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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.
161

The use of faunal evidence to reconstruct site history and Hoedjiespunt 1 (HDP1), Western Cape / The use of faunal evidence to reconstruct site history and Hoedjiespunt 1 (HDP1), Western Cape

Stynder, Deano Duane, Stynder, Deano Duane 13 December 2016 (has links)
Hoedjiespunt 1 (HDP 1 ), is one of few later Middle Pleistocene to earlier Late Pleistocene African sites to yield well provenanced MSA hominid fossils, lending special significance to this site. The vertebrate fauna from this location, which consists of a palaeontological and an archaeological site, is described and analysed using both the taphonomic and controlled comparison approaches. The information obtained via this study allows for a better understanding of the context in which and the conditions under which these two sites were formed. Stratigraphic evidence and spatial information, suggest that the bones in the palaeontological site were in all likelihood accumulated in a cavity, thus postdating the sediments in which they occur. Circumstantial evidence, in addition to Klein and Cruz-Uribe's (1984) criteria for distinguishing assemblages accumulated by hyaenas from those accumulated by people, points towards the brown hyaena as the most likely accumulator of this assemblage. It is also suspected that the bone in the archaeological assemblage, may postdate the sediments in which they occur. This is suggested by the presence at the site, of tools manufactured out of calcrete, similar to the calcrete carapace which caps the stratigraphic sequence. Although density mediated destruction seems to have been the major cause of discrepancies in skeletal part abundance in the palaeontological site, it was found not to have been severe. The composition of species represented in the two assemblages differ. It was found that, apart from containing a small percentage of marine animals, the palaeontological site is dominated by grazing ungulates and carnivores. This assemblage was accumulated during a period of lowered sea level, or "glacial". On the other hand, the sample from the archaeological site contains proportionally fewer ungulates and carnivores, more small animals and more marine animals, reflecting a period of marine transgression, or "interglacial".
162

The genetic diversity of North American vertebrates in protected areas.

Thompson, Coleen E P 29 August 2019 (has links)
No description available.
163

Radiation Induced Bystander Responses In Vertebrates Given Low Doses Of In Vivo Radiation / Bystander Resposes In Vertebrates Given In Vivo Radiation

Singh, Harleen January 2009 (has links)
<p> The bystander response phenomenon shows that radiation induced changes in cells that have not been directly targeted, but are neighbors to or receive medium from directly hit cells. Our group has performed a range of single and serial, low dose irradiations (in vivo) on two strains of mice that have been documented to show genetic differences in their response to radiation. This thesis also explores the impact of environmental radiation contamination on female and male Mink frogs (Rana septentrionalis) sampled from contaminated and background (control) radiation sites. Bladder explants established from these vertebrates are incubated in culture medium, which is then used to measure apoptotic response (cell survival and calcium flux) in the keratinocyte reporter system. </p> <p> This study reveals that culture medium from acutely irradiated C57Bl6 mice, but not Balb/c mice, induces dose-dependant clonogenic death. The administration of a priming dose(s) to C57BL6, but not Balb/c mice, leads to stimulatory growth effects in reporters regardless of the time separation between the priming and challenge dose. Similarly, ITCM corresponding to male and female contaminated frogs results in a sexdependent decrease in reporter survival, but no reduction is induced from ITCM sampled from explants from female and male frogs from uncontaminated sites. When the ITCM is measured for its calcium inducing ability, results show abnormal calcium levels in both strains of mice only after the administration of a priming dose. However, chronic exposures to male and female frogs results in the production of ITCM that induces transient calcium flux in reporters. These results indicate that genetic predisposition in mice influences the type of bystander signal that is produced after exposure to low, acute doses of radiation. However, when mice are repeatedly exposed to radiation, the bystander signal is modified in a way that may be causing unregulated growth in reporter cells. </p> / Thesis / Master of Science (MS)
164

Studies on Eukaryotic Pre-mRNA 3'-End Processing: Insights into PAS Recognition and the U7 snRNP activity

Gutierrez Tamayo, Pedro A. January 2023 (has links)
This dissertation focuses on pre-mRNA 3'-end processing in eukaryotes, a crucial step in defining the 3'end of most protein-coding mRNAs. In vertebrates, two distinct molecular machines are involved: the canonical machinery, consisting of a Cleavage Factor (CF) module, Polyadenylation Specificity (PSF) module, Cleavage Stimulation Factor, and other complexes, and the U7 snRNP machinery (U7 machinery), which consist of a core U7 snRNP complex and the Histone Cleavage Complex (HCC). U7 snRNP is involved in replication-dependent histone pre-mRNA 3'-end processing. Interestingly, the cleavage modules of the canonical and U7 machinery share an endonuclease, CPSF73, that catalyzes the cleavage reaction for 3’-end processing of pre-mRNAs. CPSF73 also possesses 5’-3’ exonuclease activity in the U7 machinery. CPSF73 has been identified as a potential target for anticancer and antimalarial small-molecule inhibitors. Traditionally, CPSF73 nuclease activity has been demonstrated using a gel-based end-point assay, using radio-labeled or fluorescently labeled RNA substrates. In Chapter Two (Ch. 2) of this dissertation introduces a novel, real-time fluorescence assay to investigate CPSF73 nuclease activity. This efficient and high-throughput assay holds potential for identifying new CPSF73 inhibitors. Chapter Three (Ch. 3) of this dissertation delves into the structural characterization of the mammalian PSF (mPSF) module in complex with the second most frequent PAS variants, AUUAAA. Structure studies have revealed the molecular mechanism underlying mPSF recognition of the most common PAS sequence, AAUAAA. This study presents a cryo-EM structure of mPSF in complex with AUUAAA. While the binding modes remain highly similar between the two PAS variants, we observed conformational differences in the A1 and U2 nucleotides in AUUAAA compared to the A1 and A2 of AAUAAA. Furthermore, CPSF30 displayed conformational changes near the U2 nucleotide of AUUAAA. Attempts to explore the binding modes of two rare PAS sequences, AAGAAA and GAUAAA, were inconclusive due to a lack of RNA density in the EM maps. An atomic model of the ternary structure (CPSF160, WDR33, CPSF30) was produced using the EM map of the AAGAAA sample. The ternary structure revealed PAS recognizing residues to be disordered in CPSF30 (ZF2 and ZF3) and WDR33. Overall, this dissertation provides insights into the intricate mechanisms of pre-mRNA 3'-end processing in mammals, laying the groundwork for future studies and potentially leading to the development of novel inhibitors targeting CPSF73.
165

Ionoregulatory Physiology of the African Lungfish, Protopterus dolloi and Protopterus annectens

Patel, Monika 12 1900 (has links)
<p> The origin of terrestrial vertebrates from water-dependent fish involved numerous morphological and physiological modifications (Benton, 1990). Interest in the adaptive mechanisms involved in the transition from aquatic to terrestrial environments has led to research involving lungfish. African lungfish are obligatory air breathers and have a primitive lung and characteristically underdeveloped gills compared to freshwater teleosts. The gills are thought to play an important role in CO2 excretion and possibly in water and ionic exchange while in aquatic conditions. At present, little is known about the basic ionoregulatory physiology of lungfishes; the aim of this thesis was to describe the basic principles of ion and water balance in two species of African lungfish, Protopterus dolloi and Protopterus annectens. Patterns and rates are very similar in the two species, apart from differences in water handling at the kidney. In aquatic conditions, plasma ion (Na+, Cl-, Ca2+) levels are lower than in teleost fish. The major site of diffusive water exchange appears to be the gills. The skin is well vascularized and also serves as site of water exchange, and likely Cl- and Ca2+ uptake as well. However, water and ion exchange rates are lower than in freshwater teleosts, probably due to the reduced gill area, though glomerular filtration, urine flow rates (an index of osmotic permeability), and urinary ion excretion rates are comparable to those of teleosts. Water exchange rates increase immediately after feeding, likely associated with specific dynamic action, and decrease with prolonged terrestrialization, likely due to disturbances in gill function. A budget analysis of ion balance indicates that both unidirectional uptake from the water and net uptake from the food (especially for Cl-) are important, whereas unidirectional efflux across the gills and/or skin is a larger route of ion loss than are feces or urine. Despite many physiological differences between freshwater teleosts and the African lungfish, water and ion balance are maintained in a broadly similar fashion and are achieved by compensating for the reduced gill area by ion acquisition via the skin and by greater ion reabsorption by the kidneys.</p> / Thesis / Master of Science (MSc)
166

Análise espacial da distribuição da fauna de vertebrados de médio e grande porte frente a dois padrões de desmatamento típicos da floresta Amazônica, na região de Alta Floresta - MT / Spatial analysis of midsized and large-bodied vertebrates according to two typical deforestation patterns of the Amazon forest in Alta Floresta region - MT State

Prist, Paula Ribeiro 25 August 2011 (has links)
A Amazônia Brasileira possui diversos tipos de padrão de desmatamento, variando do típico padrão \"espinha-de-peixe\", comum em pequenas propriedades, para grandes áreas desmatadas (padrão grandes propriedades), resultando em paisagens com diferentes estruturas, configuração e nível de perturbação. A teoria sugere que uma perda desproporcional de espécies ocorre quando a cobertura total de habitat cai para menos de 30% da paisagem, e a configuração passa então a ter um maior efeito sobre as espécies. Para analisar o efeito da configuração de habitat na persistência e riqueza de vertebrados de médio e grande porte (aves e mamíferos) foram amostradas 21 paisagens (4 x 4 km) do sul da Amazônia com quantidade similar de habitat (~25%), mas configurações de paisagem contrastantes. Entrevistas (n = 150) foram aplicadas de Fevereiro a Julho de 2009 para registrar a ocorrência de vertebrados, e o nível de perturbação das 21 paisagens, compostas de sete áreas controle (áreas não perturbadas de floresta contínua), sete paisagens com padrão de grandes propriedades e sete de espinhas-de-peixe. Métricas de paisagem foram extraídas de uma imagem Landsat-TM de 2009 e de 14 imagens Landsat-TM bianuais, para determinar o melhor preditor para a persistência das espécies. Existiu uma diferença significativa na riqueza de espécies entre os padrões espinha-de-peixe, grandes propriedades e as áreas controle, com uma média de 29.28 (SD=4.6), 38.8 (SD=5.2), e 43.5 (SD=2.2), respectivamente. Nós também encontramos um maior número de espécies especialistas nas áreas controle (média ± SD = 13.7 ± 0.95) e grandes propriedades (média ± SD = 11.71 ± 2.2), quando comparadas ao padrão espinha-de-peixe (média ± SD = 5.14 ± 2.6). Os resultados da NMDS mostram que a comunidade de vertebrados de médio e grande porte das áreas controle é muito similar à comunidade encontrada nas unidades de grande propriedade, além de todas as unidades de área controle e grande propriedade serem homogêneas entre si. Por outro lado, as unidades espinha-de-peixe, além de apresentarem uma maior heterogeneidade entre suas unidades, também se mostrou muito dissimilar em relação às outras paisagens, tanto para a comunidade de vertebrados quando para a comunidade de espécies especialistas. O padrão espinha-de-peixe também apresentou uma alta intensidade de queimadas, retirada de madeira e pressão de caça, enquanto que o padrão grandes propriedades apresentou uma leve intensidade de queimada e uma alta pressão de caça, e as áreas controle não apresentaram nenhum sinal de perturbação. O número de espécies e o número de espécies especialistas foram negativamente afetados pelo número de fragmentos e, secundariamente, pela idade de isolamento. Assim, quanto maior o número de fragmentos na paisagem e maior o tempo de isolamento, menor será a riqueza de espécies e o número de espécies especialistas. Nossos resultados demonstram que o padrão grandes propriedades leva a uma estrutura de paisagem mais favorável para a biodiversidade. Este tipo de paisagem pode manter um alto número de espécies e uma comunidade de vertebrados de médio e grande porte mais diversa, incluindo predadores de topo e grandes cracídeos, considerados fundamentais para a integridade do ecossistema, sendo mais similar às áreas controle. Por outro lado, o padrão espinha-de-peixe leva a uma paisagem mais fragmentada, com uma comunidade de vertebrados mais pobre e dominada por espécies generalistas. / The Brazilian Amazon has several types of deforestation patterns, varying from the typical \"fishbone pattern\" common in small properties, to large deforested areas (large-property pattern), resulting in landscapes with different structure, configuration and disturbance levels. Theory suggests that a disproportionate loss of species occurs when total habitat cover decreases to less than 30% of the landscape, and the landscape configuration starts to have a large effect over species. To analyse the effects of the habitat configuration on the persistence and richness of mid-sized and large-bodied vertebrates (mammals and birds), we have sampled 21 landscapes in the southern Amazonia with similar amounts of habitat (~25%) but contrasting configuration. Interviews (n = 150) were used from February to July 2009 to record the occurrence of vertebrates and the disturbance degree in the 21 landscapes, composed of seven control areas (undisturbed areas of continuous forest), seven large-properties and seven fishbone deforestation patterns. Forest-patch metrics were extracted from a 2009 Landsat-TM image and from 14 bi-annual Landsat-TM images to examine the best predictor to species persistence. There was a significant difference in species richness between fishbone, large-property and control areas with an average of 29.28 (SD=4.6), 38.8 (SD=5.2), and 43.5 (SD=2.2), respectively. We also found a higher number of specialist species in control areas (mean ± SD = 13.7 ± 0.95) and large-properties (mean ± SD = 11.71 ± 2.2), when compared with fish-bone pattern (mean ± SD = 5.14 ± 2.6). NMDS results show vertebrate community in control areas are very similar to the ones found in large-property sites, beyond all landscapes (control areas and large properties) are homogeneous among themselves. On the other hand the fish-bone landscapes are very dissimilar from them and heterogeneous among each other, concerning both the large vertebrate community and the specialist species community. The fish-bone pattern also shows a heavy intensity of fire, selective logging and hunting pressure while the large-property pattern shows a light intensity of fire and a heavy hunting pressure whereas the control areas show no sign of disturbance. The number of species and the number of specialist species were negatively affected by the number of fragments and secondarily by the isolation age. Therefore the greater the number of fragments in the landscape unit and the older is the isolation process, the fewer is the species richness as well as the number of specialist species. Our results demonstrated that large-property pattern leads to a landscape structure that is better for biodiversity. This type of landscape can maintain a higher number of species and a more diverse community of large vertebrates, including top predators and large cracids, considered fundamental for the integrity of the ecosystem, being more similar to the control areas. On the other hand, the fish-bone pattern leads to a more fragmented landscape with a poorest vertebrate community and dominated by generalist species.
167

Role Of Idiotypic Anti-Idiotypic Network In The Sustenance Of Immunological Memory

Gangadhar, Vidya 02 1900 (has links)
Living amidst a milieu of pathogenic organisms, vertebrates are in constant threat of contracting one or the other disease. As a mechanism of protection against such ‘invasions’, the vertebrate immune system has evolved to serve two main functions. One, to generate a specific immune response against the invading pathogen (in the from of specific antibodies and cell mediated immune responses). And two, to ‘remember’ the pathogen after the first exposure and mount a heightened and quicker immune response upon subsequent encounters. This phenomenon is called immunological memory, or anamnestic response and is achieved by the generation of memory B and T cells. The generation of specific Immunological memory is indeed the most important requirement/purpose of prophylactic vaccination Though different mechanisms are known to operate to maintain memory B and T cells, some aspects are still debatable. The ‘relay hypothesis’ (Nayak etal., Immunology.102(4)(2001); Nayak R etal., Microbes. Infect.(2005)), addresses some of those key issues. It describes that antigen specific memory B cells can be maintained by the interaction of membrane bound idiotypic (Id, Ab1) and anti-idiotypic (α-Id, Ab2) antibodies on B cells. Anti-Ids binding to idiotopes on Abs (Ab1) are known to be potential regulators of immunity in a variety of diseases, such as autoimmunity, cancer as well as viral, bacterial or parasitic infections. The relay hypothesis outlines the mechanism of persistence of memory cells in the absence of persisting antigen. This is achieved through the ‘internal image’ of the antigen on the Ab2 variable region, which serves as surrogate antigen thus helping in maintenance of immunological memory even in the absence of persisting antigen. It also explains that all antigens, protein or nonprotein can be converted to the common “coinage” of internal image peptides, otherwise called peptido-mimics. Peptido-mimics that have similar binding properties to MHC as the antigenic epitope, will ensure that the antigen specific memory T cells are also maintained. Hence T cell activation could also occur in the absence of nominal antigen, a potentially important process in T-B cooperation and immune regulation. Scope and objectives of this work: To demonstrate the presence of idiotypic and cognate anti-idiotypic antibody for the given antigen  To examine the likelihood of the three dimensional structural similarity between antigen and Ab2 variable region  To demonstrate the presence of peptido-mimics of the antigenic epitope in the Ab2 variable region; and if those peptido-mimics have structural and functional similarity with antigenic peptides when bound to MHC-I To examine the (immunological) memory associated phenotype of thediotypic anti-idiotypic B cells. The antigen of choice for the current study is Heamagglutinin-Neuraminidase (HN) protein of peste des petits ruminants virus (PPRV). Idiotypic (Id, Ab1), antiidiotypic (α-Id, Ab2) hybridoma against a deletion mutant of PPRV HN were generated and characterized. These hybridoma served as surrogate B cells for the study of Id α-Id B cell interactions. Anti-anti-idiotypic (Ab3) lymphocytes were also generated by immunizing syngenic BALB/c mice with Ab2 hybridoma. Results not only indicated the interplay of idiotypic and anti-idiotypic B and T cells in this cascade but also the mimicry of the antigen by Ab2. Ab2 Mab could recognize idiotopes of anti-PPRV HN Ab1 raised in diff species of animals, thus demonstrating that Ab2 was indeed an antigen mimic that interacts with Ab1 paratope irrespective of which species the Ab1 originates from. Ab2 Mab also mimicked the antigen (Hemagglutinin-neuraminidase) in functional assays by bringing about hemagglutination. Similarly, Polyclonal Ab3 which reacts with Ab2 Mab and with antigen, inhibits hemagglutination, just as Ab1 does, albeit to a lesser extent. This suggests Ab3 has functional similarity with Ab1. It is imperative that T cells be involved in this network of B cells for the maintenance of antigen specific immunological memory. This is because B cells require T cell help in the form of cytokines for proliferation and Cytotoxic T Lymphocytes (CTLs) are needed to control the specific population of Id and anti-Id B cells to maintain homeostasis. The Ab2 hybridoma as well as soluble Ab2 stimulated the proliferation of antigen specific T cells. Similarly, Ab3 splenocytes were stimulated to proliferate by the Ab2 as well as the antigen. Peptides generated from monoclonal Ab2 heavy and light chain variable regions (VH and VL) showed structural and functional similarity to the antigenic peptides in terms of p-MHC binding. These peptides stimulated the proliferation of antigen and Ab2 specific T cells, and also triggered 4-5 times higher CTL targeted cell lysis of peptide pulsed RMAS-Kd cells, as compared to a control peptide. VH, VL and antigenic peptides stabilized MHC-I on the cell surface of the TAP deficient, RMAS-Kd cell line for upto six hrs as compared to the ‘empty’ MHC-I, which remained on the surface only for one hr. The presence of peptido-mimics in the Ab2 variable region, which have structural similarity with antigenic peptide (when bound to MHC I), was also established using insilico software tools. Antigenic peptides and VH and VL peptides were modeled onto MHC-I crystal structures using the molecular modeling software InsightII and the minimization program, CNS. Putative MHC-I binding peptides from these sequences were generated using the p-MHC-I binding prediction algorithm, BIMAS. By replacing these peptides in the respective crystal structure of MHC I and superimposing the two structures, we have tried to establish that through structural similarity in binding to MHC-I, peptidomimics have a role in the maintenance of antigen-specific CTL memory. Consequently CTL memory specific to antigenic epitope can be preserved even in the absence of antigen by its peptidomimic. Following long-term immunizations, as expected of a secondary immune response, the serum Ab1 titre was found to be higher than the titer during primary response. It was also noted that though the number of Ab1 and Ab2 cell number was comparable in the total splenocyte population, Ab1 titre in the serum was higher than Ab2, immaterial of Ag/Ab2 booster. The same trend was noticed in prolifertion assay and CTL assays when the splenocytes were stimulated by Ag/Ab2 pulsed bone-marrow derived dendritic cells (BMDCs) as APCs. That is, irrespective of immunization and boost with Ag/Ab2, Ag pulsed BMDCs stimulated the proliferation and CTL lysis of long term immunized splenocytes to a greater extent than Ab2 pulsed BMDCs. Memory markers present on B and T cell surface might help maintain their close interactions in the idiotypic network. CD27/CD70 (CD27L) might play a role in maintaining these cells in a memory state. The Id α-Id B cells in addition to being triggered through the membrane bound Id, α-Id antibodies, can also be activated through CD27/CD70 to differentiate into plasma cells upon activation by antigen. Id and α-Id B cells were demonstrated to possess the CD27 memory marker on their surface in addition to the membrane bound IgM. Antigen specific IgM and CD27 double positive cells were detected in the range of 1-3% in the total splenocyte population. In conclusion: PPRV HN immunization triggered the generation of Ab1, Ab2, Ab3 (Id, α-Id, α-α-Id) cascade through the interaction of membrane bound immunoglobulin of the corresponding B cells. Ab2 was demonstrated to be a significant structural and functional mimic of the antigen. Peptidomimics of the antigenic epitope, present in the Ab2 variable region, can serve the purpose of maintaining antigen specific T cell memory response. These findings re-confirm the importance of anti-id antibodies in the regulation of immune responses. Ever since the concept of antigen mimicry by anti-Id antibody has been confirmed by several laboratories, the utility of anti-Ids as surrogate antigens for the purpose of prophylactic vaccination has received great attention. The results of the current work are especially significant for the purpose of development of vaccines for diseases related to antigens that are very cumbersome to purify (for ex., in case of several cancers) or when it is too dangerous to immunize with the antigen itself (for ex., in case of some pathogenic organisms). The results also signify that immaterial of the nature of the antigen, their respective petidomimics can establish and maintain immunological memory.
168

The utility of linear riparian rainforest for vertebrates on the Atherton and Evelyn Tablelands, North Queensland /

Hausmann, Franziska. January 2004 (has links)
Thesis (M.Phil.) -- Griffith University, 2004. / Facsimile of the author's original dissertation. Pagination of document: x, 121 leaves. Includes bibliographical references. Also available online via the World Wide Web.
169

Estradas e conectividade na Mata Atlântica: identificando áreas prioritárias para aplicação de medidas de mitigação / Roads and connectivity in the Atlantic Forest: identifying priority areas for implementation of mitigation measures

Aline Gaglia Alves 01 February 2013 (has links)
As rodovias podem representar um importante fator na fragmentação de habitat para espécies silvestres adaptadas a habitats de alta complexidade estrutural, como as florestas tropicais. As estradas reduzem a conectividade da paisagem e a capacidade da população regional em habitar todas as áreas adequadas e estes efeitos são mais significativos nas espécies que evitam a estrada, que são, muitas vezes, espécies de interior de florestas. A magnitude dos efeitos de barreira dependerá do comportamento e mobilidade destas espécies. Quando as estradas representam ralos (sink) ou barreiras para as populações, devido, respectivamente, aos atropelamentos ou à repulsa, medidas mitigadoras são indicadas para aumentar a conectividade entre as manchas de habitat separadas por essas estradas. A qualidade do habitat é um fator que deve ser considerado, mesmo com baixas frequências de atropelamentos nesses locais. O objetivo desse estudo foi propor dois métodos de seleção de áreas prioritárias para implantação de medidas mitigadoras dos efeitos das estradas sobre espécies de vertebrados florestais: Seleção Hierárquica Multivariada e Seleção Bivariada. A área de estudo foi o bioma Mata Atlântica, sendo recortado em paisagens hexagonais em três escalas diferentes (10.000, 1.000 e 100 km), usando a extensão Repeating Shapes no programa ArcGIS 9.3. Em cada hexágono foram calculados: área de floresta e de Unidade de Conservação, densidade de estradas e de hidrografia. Apenas os hexágonos cobertos por no mínimo 45% pela Mata Atlântica, com mais de 50% de cobertura florestal e mais de 1% de Unidades de Conservação foram incluídos nas análises. Após esta seleção, no método Seleção Hierárquica Multivariada, foi feita uma análise de componentes principais (PCA) com as quatro variáveis medidas, para cada escala separadamente. Os hexágonos foram então ordenados segundo o posicionamento deles no 1 Eixo da PCA de forma hierárquica e da maior para menor escala de hexágonos. Para área de estudo o método de Seleção Bivariada foi construído um gráfico de pontos, para cada escala de hexágono, com as variáveis cobertura florestal e rios. Foram selecionados os hexágonos que estavam localizados no quadrante do gráfico que representasse maior densidade de rios e maior porcentagem de cobertura florestal. Posteriormente foi feita uma simulação para avaliar se os métodos eram capazes de recuperar escores tão alto quanto a ordenação seguindo apenas o posicionamento dos hexágonos no Eixo 1 da PCA, sem uma análise hierárquica. O método de Seleção Hierárquica Multivariada foi mais eficiente para escolha de áreas prioritárias do que a Seleção Bivariada tanto para a escala intermediária (1.000 km) quanto para a menor escala (100 km). Os cinco hexágonos de 100 km mais prioritários estão localizados em São Paulo e Paraná, abrangendo quatro UCs (PARES de Jacupiranga, APA de Guaraqueçaba, APA Cananéia- Jacuípe e PARES da Ilha do Cardoso). Devido à simplicidade e fácil aplicabilidade do método, acredita-se que este pode ser uma opção interessante para escolha de áreas prioritárias para implantação de medidas mitigadoras dos efeitos de estradas / Roads may represent an important factor in fragmentation of habitat for wild species adapted to habitats of high structural complexity as rainforests. Roads reduce landscape connectivity and the capacity of the regional population live in all suitable areas and these effects are most significant in species that avoid the road, which are often species dependent on forests. The magnitude of the barrier effects depend on the behavior and mobility of these species. When roads represent "sinkers" or barriers for populations due, respectively, trampling or avoidance, mitigation measures are indicated to increase connectivity between habitat patches separated by these roads. The habitat quality is a factor that must be considered, even at low frequencies of road kill there. The goal of this study was to propose two methods of selecting priority areas for implementation of mitigation measures of roads effects on forest vertebrate species: Multivariate Hierarchical Selection and Bivariate Selection. The study area was the Atlantic Forest biome, being cut into hexagonal landscapes at three different scales (10,000, 1,000 and 100 km), using the extension "Repeating Shapes" program in ArcGIS 9.3. In each hexagon was calculated: area of forest, protected areas, density of roads and hydrograph. Only hexagons covered by at least 45% by the Atlantic Forest, with over 50% forest cover and more than 1% of protected areas were included in the analyzes. After this using the Multivariate Hierarchical selection method, we performed a principal component analysis (PCA) with the four variables measured for each scale separately. The hexagons were then ordered according to their position in the first axis of PCA, using a hierarchical manner and the smaller scale of hexagons. For the Bivariate selection method we did a dot plot for each scale hexagon, with the variables forest cover and rivers. We selected hexagons that were located in the quadrant of the graph that represented higher density of rivers and larger percentage of forest cover. After that, we made a simulation to evaluate if the two methods were able to retrieve scores as high as the ordination following only the positioning of the hexagons on Axis 1 of the PCA, without a hierarchical analysis. For the study site, the Multivariate Hierarchical selection was more efficient for choosing priority areas than Bivariate Selection for both the intermediate scale (1000 km) and to a lesser extent (100 km). The five hexagons of 100 km of highest priorities are located in São Paulo and Paraná, covering four protected areas (PARES of Jacupiranga, Guaraqueçaba APA, and APA Cananéia-Jacuípe and PARES Ilha do Cardoso). Due to simplicity and easy applicability of the method, we believe this may be an interesting option for selecting priority areas for implementation of mitigation measures of the effects of roads
170

Estradas e conectividade na Mata Atlântica: identificando áreas prioritárias para aplicação de medidas de mitigação / Roads and connectivity in the Atlantic Forest: identifying priority areas for implementation of mitigation measures

Aline Gaglia Alves 01 February 2013 (has links)
As rodovias podem representar um importante fator na fragmentação de habitat para espécies silvestres adaptadas a habitats de alta complexidade estrutural, como as florestas tropicais. As estradas reduzem a conectividade da paisagem e a capacidade da população regional em habitar todas as áreas adequadas e estes efeitos são mais significativos nas espécies que evitam a estrada, que são, muitas vezes, espécies de interior de florestas. A magnitude dos efeitos de barreira dependerá do comportamento e mobilidade destas espécies. Quando as estradas representam ralos (sink) ou barreiras para as populações, devido, respectivamente, aos atropelamentos ou à repulsa, medidas mitigadoras são indicadas para aumentar a conectividade entre as manchas de habitat separadas por essas estradas. A qualidade do habitat é um fator que deve ser considerado, mesmo com baixas frequências de atropelamentos nesses locais. O objetivo desse estudo foi propor dois métodos de seleção de áreas prioritárias para implantação de medidas mitigadoras dos efeitos das estradas sobre espécies de vertebrados florestais: Seleção Hierárquica Multivariada e Seleção Bivariada. A área de estudo foi o bioma Mata Atlântica, sendo recortado em paisagens hexagonais em três escalas diferentes (10.000, 1.000 e 100 km), usando a extensão Repeating Shapes no programa ArcGIS 9.3. Em cada hexágono foram calculados: área de floresta e de Unidade de Conservação, densidade de estradas e de hidrografia. Apenas os hexágonos cobertos por no mínimo 45% pela Mata Atlântica, com mais de 50% de cobertura florestal e mais de 1% de Unidades de Conservação foram incluídos nas análises. Após esta seleção, no método Seleção Hierárquica Multivariada, foi feita uma análise de componentes principais (PCA) com as quatro variáveis medidas, para cada escala separadamente. Os hexágonos foram então ordenados segundo o posicionamento deles no 1 Eixo da PCA de forma hierárquica e da maior para menor escala de hexágonos. Para área de estudo o método de Seleção Bivariada foi construído um gráfico de pontos, para cada escala de hexágono, com as variáveis cobertura florestal e rios. Foram selecionados os hexágonos que estavam localizados no quadrante do gráfico que representasse maior densidade de rios e maior porcentagem de cobertura florestal. Posteriormente foi feita uma simulação para avaliar se os métodos eram capazes de recuperar escores tão alto quanto a ordenação seguindo apenas o posicionamento dos hexágonos no Eixo 1 da PCA, sem uma análise hierárquica. O método de Seleção Hierárquica Multivariada foi mais eficiente para escolha de áreas prioritárias do que a Seleção Bivariada tanto para a escala intermediária (1.000 km) quanto para a menor escala (100 km). Os cinco hexágonos de 100 km mais prioritários estão localizados em São Paulo e Paraná, abrangendo quatro UCs (PARES de Jacupiranga, APA de Guaraqueçaba, APA Cananéia- Jacuípe e PARES da Ilha do Cardoso). Devido à simplicidade e fácil aplicabilidade do método, acredita-se que este pode ser uma opção interessante para escolha de áreas prioritárias para implantação de medidas mitigadoras dos efeitos de estradas / Roads may represent an important factor in fragmentation of habitat for wild species adapted to habitats of high structural complexity as rainforests. Roads reduce landscape connectivity and the capacity of the regional population live in all suitable areas and these effects are most significant in species that avoid the road, which are often species dependent on forests. The magnitude of the barrier effects depend on the behavior and mobility of these species. When roads represent "sinkers" or barriers for populations due, respectively, trampling or avoidance, mitigation measures are indicated to increase connectivity between habitat patches separated by these roads. The habitat quality is a factor that must be considered, even at low frequencies of road kill there. The goal of this study was to propose two methods of selecting priority areas for implementation of mitigation measures of roads effects on forest vertebrate species: Multivariate Hierarchical Selection and Bivariate Selection. The study area was the Atlantic Forest biome, being cut into hexagonal landscapes at three different scales (10,000, 1,000 and 100 km), using the extension "Repeating Shapes" program in ArcGIS 9.3. In each hexagon was calculated: area of forest, protected areas, density of roads and hydrograph. Only hexagons covered by at least 45% by the Atlantic Forest, with over 50% forest cover and more than 1% of protected areas were included in the analyzes. After this using the Multivariate Hierarchical selection method, we performed a principal component analysis (PCA) with the four variables measured for each scale separately. The hexagons were then ordered according to their position in the first axis of PCA, using a hierarchical manner and the smaller scale of hexagons. For the Bivariate selection method we did a dot plot for each scale hexagon, with the variables forest cover and rivers. We selected hexagons that were located in the quadrant of the graph that represented higher density of rivers and larger percentage of forest cover. After that, we made a simulation to evaluate if the two methods were able to retrieve scores as high as the ordination following only the positioning of the hexagons on Axis 1 of the PCA, without a hierarchical analysis. For the study site, the Multivariate Hierarchical selection was more efficient for choosing priority areas than Bivariate Selection for both the intermediate scale (1000 km) and to a lesser extent (100 km). The five hexagons of 100 km of highest priorities are located in São Paulo and Paraná, covering four protected areas (PARES of Jacupiranga, Guaraqueçaba APA, and APA Cananéia-Jacuípe and PARES Ilha do Cardoso). Due to simplicity and easy applicability of the method, we believe this may be an interesting option for selecting priority areas for implementation of mitigation measures of the effects of roads

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