30% habitat quantity, the effect of fragmentation is non-existent. The results here emphasize that taxonomic groups respond differently, the diversity and population size of mammals reduced only after the habitat threshold, whereas, those of trees showed linear decrease with fragmentation most likely due to fragmentation-led habitat loss. Lastly, I examined the effects of disturbance by humans and elephants on habitat structure and bird diversity by conducting a space for time substitution comparison in the mopane woodlands of Zambia. To examine the woodland structure, I modelled the structural attributes of habitat (stem diameter, stand density, and basal area) using mixed models with the proportion of affected stems by humans and elephants as explanatory variables. I found that elephant disturbance was associated with higher stem diameters, low stand densities, but no change in basal area. Human disturbance, on the other hand, was related to reductions in stand density and basal area, but no change in the stem diameter. Further, I tested species and functional diversity of birds against the covariates of habitat structure and disturbance. I found that bird communities reduced in species richness in both, human as well as elephant disturbed areas. However, the functional diversity did not change with elephant disturbance. I concluded that human disturbance reduces woody biomass (basal area is correlated with woody biomass) of mopane woodlands and functional diversity of birds whilst elephants do not. In this thesis, I conclude that human driven land use change in the miombo woodlands erodes alpha diversity of all taxonomic groups. However, increases in beta diversity of mammals with charcoal land use and trees in agricultural land use may maintain their diversities at the meta-community level.

L’objectif de ce mémoire était d’évaluer l’influence de la latitude, de variables abiotiques et du type de tourbières (bog ou fen) sur la diversité des plantes vasculaires et des bryophytes. Des inventaires ont été réalisés dans 380 tourbières du nord-ouest du Québec (49° à 55° N). Les effets de la latitude, de la continentalité, du climat et de variables abiotiques locales sur la diversité α (richesse spécifique et dispersion fonctionnelle), la diversité β (indices LCBD) et la composition ont été évalués pour les deux groupes de plantes. La diversité α des bryophytes augmentait vers le nord, alors que la diversité α des plantes vasculaires présentait des patrons différents dans les bogs et les fens en réponse à la latitude. Il y avait une homogénéisation taxonomique et fonctionnelle vers le nord pour les deux groupes de plantes et dans les deux types de tourbières. Les variables environnementales avaient des effets différents sur les deux groupes de plantes, dépendamment de l’indicateur de biodiversité utilisé. La composition taxonomique et fonctionnelle des bryophytes et des plantes vasculaires étaient principalement structurées par les conditions locales contrastantes entre les bogs et les fens, tandis que les variations bioclimatiques le long du gradient latitudinal jouaient un rôle secondaire. Les futures études et politiques de gestion des milieux naturels devraient tenir compte de plus d’un indicateur de diversité et considérer les différences entre les deux écosystèmes et les deux groupes de taxons afin de planifier les efforts de conservation et afin d’évaluer les effets des changements environnementaux. / This study aimed to evaluate the influence of latitude, abiotic variables on vascular and bryophyte diversity in bogs and fens. Inventories were conducted in 380 peatlands in northeastern Québec (49° to 55° N). Changes in α-diversity (species richness and functional dispersion), β-diversity (LCBD indices) and composition in response to latitude, continentality, climate, and local abiotic variables were evaluated for both plant groups. Bryophyte α-diversity increased northward, while vascular α-diversity showed contrasting patterns in bogs and fens in response to latitude. Environmental variables had different effects on both species’ groups, and patterns varied depending on the diversity indicator used, as α- and β-diversity and functional and taxonomic diversity were often decoupled. There was taxonomic and functional homogenization with latitude for both groups of plants in both habitats. Bryophyte and vascular taxonomic and functional composition were primarily structured by contrasting local conditions in bogs and fens, while bioclimatic variations along the latitudinal gradient played a secondary role. These results highlight the contrasting biodiversity patterns in both peatland types and the importance of local habitat conditions in structuring vascular and bryophyte biodiversity. Therefore, future studies and policies should include more than one diversity indicator and consider the differences between ecosystems and taxon groups when evaluating the effects of environmental changes on biodiversity and planning conservation.

No description available.

L'urbanisation représente une menace majeure pour la biodiversité. Ce mémoire de maîtrise vise à comprendre ses effets sur la composition fonctionnelle et l'homogénéisation biotique dans les forêts riveraines. Des inventaires floristiques ont été réalisés dans 57 forêts riveraines de la région de Montréal. Afin d'étudier la variation de la composition fonctionnelle avec l'urbanisation, des moyennes pondérées de traits par communauté ont été calculées pour les arbres, arbustes et herbacées. Chaque forêt a été caractérisée par des variables relatives au paysage urbain environnant, aux conditions locales des forêts et aux processus spatiaux. Les conditions locales, notamment les inondations, exerçaient une pression de sélection dominante sur les traits. L'effet du paysage était indirect, agissant via l'altération des régimes hydrologiques. La dispersion le long des rivières était aussi un processus important dans la structuration des forêts riveraines. Les changements dans la diversité β taxonomique et fonctionnelle des herbacées ont été étudiés entre trois niveaux d'urbanisation et d'inondation. Alors que l'urbanisation a favorisé une différenciation taxonomique, les inondations ont favorisé une homogénéisation taxonomique, sans influencer la diversité β fonctionnelle. L'urbanisation était l'élément déclencheur des changements de la diversité β, directement, en causant un gain en espèces exotiques et une diminution de la richesse totale dans les forêts très urbanisées, et, indirectement, en entraînant un important turnover d'espèces par l'altération des régimes hydrologiques. Globalement, ces résultats suggèrent que la modification des processus naturels par les activités anthropiques est le principal moteur de changements dans les communautés riveraines urbaines. / Urbanization is a major threat to biodiversity worldwide. This thesis aims at understanding its effects on plant functional composition and biotic homogenization in riparian forests. Floristic inventories were carried out in 57 riparian forests of the Montreal area. To investigate changes in functional composition with urbanization, community weighted means were computed for trees, shrubs and herbs using eight functional traits. Each forest was characterized by variables related to the surrounding urban landscape, local forest conditions and spatial processes. The relative importance of these three subsets on the functional composition was quantified by variation partitioning using redundancy analyses. Local conditions, especially flood intensity, exerted an overriding selection pressure on riparian functional communities. The effect of the landscape was suspected to be indirect, acting on trait patterns likely through alteration of hydrological disturbances in riparian forests. In addition to environmental filtering, dispersal along rivers was also an important process structuring riparian forests. Changes in taxonomic and functional β-diversity for herb species were studied between three urbanization and flood levels. While urbanization led to taxonomic differentiation, flood intensity fostered taxonomic homogenization, both without influence on functional β-diversity. Urbanization was the main trigger for all β-diversity changes, as it directly caused a gain in exotic species and a net species loss in highly urban forests, and indirectly fostered an important species turnover through alteration of the hydrological regime. Overall, these results suggest that the alteration and interruption of natural landscape-scale processes by human activities are major mechanisms underlying changes in urban riparian communities.