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Mamíferos de médio e grande porte em uma área de Caatinga de Sergipe e o nicho ecológico de Cerdocyon thous (Linnaeus 1766)Dias, Douglas de Matos 21 February 2014 (has links)
There are few studies on the mammalian fauna of the Caatinga s, with most of the first studies focuses on species richness, distribution and foraging ecology. In the state of Sergipe, northeast Brazil, the Caatinga s biome is fragmented and the knowledge of medium and large sized mammals is limited, with most of the information based mainly on inventories. Being so, this work, developed in an area of Caatinga in Sergipe, characterized the community of medium and large sized mammals focused on the richness and habitat use. Besides it evaluated the influence of the seasons on the number of species and records, and the ecological niche of the Cerdocyon thous canid. The study was conducted at the Monumento Natural Grota do Angico (MNGA), an area of 2,138 ha located between the cities of Poço Redondo and Canindé de São Francisco. Samples were taken in three habitats of the MNGA: riparian vegetation, grota and a woody shrubs caatinga s forest. The methodology used included sand plot and camera traps. Samplings were carried between November 2012 and November 2013 in monthly campaigns of 8 days. Ten species of mammals were registered through 571 records, 454 obtained by sand plots and 117 by photos; the order Carnivora being the most representative in the area. Three species were occasionally recorded out of standardized sampling: Lontra longicaudis, Euphractus sexcinctus e Dasypus sp. There were no seasonal difference in the number of records and richness. Kerodon rupestris and small cats differed in terms of habitat use: The first one being more found in the and a grotto, as the second was more found in the riparian vegetation. Overall, the community consists of species habitat generalist. The reduced size of MNGA and the degree of degradation of their environment, caused by the removal of native vegetation for agricultural practice, may have contributed to the low richness observed. Cerdocyon thous showed higher values of frequency of occurrence in the three sampled habitats (Fxy > 0.23) demonstrating its ability to adapt to various habitats. As for the trophic niche, the C. thous diet was classified as omnivorous, with a predominance of arthropods and fruit, vertebrates being consumed on a smaller scale. Even though many items were consumed by the C. thous (N = 32), it focus its diet on a few items, resulting in a low niche breadth value. This specie was constantly active during the night, with few daytime records and was completely inactive between 09:00 to 16:00 h. / Existem poucos estudos sobre a mastofauna da Caatinga, sendo que os primeiros realizados no bioma resultaram em informações sobre riqueza, distribuição e ecologia alimentar de algumas espécies. Em Sergipe, no nordeste brasileiro, esse bioma encontra-se fragmentado e o conhecimento sobre a mastofauna de médio e grande é limitado, com informações baseadas principalmente em inventários. Assim, este trabalho caracterizou, em uma área de Caatinga em Sergipe, a comunidade de mamíferos de médio e grande porte quanto à riqueza e uso do habitat, além de avaliar a influência da sazonalidade no número de registros e espécies e o nicho ecológico do canídeo Cerdocyon thous. O estudo foi realizado no Monumento Natural Grota do Angico (MNGA), uma área de 2.138 ha localizada entre os municípios de Poço Redondo e Canindé de São Francisco. As amostragens foram realizadas em três habitats do MNGA: caatinga arbustiva arbórea, grota e mata ciliar. A metodologia utilizada incluiu parcelas de areia e armadilhas fotográficas e as amostragens foram realizadas entre novembro de 2012 a novembro de 2013 em campanhas mensais de oito dias consecutivos. Foram registradas dez espécies de mamíferos através de 571 registros, sendo 454 obtidos nas parcelas de areia e 117 fotografias; sendo a ordem Carnivora a mais representativa na área. Três espécies foram registradas ocasionalmente fora das amostragens padronizadas: Lontra longicaudis, Euphractus sexcinctus e Dasypus sp. Não houve diferença sazonal para o número de registros e riqueza. Kerodon rupestris e pequenos felinos diferiram quanto ao uso do habitat: o primeiro esteve mais relacionado à grota e o segundo a mata ciliar. No geral, a comunidade é constituída de espécies habitat generalista e o tamanho reduzido do MNGA e o grau de degradação do seu entorno, resultante da supressão da vegetação nativa para a prática agrícola, podem ter contribuído para a baixa riqueza observada. Cerdocyon thous apresentou valores mais elevados de frequência de ocorrência nos três habitats amostrados (Fxy > 0.23), demonstrando a sua capacidade de adaptação a vários habitats. Com relação ao nicho trófico, sua dieta foi classificada como onívora, predominando o consumo de artrópodes e frutos, sendo vertebrados consumidos em menor escala. Embora tenha consumido muitos itens (N = 32), C. thous concentra sua dieta em poucos itens, resultando em um valor baixo de amplitude de nicho. Essa espécie esteve constantemente ativa durante o período noturno, com poucos registros diurnos e estando inativa entre as 09:00-16:00 h.
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Systematics and population genetics of the South African freshwater crab fauna (Decapoda: Potamonautidae: Potamonautes)Daniels, Savel R. (Savel Regan) 12 1900 (has links)
Thesis (PhD)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: In the present study, the systematic status, aspects of the evolutionary biology and phylogenetic
relationships among species of the African freshwater crab genus Potamonautes in South Africa
are examined. Systematic research between allopatric populations of P. brincki, using allozyme
and morphometric data has revealed the existence of a new undescribed freshwater crab species
occurring in mountain streams of the Cape Peninsula. This species is described in the present
study. In addition, the diagnostic value of carapace dentition patterns in the taxonomy of
freshwater crabs is explored among two toothed river crab species from South Africa. The
latter study utilized P. warreni and P. unispinus where considerable variation in the dentition
pattern of the former species has been recorded. Fixed differences in allozyme loci
demonstrated that these two taxa should indeed be considered separate, yet closely related
species, while the morphometric data failed to reveal this taxonomic separation. The holotype
of P. warreni is re-described. The relationship of hybrid taxa between P. depressus and P.
clarus populations are investigated. Evident from this study is that populations that occur
equidistant from the two parental taxa have undergone extensive introgressive hybridization.
Considering the pronounced sequence divergence and the occurrence of fixed allozyme loci
between populations, it is postulated that the hybrid populations should be considered to be on a
unique evolutionary trajectory worthy of conservation. The population genetic structure of P.
calcaratus is examined as this species is unique in its occupation of water holes. Results
demonstrate that the genetic population structure is the result of recent colonization and
moderate gene flow among populations. Phylogenetic relationships between the southern
African freshwater crab fauna is investigated with the use of sequence data from two
mitochondial genes (12 S rRNA and 16 S rRNA), allozymes and morphology in an attempt to
firstly, test the usefulness of freshwater crabs as biogeographic indicators, secondly to explore the relationship among hybrid taxa, and thirdly to examine Bott's (1955) subgeneric divisions.
Results demonstrated that freshwater crabs can be used as biogeographic indicators, that hybrid
taxa are phylogenetic ally closely related and that Bott's subgeneric divisions have no systematic
basis. Among the three data sets, the sequence data provided the best resolution, while the
phylogenetic inferences derived from the allozyme data and the morphology was limited. / AFRIKAANSE OPSOMMING: In hierdie studie word die sistematiek, aspekte van die evolusionêre biologie en filogenetiese
verwantskappe tussen spesies van die varswater krap genus Potamonautes ondersoek in Suid
Afrika. Navorsing op geografies geisoleerde populasies van P. brincki word met behulp van
allosieme en morfometriese data ondersoek en dui daarop dat daar 'n nuwe onbeskryfde spesie
op die berge van die Kaapse Skiereiland voorkom. Die nuwe spesies word beskryf in hierdie
studie. Die diagnostiese waarde van tand patrone in varswater krappe word tussen twee spesies
P. warreni en P. unispinus ondersoek. Genetiese data dui daarop dat alhoewel P. warreni
morfologies baie naverwant is aan P. unispin us, is genoegsame verskille in allosiem lokusse wat
daarop dui dat die twee taksa volwaardige spesies is. Die holotipe van P. warreni word
herbeskryf. Die verwantkap tussen populasies van twee hibried taksa, P. depressus en P. clarus,
word ondersoek. Resultate van hierdie studie dui daarop dat noemenswaardige verskille
voorkom tussen die twee hibridie taxa en dat die hibriede populasies geneties verskillend is. 'n
Argument word aangevoer vir die beskerming van hibriede taksa. Die populasie genetika van
P. calcaratus word ondersoek en vergelyk met vorige studies. Die data dui daarop dat minimale
geen vloei tusses populasies is en dat die populasie struktuur waarskynlik die resultaat is van
onlangse kolonisasie. Die filogenetiese verwantskap tussen die suider Afrikaanse krappe word
ondersoek met DNA, allosieme en morfologiese karakters met drie hoofdoele. Eerstens om die
gebruik van varswater krappe as biografiese indikatore te toets. Tweedens om die verwantskap
van hibriede taksa te ondersoek, en derdens om die status van Bott (1955) se subgenera te
bepaal. Resultate dui daarop aan dat varswater krappe wel gebruik kan word as biografiese
indikatore. Hibridieserende taxa naverwant is derdens en dat Bott se subgenera geen
taksonomiese basis het nie. Die DNA data het die beste resolusie gebied vir die filogenetiese
vrae, terwyl die allosieme en morfologiese data 'n laer resolusie bedied het, en meer beperk was.
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A study of sex/age ratios in wild ungulate populations : an approach to designing an appropriate sampling strategy for estimating the structure of wild ungulate populations on Rooipoort Nature ReserveLaubscher, Sarah-Jane 03 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: This thesis investigates the population structure of a number of ungulate species occurring
within Rooipoort private reserve. Specifically the study serves to make estimates of the
ratio of males to females and calves to cows within each species population under
observation, based on the data collected.
Data were also analysed to ascertain the distribution patterns of the species in question, in
relation to vegetation type and habitat. Distribution data were additionally compared to
distribution data collected at an earlier period on Rooipoort, to determine whether any
change has occurred in distribution patterns of the ungulates concerned.
Through analysis of both sex/age data and distributional data, one of the main objectives
of the study was to determine the most appropriate time of the year, length of time and
managment costs involved to undertake sex/age counts on Rooipoort. Results of the
study were also compared to existing population models of ungulates on the reserve.
Results obtained from data concluded that a single monthly sex/age count or, in some
cases, even three consecutive monthly counts, to determine age ratios, would be
insufficient to deliver a reliable estimate of population structure. A number of counts
would have to be carried out throughout the year in order to make reliable estimates.
Distribution data revealed that all habitat/vegetation types on Rooipoort would have to be
covered in order to effectively sample all of the species in question. / AFRIKAANSE OPSOMMING: Gegewens is ook ontleed om die verspreidingspatrone van hoefdiersoorte te bepaal met
betrekking tot plantegroeitipe en habitat. Die verspreidingsdata is ook vergelyk met
vorige ..studies wat op Rooipoort gedoen is om te. bepaal. of enige. veranderings in die
verpreidingspatrone van die hoefdiere onder bespreking plaasgevind het.
Een van die hoof doelwitte van die studie was om.. deur ontleding. van beide die
geslags/ouderdom data en die verspreidingsdata, die mees geskikte tye van die jaar, die
tydsduur en bestuurskoste te bepaal, om geslags/ouderdomstellings op Rooipoort uit te
voer. Resultate van die studie is ook met vertroude populasiemodelle op die reservaat
vergelyk.
Die dataontledings het aangeduidat 'n enkele maandlikse geslags/ouderdoms telling, of,
In sekere gevalle, selfs drie agtereenvolgende maandlikse tellings, om
ouderdomsverhoudings te bepaal, nie voldoende sal wees om 'n vertroubare beraming van
die bevolkings struktuur te maak. n' Aantal tellings moet gedurende die yaar uitgevoer
word om vertroubare beramings te kan doen. Verspreidingsdata het bevestig dat alle
habitate en plantegroeitipes op Rooipoort bemonster moet word om alle spesie effektief
te bemonster.
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Incorporating measurement error and density gradients in distance sampling surveysMarques, Tiago Andre Lamas Oliveira January 2007 (has links)
Distance sampling is one of the most commonly used methods for estimating density and abundance. Conventional methods are based on the distances of detected animals from the center of point transects or the center line of line transects. These distances are used to model a detection function: the probability of detecting an animal, given its distance from the line or point. The probability of detecting an animal in the covered area is given by the mean value of the detection function with respect to the available distances to be detected. Given this probability, a Horvitz-Thompson- like estimator of abundance for the covered area follows, hence using a model-based framework. Inferences for the wider survey region are justified using the survey design. Conventional distance sampling methods are based on a set of assumptions. In this thesis I present results that extend distance sampling on two fronts. Firstly, estimators are derived for situations in which there is measurement error in the distances. These estimators use information about the measurement error in two ways: (1) a biased estimator based on the contaminated distances is multiplied by an appropriate correction factor, which is a function of the errors (PDF approach), and (2) cast into a likelihood framework that allows parameter estimation in the presence of measurement error (likelihood approach). Secondly, methods are developed that relax the conventional assumption that the distribution of animals is independent of distance from the lines or points (usually guaranteed by appropriate survey design). In particular, the new methods deal with the case where animal density gradients are caused by the use of non-random sampler allocation, for example transects placed along linear features such as roads or streams. This is dealt with separately for line and point transects, and at a later stage an approach for combining the two is presented. A considerable number of simulations and example analysis illustrate the performance of the proposed methods.
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Estimating the impact of bycatch and calculating bycatch limits to achieve conservation objectives as applied to harbour porpoise in the North SeaWinship, Arliss J. January 2009 (has links)
Incidental catch, or bycatch, of harbour porpoise (Phocoena phocoena) in fishing operations is an international conservation issue. The main objective of this thesis was to develop methods for determining the impact of bycatch on the state and dynamics of porpoise populations and for calculating bycatch limits that will achieve conservation objectives in the future. I applied these methods to the North Sea as a case study. First, I analysed sighting rates of harbour porpoise on seabird surveys in the North Sea during 1980-2003 to determine whether these data could provide informative time-series of relative abundance. Some general patterns and trends in sighting rates were consistent with previous studies. However, the standardised indices of abundance were relatively imprecise and thus have limited value for a monitoring framework that relies on statistical detection of trends. Second, I used a population model to integrate available data on harbour porpoise in the North Sea and to assess the dynamics of the population during 1987-2005. There was a high probability that bycatch resulted in a decrease in abundance. The estimated life history parameters suggested a limited scope for population growth even in the absence of bycatch. The model and data were not informative about maximum population growth rate or carrying capacity. The model suggested that dispersal was the most plausible explanation for observed changes in distribution within the North Sea. Third, I considered management procedures for calculating bycatch limits. I performed simulations to compare the behaviour of the procedures, to tune the procedures to specific conservation objectives and to test the robustness of the procedures to a range of uncertainties regarding population dynamics and structure, the environment, observation and implementation. Preliminary annual bycatch limits for harbour porpoise in the North Sea ranged from 187-1685 depending on the procedure, tuning and management areas used.
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A modelling approach to elephant and tree population dynamics for a small game farmStretch, Anne-Marie January 2005 (has links)
Submitted in fulfillment of the requirements for the degree of Master of Technology: Information Technology, Durban Institute of Technology, Durban, South Africa, 2005. / Throughout Africa, growing human populations and resulting loss of wildlife habitat is a
critical issue for most animal species. It is more and more common for privately owned
small or medium sized farms to reintroduce wildlife on their land and such protected areas are fast becoming the only refuges available to wild animals. However a comprehensive understanding of the complex ecological processes taking place is vital for the effective management of restricted areas and the conservation of biodiversity. Due to the enormous complexity of an ecological system and the long periods of the related dynamics, it is very difficult to analyse the interaction between animals and plant populations without suitable computer models. In this thesis, the dynamics between elephant and trees (a major food source) are considered using computer simulations. / M
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Abundance and distribution of delphinids in the Red Sea (Egypt)Costa, Marina January 2015 (has links)
Knowledge about cetaceans in the Red Sea is limited with only a handful of sporadic or spatially-limited studies carried out to date. Funded by the Italian Cooperation through a Debt-for-Nature Swap programme and carried out in collaboration with the Egyptian NGO HEPCA, this thesis presents the results from the first ever systematic vessel-based surveys conducted in the southern Egyptian Red Sea from 2010 to 2013 using linetransect methodology. The main aims of the thesis were (a) to estimate cetacean abundance, (b) to determine distribution patterns and habitat use of the cetacean species, (c) to investigate movement patterns for species for which individual recognition techniques were suitable and (d) to identify areas of conservation concern for cetaceans with a particular focus on existing protected areas. Eight species were identified, of which five were commonly encountered (Stenella longirostris, S. attenuata, Tursiops truncatus, T. aduncus, and Grampus griseus) and three were rare (Pseudorca crassidens, Sousa plumbea, Balaenoptera edeni). Estimates of abundance using design-based line transect sampling techniques were obtained for five species: S. attenuata 10,268 (CV=0.26); S. longirostris 6,961 (CV=0.26); T. aduncus 659 (CV=0.69); T. truncatus 509 (CV=0.33), and G. griseus 367 (CV=0.37). Habitat modelling revealed that the two Stenella species were widely distributed across the study area. In contrast, T. truncatus was concentrated in waters around Ras Banas peninsula (in particular Satayah offshore reef), and T. aduncus was mainly found along the coast with possibly separate sub-populations in the northern and southern study area. G. griseus was only encountered in the southern part. The information provided in this study will allow the development of a conservation strategy for the protected areas and will serve as baseline information to carry out future survey work in the Red Sea.
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Caracterização da comunidade de mamíferos de médio e grande porte em paisagem agrícola fragmentada / Characterization of the mid and large bodied mammal community in a fragmented agricultural landscapeAlves, Maísa Ziviani 22 June 2012 (has links)
O avanço agrícola é uma das maiores causas da fragmentação de habitats, levando à diminuição e ao isolamento de áreas naturais. Assim, torna-se importante compreender qual papel da estrutura e dinâmica da paisagem na manutenção da biodiversidade local. Este estudo teve como objetivo descrever a estrutura de uma comunidade de mamíferos de médio e grande porte em paisagem fragmentada agrícola, considerando a estrutura e dinâmica da paisagem. O estudo foi realizado em unidades de paisagem (16 Km2) com matriz predominante de pasto (n = 2) e cana-de-açúcar (n = 3) (bacia do rio Corumbataí, São Paulo) de maio a outubro de 2010. O levantamento da comunidade de mamíferos foi realizado através de busca ativa por pegadas, em 15 transectos alocados nas margens de riachos, com distância percorrida padronizada em 200 m. No entorno de cada transecto foram gerados buffers (250, 500, 1000 e 2000 m de raio), para o cálculo de índices de estrutura (porcentagens dos usos do solo, densidade de drenagem, densidade de estradas e proximidade entre fragmentos) e de dinâmica (taxa anual de mudança e perfil da curva de mudança florestal) para cinco anos (1962, 1978, 1995, 2000 e 2008). A relação entre os índices de paisagem e a riqueza de espécies foi analisada através de um teste PCA (Análise de Componentes Principais), gerando um gráfico Biplot. Posteriormente, foi realizada regressão linear múltipla, para análise da influência da estrutura e dinâmica da paisagem sobre a riqueza de espécies e frequência de registros. Foram registradas 19 espécies, sendo 17 em unidades de cana-de-açúcar e 13 em unidades de pasto. A comunidade de mamíferos de médio e grande porte, presente nestas matrizes da bacia do rio Corumbataí, é representada, em grande parte, por espécies tolerantes a alterações ambientais da região. A espécie com maior frequência de registros foi Procyon cancrivorus, de hábito generalista, como a maior parte dos animais registrados. Pelo gráfico Biplot, o buffer de 1000 m foi o que melhor distinguiu os sítios amostrais em relação às matrizes de cana-de-açúcar e pasto. A riqueza apresentou relação positiva com a porcentagem de áreas florestais e densidade de drenagem. Em contrapartida, a riqueza mostrou relação negativa com a porcentagem de pasto. A riqueza e a frequência de registros não apresentaram diferença estatística significativa entre as matrizes e também não houve relação significativa entre os índices de paisagem e as variáveis dependentes. A similaridade entre a composição de espécies das comunidades amostradas nas matrizes foi de 57%. As relações entre a estrutura desta comunidade e a paisagem necessitam de mais esforços para serem melhor compreendidas, já que o método de levantamento utilizado neste estudo, assim como a escala espaço-temporal, não permitiram descrever tais relações. / Agricultural expansion is a major cause of habitat fragmentation, leading to a reduction and isolation of natural areas. It is therefore important to understand the role of agricultural landscape structure and dynamics in maintaining local biodiversity. We aimed to describe how the structure and dynamics of an agricultural landscape influenced the community of mid and large bodied mammals in the south of Brazil. From May to October 2010 we studied the mammal community in five 16 km2 landscape units located within the Corumbatai river basin, São Paulo. Landscape units contained a matrix of predominantly pasture (n = 2) and cane sugar (n = 3). We used track surveys along 15 transects (200m each) to sample the mammal community along river banks. To calculate indices of habitat structure and dynamics we generated buffers (250, 500, 1000 and 2000 m radius) around each of the transects. Within each of these distance buffers we calculated habitat structure indices (percentage of land use, drainage density, road density and proximity of fragments) and indices of habitat dynamics (annual rate of change and profile of the forest change curve) for five years (1962, 1978, 1995, 2000 and 2008). The relationship between landscape indices and species richness was analyzed through a PCA (Principal Component Analysis) and associated Biplot. Subsequently, multiple linear regression was performed to analyze the influence of landscape structure and dynamics on species richness and frequency of records. We recorded 19 species, 17 in cane sugar units and 13 in pasture units. The community of mid and large bodied mammals present in the habitat matrices of the Corumbataí river basin was represented mostly by generalist species tolerant of environmental changes. The most frequently recorded species was Procyon cancrivorus, a habit generalist. The PCA Biplot showed that the 1000m buffer was the one that best distinguished the sampling sites in relation to the sugar cane and pasture matrices. Species richness was positively related with the percentage of forested areas and drainage density. In contrast, richness was negatively related with the percentage of pasture. The richness and frequency of records showed no statistically significant difference between the two matrix types and there was no significant relationship between landscape indices and the dependent variables. The similarity between the species composition of the sampled communities in the matrices was 57%. Understanding the relationships between the composition of this community and the landscape structure and dynamics requires more efforts, as the survey method used in this study, and the spatiotemporal scale, do not permit the description of these relationships.
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Desenvolvimento de seqüências de DNA microsatélite para estudo de populações remanescentes de Jacaré-de-Papo-Amarelo (Caiman latirostris), da região central do Estado de São Paulo / Development of microsatellite DNA sequencies for the study of remnant populations of Broad-snouted caiman (Caiman latirostris), of central region of Sao Paulo StateZucoloto, Rodrigo Barban 24 February 2003 (has links)
Novos marcadores genéticos foram caracterizados para jacaré-de-papo-amarelo (Caiman latirostris) pela construção de bibliotecas enriquecidas de DNA microssatélite. Um microssatélite foi desenvolvido a partir de uma biblioteca enriquecida de DNA microssatélite (ACC/TGG)n e 12 a partir de uma biblioteca enriquecida de DNA microssatélite (AC/TG)n. Esses marcadores foram testados em indivíduos da espécie Caiman latirostris e resultaram em sete novos microssatélites polimórficos. Adicionalmente quatro marcadores microssatélites de Alligator mississipiensis previamente transferidos para Caiman latirostris foram utilizados. Amostras de sangue jacarés-de-papo-amarelo originárias de várzeas associadas ao Rio Piracicaba e alguns de seus tributários no estado de São Paulo, Brasil, foram avaliadas quanto à variação genética entre populações e o parentesco entre indivíduos. Foi detectada variabilidade entre indivíduos originários de sitos diferentes, mesmo entre aqueles com pequena distância geográfica. Os resultados sugerem que os grupos amostrados em cada sítio são compostos predominantemente por indivíduos aparentados. Uma possível combinação de alta taxa de mortalidade e baixa taxa de natalidade pode ser a explicação do baixo número de indivíduos dispersos com sucesso por geração entre os sítios estudados. Esses marcadores podem auxiliar na compreensão dos processos metapopulacionais que aparentemente ocorrem na espécie. / New genetic markers were characterized for the broad-snouted caiman (Caiman latirostris) by constructing libraries enriched for microsatellite DNA. One microsatellite was developed from a (ACC/TGG)n enriched microsatellite DNA library and 12 from a (AC/TG)n enriched microsatellite DNA library. These markers were tested in Caiman latirostris individuals and resulted in seven new polymorphic microsatellites for the specie. Additionally four Alligator mississipiensis microsatellite markers previously transferred for Caiman latirostris were used. Samples from broad-snouted caimans from small wetlands associated with the Piracicaba River and some of its tributaries in the state of São Paulo, Brazil were used to study the genetic variation between populations and parentage between individuals. Genetic variability was detected among individuals from different sites, even those within a small geographic distance. The results suggest that the groups sampled at each site are composed predominantly of related individuals. A possible combination of high mortality and low natality rates in the fragmented Caiman latirostris populations may explain the low number of successfully dispersed individuals per generation observed between the sites studied. These markers might help to understand the metapopulation processes that are occurring within this species.
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A generalized stochastic birth/death population model based on Indian RiverLagoon dolphinsUnknown Date (has links)
For over a decade, researchers at Harbor Branch Oceanographic Institute (HBOI)
have conducted surveys of the bottlenose dolphin (Tursiops truncatus) population of
Indian River Lagoon (IRL) in Florida. I have constructed a 4-stage population model
using the statistical program R. The model is used to conduct a viability analysis by
analyzing the relationship between birth, calf and adult survival rates. The power
analysis compares survey frequency to expected confidence intervals in estimating
abundance. The sensitivity analysis shows that the population is most sensitive to
changes in adult survival, followed by birth rate and calf survival. The model shows a
strong chance of viability over a 50 year time span. The population is vulnerable to long
periods of decline if birth, calf or adult survival rates fall below certain thresholds.
Overall, the model simulates the future impacts of demographic change, providing a tool
for conservation efforts. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection
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