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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Genetic differentiation of two species of buckwheat (Eriogonum)

Lemon, Jenessa Blotter 01 December 2017 (has links)
Limestone mining in the San Franicso Mountain Range of west central Utah threatens the survival of a rare endemic species of buckwheat (Eriogonum soredium). This species is an edaphic endemic, only found growing on the outcrops of the Ordovician limestone mines in the area. Eriogonum soredium is a candidate for governmental protection under the Endangered Species Act (ESA). However, a common, widespread buckwheat (Eriogonum shockleyi) appears to be closely related to the narrow endemic. The genetic relatedness of the rare and and common species will greatly influence the decision of United States Fish and Wildlife Service (USFW)of whether or not to list the rare species for governmental protection. This study investiaged the amount of genetic divergence between the two species to facilitate the decision. I found levels of population divergence intermediate between a state of no genetic distinction, and complete genetic divergence. However, the two species fall near the genetic divergence end of the continuum. This situation is not uncommon in plants, and suggests that the two species are currently in the process of speciation. Considering their morphological differences, and the ability of the genus Eriogonum to hybridize, these two species show significant amounts of divergence. These results suggest that the continued treatment of E. soredium as distinct from E. shcokelyi is warranted. The USFW will use the results of this study to aid their decision of whether or not to list E. soredium under the ESA. Should the species be listed for protection under the ESA, limitations to the expansion of limestone mining in the San Francisco Mountain Range will be considered.
2

The Vertic Clay Flora of the San Joaquin Desert: Niche, Competition & Floral Mosaics on a Novel Substrate

Fryer, Emma R 01 March 2023 (has links) (PDF)
Plant communities that occur on edaphically heterogeneous landscapes are ideal systems for exploring questions of niche and community assembly. Species with affinity for harsh substrates often have well-defined edaphic niches and are ideal models for testing ecological and evolutionary theory. While plants on substrates such as serpentine and gypsum have received much attention, those on other harsh substrates, including on vertic clay soils, have gone unstudied. Vertic clay soils are both chemically and physically challenging to plant establishment and productivity. Plant communities associated with vertic clay soils of the San Joaquin Desert appear to have a distinctive mosaic pattern of species distribution that reflect differences in soil properties across the landscape. I conducted fieldwork and a pot study with 12 native annual plant species with an affinity for vertic clay soils to determine whether the vertic clay soils at two sites in the San Joaquin Desert were heterogeneous, whether soil heterogeneity predicted the pattern of species distributions observed, and to examine the competition effects of an invasive annual grass (Bromus madritensis) on these species. I found that the vertic clay soils at both of my sites are internally heterogeneous, that soil heterogeneity does appear to shape the patchy distribution of species at both these sites, and that these species have different realized edaphic niches. I utilized treatment soils spanning a gradient of chemical stress present at both study sites in my pot study and found that competition from B. madritensis reduces biomass for all species, and that the effect of competition differed between soil types. Further, I found that species’ edaphic niche optima shift when competition is present, and that competitive ability differed across the gradient of edaphic stress in my treatment soils.
3

Land Use- Edaphic Relationships in Two Selected Areas of Woolwich Township

Mage, Julius 10 1900 (has links)
No abstract provided. / Thesis / Master of Arts (MA)
4

Ekologické a evoluční důsledky edafické diferenciace v polyploidních komplexech rostlin / Ecological and evolutionary consequences of edaphic differentiation in plant polyploid systems

Kolář, Filip January 2014 (has links)
The thesis deals with evolutionary and ecological consequences of edaphic speciation (adaptation to different soil types) and genome duplication (polyploidization), acting in concert. Using a wide range of ecological, karyological and molecular approaches, several hypotheses of general importance have been examined in three model angiosperm systems (ploidy variable species or species aggregates occurring both on and off specific substrates, including serpentines and calcareous soils). In the Knautia arvensis group (Caprifoliaceae) a unique cryptic diploid lineage in central Europe was identified to be restricted to serpentine and limestone outcrops, which served as refugia during environmental changes (forest spread, human impact) in the Holocene. These refugial populations exhibited strong evolutionary potential because they were able to polyploidize and escape beyond the borders of their original edaphically-conditioned refugia owing to hybridization with surrounding widespread homoploid genotypes. Survival of both Knautia cytotypes on serpentine soils was facilitated by their high tolerance to chemical stress factors such as high Ni concentrations and low Ca/Mg ratios. In the Galium pusillum group (Rubiaceae), a striking cytological, ecological, and taxonomic, diversity was revealed in northern and...
5

Diversidade e flutuação populacional de ácaros edáficos em um fragmento de Caatinga e três cultivos agrícolas, no Vale do São Francisco (Pernambuco), com ênfase nos Gamasina (Mesostigmata) /

Torris, Aline Finotti January 2019 (has links)
Orientador: Raphael de Campos Castilho / Resumo: As pesquisas sobre a acarofauna edáfica nos diversos biomas do território brasileiro são incipientes, sendo que em algumas localidades não se têm estudos, como no estado de Pernambuco. Um dos grupos mais encontrados em ambiente edáfico é o Gamasina (Mesostigmata), conhecidos pelo potencial como inimigos naturais de diversas pragas e parasitos. O objetivo do presente estudo foi determinar a diversidade e flutuação populacional de ácaros edáficos, com ênfase nos Gamasina, de uma região de Caatinga no Vale do São Francisco (Petrolina-PE), comparando a diversidade, distribuição e abundância desses organismos em solos de mata nativa e de cultivos de manga, uva e cebola. Amostras de solo foram coletadas mensalmente durante um ano, em quatro áreas diferentes da Caatinga: uma mata de vegetação natural, um cultivo de manga, um cultivo de uva e um cultivo de cebola. Em cada uma dessas áreas foram escolhidos 16 pontos amostrais aleatoriamente. Em cada ponto foi recolhidafoi recolhida uma amostra de solo (0-5 cm de profundidade). Os Gamasina encontrados foram divididos em morfoespécies e identificados, sempre que possível, até o nível de espécie. Durante todo o estudo foram coletados 1.151 ácaros (adultos e imaturos) de 10 famílias de Gamasina. No total de famílias encontradas, foram identificados 18 gêneros e 30 morfoespécies de Gamasina, sendo duas destas novas para a ciência. As espécies mais abundantes foram Multidentorhodacarus squamosus e Protogamasellus mica. Do total de ácaros co... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The researches about edaphic acarofauna in different biomes of the Brazilian territory are incipient, being that in some localities, as Pernambuco State,there are no studies. One of the groups most found in edaphic environment is Gamasina (Mesostigmata), known for their potential as natural enemies of various pests and parasites. The objective of the present study was to determine the diversity and population fluctuation of edaphic mites, with emphasis on the Gamasina, from a Caatinga region in the São Francisco Valley (Petrolina-PE), comparing diversity, distribution and abundance of these organisms in soils of native forest, mango, grape and onion crops. Soil samples were collected monthly during one year in four different selected areas in the Caatinga: a natural forest vegetation, a mango cultivation, a grape cultivation and an onion cultivation. In each one of these areas, 16 randomly sample points were selected. At each point a soil sample (0-5 cm depth) was collected. The Gamasina found were divided into morphospecies and identified, where possible, up to the species level. Throughout the study, 1151 mites (adult and immature) were collected from 10 families of Gamasina. In the total of families found, 18 genera and 30 morphospecies of Gamasina were identified, two of which were new to science. The most abundant species were Multidentorhodacarus squamosus and Protogamasellus mica. Of the total number of mites collected, about 47% were found in the area with grape culti... (Complete abstract click electronic access below) / Mestre
6

MATHEMATICAL MODELLING OF SOIL DIVERSITY INDICES UNDER DIFFERENT USES AND MANAGEMENTS

SILVA, Raimunda Alves 06 March 2017 (has links)
Submitted by Rosivalda Pereira (mrs.pereira@ufma.br) on 2017-10-04T20:06:24Z No. of bitstreams: 1 RaimundaSilva.pdf: 3007003 bytes, checksum: 6d2583372b22c581e239bf77c0d1338e (MD5) / Made available in DSpace on 2017-10-04T20:06:24Z (GMT). No. of bitstreams: 1 RaimundaSilva.pdf: 3007003 bytes, checksum: 6d2583372b22c581e239bf77c0d1338e (MD5) Previous issue date: 2017-03-06 / Fundação de Amparo à Pesquisa e ao Desenvolvimento Científico e Tecnológico do Maranhão / ABSTRACT: Soil is the habitat for a number of living organisms that perform essential functions to the ecosystem. The present work aimed to determine the edaphic diversity in large groups under different uses and management of the soil in Cerrado Biome. The study was developed in the city of Mata Roma (3º 70 '80.88' 'S and 43º 18' 71.27 '' W), in the eastern region of Maranhão state, Brazil. It were installed 130 pitfall traps in five areas with different management (millet, soybean, maize, eucalyptus, and pasture) and two reference areas with natural vegetation with different uses (anthropized Cerrado and preserved Cerrado). The traps remained in the field for a period of seven days, after this, the contents were maintained in plastic bottles and taken to the laboratory, where they were sampled and identified in large groups (orders and family). After identification, the biodiversity indexes were determined: (Shanon index, Pielou, Average and total richness and abundance). The data were analyzed using descriptive statistics and multivariate techniques using group dissimilarity. The geostatistical analysis was evaluated by a semivariogram, adjusted to a geostatistical, spherical, gaussian or exponential model. The multifractality was analyzed by the current method, in successive segments of different sizes of 2k , k=0 a k= 7 in the range of q = +10 to q = -10. 20,995 arthropods were collected throughout the study. The highest abundance was found for millet (9,974 individuals), and the lowest abundance values were reported for soybean (222) and maize (824), respectively. The highest biodiversity index is reported for the soybean area (2.69), although there is less abundance, in this area, the groups are evenly distributed due to the homogeneous management in the study area. The main axis in the analysis of the main components (PCA) explained 50.9% of the correlation of the groups with the sampled areas. The dendrogram had demonstrated that the area of soybean and maize are similar and had isolated the area of millet with the most dissimilar in relation to the others. The use and management of the soil in the study areas determine the occurrence of soil arthropods in function of food availability. For the areas of millet, maize, eucalyptus, anthropized Cerrado and pasture the Shanon diversity index obtained pure nugget effect. For the areas of millet, maize, anthropized Cerrado and pasture, the total diversity index was adjusted to the gaussian model. Only for the areas of soybean and pasture the staggered semivariograms showed similarity in the spatial variability of indexes, indicating that they behave similarly. The multifractality generated generalized dimension, D0, for all the indexes in the millet area, with invariant values, D0 = 1.000 ± 0.000. The singularity spectra were curves in concave parables with greater or smaller asymmetry for all areas sampled. In general, the fauna of soil presented spatial variability and multifractal parameters. / ABSTRACT: Soil is the habitat for a number of living organisms that perform essential functions to the ecosystem. The present work aimed to determine the edaphic diversity in large groups under different uses and management of the soil in Cerrado Biome. The study was developed in the city of Mata Roma (3º 70 '80.88' 'S and 43º 18' 71.27 '' W), in the eastern region of the State of Maranhão, Brazil. Were installed 130 pitfall traps in five areas with different management (Millet, Soybean, Maize, Eucalyptus, and Pasture) and two reference areas with natural vegetation with different uses (anthropized Cerrado and preserved Cerrado). The traps remained in the field for a period of seven days, after this, the contents were maintained in plastic bottles and taken to the laboratory, where they were sampled and identified in large groups (orders and family). After identification, the biodiversity indexes were determined: (Shanon index, Pielou, Average and total richness and abundance). The data were analyzed using descriptive statistics and multivariate techniques using group dissimilarity. 20,995 arthropods were collected throughout the study. The highest abundance was found for millet (9,974 individuals), and the lowest abundance values were reported for soybean (222) and maize (824), respectively. The highest biodiversity index is reported for the soybean area (2.69), although there is less abundance, in this area, the groups are evenly distributed due to the homogeneous management in the study area. The main axis in the analysis of the main components (PCA) explained 50.9% of the correlation of the groups with the sampled areas. The dendrogram had demonstrated that the area of soybean and maize are similar and had isolated the area of millet with the most dissimilar in relation to the others. The use and management of the soil in the study areas determine the occurrence of soil arthropods in function of food availability.
7

Diversidade de ácaros Gamasina (Mesostigmata) edáficos em sistema de plantio direto e sistema de integração lavoura, pecuária e floresta (ILPF) no estado do Mato Grosso /

Castro, Matheus Cardoso de. January 2019 (has links)
Orientador: Raphael de Campos Castilho / Resumo: Atualmente há pouco conhecimento sobre o impacto dos sistemas de cultivo sobre a diversidade da fauna edáfica, incluindo dos ácaros predadores Gamasina (Mesostigmata). O primeiro passo para entender a influência das práticas agrícolas na biota do solo é justamente conhecer a diversidade de organismos destes ambientes. Sendo assim, o objetivo desta pesquisa foi conhecer, determinar e comparar a diversidade de ácaros Gamasina (Mesostigmata) edáficos em plantios de soja em sistema de plantio direto e em sistema de cultivo integração lavoura, pecuária e floresta (ILPF), localizados no bioma Cerrado, no estado do Mato Grosso. Amostras de folhedo e solo foram coletadas em cultivos de soja em uma área em sistema de plantio direto com apenas um cultura (SPD) e em uma área área com sistema ILPF, também em plantio direto. Os resultados indicaram que a maior abundância de ácaros foi encontrada em sistema SPD em relação ao sistema ILPF. A maior abundância encontrada nas amostras de solos nos dois sistemas de cultivo foi da família Rhodacaridae, enquanto para as amostras de folhedo foram as famílias Laelapidae e Macrochelidae. Observou-se que o fator floresta do sistema ILPF não apresentou diferencial em relação ao sistema SPD. Tal fato pode ter ocorrido devido as mesmas atividades de tratos culturais ocorrerem em ambas as áreas, além da possibilidade de o tempo de implantação de ILPF ser curto. A espécie Gamasellodes sp. nov. foi encontrada no estudo e descrita, sendo disponibilizada a c... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Currently knowledge about the impact of cropping systems on the diversity of edaphic fauna is incipient, including Gamasina (Mesostigmata) predatory mites. The first step to understand the influence of agricultural practices on soil biota is to know the diversity of organisms in these environments. Thus, the objective of this research was to know, determine and compare the diversity of edaphic Gamasina (Mesostigmata) mites in soybean crops under no-tillage system and in crop, livestock and forest integration system (ILPF), in the Cerrado biome, in the state of Mato Grosso. Litter and soil samples were collected from soybean crops in an area under no-tillage system (SPD) and in an area with ILPF system, also under no-tillage. The results indicated that the higher abundance of mites was found in SPD in relation to ILPF. The highest abundance of edaphic mites found on soil samples in both cropping systems was from the Rhodacaridae family, while the litter samples were the families Laelapidae and Macrochelidae. It was observed that the forest factor of the integrated crop, livestock and forestry system did not differ in relation to the SPD. This fact could have occurred due to the same crops activities occurring in both areas, besides the possibility of the time of implantation of the ILPF system to be short. In addition, a new species has been found. The species Gamasellodes sp. nov was found in the study and described, and the identification key for species in the world of Gama... (Complete abstract click electronic access below) / Mestre
8

Evolution of Edaphic Ecology in Ceanothus (Rhamnaceae)

Burge, Dylan O. January 2011 (has links)
<p>Edaphic factors--those pertaining to the substrate or soil--are thought to play an important role in the diversification of flowering plants. Although edaphic factors are widely interpreted as causal agents in plant diversification, little is known about the evolutionary origin of most edaphic endemic plants, preventing inference of potential mechanisms by which substrate properties may influence speciation. The North American plant genus Ceanothus (Rhamnaceae) contains 9 edaphic-endemic species, taxa restricted to soils derived from specific geological materials. The three components of my dissertation research aim to improve understanding of how edaphic ecology has influenced the diversification of Ceanothus. First, I use DNA sequence data from the low-copy nuclear gene nitrate reductase to reconstruct the phylogeny of Ceanothus and elucidate diversification of this group into the California Floristic Province (CFP) of western North America, including the evolution of edaphic endemism. This research indicates that diversification of the two Ceanothus subgenera (Cerastes and Ceanothus) is centered on the CFP and is characterized by shallow divergence and phylogenetic relationships defined predominantly by geography. Divergence time estimation suggests that diversification of both Ceanothus subgenera began approximately 6 Ma. The nine edaphic-endemic taxa are not phylogenetically clustered in my analyses, suggesting that the origin of edaphic endemism has occurred on multiple occasions, including multiple examples of serpentine endemism. The second chapter of my dissertation uses soil chemistry data in combination with a more detailed examination of genetic variation in nitrate reductase to elucidate the evolution of a single edaphic endemic species.</p> / Dissertation
9

Northern peatland carbon biogeochemistry : the influence of vascular plants and edaphic factors on carbon dioxide and methane exchange /

Öquist, Mats, January 2001 (has links) (PDF)
Diss. (sammanfattning) Univ. : Linköping, 2001. / Härtill 5 uppsatser.
10

Diversidade de ácaros edáficos em um fragmento de mata atlântica e três cultivos agrícolas, em Jaboticabal/SP, com ênfase nos Gamasina (Mesostigmata) / Diversity of edatic mites in an atlantic forest fragment and three agricultural crops, in Jaboticabal / SP, with emphasis in the Gamasine (Mesostigmata)

Junqueira, Barbara Rodrigues 31 October 2017 (has links)
Submitted by BARBARA RODRIGUES JUNQUEIRA null (barbararodriguesj@hotmail.com) on 2017-12-13T12:08:30Z No. of bitstreams: 1 Dissertação_Barbara_Rodrigues_Junqueira (1).pdf: 4886045 bytes, checksum: acd676ff2d3642858699d8bc8b2f628e (MD5) / Approved for entry into archive by Alexandra Maria Donadon Lusser Segali null (alexmar@fcav.unesp.br) on 2017-12-13T13:15:16Z (GMT) No. of bitstreams: 1 junqueira_br_me_jabo.pdf: 4886045 bytes, checksum: acd676ff2d3642858699d8bc8b2f628e (MD5) / Made available in DSpace on 2017-12-13T13:15:16Z (GMT). No. of bitstreams: 1 junqueira_br_me_jabo.pdf: 4886045 bytes, checksum: acd676ff2d3642858699d8bc8b2f628e (MD5) Previous issue date: 2017-10-31 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / No Brasil, os estudos que visam avaliar a diversidade e abundância de ácaros edáficos predadores, como os Gamasina (Mesostigmata), ainda são incipientes, focando principalmente em áreas de vegetação natural. No entanto, compreender o impacto da agricultura nestes organismos é importante no aspecto de preservar a biodiversidade e avaliar a sensibilidade destes indíviduos aos tratos culturais. Além disso, conhecer a diversidade desses ácaros edáficos é o primeiro passo na prospecção de novos agentes de controle biológico. Dessa forma, o objetivo dessa dissertação foi determinar e comparar a diversidade e abundância de espécies de ácaros edáficos presentes em um fragmento de Mata Atlântica e em três cultivos agrícolas, em Jaboticabal, estado de São Paulo, com ênfase nos Gamasina. As coletas de solo e serrapilheira (quando presente) foram realizadas bimenstralmente, entre os meses de agosto de 2015 a junho de 2017. Foram avaliadas quatro áreas: um fragmento de Mata Atlântica e cultivos de milho, soja e mangueiras. Cada coleta consistiu em 10 pontos amostrais aleatórios. No laboratório, as amostras foram colocadas em equipamento do tipo Funil de Berlese-Tullgren modificado para extração dos ácaros. O material extraído foi triado, os ácaros foram separados por ordem, sendo os Gamasina montados em lâminas de microscopia. Em seguida, os Gamasina foram identificados, sempre que possível, até o nível de espécie. Os resultados deste estudo demonstraram que o grupo de ácaros edáficos mais abundante, para as quatro áreas de coleta, foi Oribatida (Sarcoptiformes), representando 73,5% dos ácaros coletados. Os Gamasina foram o segundo grupo mais encontrado (19%). Dentre os Gamasina foram encontradas 12 famílias, 35 gêneros e 50 morfoespécies, com destaque para Ologamasidae, representando 33,9% dos Gamasina coletados, seguida de Blattisociidae (18,3%), Laelapidae (13,2%) e Phytoseiidae (11,8%). No fragmento de vegetação natural foram coletados cerca de 52% dos Gamasina, com 25% no cultivo de mangueira, 19% na soja e 4% no milho. A área de vegetação natural também foi a que apresentou maior diversidade de gêneros e morfoespécies seguido pelo cultivo de mangueiras, soja e milho. Nesse estudo também foram encontradas novas espécies para ciência e até um novo gênero, Ologamasidae n. gen. n. sp., que é descrito baseado na morfologia de fêmeas e machos adultos coletados no fragmento de Mata Atlântica. Esse estudo demonstra que o impacto da ação antrópica afeta a comunidade de ácaros edáficos qualitativa e quantitativamente, ou seja, nas áreas de cultivo agrícola obteve-se menor diversidade e abundância de Gamasina. / In Brazil, studies aimed to evaluate the diversity and abundance of edaphic predatory mites, such as the Gamasina (Mesostigmata), are still incipient, focusing mainly on areas of natural vegetation. However, understanding the impact of agriculture on these organisms is important in terms of preserving biodiversity and assessing the sensitivity of these individuals to agricultural managements. In addition, knowing the diversity of these soil mites is the first step in prospecting for new biological control agents. Thus, the objective of this study was to determine and compare the diversity and abundance of edaphic mite species present in a fragment of Atlantic Forest and three agricultural crops, in Jaboticabal, state of São Paulo, with an emphasis on Gamasina. Soil and litter (when present) were collected bi-monthly, between August 2015 and June 2017. Four areas were evaluated: a fragment of Atlantic Forest, corn, soybean and mango crops. Each sample consisted on ten random sampling points. In the laboratory, the samples were placed in a modified Berlese-Tullgren funnel for the extraction of mites. The extracted material was screened and the mites were separated in order, the Gamasina being mounted on microscopic slides. Then were identified, when possible, to species level. The results of this study showed that Oribatida (Sarcoptiforme) was the most abundant mite collected, representing 73.5% of total miltes, for the four areas. Gamasina were the second most abundant group (19%). Among the Gamasina, 12 families, 35 genera and 50 morphospecies were found, mainly Ologamasidae, representing 33.9% of the Gamasina collected, followed by Blattisociidae (18.3%), Laelapidae (13.2%) and Phytoseiidae (11, 8%). In the natural vegetation fragment, about 52% of the Gamasina were collected, 25% in mango culture, 19% in the soybean area and 4% in the corn area. The area of natural vegetation was also the one that presented greater diversity of genera and morphospecies followed by the cultivation of mango, soybean and corn. In this study new species were also found for science and even a new genus, Ologamasidae n. gen. n. sp., which is described based on the morphology of adult females and males collected in the Atlantic Forest fragment. This study demonstrates that the impact of anthropic action affects the community of soil mites qualitatively and quantitatively, that is, in the agricultural cultivation areas, there was less diversity and abundance of Gamasina. / 134530/2015-2

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