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.

A avicultura é uma das atividades de produção animal que mais se desenvolveram nos últimos anos. Neste contexto, o Brasil encontra-se em posição privilegiada, sendo o terceiro maior produtor e o principal exportador de carne de frango do mundo. Com esta enorme expansão e também com o crescente aumento dos custos de produção têm se observado, já há algum tempo, um grande interesse pelo aumento do número de aves por m², proporcionando assim uma otimização da produção por área. Porém, estudos mostram que altas densidades levam a um ambiente desfavorável às aves, gerando estresse e causando um declínio nos índices produtivos, como conversão alimentar, consumo de ração e ganho de peso diário. Por outro lado, na maioria das vezes, proporciona uma maior rentabilidade ao produtor devido a uma maior produção de carne por unidade de área. O aumento da densidade de alojamento leva a uma queda no grau de bem-estar das aves, podendo ser observado nestes animais problemas ao caminhar, aumento dos índices de dermatites de contato, artrites, escoriações e feridas de pele, que levam a condenações de carcaças. Também, devido ao estresse, podem-se ocasionar alterações fisiológicas como aumento no nível sérico de proteínas, glicose e triglicerídeos, com variação na relação heterófios: linfócitos. Em vista disso e com a introdução de novas linhagens comerciais no mercado avícola, torna-se necessário para a indústria e o produtor, definir características e limites de produção, pois as linhagens podem apresentar diferentes respostas em relação ao ambiente em que são submetidas. Neste contexto, o presente trabalho tem por objetivo abordar em um primeiro momento através de uma revisão bibliográfica o efeito de altas densidades de alojamento sobre o desempenho zootécnico, bem-estar animal, rendimento e qualidade de carcaça em frangos de corte. O segundo objetivo do trabalho é elaborar um capítulo com um artigo intitulado: “Efeito da densidade populacional sobre o desempenho zootécnico, bem-estar animal, rendimento e qualidade de carcaça em frangos de corte de diferentes linhagens comerciais." / The poultry industry is one of the activities of livestock that have developed over the past years. In this context, Brazil is in a unique position, being the third largest producer and largest exporter of chicken meat in the world. With this massive expansion and also with the increasing costs of production have been observed for some time, a great interest in increasing the number of birds per m², providing an optimization of production by area. However, studies show that high densities lead to an unfavorable environment for the birds, causing stress and causing a decline in production indices, such as feed conversion, feed intake and daily weight gain. Moreover, in most cases, provide greater economy to the grower because of a higher meat production per unit area. Increased housing density leads to a decrease in the level of welfare of the birds can be observed in these animals when walking problems, increased rates of contact dermatitis, arthritis, bruises and wounds of the skin, leading to condemnation of carcasses. Also, due to stress, can cause physiological changes such as an increase in serum protein, glucose, and triglycerides with variation in the heterófios: lymphocytes. In view of this and the introduction of new strains in commercial poultry market, it becomes necessary for industry and producer, defining features and limits production because the lines may have different responses to the environment in which they are subjected. In this context, this work aims to address at first through a literature review of the effect of high housing densities on live performance, animal welfare, performance and carcass quality in broilers. The second objective is to develop a chapter with an article entitled: "Effect of population density on live performance, animal welfare, performance and carcass quality in broilers of different commercial strains."

A avicultura é uma das atividades de produção animal que mais se desenvolveram nos últimos anos. Neste contexto, o Brasil encontra-se em posição privilegiada, sendo o terceiro maior produtor e o principal exportador de carne de frango do mundo. Com esta enorme expansão e também com o crescente aumento dos custos de produção têm se observado, já há algum tempo, um grande interesse pelo aumento do número de aves por m², proporcionando assim uma otimização da produção por área. Porém, estudos mostram que altas densidades levam a um ambiente desfavorável às aves, gerando estresse e causando um declínio nos índices produtivos, como conversão alimentar, consumo de ração e ganho de peso diário. Por outro lado, na maioria das vezes, proporciona uma maior rentabilidade ao produtor devido a uma maior produção de carne por unidade de área. O aumento da densidade de alojamento leva a uma queda no grau de bem-estar das aves, podendo ser observado nestes animais problemas ao caminhar, aumento dos índices de dermatites de contato, artrites, escoriações e feridas de pele, que levam a condenações de carcaças. Também, devido ao estresse, podem-se ocasionar alterações fisiológicas como aumento no nível sérico de proteínas, glicose e triglicerídeos, com variação na relação heterófios: linfócitos. Em vista disso e com a introdução de novas linhagens comerciais no mercado avícola, torna-se necessário para a indústria e o produtor, definir características e limites de produção, pois as linhagens podem apresentar diferentes respostas em relação ao ambiente em que são submetidas. Neste contexto, o presente trabalho tem por objetivo abordar em um primeiro momento através de uma revisão bibliográfica o efeito de altas densidades de alojamento sobre o desempenho zootécnico, bem-estar animal, rendimento e qualidade de carcaça em frangos de corte. O segundo objetivo do trabalho é elaborar um capítulo com um artigo intitulado: “Efeito da densidade populacional sobre o desempenho zootécnico, bem-estar animal, rendimento e qualidade de carcaça em frangos de corte de diferentes linhagens comerciais." / The poultry industry is one of the activities of livestock that have developed over the past years. In this context, Brazil is in a unique position, being the third largest producer and largest exporter of chicken meat in the world. With this massive expansion and also with the increasing costs of production have been observed for some time, a great interest in increasing the number of birds per m², providing an optimization of production by area. However, studies show that high densities lead to an unfavorable environment for the birds, causing stress and causing a decline in production indices, such as feed conversion, feed intake and daily weight gain. Moreover, in most cases, provide greater economy to the grower because of a higher meat production per unit area. Increased housing density leads to a decrease in the level of welfare of the birds can be observed in these animals when walking problems, increased rates of contact dermatitis, arthritis, bruises and wounds of the skin, leading to condemnation of carcasses. Also, due to stress, can cause physiological changes such as an increase in serum protein, glucose, and triglycerides with variation in the heterófios: lymphocytes. In view of this and the introduction of new strains in commercial poultry market, it becomes necessary for industry and producer, defining features and limits production because the lines may have different responses to the environment in which they are subjected. In this context, this work aims to address at first through a literature review of the effect of high housing densities on live performance, animal welfare, performance and carcass quality in broilers. The second objective is to develop a chapter with an article entitled: "Effect of population density on live performance, animal welfare, performance and carcass quality in broilers of different commercial strains."

No description available.

Approximately 475 acres of aspen, oak brush, and grass-forb-shrub communities were treated with herbicides. The populations of arthropods, birds, and mammals were investigated on treated and untreated areas and the results were compared. There was no difference between soil arthropod populations on treated and untreated aspen plots but a significant increase in these populations on treated meadow plots. The foliage insect populations were significantly lower on the treated aspen plots but were significantly higher on the treated meadow plots. The aquatic invertebrates were not affected by the treatments. Bird populations ware lower in the treated area during the nesting season (June), higher in the treated area during July and August and nearly the same in each area during September. Small mammal populations decreased significantly on the treated meadow plots. Microtus populations increased while all other small mammals decreased in numbers on treated aspen plots. Use of the treated areas by mule deer was significantly reduced, while use of the same areas by elk was slightly increased.

Studies on density related indices of white-tailed deer were conducted on the Conservation Research Center (CRC) in Warren County, Virginia from June 1985 to April 1986. Food habits and bark-stripping by deer were also evaluated. Whole body weights, stored fat status, abomasal parasite counts, and blood indices from five deer collected in September on the CRC were compared to deer collected from two reference areas in Southwest Virginia. Abomasal parasite count values for the three areas were recorded as 2568, 1292, and 292. No consistent effects of deer density on physical and physiological indices were observed. Rumen contents from the five deer collected on the CRC were used to determine food habits. The fall diet consisted of green herbage and foliage of woody plants (70% of the total volume) and fruits (30%) such as acorns, apples, and black cherry. No consistent effect of deer density on forage use in meadows was observed on the CRC. Meadow utilization decreased as the growing season progressed. Meadows were utilized more at the edge than 200 m from the edge (P = 0.06). No significant difference (P > 0.05) was found in percentage of dogwood twigs browsed during winter among areas with different deer densities. Fecal crude protein values were higher during summer than winter (P < 0. 0001) but there also was an area-season interaction ( P < 0. 01). Acid detergent fiber values were significantly different areawise (P < 0.01), seasonwise, and areas-season interactionwise (P = 0.0001). Deer density was positively related to winter ADF values. Bark-stripping occurred on slippery elm trees during the winter in a high deer density area. No significant association was found between stripping of slippery elms and age, dbh, and height classes. Protein (P < 0.001) and starch (P < 0.01) contents of the bark were significantly higher in slippery elms than in any other tree species. / M.S.

A model of the trophic dynamics among key macroinvertebrate and fish populations in the New River, West Virginia, was developed to help define the roles of predation, competition, and fishery exploitation in the food web of this large, warmwater stream. The fates of production of the harvested crayfish (Orconectes virilis, Orconectes sanbornii sanbornii, and Cambarus sciotensis), hellgrammite (Corydalus cornutus larvae), smallmouth bass (Micropterus dolomieui), rock bass (Ambloplites rupestris), and flathead catfish (Pylodictis olivaris) populations were quantified to evaluate the status of these stocks and to aid specification of the model. Analysis and application of the model were designed to address three research objectives, which were to (1) quantify the roles that predation, competition, and exploitation have in structuring the prey-predator assemblage, (2) evaluate through simulation the effects of multispecies exploitation, and (3) assess through simulation the impacts to the food web of reductions in aquatic insect production associated with the systematic control of black fly larvae in the New River. The trophic basis of production of smallmouth bass, rock bass, and flathead catfish was primarily aquatic insects (in young fishes) and crayfish (in older fishes). Hellgrammites and prey fishes were inconsequential in that regard. Predation by these fishes (primarily smallmouth bass and rock bass) accounted for 76% of the production of ages-1 and -2 crayfish, and harvest by people was equivalent to 5% of crayfish production. Fish predation (primarily by rock bass) and harvest accounted for 14% and 8%, respectively, of the annual production of ages-1 and -2 hellgrammites. Anglers harvested the equivalents of about 91% and 12% of the annual production of fully-recruited smallmouth bass and rock bass, respectively; the extent of flathead catfish harvest was unclear. Error analysis of the model suggested that “bottom-up" (food-limitation) effects were more important than “top-down" (mortality from predation) effects, interspecific and intraspecific competition, and exploitation in maintaining the structure of the prey-predator assemblage in the New River. Exploitation was important in causing transitions in assemblage structure. Simulations of multispecies exploitation demonstrated that production and yield of populations are strongly dependent on food web interactions. Simulation of a 50% reduction in aquatic insect production, similar to that observed following poisoning of black fly Iarvae, predicted substantial declines in insectivores and their predators. Management of New River resources for maxi- mum benefits to people will necessarily involve new approaches to addressing problems in a food web context. / Ph. D.

Thesis (PhD)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: The aims of this study were to investigate genetic issues pertaining to the conservation of the Knysna seahorse, Hippocampus capensis, and to determine the phylogenetic placement of this endangered estuarine species among marine seahorses. This was accomplished by focusing on three aspects of the taxonomy: the interspecific level; the inter-population level; and the intra-population level. To determine which species are closely related to H. capensis, and how the evolutionary history of this lineage relates to that of other seahorses, sequence data derived from four gene fragments (the nuclear RPI and Aldolase and the mitochondrial 16S rRNA and cytochrome b genes) were used to determine the phylogenetic relationships among 30 species belonging to the genus Hippocampus. There were marked differences in the rate of evolution among these gene fragments, with Aldolase evolving the slowest and the mtDNA cytochrome b gene the fastest. Among individual partitions, the RPI gene recovered the highest number of nodes supported by >70% bootstrap values from parsimony analysis, and >95% posterior probabilities from Bayesian inference. The combined analysis based on 2317 nucleotides resulted in the most robust phylogeny. A distinct phylogenetic split was identified between the pygmy seahorse, H. bargibanti, and a clade including all other species. Three species from the western Pacific Ocean included in this study, namely H. bargibanti, H. breviceps, and H. abdominalis, occupy basal positions in the phylogeny. This and the high species richness in the region suggest that the genus probably originated in this region. There is also fairly strong molecular support for the remaining species being subdivided into three main evolutionary lineages: two West Pacific clades and a clade of species present in both the Indo-Pacific and the Atlantic Ocean, which includes H. capensis. The phylogeny obtained herein suggests that seahorses belonging to the latter clade colonised the Atlantic Ocean at least twice, once before the closure of the Tethyan Seaway, and once afterwards. Phylogenies reconstructed using mitochondrial DNA gene fragments (l6S rRNA, cytochrome band 382 bp of the rapidly evolving control region) indicate that H. capensis is closely related to an Indian Ocean lineage of H. kuda and a Red Sea lineage of H. fuscus. Other lineages closely associated with these taxa include H. kuda from the West Pacific, the East Atlantic species H. algiricus, the West Atlantic species H reidi, the East Pacific species H ingens, and the Hawaiian species H fisheri. No control region alleles were shared among H capensis and any of the marine seahorses, suggesting that the Knysna seahorse is phylogenetically distinct. The evolutionary history of H capensis, and the extent of gene flow between its three known populations, were investigated using control region sequences from 138 specimens. Most samples were obtained by taking fin clips; this method was studied on captive seahorses and no negative effects were found. Similarly high levels of genetic diversity were found in two of the wild populations (Knysna and Keurbooms Estuaries), whereas diversity in the third population (Swartvlei Estuary) was lower. Although most haplotypes are shared among at least two populations, based on the haplotype frequency distributions the three assemblages constitute distinct management units. The extant population structure of H capensis suggests that the Knysna seahorse originated in the large Knysna Estuary. The presence of seahorses in the two smaller estuaries is either the result of a vicariance event at the beginning of the present interglacial period, or colonisation of the estuaries via the sea, or a combination of the two. Population genetic parameters of the Knysna population and those of two populations of closely related marine seahorses (H kuda from the Philippines and H fuscus from the Red Sea) were similar, suggesting that the Knysna population is not genetically impoverished, despite its comparatively small area of occupancy. / DEUTSCHE ZUSAMMENFASSUNG: Die hier prasentierte wissenschaftliche Studie beschaftigte sich mit genetischen Themen relevant flïr den Artenschutz des Knysna Seepferds, Hippocampus capensis, und den phylogenetischen Beziehungen dieser ausschliesslich in Estuaren (Flussmtindungen) vorkommenden gefahrdeten Art mit den im Meer lebenden Seepferden. Die folgenden taxonomischen Einheiten wurden verglichen: Arten, Populationen und Sub-Populationen. Urn festzustellen, welche Arten nah mit H. capensis verwand sind, und wie die Evolution dieser Gruppe sich von der anderer Seepferdgruppen unterscheidet, wurden genetische Sequenzen von vier Genen (den nuklearen RPI und Aldolase und den mitochondrischen 16S rRNA und Cytochrom b Genen) von 30 Seepferdarten verwendet und phylogenetische Beziehungen rekonstruiert. Betrachtliche Unterschiede wurden festgestellt hinsichtlich der Geschwindigkeit in der Mutationen stattgefunden haben: Aldolase mutierte am langsamsten und Cytochrom b am schnellsten. Eine auf RPI Sequenzen basierende Phylogenie hatte die hëchste Anzahl von Gabelungspunkten, die sowohl von parsimonischen Analysen, als auch von bayesischer Inferenz untersttitzt wurden. Die robusteste Phylogenie wurde jedoch gefunden, wenn Sequenzen von allen vier Genen kombiniert wurden (im ganzen 2317 Nukleotide). Eine betrëchtliche genetische Distanz wurde zwischen dem Pygmaen-Seepferd, H. bargibanti, und einer Gruppe, die aus allen anderen Arten bestand, gefunden. Drei Arten vom westlichen Pazifik, namlich H. bargibanti, H. breviceps und H. abdominalis, hatten basale Positionen in der Phylogenie. Das, und der Artenreichtum dieser Region, sind Anzeichen daflïr, dass Seepferde mëglicherweise ursprtinglich aus dem westlichen Pazifik stammen. Es wurde weiterhin gefunden, dass alle tibrigen Seepferdarten in drei Hauptgruppen unterteilt werden kannen: die Verbreitungsgebiete zweier dieser Gruppen beschranken sich hauptsachlich auf den westlichen Pazifik, aber die dritte Gruppe kommt sowohl im Indo-Pazifik, also auch im Atlantik vor (H. capensis ist mit dieser letzteren Gruppe assoziiert). Es gibt gute Anzeichen dafllr, dass die Seepferde der letztgenannten Gruppe den Atlantik mindestens zweimal kolonisiert haben, einmal vor der Schliessung der tethyschen Seeverbindung, und einmal danach. Phylogenien, die ausschliesslich mit mitochondrischen Genen rekonstruiert wurden (16S rRNA, Cytochrom b und 382 Nukleotide der schnell-mutierenden Kontollregion), zeigen, dass H capensis sehr nah verwandt mit H kuda aus dem Indischen Ozean und H fuscus aus dem Roten Meer ist. Andere nah verwandte Arten sind H kuda from westlichen Pazifik, H algiricus vom ëstlichen Atlantik, H reidi vom westlichen Atlantik, Hingens vom ëstlichen Pazifik, sowie die in Hawaii vorkommende Art H fisheri. Keine der Kontrollregionallele, die in H capensis gefunden wurden, kamen in anderen Arten vor. Dies zeigt, dass das Knysna Seepferd eine eigenstandige Art ist, und Paarungen mit anderen Arten nicht vorkommen. Die Evolutionsgeschichte von H capensis, und das Ausmass von genetischem Austausch zwischen den drei Populationen dieser Art, wurden untersucht, indem Kontrollregionsequenzen von 138 Individuen analysiert wurden. Die meisten Proben stammten von Flossenschnitten; diese Methode wurde zuvor an in Gefangenschaft lebenden Seepferden ausprobiert, und es wurden keine negativen Folgeerscheinungen beobachtet. Genetische Diversitat war ungefahr gleich hoch in zwei der Populationen (Knysna und Keurbooms Estuare), aber eine deutlich niedrigere Diversitat wurde in der dritten Population gefunden (Swartvlei Estuar). Obwohl die meisten Allele in mindestens zwei Populationen gefunden wurden, sind die drei Populationen unterschiedliche genetische Einheiten, eine Schlussfolgerung, die hauptsachlich auf Unterschiede in der relativen Haufigkeit der Allele beruht. Die Populationsstruktur von H capensis deutet darauf hin, dass diese Art ihren Ursprung im Knysna Estuar hat. Die Prasenz von Seepferden in den beiden anderen Estuaren ist entweder das Resuitat von Vikarianz (eine Spaltung der urspri.inglichen Population) zu Beginn der jetzigen Interglazialzeit, oder Kolonisierung der Estuare durchs Meer, oder eine Kombination beider Szenarios. Populationsgenetische Parameter der Knysna Population und die zweier Populationen von nah verwandten Arten (H kuda aus den Philippinen und H fuscus aus dem Roten Meer) zeigten keine grossen Unterschiede. Dies deutet darauf hin, dass das Knysna Seepferd trotz seines vergleichbar kleinen Verbreitungsgebietes nicht unter geringer genetischer Diversitat leidet. / AFRIKAANSE OPSOMMING Die doelwitte van hierdie studie was om die Knysna seeperdjie, Hippocampus capensis, te ondersoek relatief tot die spesie se bewaring asook om die filogenetiese posisie van hierdie bedreigte estuariene spesie binne mariene seeperdjies te bepaal. Drie aspekte van die taksonomie word ondersoek: interspesie verwantskappe, interbevolking verwantskappe en intra-bevolking verwantskappe. Om te bepaal watter spesies na verwant is aan H capensis, asook om die evolusionêre geskiedenis van hierdie groep met die van ander groepe te vergelyk, word nukleotieddata van vier ONS fragmente (die nukleêre RPI intron en Aldolase, en die mitochondriale 16S rRNA en sitokroom b fragmente) van 30 spesies van die genus Hippocampus gebruik. Aansienlike verskille in die tempo van evolusionêre verandering tussen hierdie ONS fragmente word gevind: Aldolase was die stadigste en die mitochondriale sitokroom b die vinnigste. Die RPI intron het die meeste knoesteringe gehad wat ondersteun word deur hoë stewelvasgordnommers (>70%) van parsimoniese analises en hoë agterwaarskynlikheide (>95%) van Bayesiese gevolgtrekkinge. Die kombineerde analise wat 2317 nukleotiede ingesluit het, het die beste filogenie geproduseer. 'n Besliste filogenetise verdeling was gevind tussen die pigmee seeperdjie, H bargibanti, en 'n groep wat al die ander spesies ingesluit het. Drie spesies van die westelike Stille Oseaan wat in hierdie studie ingesluit is, H bargibanti, H breviceps en H abdominalis, neem primitiewe posisies in die filogenie in. Dit, en die hoë spesiesrykdom in daardie gebied dui aan dat dit moontlik is dat die genus in die westelike Stille Oseaan ontstaan het. Daar is ook taamlike goeie molekulêre ondersteuning dat al die ander spesies in drie evolusionêre hoofgroepe verdeel kan word: twee groepe wat hoofsaaklik in die westelike Stille Oseaan voorkom, en 'n groep van spesies wat in die Stille Oseaan, die Indiese Oseaan en in die Atlantiese Oseaan voorkom, wat H capensis insluit. Die filogenie wat hier gevind is dui aan dat seeperdjies van hierdie laas genoemde groep die Atlantiese Oseaan minste twee keer gekoloniseer het, een keer voor die sluiting van die Tetiese Seepad, en een keer daarna. Filogenies wat met mitochondriale ONS fragmente gerekonstrueer is (16S rRNA, sitokroom b en 382 nukleotide van die vinnig evolveerende kontrolestreek) dui aan dat H capensis na verwant is aan 'n groep van H kuda wat in die Indiese Oseaan voorkom en H fuscus van die Rooi See. Ander groepe wat na verwant is aan hierdie takson is H kuda van die westelike Stille Oseaan, H algiricus van die Oos Atlantiese Oseaan, H reidi van die Wes Atlantiese Oseaan, en die Hawaiise spesie H fisheri. Geen kontrolestreek allele was gedeel tussen H capensis en enige mariene seeperdj ie spesies; dit dui aan dat die Knysna seeperdjie filogeneties verskillend is. Die evolusionêre geskiedenis van H capensis, en die omvang van die genetiese interaksies tussen sy drie bekende bevolkings, word ondersoek met kontrolestreek nukleotieddata van 138 monsters. Die meeste van hierdie monsters was verkry deur vinknipsels; hierdie metode was getoets op seeperdjies in gevangenskap en geen negatiewe gevolge was gevind nie. Genetiese diversiteit was omtrent dieselfde in twee van die natuurlike bevolkings (Knysna en Keurbooms Estuariums), maar diversiteit in die derde bevolking (Swartvlei Estuarium) was laër. Alhoewel die meeste allele gedeel was tussen ten minste twee bevolkings, dui die verspreiding van allelfrekwensies aan dat die drie bevolkings aparte bestuurseenhede is. Die ekstante bevolkingsstruktuur van H capensis dui aan dat die Knysna seeperdjie in die groot Knysna Estuarium ontstaan het. Die teenwordigheid van seeperdjies in die twee kleiner estuariums is óf die resultaat van 'n vikariansie voorval aan die begin van hierdie interglasiale tydperk, óf kolonisasie van die estuariums deur die see, óf 'n kombinasie van albei. Bevolkingsgenetiese parameters van die Knysna bevolking en van twee bevolkings van na verwante seeperdjie spesies (H kuda van die Filippyne en H fuscus van die Rooi See) was soortgelyk, wat aandui dat die Knysna bevolking nie geneties verarm is nie, alhoewel dit 'n betreklik kleiner streek bewoon.

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.

Hylaeamys yunganus, é um roedor da tribo Oryzomyini que apresenta amostras distribuídas ao longo das florestas tropicais da Amazônia e ocupa um amplo gradiente altitudinal, que se estende do nível do mar até altitudes ao redor de 2000m. Informações disponíveis na literatura sugerem que as populações de H. yunganus da Venezuela, Colômbia, Equador, Peru e oeste do Brasil apresentam grande tamanho corpóreo, enquanto que é característico das populações da Guiana Francesa, Guyana, Suriname e ao longo da região leste da Bacia Amazônica, um tamanho menor. Dentro deste contexto, considerando novas amostras disponíveis e novas abordagens metodológicas (morfológicas quantitativas e moleculares), o presente estudo buscou avaliar as diferenças entre as populações do leste e oeste de H. yunganus. Além disso, buscou verificar a existência de similaridade morfológica entre as populações da Amazônia oriental e da Amazônia ocidental com populações simpátricas de H. megacephalus e H. perenensis, respectivamente. Localidades geográficas próximas foram agrupadas com o propósito de obter amostras mais robustas para as análises estatísticas. As análises morfométricas e morfológicas foram conduzidas em indivíduos adultos de acordo com o desgaste dos molares e de ambos os sexos. Os caracteres morfométricos consistiram em 17 crânio-dentárias. As normalidades foram testadas uni e multivariadamente utilizando os testes de Kolmogorov- Smirnov e Kurtose de Mardia, respectivamente. As análises de variação geográfica basearam-se em diagramas Dice-Leraas, Análises de Componentes Principais e Análises Discriminantes. Utilizando um fragmento de 414 pb do gene mitocondrial do citocromo b foram realizadas árvores filogenéticas pelos métodos de Neighbour-Joining e Bayesiana. Foi também conduzida uma análise da rede de haplótipos para reconhecer os agrupamentos dos haplótipos na espécie. Ao longo da distribuição da espécie foram encontrados padrões de divergência baseados em dados morfológicos (nas análises uni e multivariadas). As populações do leste são menores em diversas dimensões cranianas que os indivíduos da porção oeste da distribuição. As análises moleculares revelam uma congruência parcial com as análises morfológicas: os indivíduos da porção oeste são mais próximos entre si e formam um clado divergente dos indivíduos do leste. A diferença existente é que o clado leste, tem a presença de espécimes de Potaro e Barima-Waini (Guiana), localidades que apresentam diferenças morfológicas tanto com o grupo leste como oeste, dependendo da análise estatística. Concluiu-se que existe variação geográfica em H. yunganus ao longo da distribuição na Amazônia, porém de forma gradual e não abrupta, entre as populações do leste e do oeste da Amazônia. / Hylaeamys yunganus is a rodent of the Oryzomyini tribe presenting samples distributed through the Amazon rainforests and occupies a wide altitudinal gradient, which extends from sea level up to ca. 2,000m. Information available in the literature suggests that populations of H. yunganus from Venezuela, Colombia, Ecuador, Peru and western Brazil have large body size, whereas populations from French Guiana, Guyana, Suriname and the eastern Amazon Basin have a smaller size. Within this context, considering new samples available and new methodological approaches (quantitative morphological and molecular), this study evaluated the differences between the eastern and western populations of H. yunganus. In addition, investigates the existence of morphological similarity between the populations of the eastern Amazon and the western Amazon with sympatric populations of H. megacephalus and H. perenensis, respectively. Close geographic locations were grouped in order to obtain samples for more robust statistical analysis. The morphometric and morphological analysis were conducted in adults according to the molar wear in both sexes. The morphometric characters consisted of 17 cranio-dental measurements. The normality was tested using univariate and multivariate tests of Kolmogorov- Smirnov and Mardi kurtosis, respectively. Geographic variation analysis was based on Dice- Leraas diagrams, Principal Components Analysis and Discriminant Analysis. Using a fragment of 414 bp of the mitochondrial cytochrome b gene were performed phylogenetic trees by the Neighbour-Joining and Bayesian methods. It was also conducted a haplotype network analysis in order to recognize groups of haplotypes in the species. Through the species distribuition divergent patterns were found in morphology (uni and multivariate analyses). The eastern populations presented smaller cranial dimentions than the western ones. The molecular analyses revealed partial congruence with this pattern. The western samples are close to each other forming a separated group from the eastern samples. The eastern clade has samples from Potaro and Barima-Waini (Guyana) that present mophological differences with the eastern group as well as with the western one, depending on the statistical analysis. In short, H. yunganus presents geographical variation through its distribution in a gradual pattern between the eastern and the western Amazon.