Dissertations / Theses on the topic 'Reptile populations'
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Baxter-Gilbert, James H. "The Long Road Ahead: Understanding Road-related Threats to Reptiles and Testing if Current Mitigation Measures are Effective at Minimizing Impacts." Thesis, Laurentian University of Sudbury, 2014. https://zone.biblio.laurentian.ca/dspace/handle/10219/2137.
Full textRodrigues, Murilo Guimarães 1978. "Estimating vital rates with imperfect detection in amphibian and reptile populations = Estimando taxas vitais com detecção imperfeita em populações de anfíbios e répteis." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/316218.
Full textTese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: A ecologia de populações investiga os fatores que levam a variação das taxas vitais e, consequentemente, no número de indivíduos. Isso inclui testar hipóteses sobre aspectos da história de vida das espécies e entender os fatores que podem modular a dinâmica populacional. No entanto, a obtenção de dados para testar hipóteses pode ser difícil para populações que apresentam probabilidades de detecção < 1, como anfíbios e répteis. A marcação e recaptura é amplamente usada para estimar a detecção e inferir aspectos de dinâmica populacional e testar hipóteses ecológicas. Neste trabalho empregamos a teoria de marcação e recaptura para testar hipóteses relacionadas à ecologia e conservação de populações de anfíbios e répteis. Utilizamos o programa MARK para implementar modelos de populações abertas e fechadas incorporando a probabilidade de detecção dos indivíduos, para obter estimativas de sobrevivência, e outros parâmetros populacionais usando máxima verossimilhança. Organizamos esta tese em quatro capítulos. Iniciamos enfatizando a importância da probabilidade de detecção, além de simular cenários hipotéticos para demonstrar a relação entre esforço de campo, tamanho ótimo amostral e viés amostral. Em seguida comparamos o efeito de duas técnicas de marcação, o corte de artelhos e o implante de microchips, sobre a sobrevivência individual do sapo ferreiro, Hypsiboas faber. No terceiro capítulo estimamos a sobrevivência e o crescimento populacional da jararaca-ilhoa, Bothrops insularis incorporando emigração temporária aos modelos. Além do estudo de taxas vitais e de dinâmica nas populações, a alocação de energia e suas consequências na sobrevivência individual podem ser testadas com modelos de marcação e recaptura. Assim, no quarto e último capítulo consideramos dois caracteres sexuais presentes no sistema de acasalamento dos lagartos, o tamanho da mandíbula e a coloração chamativa, para comparar as estimativas de sobrevivência entre machos e fêmeas do lagarto cauda de chicote, Cnemidophorus cf. ocellifer. . De forma geral, observamos que a probabilidade de detecção individual nos sistemas estudados foi baixa e condizente com a detecção de vertebrados em ambientes tropicais. Além disso, a inclusão de covariáveis na investigação de parâmetros vitais e no processo de detecção é fundamental para o melhor entendimento dos fatores que explicam a dinâmica de uma população. Especificamente observamos que: (i) demonstramos que as taxas que não incorporam a detecção são enviesadas em relação às estimativas que consideram a detecção, (ii) as estimativas de sobrevivência foram similares em indivíduos de Hypsiboas faber marcados com ablação de artelhos e microchips , (iii) Bothrops insularis apresentou baixa probabilidade de sobrevivência anual e crescimento populacional anual negativo. Por fim, (iv) machos maiores do lagarto Cnemidophorus cf. ocellifer apresentaram sobrevivência mensal menor do que machos menores, mas o oposto foi observado para as fêmeas
Abstract: Population ecology aims to search for factors that lead to variation in vital rates and consequently, in the number of individuals. This includes testing hypotheses about natural history traits and threats to populations. However, obtaining data to test hypotheses is challenging because following individuals in the field can be difficult, especially for amphibians and reptiles, where detection probabilities are often < 1. Mark-recapture methods are widely used to estimate detection probabilities and to test ecological hypothesis. Here we used mark-recapture methods to test hypotheses related to ecology and conservation of amphibian and reptile populations. We implemented open- and closed-population models in Program MARK, to account for detection probabilities and to calculate survival estimates and other population parameters. We organized this dissertation into four chapters. In the first chapter we emphasize the importance of considering detection probabilities besides simulating hypothetical scenarios to show the relationship between field effort, sample size and precision. In the second chapter we used a Cormack-Jolly-Seber model to compare the effect of two amphibian marking techniques, toeclipping and PIT tagging, on survival in the blacksmith tree frog, Hypsiboas faber. In the third chapter our goal was to estimate survival and population growth of the golden lancehead, Bothrops insularis accounting for temporary emigration using Pollock's Robust Design. Besides the study of vital rates and population dynamics, energy allocation and its consequences for survival are testable with mark-recapture models. Thus, in the last chapter we used two traits from the lizard mating system, namely jaw size and courtship coloration, to compare survival estimates between males and females of the whiptail lizard, Cnemidophorus cf. ocellifer. In summary we observed that detection probability on the studied populations were low and similar to other vertebrate populations from the tropics. However, including covariates in estimation models of vital rates and detection is important to obtain more accurate results to explain population dynamics. Specifically we conclude that (i) return rates were biased low in relation to survival estimates that account for detectability, (ii) the estimates of survival were similar between toe-clipped and PIT tagged individuals of Hypsiboas faber, (iii) Bothrops insularis showed low survival probability and negative annual population growth. And (iv) larger Cnemidophorus cf. ocellifer males showed lower monthly survival probability than smaller males but the opposite was found for females
Doutorado
Ecologia
Doutor em Ecologia
Lettink, Marieke, and n/a. "Adding to nature : can artificial retreats be used to monitor and restore lizard populations?" University of Otago. Department of Zoology, 2008. http://adt.otago.ac.nz./public/adt-NZDU20080715.091040.
Full textGuzinski, Jaro, and guzi0002@flinders edu au. "Investigating genetic population substructure of an Australian reptile tick, Bothriocroton hydrosauri, using highly polymorphic microsatellite markers." Flinders University. School of Biological Sciences, 2009. http://catalogue.flinders.edu.au./local/adt/public/adt-SFU20090324.125811.
Full textBissell, Ahrash N. "Population differences and behavior of lizards : on the road to speciation? /." view abstract or download file of text, 2001. http://wwwlib.umi.com/cr/uoregon/fullcit?p3024506.
Full textTypescript. Includes vita and abstract. Includes bibliographical references (leaves 121-147). Also available for download via the World Wide Web; free to University of Oregon users.
Wasiolka, Bernd. "The impact of overgrazing on reptile diversity and population dynamics of Pedioplanis l. lineoocellata in the southern Kalahari." Phd thesis, Universität Potsdam, 2007. http://opus.kobv.de/ubp/volltexte/2008/1661/.
Full textIn semi-arid savannah ecosystems, the vegetation structure and composition, i.e. the architecture of trees, shrubs, grass tussocks and herbaceous plants, offer a great variety of habitats and niches to sustain animal diversity. In the last decades intensive human land use practises like livestock farming have altered the vegetation in savannah ecosystems worldwide. Extensive grazing leads to a reduction of the perennial and herbaceous vegetation cover, which results in an increased availability of bare soil. Both, the missing competition with perennial grasses and the increase of bare soils favour shrub on open ground and lead to area-wide shrub encroachment. As a consequence of the altered vegetation structure and composition, the structural diversity declines. It has been shown that with decreasing structural diversity animal diversity decline across a variety of taxa. Knowledge on the effects of overgrazing on reptiles, which are an important part of the ecosystem, are missing. Furthermore, the impact of habitat degradation on factors of a species population dynamic and life history, e.g., birth rate, survival rate, predation risk, space requirements or behavioural adaptations are poorly known. Therefore, I investigated the impact of overgrazing on the reptile community in the southern Kalahari. Secondly I analysed population dynamics and the behaviour of the Spotted Sand Lizard, Pedioplanis l. lineoocellata. All four chapters clearly demonstrate that habitat degradation caused by overgrazing had a severe negative impact upon (i) the reptile community as a whole and (ii) on population parameters of Pedioplanis l. lineoocellata. Chapter one showed a significant decline of regional reptile diversity and abundance in degraded habitats. In chapter two I demonstrated that P. lineoocellata moves more frequently, spends more time moving and covers larger distances in degraded than in non-degraded habitats. In addition, home range size of the lizard species increases in degraded habitats as shown by chapter three. Finally, chapter four showed the negative impacts of overgrazing on several population parameters of P. lineoocellata. Absolute population size of adult and juvenile lizards, survival rate and birth rate are significantly lower in degraded habitats. Furthermore, the predation risk was greatly increased in degraded habitats. A combination of a variety of aspects can explain the negative impact of habitat degradation on reptiles. First, reduced prey availability negatively affects survival rate, the birth rate and overall abundance. Second, the loss of perennial plant cover leads to a loss of niches and to a reduction of opportunities to thermoregulate. Furthermore, a loss of cover and is associated with increased predation risk. A major finding of my thesis is that the lizard P. lineoocellata can alter its foraging strategy. Species that are able to adapt and change behaviour, such as P. lineoocellata can effectively buffer against changes in their environment. Furthermore, perennial grass cover can be seen as a crucial ecological component of the vegetation in the semi-arid savannah system of the southern Kalahari. If perennial grass cover is reduced to a certain degree reptile diversity will decline and most other aspects of reptile life history will be negatively influenced. Savannah systems are characterised by a mixture of trees, shrubs and perennial grasses. These three vegetation components determine the composition and structure of the vegetation and accordingly influence the faunal diversity. Trees are viewed as keystone structures and focal points of animal activity for a variety of species. Trees supply animals with shelter, shade and food and act as safe sites, nesting sites, observation posts and foraging sites. Recent research demonstrates a positive influence of shrub patches on animal diversity. Moreover, it would seem that intermediate shrub cover can also sustain viable populations in savannah landscapes as has been demonstrated for small carnivores and rodent species. The influence of perennial grasses on faunal diversity did not receive the same attention as the influence of trees and shrubs. In my thesis I didn’t explicitly measure the direct effects of perennial grasses but my results strongly imply that it has an important role. If the perennial grass cover is significantly depleted my results suggest it will negatively influence reptile diversity and abundance and on several populations parameters of P. lineoocellata. Perennial grass cover is associated with the highest prey abundance, reptile diversity and reptile abundance. It provides reptiles both a refuge from predators and opportunities to optimise thermoregulation. The relevance of each of the three vegetation structural elements is different for each taxa and species. In conclusion, I can all three major vegetation structures in the savannah system are important for faunal diversity.
Ineich, Ivan. "Recherches sur le peuplement et l'évolution des Reptiles terrestres de Polynésie française." Montpellier 2, 1987. http://www.theses.fr/1987MON20238.
Full textBell, Kristen E. "Conservation ecology of amphibians and reptiles in Sarapiqui, Costa Rica : forest fragmentation and long term population change." FIU Digital Commons, 2005. http://digitalcommons.fiu.edu/etd/1481.
Full textBissell, Kristin Marie. "Modeling habitat ecology and population viability of the Eastern Massasauga Rattlesnake in southwestern lower Michigan." Diss., Connect to online resource - MSU authorized users, 2006.
Find full textTitle from PDF t.p. (viewed on Nov. 20, 2008) Includes bibliographical references (p. 118-124). Also issued in print.
Sung, Yik-hei, and 宋亦希. "Impacts of illegal trapping and plantation forestry on herpetofaunal populations." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B48199308.
Full textpublished_or_final_version
Biological Sciences
Doctoral
Doctor of Philosophy
Dalem, Anak Agung Gde Raka, University of Western Sydney, and Faculty of Science and Technology. "Demography and movement patterns of a population of eastern snake-necked turtles, Chelodina longicollis (Shaw, 1794)." THESIS_FST_xxx_Dalem_A.xml, 1998. http://handle.uws.edu.au:8081/1959.7/63.
Full textMaster of Science (Hons)
Miranda, José Roberto. "Écologie des peuplements de Reptiles du tropique semi-aride brésilien (région d'Ouricuri-PE)." Montpellier 2, 1986. http://www.theses.fr/1986MON20154.
Full textBerglind, Sven-Åke. "Population Dynamics and Conservation of the Sand Lizard (Lacerta agilis) on the Edge of its Range." Doctoral thesis, Uppsala universitet, Evolutionär funktionsgenomik, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-5750.
Full textPatterson, Lucy. "Food Availability, Thermal Quality, and Habitat Selection in Yarrow’s Spiny Lizards (Sceloporus Jarrovii)." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37827.
Full textHurston, Heather. "Historical Land Fragmentation and its Effects on Genetic Diversity and Parasitism of Island Populations of Podarcis erhardii (Lacertidae, Reptilia)." ScholarWorks@UNO, 2007. http://scholarworks.uno.edu/td/1072.
Full textRoush, Danielle Marie. "Review of Genetic and Maternal Effects on TSD in Reptiles and Identification of Population Differentiation in Putative TSD Genes in Chelydra serpentina." Thesis, The University of North Dakota, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10814732.
Full textVariation in sex ratio among clutches of eggs from different females is common in reptiles with TSD, but the mechanisms that cause this variation are unknown. In an effort to shed light on these mechanisms, we first critically review literature that examines variation in temperature-dependent sex determination (TSD) within species. Genetic variation in TSD and maternal effects on TSD are two major mechanisms that have received attention. We outline the types of experiments and data required to demonstrate that a) genetic variation, b) maternally derived steroids, or c) both factors influence variation in sex ratio among clutches. Next, we compare allele frequencies between populations of Chelydra serpentina that differ in thermosensitivity of sex determination and identify population differentiation in putative TSD genes.
Sangal, Vartul. "Multilocus sequence typing analyses of Salmonella enterica subspecies enterica." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2009. http://dx.doi.org/10.18452/15883.
Full textSerovars of Salmonella enterica subspecies enterica are generally pathogenic to humans and other mammals. In this study, I examined the population structure of one of the most common serovars of this subspecies isolated from humans and food animals, serovar Newport, using a multilocus sequence typing scheme. This scheme was also used to analyze isolates of this subspecies from chronic human carriers and reptiles to determine whether isolates from these sources represent distinct populations than those from other hosts. Multilocus sequence typing has extensively been used to study evolution and population structure of a wide range of organisms. 400-600 bp fragments of 7 housekeeping genes were sequenced and every unique sequence of each gene fragment was given a distinct allele number. Each unique combination of alleles was assigned a distinct sequence type number. The data were used in further analyses. Three lineages, namely Newport-I, Newport-II and Newport-III were identified within serovar Newport which were associated to European humans, animals and humans in North America, respectively. Multidrug resistance phenotypes were most common in Newport-II whereas most isolates in Newport-III were pan-susceptible. When compared to other serovars, the numbers of lineages within Newport were higher than for Enteritidis, Kentucky and Typhimurium but lower than for Paratyphi B. Therefore, serovars of S. enterica subspecies enterica vary greatly in their population structures. The sequence types observed for isolates from chronic human carriers were generally the most common among human-clinical and animal isolates. Most isolates from non-carrier humans plus animals were genetically identical to the carried isolates within most serovars. Genetic diversity was also comparable between isolates from these sources. These results suggest that salmonellae from chronic human carriers belong to the same population as isolates from non-carrier humans and animals. For most serovars, most isolates from reptiles were genetically identical to those from humans or other warm blooded animals. However, in serovars Bovismorbificans, Decatur, Miami and Oranienburg, most reptile isolates were genetically distinct from isolates from other hosts. Only few reptile isolates were tested from Bovismorbificans, Decatur and Miami and only few non-reptile isolates were tested from Oranienburg, and in larger numbers of such isolates would be needed to determine whether these differences are statistically significant.
Hawkins, Emily. "Demography, Movement Patterns, and Habitat Selection of Blanding's Turtles at Canadian Nuclear Laboratories in Chalk River, Ontario." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/35563.
Full textCosendey, Beatriz Nunes. "Densidade populacional do lagarto endêmico Cnemidophorus littoralis em três restingas do estado do Rio de Janeiro: implicações na sua conservação." Universidade do Estado do Rio de Janeiro, 2015. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=8915.
Full textCnemidophorus littoralis é um lagarto teiídeo ameaçado de extinção, endêmico de restinga e restrito ao estado do Rio de Janeiro, tendo sido encontrado em apenas quatro restingas da região: restinga de Grussaí (limite norte), restinga de Jurubatiba, restinga de Maricá e restinga de Marambaia (limite sul). Devido à sua restrita distribuição, os efeitos da degradação de hábitat e mudanças climáticas são especialmente danosos para os indivíduos dessa espécie, podendo levar a uma extinção local ou até total. A fim de aumentar a gama de informações sobre esta espécie de lagarto, investigamos a sua densidade e o seu tamanho populacional em três áreas de restingas, além de termos registrado as temperaturas às quais estão sujeitos nos diferentes micro-hábitats disponíveis, bem como suas preferências a determinadas estruturas da vegetação, e a situação atual de degradação das restingas, comparando-a com a de anos anteriores. O presente trabalho foi realizado nas restingas de Barra de Maricá (Maricá), Jurubatiba (Macaé) e Grussaí (São João da Barra). Os resultados revelaram uma diferença na estrutura da vegetação entre as três restingas, sendo a de Grussaí a que mais se destaca. Essa restinga é também a que apresenta menor densidade populacional e maior índice de degradação. Por outro lado, a restinga de Jurubatiba foi o local com menor quantidade de distúrbios encontrados, possuindo a maior densidade populacional dentre as três e se caracterizando como a melhor área para manutenção da espécie. O folhiço no bordo de moita foi, no geral, o hábitat mais utilizado pelos lagartos, sendo o período entre 10h00 e 11h00 o que teve maior número de avistamentos. A altura de arbusto demonstrou influenciar negativamente a ocupação dos indivíduos na restinga de Grussaí, enquanto os períodos de observação ao longo do dia influenciaram a detectatibilidade dos indivíduos nas três restingas. As restingas também apresentaram uma temperatura ambiente semelhante ao longo do dia, sendo Maricá a restinga com média mais alta (34,6C), seguida por Grussaí (33,9C) e por último Jurubatiba, com uma média de 33,2C. As temperaturas corpóreas às quais os indivíduos estariam sujeitos nos micro-hábitats disponíveis variaram de 27C (folhiço sobre vegetação) a 42,5C (areia nua), na restinga de Grussaí e de 28C (folhiço no interior de moita) a 32,9C (areia nua) na restinga de Jurubatiba. Uma vez que a estrutura do ambiente influencia na característica termal dos lagartos e, consequentemente, na manutenção das populações, a conservação das restingas e de suas estruturas vegetacionais são indispensáveis para a perpetuação da espécie.
Cnemidophorus littoralis is a teiid lizard endemic to restingas and restrict to the state of Rio de Janeiro, being found only in four restingas: restinga de Grussaí (north limit), restinga de Jurubatiba, restinga de Maricá e restinga de Marambaia (south limit). Its current conservation status is "in danger". Due to its restricted distribution, the effects of hábitat degradation and climate changes are specially harmful to individuals of this species, which may lead to local or even total extinction. In order to raise the level of information about this lizard species, we investigated the population density and population size in three areas of restinga, besides recording the temperatures to which they are subject in different micro-hábitats available as well as their preferences for certain vegetation structures and the current situation of degradation of restingas, comparing it to the previous years. The present study took place in Barra de Maricá (Maricá), Jurubatiba (Macaé) and Grussaí (São João da Barra). The results showed a difference between the vegetation structures of the three restingas, being restinga de Grussaí the most different one. This restinga is also the one with the lowest density and the highest degradation index. On the other hand, restinga de Jurubatiba was the site where we found lowest disturbance, having the highest density among the three and being characterized as the best area for the maintenance of the species. The litter on the edges of bushes was, overall, the hábitat most widely used by lizards, and the period between 10:00 am and 11:00 am was the one when most of the sightings ocurred. Shrub height showed a negative effect on the occupation of the individuals in restinga de Grussaí, while the periods of observation along the day influenced the detectability of individuals in the three restingas. The restingas had similar temperature throughout the day, Maricá being the one with highest average temperature (34,6C), followed by Grussaí (33,9C) and finally Jurubatiba, with 33,2C average. The body temperature to which the individuals were subject in the micro-hábitats ranged from 27C (litter above vegetation) to 42,5C (bare sand) in Grussaí, and from 28C (litter inside shrub) to 32,9C (bare sand) in Jurubatiba. Since environmental structure influences the thermal characteristic of lizards, hence maintaining populations, conservation of restingas and its vegetation structures are essential for the perpetuation of the species
Mou, Yung-Ping. "Ecologie comparee de deux populations de lezards des murailles, podarcis muralis (laurenti, 1768), en france." Paris 6, 1987. http://www.theses.fr/1987PA066544.
Full textJonaitis, Lauren A. "Using Roadkill as a Lens to Understand Animal Movement and Mortality." Bowling Green State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1497912666154545.
Full textHenle, Klaus. "Population ecology and life history of a lizard community in arid Australia." Phd thesis, 1988. http://hdl.handle.net/1885/140211.
Full textSarre, Stephen. "The ecological and evolutionary consequences of habitat fragmentation on two species of gecko (Oedura reticulata and Gehyra variegata)." Phd thesis, 1994. http://hdl.handle.net/1885/140318.
Full textDiLeo, Michelle Francis. "The influence of landscape on genetic structure of a threatened reptile: the eastern massasauga rattlesnake." Thesis, 2011. http://hdl.handle.net/1974/6843.
Full textThesis (Master, Biology) -- Queen's University, 2011-10-14 15:06:35.956
Guzinski, Jaromir Anthony. "Investigating genetic population substructure of an Australian reptile tick, Bothriocroton hydrosauri, using highly polymorphic microsatellite markers." 2008. http://catalogue.flinders.edu.au/local/adt/public/adt-SFU20090324.125811/index.html.
Full textWasiolka, Bernd [Verfasser]. "The impact of overgrazing on reptile diversity and population dynamics of Pedioplanis l. lineoocellata in the southern Kalahari, South Africa / von Bernd Wasiolka." 2007. http://d-nb.info/988046261/34.
Full textROW, JEFFREY. "Origins of genetic variation and population structure of foxsnakes across spatial and temporal scales." Thesis, 2011. http://hdl.handle.net/1974/6271.
Full textThesis (Ph.D, Biology) -- Queen's University, 2011-01-11 10:40:52.476
Barun, Arijana. "The small Indian mongoose (Herpestes auropunctatus) on Adriatic Islands: impact, evolution, and control." 2011. http://trace.tennessee.edu/utk_graddiss/947.
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