The North Pacific humpback whale (Megaptera novaeangliae) is a wide-ranging baleen whale species with a complex life history and population structure. As seasonal migrants, humpback whales are known to inhabit cooler, high-latitude waters when foraging and low-latitudes for mating and calving. Beyond this general migratory pattern, a number of demographic characteristics including, abundance, distribution, seasonal occurrence, and prey preferences remain unknown or poorly described. A complete understanding of humpback whale ecology is therefore lacking. Many methods used to explore these aspects of cetacean ecology are either prohibitively expensive or limited in the scope of what can be learned from their use. Fortunately, in recent years, the analysis of stable isotope ratios of animal tissues has proved a valuable and relatively inexpensive technique for providing information on trophic position, diet, and feeding origins of migratory populations. This study employed techniques in stable isotope ecology to increase knowledge of the population structure, migration routes, and foraging ecology of North Pacific humpback whales. Skin samples were collected from free-ranging humpback whales throughout all known feeding and breeding grounds and were analyzed for stable carbon ([delta]13C) and nitrogen ([delta]15N) isotope ratios. The population structure of humpback whales was first explored through geographic differences in stable isotope ratios. Stable isotope ratios varied significantly with location of sample collection. Based on this analysis, foraging animals were separated into six feeding groups. Classification tree analysis was then used to determine which isotopic variables could be used to predict group membership. Probable migratory linkages were then described by applying results of classification trees to [delta]13C and [delta]15N of animals sampled on breeding grounds. Strong migratory connections between the eastern-most foraging and breeding areas and the western-most areas were reflected in similarities of stable isotope ratios. Foraging ecology was then examined through calculation and comparison of the relative trophic levels of the six feeding groups. Isotopic values suggest some feeding groups are piscivorous, while others feed on a more mixed diet. These results can be used to determine if differences in diet composition between groups result in differences in accrued nutritional benefits, negatively impacting reproductive success and survival relative to fish eating groups. Finally, to gain insight into specific foraging habits, the diet of one group of humpback whales was modeled using an isotope mixing model. The [delta]13C and [delta]15N of Kodiak Island, Alaska humpback whales and several species of potential prey indicate that these animals likely rely heavily on euphausiids (Thysanoessa spinifera), Pacific sandlance (Ammodytes hexapterus), and capelin (Mallotus villosus). This study represents the first application of stable isotope ecology to an entire population of marine mammals. Stable isotope analysis was successfully applied to describe and improve understanding of the demographics of North Pacific humpback whales.

In the lowlands of Southeast Asia, the island of Borneo faces rates of primary forest degradation and deforestation exceeding tropical forests across the globe. For critically endangered Bornean orangutans (Pongo pygmaeus wurmbii), habitat loss greatly threatens the long-term stability of remaining populations. With rates of forest loss and fragmentation on the rise, it is critical we explore the role of anthropogenically-modified landscapes in conserving wild orangutans. Here I investigate orangutan habitat quality within Gunung Palung National Park (GPNP), in Borneo, Indonesia, focusing on the conservation value of a secondary forest with a history of logging. Orangutans in GPNP flexibly inhabit a range of habitats within the primary forest, suggesting the nearby secondary forest could provide population support if sufficient resources are available. Monthly phenology and focal follow data were utilized to assess feeding behavior in relation to food availability. While overall fruit availability was consistently higher in the primary forest, the abundance and fruiting frequency of preferred foods were significantly greater in the secondary forest. The fruiting pattern of preferred resources also significantly predicted orangutan presence. These findings suggest post-disturbance landscapes, if safeguarded and able to become secondary forest, could be vital areas of refuge for Bornean orangutans across an ever-changing landscape.

No description available.

Thesis (MSc(Conservation Ecology and Entomology)--University of Stellenbosch, 2006. / The stomachs of 286 crocodiles (17 cm to 166 cm snout to vent length) were lavaged over a two year period. Crocodylus niloticus has a similar ontogenetic shift in diet to that of other crocodilians. Yearlings predated primarily on aquatic insecta and arachnida, as crocodile size increased (juveniles) the diet became more diverse including crustacea, amphibia and fish. The largest size class (sub-adults) consumed primarily fish. Yearlings fed consistently throughout the year, however a higher proportion of empty stomachs occurred within the juvenile and sub-adult size classes during the winter months. A captive experiment with wild caught crocodiles (0.7 kg - 20 kg) indicated a decrease in satiation rate (maximum mass of food eaten as a percentage of crocodile body mass) from 11.3 % to 6.5 % with an increase in crocodile size. Wild yearlings consumed 0.48 % of their body mass in prey per day, and juveniles, 0.23 %. The wild food conversion rates of natural prey were low, 32 % and 40 % for yearlings and juveniles respectively. This was possibly due to a high percentage of indigestible (chitinous) invertebrate mass in the diet. The percentage of stomach stone mass to crocodile body mass increased with crocodile size. Seven species of nematodes were found within the stomachs, four of which represent new geographic records.

The food of the stone marten (Martes foina) was studied in synantrophic enviroment in four localities. Localities were choosen with the aim to follow an urbanization gradient from the center of the city, through its periphery to small villages. The composition of a diet was studied by non-invasive method, by analysis of faeces. Macroscopic remains of the food were divided into eleven categories (mammals, birds, bird eggs, fish, unidentified vertebrates, invertebrates, fruits, vegetative plant parts, anthropogenic material, stones and unidentified remains). 104 different animal and plant taxa were identified. There was often found anthropogenic material. Differences in the diet according the type of enviroment as well as seasonal changes were investigated by comparing of frequency of occurrence and procentual weight of remains. There were found differences between marten's food in urban and rural enviroment, especially as concerned the categories mammals, birds and fruits. Consumption of mammals follows the urbanization gradient, in urban enviroment it is the lowest, in rural localities it is higher. On the contrary, bird frequence was higher in urban environment, in rural enviroment it was lower. Weight of fruit remains was higher in rural localities than in urban ones. There were also seasonal...

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No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) PDF - Gustavo Correia de Moura.pdf: 4048269 bytes, checksum: 93440f590dbf6da5c94a68be759a0082 (MD5) Previous issue date: 2015-08-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This study aimed to analyze the drivers factors of biomass, functional diversity and fatty acids of the zooplankton community in two tropical estuaries with different trophic states (Mamanguape and Paraíba do Norte), located in Northeastern Brazil. The study was divided into two manuscripts which were sampled in dry and rainy season, as follows: Nov/2013 to Jul/2014, for the first manuscript and Dec/2014 and Jul/2014 to the second manuscript, respectively. Four sample zones were selected along each estuary and in each one were selected three sites where at each site three biotic samples (zooplankton community) and abiotic (environmental variables) were sampled. The fatty acid profiles were obtained from gas chromatography techniques from selected copepod species. In the first study, we tested whether the estuarine connectivity, the phylogenetic relationships and the local environmental conditions are the main drivers of the pattern of distribution of biomass and functional diversity of the zooplankton community. It was observed that these three components are sufficient to explain the variation in Mamanguape estuary that is located in a conservation area, and different than is commonly expected, the connectivity can provide greater explicability for the community distribution, when compared to the environmental conditions. However, the three components used were not sufficient to explain the variation in Paraíba do Norte estuary which is influenced by anthropogenic impacts. The study shows the importance of spatial variable to assess the drivers factors of biomass and functional diversity of the zooplankton community, as this part of the analysis the effects of dispersal ability of species and the physical forces acting on the system. Moreover, a thorough investigation is needed to clarify the factors that determine and shape the zooplankton communities in high impacted tropical systems. In the second study, we tested whether the profiles of fatty acids can reveal spatial and temporal changes in diet of copepods, and therefore can be used as indicators of the trophic status of estuaries. It was observed that the fatty acid composition of zooplanktonic organisms revealed seasonal and temporal variations in trophic ecology of copepods in both tropical estuaries. In addition, the profiles of fatty acids were able to reveal differences in the quality of potential food sources in the two estuaries with different levels of anthropogenic impact, with a lower quality of food sources in the most impacted system (Paraíba do Norte estuary). In this study the profiles of fatty acids were sensitive to natural and anthropogenic stresses, being a fast tool to assess the trophic status of tropical estuaries. / O presente estudo teve por objetivo analisar os fatores direcionadores da biomassa, diversidade funcional e ácidos graxos da comunidade zooplanctônica em dois estuários tropicais com diferentes estados tróficos (Mamanguape e Paraíba do Norte), localizados no Nordeste do Brasil. O estudo foi dividido em dois manuscritos os quais tiveram amostragens realizadas no período de seca e cheia, sendo: nov/2013 e jul/2014, para o primeiro manuscrito e dez/2014 e jul/2014 para o segundo manuscrito, respectivamente. Foram selecionados quatro zonas amostrais ao longo de cada estuário e em cada uma foram selecionados três pontos onde em cada ponto três amostras bióticas (comunidade zooplanctônica) e abióticas (variáveis ambientais) foram coletadas. Os perfis de ácidos graxos foram obtidos à partir de técnicas de cromatografia gasosa das espécies de copépodes selecionados. No primeiro estudo, foi testado se a conectividade estuarina, as relações filogenéticas e as condições ambientais locais são os principais direcionadores do padrão de distribuição da biomassa e diversidade funcional da comunidade zooplanctônica. Observou-se que esses três componentes são suficientes para explicar a variação no estuário Mamanguape que se localiza em uma área de conservação, e que diferente do que é comumente esperado, a conectividade pode apresentar uma explicabilidade maior na distribuição da comunidade, quando comparada às condições ambientais. No entanto, os três componentes utilizados não foram suficientes para explicar a variação no estuário Paraíba do Norte o qual sofre a influência de impactos antrópicos. O estudo mostra a importância da variável espacial para avaliar os fatores direcionadores da biomassa e diversidade funcional da comunidade zooplanctônica, visto que esta integra à análise os efeitos da capacidade de dispersão das espécies e das forças físicas que atuam no sistema. Além disso, uma investigação aprofundada é necessária para esclarecer os fatores que determinam e moldam as comunidades zooplanctônicas em sistemas tropicais muito impactados. No segundo estudo, foi testado se os perfis de ácidos graxos podem revelar mudanças espaciais e temporais na dieta de copépodos, e por conseguinte, possam ser usados como indicadores do estado trófico dos sistemas estuarinos. Foi possível observar que a composição de ácidos gráxos dos organismo zooplanctônicos revelaram variações sazonais e temporal na ecologia trófica dos copépodos nos dois estuários tropicais. Além disso, os perfis de ácidos gráxos foram capazes de revelar diferenças na qualidade das potenciais fontes de alimento nos dois estuários com diferentes níveis de impacto antrópico, com uma menor qualidade de fontes alimentares presente no sistema mais impactado (estuário do Paraíba do Norte). Nesse estudo os perfis de ácidos gráxos foram sensíveis à estresses naturais e antrópicos, mostrando ser uma ferramenta rápida para avaliar o estado trófico de estuários tropicais.

Understanding the ways in which animals utilize space and obtain food are central themes in modern ecology. Formulating broad principles and elucidating the factors explaining such patterns are limited, however, by the availability of data from a broad range of species and systems. This problem especially true of snakes, a predator group about which even the most basic natural history data are often entirely lacking, even among abundant, widespread, and ecologically-important species. I studied the natural history and ecosystem role of one such species, the fer-de-lance (Bothrops asper) in lowland rainforest in Costa Rica. B. asper is a large, cryptic pitviper that is highly abundant in many Central American ecosystems and is strongly relevant to human health due to high incidence of snakebite, yet its biology under natural conditions is almost entirely undocumented. I used radiotelemetry to quantify home range, movement patterns, habitat usage, and foraging behavior. B. asper was found to have smaller home ranges and reduced movement patterns than similarly-sized temperate pitvipers, likely due to a greater reliance upon ambush foraging in patches of high prey density. Snakes also demonstrated strong selection for swamp habitat, which may reflect efforts to exploit frogs as a primary food source due to low availability of small mammals at the study site. I subsequently addressed the trophic status of this B. asper population using a supplemental-feeding experiment. In comparison to control snakes, individuals receiving supplemental food had smaller home ranges, shorter and less frequent movements, increased mass acquisition, and shifted to primarily forest rather than swamp habitat. These results support the suggestion that B. asper at the study site are strongly food-limited. Finally, I tested the hypothesis that fer-de-lance mediate local seed-predation rates by influencing habitat usage and foraging behavior of rodents. A series of behavioral experiments conflicted with many existing studies in failing to support this idea, as three rodent species demonstrated little snake avoidance, and none of likely ecological relevance. Collectively, this dissertation represents the first comprehensive field study of Bothrops asper and is among the first for any tropical snake, and suggests several avenues for future research.

C'est dans le contexte délicat du milieu marin, marqué par l'écroulement des stocks halieutiques et la conservation urgente des espèces de prédateurs marins, que s'inscrit cette étude sur la déprédation (i.e. prélèvement des poissons capturés) par les orques et les cachalots sur la pêche à la palangre dans la ZEE de l'Archipel de Crozet. Le premier objectif a été d'évaluer les conséquences socio-économiques du phénomène. Entre 2003 et 2010 les orques ont interagi avec un total de 43,3% des palangres relevées et les cachalots avec 57,5%, les deux espèces étant présentes simultanément sur 27.8% des palangres (n =5 438). Les orques, seules ou associées aux cachalots ont été estimées prélever 926 ± 76 tonnes de légines sur l'ensemble de la période, représentant un taux de déprédation de 17,7%. Trois facteurs opérationnels ont été identifiés comme faisant varier la déprédation par les orques : i) utilisation de palangres courtes (<5 000 m) en absence d'orques, ii) déplacement du navire sur des distances supérieures à 75 km pour quitter une zone confrontée à la déprédation et changer de zone, iii) utilisation de vitesse de remontée des hameçons à bord supérieures à 50 ham.min-1. Le deuxième objectif de cette étude a été d'évaluer les conséquences démographiques de la déprédation sur la population d'orques de Crozet. Le suivi à long terme des individus a permis de mettre en évidence des réponses différentielles des unités sociales en fonction de leur degré d'interaction avec les pêcheries. En effet, les années 1990 sont d'abord marquées par une sur-mortalité des orques interagissant à des hauts niveaux avec les pêcheries, confirmant l'effet de réponses de type létales de la part des navires braconniers sur les individus. Cette tendance s'inverse à partir de 2003 avec une survie et une reproduction supérieure dans les unités à fort taux d'interaction, suggérant un effet bénéfique de la déprédation. Avec l'augmentation des cas de déprédation dans le monde, la portée de cette étude est globale, d'une part par ses résultats positifs issus d'une collaboration entre pêcheurs, gestionnaires et scientifiques, et d'autre part par la précision des priorités de conservation impliquées.

Habitat fragmentation potentiates biodiversity loss worldwide. Species preservation requires an integrated understanding of wildlife-habitat relationships; however, responses to habitat fragmentation may vary considerably as a function of the species ecological flexibility and the unique attributes of each fragment habitat. In this dissertation, I explore the behavioural and health ecology of an ecologically flexible primate, the ringtailed lemur (Lemur catta), occupying forest fragments in south-central Madagascar that differ in isolation, degree of anthropogenic pressure, and L. catta food resource structure. Anja Special Reserve is a 34 ha rocky-outcrop forest fragment that is highly isolated from other forests containing L. catta. L. catta in this reserve have access to abundant food and water resources year-round due to the introduction of non-native fruit trees and the construction of an artificial lake adjacent the reserve, which support a population density of L. catta (6.6 lemurs/ha) that is higher than at any other site in which the species has been studied. In comparison, the Tsaranoro Valley forest is a 53 ha rocky-outcrop forest fragment that is surrounded by a matrix of grassy savannah and a few anthropogenic crops. While land clearing is pronounced in the valley, a few fragments remain within range for L. catta dispersal. L. catta in this fragment have limited access to introduced or anthropogenic resources and the population density (1.13 lemurs/ha) is one-sixth that at Anja. During the late dry season of 2010 and mid- to late-wet season of 2011, I collected continuous time focal animal data to examine behavioural patterns related to habitat use (ranging, matrix use, terrestriality), activity budgets, and feeding ecology of L. catta in each fragment. In addition, I examined two health parameters, stress and endoparasitism, through the collection of fecal samples from focal individuals. I compared these variables between and within populations to examine the potential impacts of habitat fragmentation on an ecologically adaptable primate. L. catta at Anja depended on smaller home range areas and a focused diet consisting largely of introduced food resources, and correspondingly exhibited lower energy expenditure, while spending more time engaging in rest and social acitivities when compared with the Tsaranoro lemurs. In comparison, L. catta at Tsaranoro occupied large home ranges, traveled greater distances to forage in the matrix habitat surrounding the fragment, and exhibited a more broad-based dietary strategy that contained few introduced or anthropogenic resources. From a health perspective, L. catta at Anja exhibited higher stress levels throughout the study period, while L. catta at Tsaranoro exhibited a greater prevalence of endoparasites, which may be reflective of differences in the social pressures and ranging patterns of L. catta between the two fragments, respectively. These results illustrate differences in the quality of the habitats and the potential fitness consequences that the L. catta populations must cope with, with important implications regarding the long-term suitability of these fragments for sustaining these populations. Such information is integral when assessing the viability of wildlife populations in degraded landscapes and should be a primary consideration for wildlife managers in biodiversity conservation. / Graduate / 0327 / 0329 / denisegabrie@gmail.com

Freshwater mussels are the most imperiled group of freshwater invertebrates globally. Recent research suggests a better understanding of mussel feeding ecology may facilitate and improve conservation efforts. The use of stable isotopes is becoming an increasingly common method to study aquatic food webs. Carbon (C) and nitrogen (N) are two of the most frequently employed elements in food web studies. Differences in natural abundance of 13C/12C can indicate which food sources are the basal sources of carbon incorporated into a consumer’s tissue, while the ratio of 15N /14N provides a method of assessing trophic position within a food web. Attached macroalgae, including the genus Cladophora, may be the dominant primary producers in running water systems. Cladophora, however, has not yet been indicated as a prominent assimilated food source for freshwater mussels. The overall purpose of this study was to assess if the diet of two common Green River mussel species, Amblema plicata (Say) and Elliptio dilatata (Rafinesque) were influenced by the seasonal change in availability of Cladophora during a summer-autumn rapid growth period. Two specific questions were asked: 1) Are the assimilated diets different between control and treatment areas, and 2) are the assimilated diets influenced by differing Cladophora levels across the study period? A mesocosm approach was employed in order to manipulate Cladophora levels within a treatment area. Seventy-two mussels, 36 each species, were sampled across four months,twice between control (= reach-scale, heavy Cladophora cover) and treatment (= localscale removal of Cladophora) areas. The freeware program, IsoSource, a concentration weighted linear mixing model, was used to determine the potential contribution of potential food sources to the diet of both mussel species. IsoSource revealed that Cladophora was the primary assimilated food source for both species across the study period. Although assimilated diets were not different between control and treatment areas, diets were, however, influenced by Cladophora availability across time. The results of this study indicate that, during bloom conditions, Cladophora is the primary carbon source for both A. plicata and E. dilatata and may form the base of food webs in the upper Green River.