Дисертації: "Animal populations"

1

Brännström, Åke. "Modelling animal populations." Doctoral thesis, Umeå universitet, Matematik och matematisk statistik, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-205.

Повний текст джерела

Анотація:

This thesis consists of four papers, three papers about modelling animal populations and one paper about an area integral estimate for solutions of partial differential equations on non-smooth domains. The papers are: I. Å. Brännström, Single species population models from first principles. II. Å. Brännström and D. J. T. Sumpter, Stochastic analogues of deterministic single species population models. III. Å. Brännström and D. J. T. Sumpter, Coupled map lattice approximations for spatially explicit individual-based models of ecology. IV. Å. Brännström, An area integral estimate for higher order parabolic equations. In the first paper we derive deterministic discrete single species population models with first order feedback, such as the Hassell and Beverton-Holt model, from first principles. The derivations build on the site based method of Sumpter & Broomhead (2001) and Johansson & Sumpter (2003). A three parameter generalisation of the Beverton-Holtmodel is also derived, and one of the parameters is shown to correspond directly to the underlying distribution of individuals. The second paper is about constructing stochastic population models that incorporate a given deterministic skeleton. Using the Ricker model as an example, we construct several stochastic analogues and fit them to data using the method of maximum likelihood. The results show that an accurate stochastic population model is most important when the dynamics are periodic or chaotic, and that the two most common ways of constructing stochastic analogues, using additive normally distributed noise or multiplicative lognormally distributed noise, give models that fit the data well. The latter is also motivated on theoretical grounds. In the third paper we approximate a spatially explicit individual-based model with a stochastic coupledmap lattice. The approximation effectively disentangles the deterministic and stochastic components of the model. Based on this approximation we argue that the stable population dynamics seen for short dispersal ranges is a consequence of increased stochasticity from local interactions and dispersal. Finally, the fourth paper contains a proof that for solutions of higher order real homogeneous constant coefficient parabolic operators on Lipschitz cylinders, the area integral dominates the maximal function in the L2-norm.

Стилі APA, Harvard, Vancouver, ISO та ін.

2

Brännström, Åke. "Modelling animal populations : tools and techniques /." Umeå : Univ, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-205.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

3

Alston, Robert David. "The statistical analysis of animal populations." Thesis, University of Kent, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294317.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

4

Campana, Michael Gray. "Diachonic DNA analyses of animal breeds and populations." Thesis, University of Cambridge, 2011. https://www.repository.cam.ac.uk/handle/1810/236764.

Повний текст джерела

Анотація:

Humans are dependent on the animals they raise and breed for food and secondary products. Archaeological and genetic investigations can provide critical insights into the history and development of these breeds and help understand human activities in the past. Furthermore, many well-adapted breeds are endangered and archaeological and genetic data can help inform future breed conservation choices. Utilising ancient DNA data could potentially permit detailed diachronic analyses of the development of animal breeds. Ancient DNA analyses have typically focussed on large-scale biogeographic patterns in time and space, such as the spread of domesticates or the movements of peoples. Few studies have attempted fine-scale diachronic analysis within single animal populations or breeds. This is largely due to restricted sample availability and the limited phylogenetic resolution provided by the mitochondrial genome, the most commonly used ancient DNA marker. In this thesis, I demonstrate that fine-scale diachronic analyses within single animal populations and breeds over short time scales are feasible. First, in order to address the limitations of sample size, I assessed three sample screening methods’ abilities (maximum mitochondrial DNA amplicon length, NanoDrop® spectrometry and collagen preservation) to select samples in which DNA was preserved and analysed the utility of parchment as a novel source of ancient and historic DNA. None of the screening methods accurately predicted DNA preservation, but collagen preservation was able to weed out extremely poorly preserved samples from further analysis. All but one of the tested parchments produced multiple sequences matching several different species. Parchment therefore was not appropriate for fine-scale diachronic analyses. Next, I assessed whether analysing the nuclear genome could permit fine-resolution diachronic genetic studies. Since single nucleotide polymorphisms are ideal candidate nuclear markers for diachronic DNA analyses, I assessed the accuracy of the nuclear SNP-typing methodology, SNaPshot™, by genotyping three coat colour markers for a sample of historic Thoroughbred horses for which both phenotypic and correct genotypic information were known from pedigree information in the General Stud Book. The SNaPshot™ protocol was found to provide accurate genotypic information in all cases. Finally, as a proof of method, I compared the diachronic information provided by the mitochondrial and nuclear genomes in Icelandic and Thoroughbred horses. Specifically, in the Icelandic horse, I analysed the mitochondrial D-loop and three coat colour genes in modern and historic populations. In the Icelandic horse, I found statistically significant evidence for genetic change in the mitochondrial genome over the last 150 years. I found no evidence for change in coat colour allele frequencies. Conversely, in the biased and small historic Thoroughbred dataset, the mitochondrial genome was insufficient to provide population-level information, but I was able to show that allele frequencies in the nuclear MSTN gene, a gene previously shown to influence racing performance, have changed significantly in the past century.

Стилі APA, Harvard, Vancouver, ISO та ін.

5

Laine, Kari. "Long-term variations in plant quality and quantity in relation to cyclic microtine rodents at Kilpisjärvi, Finnish Lapland." Oulu, Finland : University of Oulu, 1988. http://catalog.hathitrust.org/api/volumes/oclc/18696609.html.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

6

Waldick, Ruth. "Assessing the status of the endangered North Atlantic right whale using genetic and demographic data." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ66244.pdf.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

7

Okell, Claire Natasha. "Animal health in arid lands and recommendations for strategic animal health service provision in mobile populations." Thesis, Royal Veterinary College (University of London), 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.731270.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

8

Simonis, Molly C. "Monitoring Ohio Bat Communities and Populations Using Mobile Acoustics." Wright State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=wright1532278749872479.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

9

Ward, Eric John. "Incorporating model selection and decision analysis into population dynamics modeling /." Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/5319.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

10

Koons, David Nelson Grand James Barry. "Transient population dynamics and population momentum in vertebrates." Auburn, Ala, 2005. http://repo.lib.auburn.edu/EtdRoot/2005/SPRING/Forestry_and_Wildlife_Sciences/Dissertation/KOONS_DAVID_55.pdf.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

11

Samaranayaka, Ari, and n/a. "Environmental stochasticity and density dependence in animal population models." University of Otago. Department of Mathematics & Statistics, 2006. http://adt.otago.ac.nz./public/adt-NZDU20060907.114616.

Повний текст джерела

Анотація:

Biological management of populations plays an indispensable role in all areas of population biology. In deciding between possible management options, one of the most important pieces of information required by population managers is the likely population status under possible management actions. Population dynamic models are the basic tool used in deriving this information. These models elucidate the complex processes underlying the population dynamics, and address the possible consequences/merits of management actions. These models are needed to guide the population towards desired/chosen management goals, and therefore allow managers to make informed decisions between alternative management actions. The reliability that can be placed on inferences drawn from a model about the fate of a population is undoubtedly dependent on how realistically the model represents the dynamic process of the population. The realistic representation of population characteristics in models has proved to be somewhat of a thorn in the side of population biologists. This thesis focuses in particular on ways to represent environmental stochasticity and density dependence in population models. Various approaches that are used in building environmental stochasticity into population models are reviewed. The most common approach represents the environmental variation by changes to demographic parameters that are assumed to follow a simple statistical distribution. For this purpose, a distribution is often selected on the basis of expert opinion, previous practice, and convenience. This thesis assesses the effect of this subjective choice of distribution on the model predictions, and develops some objective criteria for that selection based on ecological and statistical acceptability. The more commonly used distributions are compared as to their suitability, and some recommendations are made. Density dependence is usually represented in population models by specifying one or more of the vital rates as a function of population density. For a number of reasons, a population-specific function cannot usually be selected based on data. The thesis develops some ecologically-motivated criteria for identifying possible function(s) that could be used for a given population by matching functional properties to population characteristics when they are known. It also identifies a series of properties that should be present in a general function which could be suitable for modelling a population when relevant population characteristics are unknown. The suitability of functions that are commonly chosen for such purposes is assessed on this basis. I also evaluate the effect of the choice of a function on the resulting population trajectories. The case where the density dependence of one demographic rate is influenced by the density dependence of another is considered in some detail, as in some situations it can be modelled with little information in a relatively function-insensitive way. The findings of this research will help in embedding characteristics of animal populations into population dynamics models more realistically. Even though the findings are presented in the context of slow-growing long-lived animal populations, they are more generally applicable in all areas of biological management.

Стилі APA, Harvard, Vancouver, ISO та ін.

12

McLoughlin, Eimear Maureen. "Time series analysis and modelling of diseases in production animal populations." Thesis, Queen's University Belfast, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334509.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

13

Beardmore, Ivana. "Social groupings and disease dynamics in animal populations : a theoretical study." Thesis, University of Bath, 2002. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.647821.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

14

Riley, Meghan D. "Monitoring of Amur tigers for their conservation." Laramie, Wyo. : University of Wyoming, 2009. http://proquest.umi.com/pqdweb?did=1935340891&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

15

Neal, David R. "Finite difference approximations of advection-diffusion equations for modeling shark populations /." Electronic version (PDF), 2007. http://dl.uncw.edu/etd/2007-3/neald/davidneal.pdf.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

16

Clarke, Paul D. "The generally weak influence of density-dependent regulation on natural animal populations." Thesis, University of Ottawa (Canada), 1996. http://hdl.handle.net/10393/10051.

Повний текст джерела

Анотація:

Animal population densities are thought to be "regulated" by density-dependent processes (Haldane, 1953; Royama, 1977: Berryman, 1991). The perceived importance of these processes to biologists is evident from the vast amount of research dedicated to this idea (Inchausti, 1994). Most of this research addresses the problem(s) of detecting the effect of density-dependent regulatory processes using time series data. However, the question of the relative importance of density-dependent factors upon rates of change of population abundances is rarely addressed. In this thesis, I quantify the importance of density-dependent factors in 303 natural animal populations. I found that, on average, only $\approx$19% of the temporal variability in per capita growth rate could be statistically related to population density. Yet research effort concentrates overwhelmingly on density-dependent processes. I conclude that the effects of density-dependent processes within natural animal populations are generally weak and disproportionately studied. Because many, if not all, ecological processes act on some characteristic temporal or spatial scale (O'Neill et al., 1986; Wiens, 1989; Pimm, 1991; Maurer, 1994; Fleishman, 1995) I also address the question of how the characteristic time of density-dependent regulatory processes might affect the estimates of the influence of regulatory processes on a population's per capita growth rate. I hypothesized that if density-dependent regulatory processes operate on a characteristic temporal scale that sampling with a sampling period commensurate with the characteristic time of these processes would yield the maximal amounts of variability in the per capita growth rate statistically related to the variability in N. Simulated population time series were generated using a logistic growth model with a stochastic term added. Based on the analysis of the simulated time series, the characteristic time of density-dependent regulatory processes is predicted to be independent of life-history traits correlated with body size. The characteristic times are predicted to be integral multiples of 1 year (1, 2, 3 and 4 years) for all modelled body sizes. These predictions, regarding characteristic times, were found to be suspect after further testing supported the contention that these results may be methodological artifacts. I suggest that these results are due to the pragmatic criteria imposed to constrain the number of possible subsamples to be analyzed. I further suggest that to better address the characteristic time hypothesis, time-slices with different time periods between successive population densities are required.

Стилі APA, Harvard, Vancouver, ISO та ін.

17

Knott, Sara Anne. "Statistical methods for the detection of major genes in farm animal populations." Thesis, University of Edinburgh, 1990. http://hdl.handle.net/1842/11830.

Повний текст джерела

Анотація:

Animal breeding theory is based on the assumption that traits are controlled by many genes each having small effect, however, genes with a large effect have been identified in favourable circumstances. Where major genes can be identified, and individual animals genotyped, exploitation of the genetic variation can be optimised. Segregation analysis has been proposed as a suitable method for detecting major genes. It involves maximising and comparing the likelihood of the data under different genetic models to ascertain the most likely genetic structure. To identify a major gene the likelihood of the data under a polygenic model is maximised and compared with the maximum likelihood under the mixed model (i.e. containing a major gene and polygenic component). A significant improvement in the likelihood obtained by incorporating the major gene gives evidence for its existence. Equations for the exact mixed model and polygenic likelihoods can be obtained, however the mixed model likelihood involves the integration of a complex function. Several approximations to this likelihood have been investigated. The first effectively retains the integration and approximates crossproduct terms involving the major gene and the polygenic component. The second (Herm) approximates the integration with a summation using the Hermite polynomial. The likelihood has been maximised using a quasi-Newton algorithm. The third and fourth methods are extensions of mixed model methods (in the statistical sense, i.e. including fixed and random effects), which are already familiar to animal breeders. One replaces the integration with a single estimate of the mode of each sire's transmitting ability distribution (ME1), the other estimates three modes one for each possible major genotype of the sire (ME3). These have been implemented using an expectation-maximisation algorithm. The first approximation was thought too complex to extend to include, for example, fixed effects. The operational characteristics of the other three methods have been investigated using simulated data. The Monte-Carlo simulation program uses Boolean algebra to describe the genotype of individuals at each locus and the inheritance of the alleles. Different genetic models have been considered and the data was analysed twice, firstly assuming that the polygenic heritability was known and fixing it at the expected value, secondly estimating the heritability from the data. For all the analyses the simulated data contained 50 sires each with 20 half-sib offspring. Segregation analysis is capable of detecting a major gene segregating in a population and accurately estimating its effect and frequency. Approximations to the mixed model likelihood make the method feasible for large data sets.

Стилі APA, Harvard, Vancouver, ISO та ін.

18

Nordstrom, Lisa A. "Tapirs and Rhinoceroses in Captivity: An Examination of the North American Captive Populations and their Husbandry." DigitalCommons@USU, 2006. https://digitalcommons.usu.edu/etd/6607.

Повний текст джерела

Анотація:

A..11 species of Tapiridae and Rhinocerotidae are threatened or endangered in the wild. Captive populations have been established for most of these species, but successful management has proved challenging. Effective ex situ conservation strategies, however, rely on the ability of zoological institutions to maintain and breed these endangered species. In this study, I examined the captive environment to identify the factors associated with reproduction, mortality, and health of rhinos and tapirs. Zoological institutions in the North American region that currently housed rhinos and/or tapirs were surveyed in 2003. Attaining an approximately 90% response rate, I compiled information on the following variables to describe the captive environment: number of enclosures, enclosure type, enclosure area, number of animals, public viewing, percent of walls surrounding the enclosure, enclosure substrate, topography, vegetation, mud wallows, pools, shelters, percent shade, climate, diet, feeding regime, time spent by keepers, and vaccinations. Information regarding the incidence of health problems also was obtained through the survey. Studbook data was used to obtain life history and demographic information. Three species of tapirs [Baird's (Tapirus bairdii), South American (T. terrestris), and Malay (T. indicus)] and three species of rhinos [black (Diceros bicornis), white (Ceratotherium simum), and Indian (Rhinoceros unicornis)] were included in this study. Due to the small captive population sizes, genetic and demographic Allee effects were detected. While tapirs responded similarly to their captive environment, each rhino species responded differently. Both exhibit area and completely were associated with the responses of captive tapirs and rhinos. Climate also was an influential factor for both groups of species. Other key factors included density, diet, keeper time, percent of public perimeter, and vaccinations. Complex interactions among the variables were found, including a nonlinear relationship between mean exhibit size and reproduction for black rhinos. The results of this study can be used to improve the captive management of tapirs and rhinos. By identifying the patterns associated with successful reproduction, reduced mortality, and fewer health problems, we can move towards establishing self-sustaining populations for these species. This goal is critical for the continued husbandry and conservation of these species.

Стилі APA, Harvard, Vancouver, ISO та ін.

19

Silva, Marjorie da. "Phylogeographic analysis in populations of Protonectarina sylveirae (Saussure, 1854) (Hymenoptera, Vespidae, Polistinae) /." São José do Rio Preto, 2016. http://hdl.handle.net/11449/138905.

Повний текст джерела

Анотація:

Orientador: Fernando Barbosa Noll
Banca: Eduardo Andrade Botelho de Almeida
Banca: Camila Cherem Ribas
Banca: Adriana Coletto Morales Corrêa e Castro
Banca: James M. Carpenter
Resumo: Os processos históricos e ecológicos de diversificação da fauna têm sidoamplamente estudados sob a luz da filogeografia, disciplina que lida com oarranjo espacial das linhagens genéticas. As vespas enxameadoras (Epiponini)como Protonectarina sylveirae (Saussure) são representantes comuns da faunaNeotropical. Esta espécie ocorre amplamente pela floresta Atlântica e apresentauma distribuição peculiar dentro de Epiponini devido à sua ausência na regiãoAmazônica. Apesar de muitos estudos apontarem para a existência dedescontinuidades filogeográficas para diferentes organismos na floresta Atlântica,explicações sobre as causas de tais padrões permanecem inconclusivas. Estetrabalho teve como objetivo investigar o padrão filogeográfico de P. sylveirae,com especial interesse na presença de estruturação genética e diferenciaçãomorfológica, bem como nos eventos históricos que possam explicar o padrãofilogeográfico observado. Os espécimes de P. sylveirae foram coletadosativamente em 13 áreas ao longo de sua distribuição para a extração, amplificaçãoe sequenciamento dos genes mitocondriais 12S, 16S e COI. Foram realizadasanalyses de diversidade genética, demografia histórica, tempo de divergência eestruturação populacional. Identificou-se 22 haplótipos, uma forte estruturaçãogenética foi encontrada pela análise de variância molecular (AMOVA) e a rede dehaplótipos revelou 3 grupos de haplótipos, também corroborados pela AMOVA.As análises de demografia...
Abstract: Ecological and historical processes of fauna diversification have been widelystudied under the light of phylogeography, a discipline that deals with the spatialarrangements of genetic lineages. Swarm-founding wasps (Epiponini) asProtonectarina sylveirae (Saussure) are common representatives of Neotropicalfauna. This species is widespread in Atlantic forest and presents a peculiardistribution within Epiponini because of its absence in Amazon region. Manystudies point to the existence of recurrent phylogeographical discontinuities todifferent groups of organisms in Atlantic forest, but the explanations about eventscausing this patters remain inconclusive. This work aimed to investigate thephylogeographic pattern of P. sylveirae with special interest in presence of geneticstructure, morphological differences among populations, and historical event(s)which could explain the observed phylogeographic pattern. Specimens of P.sylveirae were actively collected in 13 areas throughout its distribution for DNAextraction and amplification of mitochondrial genes 12S, 16S and COI. Analysisof genetic diversity, historical demography, divergence time, and populationstructure were performed. Twenty-two haplotypes were identified, a stronggenetic structuration was found by the analysis of molecular variance (ANOVA)and the haplotype network revealed three haplotype groups, also corroborated byAMOVA. Analysis of historical demography showed that populations of ...
Doutor

Стилі APA, Harvard, Vancouver, ISO та ін.

20

Silva, Camila Ferreira da. "Estrutura e dinâmica de populações de Hydrochoerus hydrochaeris (Linnaeus, 1766) (Rodentia) em duas áreas urbanas no norte do Paraná, Brasil." Universidade Tecnológica Federal do Paraná, 2015. http://repositorio.utfpr.edu.br/jspui/handle/1/1679.

Повний текст джерела

Анотація:

Fundação Boticário; CAPES
O presente estudo teve como objetivo avaliar a ecologia populacional de Hydrochoerus hydrochaeris (Linnaeus, 1766) em duas áreas urbanas no norte do Paraná, uma aberta e outra protegida, avaliando os efeitos desses dois diferentes tipos de ambientes sobre a estrutura e dinâmica da população e suas implicações para conservação da espécie. Os monitoramentos das populações foram realizados mensalmente no período entre junho de 2014 e março de 2015 no Parque Lago Jaboti (Apucarana/PR) e na Unidade de Conservação Parque Arthur Thomas (Londrina/PR). Para realização do levantamento de dados populacionais foi empregada a metodologia de censos totais (contagem direta de indivíduos). Foram avaliados parâmetros ecológicos das populações de capivaras, tais como, densidade ecológica, abundância, distribuição etária e taxa de natalidade, assim como, realizada a análise da paisagem. Foi aplicada a Análise de Variância (ANOVA), para testar as diferenças entre as médias da abundância de cada faixa etária por ano de observação, bem como as diferenças entre as médias da densidade ecológica ao longo dos anos de observação. O padrão de relação entre as classes de uso e ocupação do solo na paisagem e os parâmetros ecológicos das populações de capivaras foi avaliado pela Análise de Componentes Principais (ACP). A tendência de variação das abundâncias médias ao longo do tempo para o Parque Arthur Thomas revelou queda abrupta da população em curto período de tempo (2014 16±9, 14 e 2015 7±1), assim como a densidade ecológica em 2015 (0,05 ind./ha). Por outro lado, o Parque Lago Jaboti, apresentou aumento da abundância absoluta, com recuperação marcante da população no mesmo período (2014 38±8,30 e 2015 45±1,73) e chegando com uma densidade ecológica em 2015 de (2 ind./ha). A taxa de natalidade encontrada para o Parque Lago Jaboti foi superior à do Parque Arthur Thomas, que apresentou taxa negativa entre 2012 e 2015. A análise do uso e ocupação do solo demonstrou diferenças expressivas do ponto de vista da contribuição relativa dos elementos da paisagem na heterogeneidade espacial. O Parque Arthur Thomas apresentou áreas de vegetação densa e de zona urbana relativamente superiores àquelas verificadas no Parque Lago Jaboti que revelou proporções relativamente maiores das áreas de agricultura/campo e solo exposto. Dessa forma, o presente estudo revelou que a estrutura populacional local está diretamente relacionada às características espaciais de ambas as paisagens estudadas, como pode ser observado pela maior abundância e densidade verificada no Parque Lago Jaboti em comparação com Parque Arthur Thomas nos últimos anos de estudo.
This study aimed to evaluate the population ecology of Hydrochoerus hydrochaeris (Linnaeus, 1766) in two urban areas in the north of Paraná, an open and other protected by assessing the effects of these two different types of environments on the structure and dynamics of the population and its implications for conservation of the species. The monitoring of the populations were performed monthly between June 2014 and March 2015 in Jaboti Lake Park (Apucarana / PR) and Conservation Unit Parque Arthur Thomas (Londrina / PR). To conduct the survey population data was used the methodology of total census (direct counting of individuals).They were evaluated ecological parameters of the populations of capybaras, such as ecological density, abundance, age distribution and birth rate, as well as performed the analysis of the landscape. It was applied to analysis of variance (ANOVA) to test the differences between the averages of the abundance of each age group per year of observation, as well as the differences between the average ecological density over the years of observation. The standard relationship between the use of classes and land use in the landscape and the ecological parameters of the capybara populations was evaluated by Principal Component Analysis (PCA). The trend of variation of average abundance over time to Thomas Arthur Park revealed abrupt decrease of the population in a short period of time (2014 16 ± 9, 14 ± 1 and 2015 7±1) as well as ecological density in 2015 (0.05 ind./ha). On the other hand, the Jaboti Lake Park, showed an increase in absolute abundance, with marked recovery of the population in the same period (2014 38±8,30 and 2015 45±1,73) and coming up with an ecological density in 2015 (2 ind ./ha). The birth rate found Lake Park Jaboti was superior to Arthur Thomas Park, which had a negative rate between 2012 and 2015. The use and land cover analysis showed significant differences from the point of view of the relative contribution of landscape elements in the spatial heterogeneity. Arthur Thomas Park shows areas of dense vegetation and urban areas relatively higher than those observed in Jaboti Lake Park that revealed relatively higher proportions of the areas of agriculture / field and exposed soil. Thus, the present study revealed that the local population structure is directly related to the spatial characteristics of both studied landscapes, as can be seen by the greater abundance and density seen in Jaboti Lake Park compared to Arthur Thomas Park in recent years of study.

Стилі APA, Harvard, Vancouver, ISO та ін.

21

Baker, Melia. "Skeletal Development in Oviparous and Viviparous Populations of Saiphos equalis." Digital Commons @ East Tennessee State University, 2011. https://dc.etsu.edu/honors/129.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

22

Nuttall, Daniel B. "Sustaining human and non-human animal populations, from competition to coexistence : a model." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2002. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/NQ65831.pdf.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

23

CAPODIFERRO, MARCO ROSARIO. "From modern mitogenomes to archaeogenomics: exploring the past of human and animal populations." Doctoral thesis, Università degli studi di Pavia, 2019. http://hdl.handle.net/11571/1231867.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

24

Osmers, Karl Benjamin. "Genetic structuring between gemsbok (oryx gazella) populations and the impact of the founder effect on isolated populations." Thesis, University of Limpopo (Turfloop Campus), 2012. http://hdl.handle.net/10386/746.

Повний текст джерела

Анотація:

Thesis (M.Sc. (Zoology)) --University of Limpopo, 2012
A microsatellite-based study was performed on five populations of Gemsbok (Oryx gazella). This study was aimed at estimating genetic diversity in introduced South African gemsbok populations (an opportunity that arose when additional animals from the same source were imported into South Africa), and determine genetic structure. Population sizes at the time of sampling were: Namibia (n = 6500), Cohen (n = 70), Tempelhof (n = 55), STS Kalahari Game Ranch (n = 1000) and Elias (n = 35). The purpose of the study was to determine the genetic structure of the aforementioned O. Gazelle populations, and to assess the impact of the founder effect on isolated populations. The following primers (BMS1237, MAF46, OARFC304, OARHH64, ETH225, RBP3, MAF50, HDZ8) developed for commercial purposes in the bovine group were used. Genetic diversity were calculated as Expected Heterozygosity (He), proportion of polymorphic loc (P) and number of alleles per locus (A). Conformation to expected Hardy-Weinberg equilibrium of genotypes was also determined, using a Chi-square test. Tests for the signature of bottlenecks in the populations studied were also performed. Genetic drift/differentiation was tested by using FST and RST coefficients. Assignment tests were performed to identify the true number of genetic populations (clusters). Genetic distance was used as an additional measure of differentiation. The results indicated that all loci showed allelic polymorphism in all the populations except one (at the OARHH64 locus). The South African Cohen population displayed the highest level of genetic diversity, with He = 0.595 ± 0.247. This population also did not show evidence of a bottleneck. Genetic distance values indicated the greatest similarity between the Cohen and Namibian populations, in line with the Namibian origin of the Cohen group. Greatest distance was observed between the STS and Tempelhof populations. conclusion, results from this study reflects the origins of populations and suggest that inbreeding in small isolated populations may be less than previously estimated.

Стилі APA, Harvard, Vancouver, ISO та ін.

25

Schofield, Matthew R., and n/a. "Hierarchical capture-recapture models." University of Otago. Department of Mathematics & Statistics, 2007. http://adt.otago.ac.nz./public/adt-NZDU20080129.161029.

Повний текст джерела

Анотація:

A defining feature of capture-recapture is missing data due to imperfect detection of individuals. The standard approach used to deal with the missing data is to integrate (or sum) over all the possible unknown values. The missing data is completely removed and the resulting likelihood is in terms of the observed data. The problem with this approach is that often biologically unnatural parameters are chosen to make the integration (summation) tractable. A related consequence is that latent variables of interest, such as the population size and the number of births are only available as derived quantities. As they are not explicitly in the model they are not available to be used in the model as covariates to describe population dynamics. Therefore, models including density dependence are unable to be examined using standard methods. Instead of explicitly integrating out missing data, we choose to include it using data augmentation. Instead of being removed, the missing data is now present in the likelihood as if it were actually observed. This means that we are able to specify models in terms of the data we would like to have observed, instead of the data we actually did observe. Having the complete data allows us to separate the processes of demographic interest from the sampling process. The separation means that we can focus on specifying the model for the demographic processes without worrying about the sampling model. Therefore, we no longer need to choose parameters in order to simplify the removal of missing data, but we are free to naturally write the model in terms of parameters that are of demographic interest. A consequence of this is that we are able write complex models in terms of a series of simpler conditional likelihood components. We show an example of this where we fit a CJS model that has an individual-specific time-varying covariate as well as live re-sightings and dead recoveries. Data augmentation is naturally hierarchical, with parameters that are specified as random effects treated as any other latent variable and included into the likelihood. These hierarchical random effects models make it possible to explore stochastic relationships both (i) between parameters in the model, and (ii) between parameters and any covariates that are available. Including all of the missing data means that latent variables of interest, including the population size and the number of births, can now be included and used in the model. We present an example where we use the population size (i) to allow us to parameterize birth in terms of the per-capita birth rates, and (ii) as a covariate for both the per-capita birth rate and the survival probabilities in a density dependent relationship.

Стилі APA, Harvard, Vancouver, ISO та ін.

26

Johnson, Linda Gail. "Effects of habitat patch size and isolation on the population structure of two siphonarian limpets." Thesis, Rhodes University, 2011. http://hdl.handle.net/10962/d1005364.

Повний текст джерела

Анотація:

Habitat fragmentation is a fundamental process that determines trends and patterns of distribution and density of organisms. These patterns and trends have been the focus of numerous terrestrial and marine studies and have led to the development of several explanatory hypotheses. Systems and organisms are dynamic and no single hypothesis has adequately accounted for these observed trends. It is therefore important to understand the interaction of these processes and patterns to explain the mechanisms controlling population dynamics. The main aim of this thesis was to test the effect of patch size and isolation on organisms with different modes of dispersal. Mode of dispersal has previously been examined as a factor influencing the effects that habitat fragmentation has on organisms. Very few studies have, however, examined the mode of dispersal of marine organisms because it has long been assumed that marine animals are not directly influenced by habitat fragmentation because of large-scale dispersal. I used two co-occurring species of siphonariid limpets with different modes of dispersal to highlight that not only are marine organisms affected by habitat fragmentation but that they are affected in different ways. The two species of limpet, Siphonaria serrata and Siphonaria concinna, are found within the same habitat and have the same geographic range along the South African coastline, however, they have different modes of dispersal and development. The effect of patch size on organism density has been examined to a great extent with varied results. This study investigated whether habitat patch size played a key role in determining population density and limpet body sizes. The two species are found on the eastern and southern coasts of South Africa were examined across this entire biogeographic range. Patch size was found to have a significant effect on population density of the pelagic developer, S. concinna, but not the direct developing S. serrata. Patch size did play a role in determining limpet body size for both species. S. concinna body size was proposed to be effected directly by patch size whilst S. serrata body size was proposed to be affected indirectly by the effects of the S. concinna densities. The same patterns and trends were observed at five of the seven examined regions across the biogeographic range. The trends observed for S. concinna with respect to patch size conform to the source-sink hypothesis with large habitat patches acting as the source populations whilst the small habitat patches acted as the sink populations. Many previous studies have focused on the effects of habitat patch size at one point in time or over one season. I tested the influence of habitat patch size on the two species of limpets over a period of twelve months to determine whether the trends observed were consistent over time or whether populations varied with time. S. concinna showed a consistently significant difference between small and large patches; whilst S. serrata did not follow a consistent pattern. The mode of dispersal for the two limpets was used to explain the different trends shown by the two species. This examination allowed for the determining of source and sink populations for S. concinna through the examination of fluctuations in limpet body sizes and population densities at small and large habitat patches over twelve months. The direct developing S. serrata trends could not be explained using source-sink theory, as populations were independent from one another. S. serrata demonstrated body size differences at small and large patches which, may be explained by interspecific and intraspecific competition. Habitat isolation is known to play an important role in determining the structure of assemblages and the densities of populations. In this study the population density of the pelagic developing S. concinna showed a weak influence of degree of isolation whilst that of the direct developing S. serrata did not, which may be because of habitat patches along the South African coastline not having great enough degrees of isolation. The population size-structure was influenced directly influenced by isolation for S. concinna, whilst the different population size structure for S. serrata may be explained by assemblage co-dependence. The mode of dispersal showed effects on the relationship of population density and population size-structure with habitat size and isolation. This study indicates the importance of investigating patterns and processes across a range of spatial and temporal scales to gain a comprehensive understanding of factors effecting intertidal organisms.

Стилі APA, Harvard, Vancouver, ISO та ін.

27

Robbins, Julie. "Structure and dynamics of the Gulf of Maine humpback whale population/." St Andrews, 2007. http://hdl.handle.net/10023/328.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

28

Marucco, Francesca. "Spatial population dynamics of recolonizing wolves in the western Alps." Diss., [Missoula, Mont.] : The University of Montana, 2009. http://etd.lib.umt.edu/theses/available/etd-10092009-140452.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

29

Parsons, Kim Michelle. "The use of molecular and observational data to infer the structuring of bottlenose dolphin populations." Thesis, University of Aberdeen, 2002. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=217232.

Повний текст джерела

Анотація:

Knowledge of the structuring of natural populations is important for understanding both evolutionary processes and population ecology, and for supporting management decisions. Conventional methods of direct observation often suffer from a lack of resolution, particularly when studying mobile animals in a marine environment. In this study, I combined direct observation with indirect molecular genetic approaches to infer the social and population structure of coastal (inshore) bottlenose dolphins, Tursiops truncatus. Genetic diversity and structure of bottlenose dolphins around the UK and Ireland was examined using tissue samples from stranded dolphins and incidental fisheries by-catch. Mitochondrial DNA (mtDNA) sequence data indicated significant subdivision among four main sample regions (NE Scotland, Wales, NW Scotland and Ireland). Genetic divergence between NE and NW Scotland populations, and low genetic diversity within the NE Scotland population, provide further support for the precautionary approach currently applied to the management of this population. Inference from both mtDNA and nuclear microsatellite genetic markers, and direct observational data were used to examine the social and population structure of bottlenose dolphins in the NE Bahamas. Novel strategies for collecting genetic samples (remote biopsy and faecal sampling) from free-ranging dolphins were developed and validated, enabling an individual-based analysis of population subdivision. Patterns of individual associations in two contrasting habitats indicated that environmental pressures affect dolphin grouping patterns; with a genetic basis for social affiliations occurring only where predation pressures are low. Nonetheless, a particularly notable feature of the social structure in both habitats was the persistence of stable alliances among maternally related males. At the population level, the significant degree of genetic structuring revealed among three sampled regions on Little Bahama Bank, supported the high degree of site fidelity suggested by individual-based photo-identification data. Contrary to the patterns of male dispersal and female philopatry common among both mammals and bottlenose dolphins, sex-specific patterns of genetic differentiation inferred from both mtDNA and microsatellite markers were indicative of female-mediated gene flow. This study provides novel insight into the factors governing the patterns of structuring within populations of highly mobile small cetaceans, and demonstrates the value of integrating both direct (field-based) and indirect (molecular genetic) data in the study of free-ranging animals.

Стилі APA, Harvard, Vancouver, ISO та ін.

30

Wu, Longyang. "Comparison of methods for modifying animal model solutions to reduce inbreeding in finite populations." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0019/NQ55645.pdf.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

31

Chalmers, Rachel. "The distribution of Cryptosporidium in livestock and wild animal populations on a Warwickshire farm." Thesis, Coventry University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318154.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

32

Vandendriessche, Stien. "Molecular epidemiology of livestock-associated staphylococcus aureus in animal and human populations in Belgium." Doctoral thesis, Universite Libre de Bruxelles, 2012. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209576.

Повний текст джерела

Анотація:

Staphylococcus aureus is a major opportunistic pathogen causing a wide range of infections in humans and animals. Methicillin-resistant S. aureus (MRSA) has traditionally been regarded as a strictly human problem, initially confined to the healthcare settings and later a matter of concern in the general community too. All this changed in 2005 with the isolation of a specific MRSA clone, assigned to Clonal Complex (CC)398, from pigs and pig farmers in the Netherlands. These findings triggered worldwide investigation, showing the presence of this livestock-associated (LA)-MRSA clone in a variety of farm animals and in persons in contact with affected animals. Furthermore, the capacity of LA-MRSA CC398 to cause infections in humans and animals has been well documented. Recently, MRSA with a divergent mecA-homologue gene variant has been discovered in bovines and humans. Together, these emerging MRSA strains from animal sources have raised new questions as to their origin and inter-host transmission, as well as raised global concern in both veterinary and human medicine about health risks posed by MRSA prevailing in livestock.

In the present work, we aimed to investigate the extent and molecular epidemiology of the LA-MRSA reservoir in animal and human populations, including on livestock farms and in acute-care hospitals in Belgium. As a secondary objective, the presence of methicillin susceptible S. aureus (MSSA) CC398, from which MRSA CC398 could locally emerge by acquisition of the Staphylococal Cassette Chromosome mec (SCCmec) element, was assessed. To this end, we undertook an extensive and systematic cross-sectional survey of S.aureus and MRSA carriage among humans and animals on pig, veal calf, dairy cattle, beef cattle, broiler and horticulture farms. A questionnaire, completed by all farm residents, was used to assess occupational risk factors for human MRSA CC398 carriage. Bacterial genetic characterisation was done by spa typing, SCCmec typing and multi-locus sequence typing (MLST). Antimicrobial susceptibility profiles were determined; the presence of resistance genes and toxin genes were determined by PCR. A second set of S. aureus clinical isolates from two national surveys organised in 2005 and 2008 were characterised using the same methods.

Carriage of MRSA CC398 was highly prevalent in animals and humans on pig and veal calf farms and to a significantly lesser extent on beef, dairy, broiler and horticulture farms (Chapter 5.1). Persons who work with pigs or veal calves on a daily basis are at significantly higher risk for MRSA CC398 carriage compared to farm-exposed persons who work with them less regularly or never. In accordance with the results from the present work as well as those from others, it appears important to assess the impact of interventions at farm-level that aim to reduce the MRSA carriage rate in animals, as this would also reduce the risk for MRSA carriage in farmers and relatives.

MRSA CC398 isolates, especially those from veal calf farms, were frequently multi-resistant and thereby represent a reservoir of antimicrobial resistance determinants that could be transferred to other, more human-adapted staphylococci or other micro-organisms (Chapter 5.1). Additionally, this multi-resistance phenotype should be considered when applying empiric treatment of human staphylococcal infections in livestock-exposed persons. Only very few major “human-associated” virulence factors were detected, indicating a limited virulence capacity of LA-MRSA CC398 isolates. MRSA strains with the mecA homologue mecC, which is difficult to detect using conventional diagnostic methods, were found in beef and dairy cattle, but not in humans.

MSSA CC398 strains from which MRSA CC398 might locally emerge were frequently detected in humans and animals on pig, veal and broiler farms, all of which are commonly known to be affected by MRSA CC398 (Chapter 5.2). Three porcine MSSA CC398-t011 isolates harbored remnant DNA of a composite SCCmec V(5C2&5)c element, from which the mec gene complex was lacking. These findings indicate that the strains were previously involved in SCCmec recombination events. Processes similar to the one described here likely contribute to the enormous diversity of SCCmec elements observed in staphylococci.

Although LA-MRSA CC398 strains were frequently detected in livestock and livestock-exposed persons, they only represented a minority (~1%) of the MRSA strains from hospitalised patients. This suggests that this specific MRSA clone has not yet spread among Belgian patients without livestock contact (Chapter 5.3). However, similar to what has been seen in other countries, we observed a recent emergence of severe infections, caused by a human-adapted subclone of MSSA CC398, in hospitalised patients without livestock contact (Chapter 5.4).

Once more has S. aureus proven its versatility: it has optimally adapted to the selective pressure exerted by intensive animal farming by acquisition of mobile genetic elements, such as resistance determinants. Clearly MRSA is no longer a strictly human problem. Working across the human and veterinary health sectors will be essential to tackle the dissemination and pathogenic evolution of MRSA in livestock.

Doctorat en Sciences biomédicales et pharmaceutiques
info:eu-repo/semantics/nonPublished

Стилі APA, Harvard, Vancouver, ISO та ін.

33

Dorigatti, Ilaria. "Mathematical modelling of emerging and re-emerging infectious diseases in human and animal populations." Doctoral thesis, Università degli studi di Trento, 2011. https://hdl.handle.net/11572/369140.

Повний текст джерела

Анотація:

The works presented in this thesis are very different one from the other but they all deal with the mathematical modelling of emerging infectious diseases which, beyond being the leitmotiv of this thesis, is an important research area in the field of epidemiology and public health. A minor but significant part of the thesis has a theoretical flavour. This part is dedicated to the mathematical analysis of the competition model between two HIV subtypes in presence of vaccination and cross-immunity proposed by Porco and Blower (1998). We find the sharp conditions under which vaccination leads to the coexistence of the strains and using arguments from bifurcation theory, draw conclusions on the equilibria stability and find that a rather unusual behaviour of histeresis-type might emerge after repeated variations of the vaccination rate within a certain range. The most of this thesis has been inspired by real outbreaks occurred in Italy over the last 10 years and is about the modelling of the 1999-2000 H7N1 avian influenza outbreak and of the 2009-2010 H1N1 pandemic influenza. From an applied perspective, parameter estimation is a key part of the modelling process and in this thesis statistical inference has been performed within both a classical framework (i.e. by maximum likelihood and least square methods) and a Bayesian setting (i.e. by Markov Chain Monte Carlo techniques). However, my contribution goes beyond the application of inferential techniques to specific case studies. The stochastic, spatially explicit, between-farm transmission model developed for the transmission of the H7N1 virus has indeed been used to simulate different control strategies and asses their relative effectiveness. The modelling framework presented here for the H1N1 pandemic in Italy constitutes a novel approach that can be applied to a variety of different infections detected by surveillance system in many countries. We have coupled a deterministic compartmental model with a statistical description of the reporting process and have taken into account for the presence of stochasticity in the surveillance system. We thus tackled some statistical challenging issues (such as the estimation of the fraction of H1N1 cases reporting influenza-like-illness symptoms) that had not been addressed before. Last, we apply different estimation methods usually adopted in epidemiology to real and simulated school outbreaks, in the attempt to explore the suitability of a specific individual-based model at reproducing empirically observed epidemics in specific social contexts.

Стилі APA, Harvard, Vancouver, ISO та ін.

34

Dorigatti, Ilaria. "Mathematical modelling of emerging and re-emerging infectious diseases in human and animal populations." Doctoral thesis, University of Trento, 2011. http://eprints-phd.biblio.unitn.it/458/2/thesis_Dorigatti_2.pdf.

Повний текст джерела

Анотація:

The works presented in this thesis are very different one from the other but they all deal with the mathematical modelling of emerging infectious diseases which, beyond being the leitmotiv of this thesis, is an important research area in the field of epidemiology and public health. A minor but significant part of the thesis has a theoretical flavour. This part is dedicated to the mathematical analysis of the competition model between two HIV subtypes in presence of vaccination and cross-immunity proposed by Porco and Blower (1998). We find the sharp conditions under which vaccination leads to the coexistence of the strains and using arguments from bifurcation theory, draw conclusions on the equilibria stability and find that a rather unusual behaviour of histeresis-type might emerge after repeated variations of the vaccination rate within a certain range. The most of this thesis has been inspired by real outbreaks occurred in Italy over the last 10 years and is about the modelling of the 1999-2000 H7N1 avian influenza outbreak and of the 2009-2010 H1N1 pandemic influenza. From an applied perspective, parameter estimation is a key part of the modelling process and in this thesis statistical inference has been performed within both a classical framework (i.e. by maximum likelihood and least square methods) and a Bayesian setting (i.e. by Markov Chain Monte Carlo techniques). However, my contribution goes beyond the application of inferential techniques to specific case studies. The stochastic, spatially explicit, between-farm transmission model developed for the transmission of the H7N1 virus has indeed been used to simulate different control strategies and asses their relative effectiveness. The modelling framework presented here for the H1N1 pandemic in Italy constitutes a novel approach that can be applied to a variety of different infections detected by surveillance system in many countries. We have coupled a deterministic compartmental model with a statistical description of the reporting process and have taken into account for the presence of stochasticity in the surveillance system. We thus tackled some statistical challenging issues (such as the estimation of the fraction of H1N1 cases reporting influenza-like-illness symptoms) that had not been addressed before. Last, we apply different estimation methods usually adopted in epidemiology to real and simulated school outbreaks, in the attempt to explore the suitability of a specific individual-based model at reproducing empirically observed epidemics in specific social contexts.

Стилі APA, Harvard, Vancouver, ISO та ін.

35

Gillis, Darren Michael. "Animal aggregation, interference and the ideal free distribution." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63332.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

36

Dalton, Sara. "Strategies for Reducing Mosquito-Borne Disease Vulnerability in Equine Populations: A Kentucky Case Study." TopSCHOLAR®, 2006. http://digitalcommons.wku.edu/theses/451.

Повний текст джерела

Анотація:

This research examined equine management practices that limit or contribute to the spread of West Nile virus and other mosquito-bome disease. I hypothesize that there is a relationship between equine management practices and outbreaks of mosquito-borne disease in horse populations. Improved and appropriate mosquito habitat management may limit the risk of mosquito-borne disease in humans and horses by helping to lower the mosquito populations. The study goals were to recognize equine management practices and mosquito prevention practices that foster outbreaks of mosquito-borne disease. This study used a questionnaire for county level analysis of equine management practices and the relationship to mosquito-borne disease. This study is important because horses live in a natural setting among unmanaged elements, such as pastures with ponds, wooded areas, and riparian areas. However, horses themselves are highly managed. Equine management practices include pasture horses, who live exclusively outdoors, stabled horses who receive some turn-out time, and ultra-managed horses, such as race horses. Kentucky's economy is partially dependant on the horse industry, which is responsible for over 51,000 jobs and is a major part of the culture of Kentucky. Equine diseases can significantly affect this section of the state's economy. The study area consisted of three categories of noncontiguous counties, with each group containing three to four Kentucky counties. The three selected categories of study highlighted areas of West Nile virus incidence in equine populations. Surveys were distributed to horse owners and barn managers to collect data on differences in equine management practices and outbreaks of mosquito-borne disease. Two categories represented counties with large equine populations, and one category represented counties with low equine populations. Category I consists of the three counties that were selected based on high horse populations and high incidence of West Nile virus in 2002—Barren, Fleming, and Nelson counties. Category II consists of four counties with high equine populations and low incidence of West Nile virus in 2002 - Allen, Grant, Jessamine, and Meade counties. The third category looks at low equine populations and high incidence of West Nile virus in 2002 - Carlisle, Marion, Russell, and Todd counties. Areas with low equine populations and low incidence of West Nile virus were not considered for the study because those areas do not have either high horse populations or high incidence of West Nile virus and hence were not relevant for this particular research question about equine management practices. A minimum of thirty surveys was collected for each category. Statistical analysis was used to determine relationships between incidences of disease, management practices, and knowledge of mosquito prevention. Each survey question was analyzed using the two-tailed version of the two-sample difference of proportion test. West Nile virus is an important disease to study due to the potential economic loss to the horse industry but also because the disease has been responsible for sickness and death in human and animal populations. I studied horses because of the their mix of unmanaged and managed habitat. This study did find a difference in equine management practices when it came to vaccination to prevent West Nile virus occurrences in horse populations. Horse people in categories with high horse populations had a higher use of a West Nile virus vaccine to prevent disease than people use in the low horse population category. While statistics from this study show that there is little or no difference in other equine management practices between the three categories, this research demonstrates that few horse owners and barn mangers limit mosquito habitat around their animals or are aware of IPM techniques. Vaccination lowers the chance that a horse will develop West Nile virus, but it is important that active equine management programs include limiting mosquito habitat to assist in prevention of mosquito-borne disease. Limiting mosquito-borne disease is an important preventive strategy that could protect the health of both horses and humans.

Стилі APA, Harvard, Vancouver, ISO та ін.

37

Colyn, Robin. "Optimising camera trap density and position to determine medium and large mammal species richness and occupancy on the Cape Peninsula, South Africa." Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2433.

Повний текст джерела

Анотація:

Thesis (MTech (Nature Conservation))--Cape Peninsula University of Technology, 2016.
Largely due to anthropogenic causes, biodiversity and particularly species diversity is changing at an extraordinary rate, with declines in species abundance, community composition and extinction risk being of crucial concern. Monitoring of state variables of biodiversity such as species richness and occupancy are of significant importance in determining the severity of threats placed on species, populations and communities. As a non-invasive monitoring method camera traps are noted as being an effective, accurate and rapid means of compiling species richness estimates of medium to large terrestrial mammals. However, crucial elements of camera trap survey design are rarely empirically addressed, which has questioned the need for a standardised camera trapping protocol. Table Mountain National Park (TMNP) is a protected area that is under serious anthropogenic pressure through urban and peri-urban development. Although it is the last refuge for a number of large mammal species on the Cape Peninsula, current mammalian species richness knowledge within the TMNP are limited. Accurate and current species richness estimates are therefore needed within TMNP and more specifically the Cape of Good Hope (CoGH), which exclusively hosts a number of medium and large mammal species. The aims of this study were to optimise a camera survey protocol for the Peninsula region, with a focus on camera density, placement and survey duration that will enable accurate estimations of medium to large mammal species richness and occupancy.

Стилі APA, Harvard, Vancouver, ISO та ін.

38

Hedlund, Charise Ann 1966. "Trichomonas gallinae in avian populations in urban Tucson, Arizona." Thesis, The University of Arizona, 1998. http://hdl.handle.net/10150/278648.

Повний текст джерела

Анотація:

I studied Trichomonas gallinae, a flagellated protozoan that is the causative agent of the avian disease trichomoniasis. The purpose of my study was to assess (1) the incidence of trichomonads in wild birds, (2) the prevalence of trichomonads in water sources utilized by wild birds, and (3) possible methods to control the transmission of trichomonads in water sources utilized by wild birds. I trapped 403 birds during 1994 and 1995. Approximately 1/3 of these birds tested positive for T. gallinae, however, none exhibited any signs of lesions. I collected water samples from 10 bird baths, isolating flagellated protozoa from 2 of them. I could not identify the species of flagellated protozoa. I determined that high temperatures (50°C), near ultra-violet radiation, and natural sunlight are effective against trichomonads. In addition, the highest effective dilutions of Chlorox, Nolvasan, and distilled white vinegar active against trichomonads were determined.

Стилі APA, Harvard, Vancouver, ISO та ін.

39

McClenachan, Loren Elizabeth. "Historical change in marine animal populations and coastal ecosystems in the Caribbean and Florida Keys." Diss., [La Jolla] : University of California, San Diego, 2009. http://wwwlib.umi.com/cr/ucsd/fullcit?p3369566.

Повний текст джерела

Анотація:

Thesis (Ph. D.)--University of California, San Diego, 2009.
Title from first page of PDF file (viewed September 15, 2009). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.

Стилі APA, Harvard, Vancouver, ISO та ін.

40

Berkson, James Meyer. "Opportunities for management created by spatial structures : a case study of Finnish reindeer." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/27799.

Повний текст джерела

Анотація:

This study examines opportunities for renewable resource management when population data are collected by spatial subdivisions. In particular I look at potential applications for the design of management experiments, the distribution of monitoring resources, and the improvement of parameter estimation. Methods are developed to rank possible groupings of subdivisions for use as experimental units. Factors external to the experiment can cause differences between experimental units. Selecting subdivisions that have reacted similarly in the past to external factors could minimize the risk of external factors creating differences in experimental units. Methods are developed to identify subdivisions that could provide information about similar subdivisions when monitoring resources are low or when stratified sampling is being used. The use of these subdivisions as "index units" could notify managers of extremely good or bad years in a large number of subdivisions. Two methods developed by Walters (1986) provide innovative estimation techniques that can be used with subdivided populations. A Bayesian approach allows parameter estimates to be adjusted using a known distribution. Another approach allows similar subdivisions to be estimated jointly more accurately than would be possible individually. Not all renewable resource data sets provide reliable information for use with these applications. Data sets where there is little common variation, high levels of autocorrelation in the noise, or even modest amounts of measurement error are inappropriate for most methods. A series of steps is introduced for managers to test the reliability of the methods on their particular data sets. Data on Finnish reindeer (Rangifer tarandus tarandus) are used throughout the thesis to illustrate the methods. The reindeer data appear to be appropriate for these methods when tested using the steps developed. Possible experimental units and index units for monitoring are identified. Walters' (1986) methods of parameter estimation are used on the data set as well. The reindeer data show that subdivisions with similar external effects were located close to one another. This pattern was at least partially caused by the existence of extremely bad years occurring within geographic regions. The reindeer subdivisions are very highly managed and provide little evidence of any kind of density dependence. Managers could potentially benefit by conducting experiments to test the biological limits of the population growth rates and carrying capacities within subdivisions.
Science, Faculty of
Zoology, Department of
Graduate

Стилі APA, Harvard, Vancouver, ISO та ін.

41

Zipfel, Katherine J. "The distribution and status of native walleye (Sander vitreus) stocks in West Virginia." Ohio : Ohio University, 2006. http://www.ohiolink.edu/etd/view.cgi?ohiou1164229538.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

42

Kreuder, Johnson Christine. "Evaluation of survey methods used to assess distribution and abundance and characterization of patterns of mortality in southern sea otters /." Restricted to UC campuses, 2003. http://bibpurl.oclc.org/web/22018.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

43

Tracey, John Paul. "Assessing estimators of feral goat (Capra hircus) abundance." Connect to this title online, 2004. http://cicada.canberra.edu.au/public/adt-AUC20050708.103427/.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

44

Heywood, Ben. "Investigations into the use of quantified Bayesian maximum entropy methods to generate improved distribution maps and biomass estimates from fisheries acoustic survey data /." St Andrews, 2008. http://hdl.handle.net/10023/512.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

45

Portelinha, Thiago Costa Gonçalves. "Estrutura populacional e alometria reprodutiva de Podocnemis expansa (Testudines, Podocnemididae) no entorno do Parque Nacional do Araguaia, Tocantins." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/91/91131/tde-21062010-081308/.

Повний текст джерела

Анотація:

Dentre os répteis que ocorrem na Amazônia, os quelônios se destacam pela sua diversidade e importância econômica. Podocnemis expansa, conhecida popularmente como tartaruga-da-amazônia, é considerada o maior quelônio de água doce da América do Sul e tem sido explorada intensamente, por séculos, por inúmeras comunidades indígenas e ribeirinhas. O presente estudo teve como objetivo ampliar os conhecimentos acerca da ecologia populacional e da biologia reprodutiva de P. expansa no rio Javaés, Estado do Tocantins, no entorno do Parque Nacional do Araguaia (Ilha do Bananal). No primeiro capítulo desta dissertação foram investigados alguns aspectos da ecologia populacional. Os trabalhos em campo foram realizados entre os anos de 2004 e 2009 e os animais foram capturados pelos métodos de mergulho e arrasto de rede. Com os resultados obtidos, foi observado que a estrutura etária (baseada no comprimento da carapaça) dos indivíduos apresentou um padrão unimodal para os machos e um padrão não definido para as fêmeas. A população estudada era constituída basicamente por fêmeas jovens e machos adultos, apresentando uma razão sexual desviada para as fêmeas de 1:1,4 (:). A abundância relativa variou entre 0,4 e 8,6 animais/hora, dependendo do método de captura empregado, e a maioria dos animais (73,7%) encontrava-se concentrada em apenas um ponto específico do rio. No segundo capítulo, foram estudadas as relações alométricas entre o tamanho corpóreo da fêmea, seus rastros, as variáveis da ninhada e a forma dos ninhos em ambiente natural. O trabalho de campo foi realizado em uma praia de desova da área estudada, entre os meses de setembro e dezembro de 2008. Os resultados mostraram que o tamanho corpóreo da fêmea de P. expansa pode ser estimado em função do seu rastro, que fêmeas maiores deixam rastros maiores na areia, além de produzirem mais ovos (tamanho da ninhada) e com maior massa (massa da ninhada) do que fêmeas menores e que as variáveis largura da carapaça e massa da fêmea podem ser consideradas como confiáveis para estabelecer relações nos estudos de alometria com P. expansa.
Among the reptiles found in the Amazon, the turtles stand out because of its diversity and economic importance. Podocnemis expansa, popularly known as Amazon river turtle, is considered the largest freshwater turtle in South America and has been heavily exploited for centuries by many indigenous and riverine communities. This study aimed to expand the knowledge about the population ecology and the reproductive biology of P. expansa in the Javaés River, Tocantins State, around the Parque Nacional do Araguaia (Iha do Bananal). In the first chapter of this dissertation some aspects of population ecology were investigated. Fieldwork was carried out between 2004 and 2009, and the animals were captured by diving and trawling net. The age structure (based on carapace length) of the animals showed a unimodal pattern for males and not a standard defined for females. The population consisted mainly of young females and adult males, with a sex ratio of 1:1.4 (:), biased to females. The relative abundance varied between 0.4 and 8.6 animals per hour depending on the method of capture employed, and most animals (73.7%) was concentrated in a single specific point of the river. In the second chapter, the allometric relationships between female body size, their tracks, the clutch variables and nest form in natural environment were investigated. Fieldwork was carried out on a nest beach of the study area, between September and December 2008. Results indicated that P. expansa female body size can be estimated based on her track. Larger females leave larger foot tracks in the sand and produce more eggs (clutch size) with greater mass (clutch mass) than smaller females. Female carapace width and female body mass can be regarded as reliable to establish relationships in studies of allometry with P. expansa.

Стилі APA, Harvard, Vancouver, ISO та ін.

46

Herreman, Jason K. "Geneflow and diet for two declining harbor seal (Phoca vitulina) populations in Alaska." Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1445035601&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

47

Compton, Robert I. "Population fragmentation and white sucker introduction affect populations of bluehead suckers, flannelmouth suckers, and roundtail chubs in a headwater stream system, Wyoming." Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1404346401&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

48

King, Hayley C. "Non-invasive monitoring of environmental Mycobacterium bovis shedding in wild European badger (Meles meles) populations." Thesis, University of Warwick, 2015. http://wrap.warwick.ac.uk/77509/.

Повний текст джерела

Анотація:

The herd-level incidence of Mycobacterium bovis has been increasing in the United Kingdom (UK) and Republic or Ireland (RoI) for the past thirty years, resulting in substantial economic and animal welfare issues. Failure to control this pathogen in cattle is in part due to European badgers (Meles meles), a wildlife reservoir that are responsible for a proportion of transmission of M. bovis to cattle. Monitoring infection in badger populations is currently limited due to the need to trap badgers, which requires highly trained field staff and is expensive. In addition, although contact with infected badger faeces is a potential transmission route to cattle, very little is known about the extent and variability of the environmental pool of M. bovis shed by badgers. In this project we evaluated the suitability of using environmental badger faeces and a quantitative PCR (qPCR) assay to diagnose and monitor M. bovis in badger populations and described the extent of this environmental pool of potential infection. The first study identified that intensive environmental faecal sampling and analysis with qPCR is at least, if not more, sensitive at diagnosing M. bovis in badger populations than the currently used immunoassays. This study also identified that even within a high prevalence population, the levels of shedding of M. bovis in faeces are highly variable between groups and between seasons, suggesting that there may be heterogeneity in transmission risk throughout the year. Using this non-invasive qPCR method to monitor the first field trial of oral BCG vaccination identified a trend of decreasing levels of M. bovis in faeces with increasing vaccination levels however, these results failed to reach statistical significance, highlighting the importance of adequate sample sizes when implementing this method. Finally, characterisation of the gut and faecal microbiota from animals shedding M. bovis in faeces confirmed that the source of faecal M. bovis is most likely sputum that has been expelled from the lungs, and not from colonisation of the gut. The work presented here suggests that this non-invasive monitoring method can be applied to examine the variable pool of M. bovis over periods of time and large areas, providing an epidemiological tool which has the potential to be implemented to monitor infection in badger populations and disease intervention strategies.

Стилі APA, Harvard, Vancouver, ISO та ін.

49

Hanson, John Mark 1955. "Patterns of animal abundance in lakes : the role of competition in the fish-macroinvertebrate relationship." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=71975.

Повний текст джерела

Анотація:

Data taken from the literature were used to develop and evaluate models predicting fish biomass and yield, crustacean zooplankton biomass, and profundal macrobenthos biomass in lakes. Total phosphorus concentration and macrobenthos biomass/mean depth were the best univariate predictors of fish biomass and yield. Phosphorus concentration was also the best predictor of zooplankton and macrobenthos biomass. In experiments testing for inter- and intraspecific competition, conducted in situ at densities based on measured natural fish densities, growth of yellow perch (Perca flavescens) and pumpkinseed (Lepomis gibbosus) reared alone was inversely related to density. Both species primarily ate macroinvertebrates when reared alone. When reared together: perch growth was significantly depressed compared to that of perch reared alone; pumpkinseed growth was equivalent to that of pumpkinseed reared alone; and the diet of perch changed to include food of inferior quality (microcrustaceans) in the presence of the superior competitor, pumpkinseed, whose diet did not change.

Стилі APA, Harvard, Vancouver, ISO та ін.

50

Hatten, Inger Suzanne. "The effects of urbanization on raccoon population demographics, home range, and spatial distribution patterns /." free to MU campus, to others for purchase, 2000. http://wwwlib.umi.com/cr/mo/fullcit?p9999295.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Дисертації з теми "Animal populations"

Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями