A quebra de frutos encapsulados por macacos-prego com o auxílio de ferramentas é tipicamente objeto de observação e scrounging por coespecíficos, bastante tolerados e em geral mais jovens e menos proficientes. O presente estudo teve como objetivo examinar o processo de escolha, pelos observadores, dos alvos de observação, e se esta escolha pode otimizar as oportunidades de scrounging. A pesquisa foi realizada com um grupo de macacos-prego selvagens (Cebus libidinosus) na Fazenda Boa Vista (Piauí - Brasil), numa área de ecótono cerrado/caatinga. A partilha de alimento fora dos episódios de quebra de cocos e o uso de ferramentas para a quebra de outros itens alimentares encapsulados também foram abordados. Indivíduos de todas as classes de idade e sexo se envolveram na observação da quebra de cocos, havendo uma grande variação individual. Nossas análises mostram que os macacos preferencialmente escolhidos como alvos de observação foram aqueles que apresentaram maior Freqüência, Proficiência e Produtividade na quebra de cocos. Apesar de haver interações agonísticas durante os eventos de observação, os alvos se mostram muito tolerantes à observação e ao scrounging - 25% dos episódios de quebra são observados e mais da metade destes eventos de observação resultam em scrounging. Os observadores tiveram a oportunidade de comer os restos dos cocos e de manipular os itens do sítio de quebra. Estas observações reforçam a noção de que as condições e possibilidades vivenciadas pelo observador-scrounger otimizam as oportunidades para que ocorram processos de aprendizagem socialmente mediada, ao menos por realce de estímulo. Tal exposição próxima ao comportamento do alvo poderia influenciar aspectos mais finos do comportamento dos observadores, ao longo de sua história de aprendizagem. O presente estudo aborda estas interações entre manipuladores de ferramentas e observadores/scroungers pela primeira vez em uma população selvagem e discute as semelhanças e discrepâncias em relação aos resultados anteriormente obtidos com uma população em semil-liberdade. / The tool-aided cracking of encapsulated fruit by capuchin monkeys is a frequent target of observation and scrounging by conspecifics, well-tolerated and usually younger and less proficient. The present study aimed to examine the process of observational targets choice by the observers, and whether this choice can optimize scrounging opportunities. The research was conducted with a group of wild bearded capuchin monkeys (Cebus libidinosus) in Fazenda Boa Vista (Piauí, Brazil), in an ecotone area between cerrado and caatinga savanna-like environments. Food sharing in contexts other than nut cracking, as well as the use of tools to crack open other food items were also analyzed. Individuals from all age and sex classes were involved in nut cracking observation. Our analyses show that the monkeys preferentially chosen as observational targets were the ones exhibiting the greater Frequency, Proficiency, and Productivity in nut cracking. In spite of a few agonistic interactions during observation events, the targets tend to be very tolerant to observation and to scrounging (25% of the nut cracking events are observed, and more than half of these resulted in scrounging). The observers had the opportunity of eating nuts leftovers and of manipulating items from the cracking sites, both in the presence and in the absence of the targets. These findings strengthen the idea that the conditions and possibilities experienced by the observers-scroungers optimize the opportunities for socially biased learning processes, at least by stimulus enhancement. Such close exposure to the targets behavior could also influence finer details of the observers behavior in the long run. The present study is the first one to deal with these interactions between tool manipulators and observers/scroungers in a wild population and discusses the similarities and differences from previous observations from a semi-free population.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / A range of behavioral strategies and sensory abilities allow animals to minimize costs involved in the search for food. Among the factors involved in the variation of foraging costs, the availability of resources represents a central role and it is recognized for modulating the animal home range. Some species of termites can exhibit characteristics that make the foraging process even more expensive. Species belonging to the genus Nasutitermes, for example, have an extra cost in foraging: in addition to build a network of tunnels to access resources, they have a large number of soldiers, a caste trophically dependent. In the present study: (i) we evaluated the foraging pattern in Nasutitermes aff. coxipoensis (Termitidae: Nasutitermitinae), including the searching strategy and the role of soldiers; and (ii) we analyzed whether colonies of this species responds to variations in the availability of food resources. Manipulative experiments were conducted in the field and in the laboratory to analyze the pattern of foraging in N. aff. coxipoensis. For this, 35 nests were transplanted into areas of dunes in Pirambu-SE. Seven plots were established in a continuous increament in the density of resources (sugarcane baits). Laboratory tests were conducted to examine the role of chemical signals (eg. trail pheromone) present in the sternal gland of workers and soldiers. During 10 consecutive days it was measured: the number of trails and tunnels, their total length, number of branches and the tunneling speed (cm/day). Data were analyzed using generalized linear models and mixed linear models. Nasutitermes aff. coxipoensis showed mainly nocturnal foraging. Soldiers were the first individuals to start the foraging, however, in established trails, the number of workers were always higher than soldiers. The number of active trails remained constant over the observation period, while the number of tunnels increased. In groups of soldiers and workers, the workers chose to follow the trail signals of soldiers. The number of trails, the total length and their branches decreased with increment of resource availability. The conversion of trails in tunnels increased in areas with higher resource density. Our results suggest that the costs involved in the production of soldiers in N. aff. coxipoensis seem to be compensated by their decisive role during the foraging process. Colonies of this species seem to optimize their foraging through a combined strategy of constructing trails and tunnels. In places with low resource availability, termites forage mainly on trails, avoiding to convert trails in tunnels. This strategy has not yet been reported in the literature. Thus, N. aff. coxipoensis presents strategies in order to optimize the foraging, minimizing costs involved in this process. These results can contribute to the key question about the evolution of termite foraging behavior, as well as to understand the mechanisms involved in the distribution patterns and structuring communities of these insects. / Uma gama de estratégias comportamentais e habilidades sensoriais permite aos animais minimizar os custos envolvidos na busca por alimento. Dentre os fatores envolvidos na variação dos custos de forrageio, a disponibilidade de recursos representa um papel central e é reconhecida por modular as áreas de uso dos animais. Algumas espécies de cupins exibem características que podem tornar o processo de forrageio ainda mais oneroso. Espécies do gênero Nasutitermes, por exemplo, apresentam gastos extras no forrageio, uma vez que além de construírem uma rede de túneis para acessar os recursos, ainda apresentam um elevado número de soldados, indivíduos troficamente dependentes. No presente estudo, avaliamos (i) o padrão de forrageio em Nasutitermes aff. coxipoensis (Termitidae: Nasutitermitinae), incluindo as estratégias de busca e o papel dos soldados; e (ii) analisamos se colônias desta espécie respondem à variação na disponibilidade de recursos. Experimentos manipulativos foram conduzidos em campo e em laboratório a fim de analisar o padrão de forrageio de N. aff. coxipoensis. Para isso, 35 ninhos foram transplantados em áreas de dunas, em Pirambu- SE. Foram estabelecidas sete parcelas em um contínuo de aumento da densidade de recursos (iscas de cana-de-açúcar). Testes em laboratório foram realizados a fim de analisar o papel dos sinais químicos (ex. feromônio de trilha) presente na glândula esternal de operários e soldados. Durante 10 dias consecutivos foram quantificados: o número de trilhas e de túneis, o comprimento total, o número de ramificações destes e a velocidade de construção dos túneis. Os dados foram analisados utilizando-se modelos lineares generalizados e modelos mistos. Nasutitermes aff. coxipoensis apresentou forrageio principalmente noturno. Soldados foram os primeiros indivíduos a iniciarem o forrageio, no entanto, em trilhas já estabelecidas, o número de operários foi sempre maior do que o de soldados. O número de trilhas ativas permaneceu constante ao longo do período de observação, enquanto o número de túneis aumentou de forma gradativa. Em grupos compostos por soldados e operários, os operários preferiram seguir os sinais de trilha dos soldados. O número de trilhas, o comprimento total e suas ramificações reduziram com o aumento da disponibilidade de recursos. A conversão de trilhas em túneis aumentou em locais com maior densidade de recursos. Nossos resultados sugerem que os custos envolvidos na produção de soldados de Nasutitermes aff. coxipoensis parecem ser compensados pelo seu papel decisivo no forrageio. Colônias desta espécie parecem otimizar o forrageio através de uma estratégia combinada de formação de trilhas e túneis. Em locais com baixa disponibilidade de recursos os cupins forrageiam preferencialmente em trilhas, evitando a conversão destas em túneis. Tal estratégia, ainda não foi relatada na literatura. Assim, N. aff. coxipoensis apresenta estratégias para otimização do forrageio, minimizando os custos envolvidos nesse processo. Os resultados deste estudo podem contribuir para a investigação de questões sobre evolução do comportamento de forrageio de cupins, assim como para desvendar os mecanismos envolvidos nos padrões de distribuição e estruturação de comunidades desses insetos.

En raison des changements climatiques actuels, il est primordial de comprendre comment les écosystèmes vont réagir et tout particulièrement comment les chaînes trophiques vont être impactées. Pour cela, le comportement des oiseaux marins peut être utilisé comme des indicateurs des changements se déroulant au sein de l’écosystème. Cependant, un des défis actuels dans l’étude du comportement animal est d’identifier comment la structure temporelle du comportement est dépendante des conditions intrinsèques et extrinsèques et comment la complexité de cette organisation comportementale évolue sur un gradient allant de la stochasticité au déterminisme en fonction des changements environnementaux. Ma thèse a donc pour objectif d’étudier si un comportement complexe est adapté pour faire face à une perturbation du système chez les oiseaux marins et plus particulièrement chez deux espèces de manchots étant exposées à des changements environnementaux. / Due to ongoing climate change, it is necessary to understand how ecosystems will react and more particularly, how species may cope with the challenges of living in unstable systems. Seabirds’ behavior provides a way to monitor changes occurring in the marine environment, but identifying how the temporal structure and complexity of behavior depend on intrinsic and extrinsic parameters are underexplored topics in the field of animal behavior. My thesis aims to investigate if behavioral organization, through a gradient of stochasticity-determinism complexity, allows little and adélie penguins to buffer changes in the environment under a fractal analysis approach.

La forte hétérogénéité de l'écosystème marin se traduit par une production inégale des ressources sur un large éventail d'échelles spatio-temporelles, qui conditionne par conséquent les déplacements des tortues marines. Considéré comme l’un des plus dynamiques au monde, le plateau des Guyanes est une région très complexe d'un point de vue océanographique et qui héberge trois des sept espèces de tortues marines présentes dans le monde (la tortue olivâtre, la tortue verte et la tortue luth). L'objectif de cette thèse était de comprendre comment les contraintes océanographiques peuvent-elles influencer les déplacements en mer de ces trois espèces. Le déploiement de 55 balises satellites sur des femelles reproductrices en Guyane française a permis de fournir des informations sur leurs trajectoires, sur leur comportement de plongée et sur les caractéristiques de leur environnement. Notre étude a mis en évidence une forte plasticité comportementale interspécifique qui semble être principalement dictée par les traits reproducteurs, les stratégies de reproduction, les conditions locales de l'habitat ou encore les adaptations physiologiques. / The strong heterogeneity of the marine ecosystem leads to a patchy distribution of the resources in time and space, shaping therefore the movements of sea turtles. Considered as the most dynamic ecosystem in the world, the Guiana shield is a highly dynamic system which hosts three of the seven sea turtle species in the world (the olive ridley, the green turtle and the leatherback turtle). The aim of this thesis was to understand how the oceanographic constraints can influence the at-sea movements of these three species during the reproduction and the migration phases. The deployment of 55 satellite tags on adult females in French Guiana provided information on their trajectories, their diving behavior and on the environment encountered. Our study shows a strong behavioral plasticity between species, which seems to be mainly dictated by the reproductive traits and strategies, the local conditions of the habitat and the physiological adaptations.

Made available in DSpace on 2014-06-11T19:35:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-05-26Bitstream added on 2014-06-13T19:25:11Z : No. of bitstreams: 1 bianconi_gv_dr_rcla.pdf: 2615245 bytes, checksum: e626d43cffce5b3b04c96086c87decdf (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Filostomídeos frugívoros são considerados elementos-chave na conservação e restauração florestal dado à sua representatividade numérica (espécies e indivíduos), alto potencial de deslocamento e eficiência na dispersão de sementes. Técnicas que potencializem esse papel ecológico podem ter grande aplicação na recuperação de hábitats degradados, comuns à Mata Atlântica brasileira. Estudos com óleos essenciais isolados de frutos quiropterocóricos maduros sugeriram que eles podem ser utilizados para atrair e capturar morcegos frugívoros no interior de áreas florestais. Assim, a presente tese foi desenvolvida para fundamentar o caráter prático-funcional desta nova ferramenta, na medida em que se propôs a investigar os movimentos e o uso do hábitat fragmentado por espécies frugívoras, bem como as suas respostas a atrativos odoríferos instalados na matriz agropecuária de uma paisagem intensamente fragmentada no sul do Brasil (municípios de Fênix e São Pedro do Ivaí, estado do Paraná). Seus resultados indicaram uma atração altamente significativa dos morcegos aos óleos, um elevado potencial de dispersão de um grande número e diversidade de propágulos, e a possibilidade de manter os indivíduos por algum tempo sobrevoando pontos específicos da matriz, o que incrementaria, sobremaneira, a chuva-de-sementes no local. Os métodos de marcação/recaptura e radiotelemetria demonstraram existir uma alta mobilidade de Artibeus lituratus (Olfers, 1818) e Carollia perspicillata (Linnaeus, 1758), morcegos frugívoros mais comuns na região, dentro e entre os remanescentes florestais, com a utilização conjunta de diferentes elementos da paisagem (fragmentos, matriz agropecuária, pomares, rios, etc.). A matriz agropecuária da região parece não inibir os deslocamentos das espécies, padrão este relevante para o processo de dispersão de sementes e para a eficácia... / Frugivorous phyllostomids are considered key elements to forest conservation and restoration due to their representative number (species and individuals), high mobility, and efficiency as seed dispersers. Techniques to improve this ecological role can find great application in the recovery of degraded habitats, usually found in the Brazilian Atlantic Forest. Previous tests with essential oils from ripe chiropterochoric fruits suggested they can be used to attract and capture fruit-eating bats inside forest remnants. The present thesis was conducted to provide the basis to functional and practical characteristics of this new tool. Thus, we investigated the movements and use of a fragmented habitat by frugivorous species, as well as bats’ response to odor attractives installed in the agropecuary matrix of an extremely fragmented field at South Brazil (city of Fênix and São Pedro do Ivaí, State of Paraná). The results indicate a significant bat attraction to the essential oils, a great potential for dispersion of a large number and diversified seeds, the possibility of keeping bats flying for some time over specific locations of the matrix, which can increase significantly seeds dispersion in specific spots. By using mark/recapture and radiotelemetry techniques we observed high mobility of Artibeus lituratus (Olfers, 1818) and Carollia perspicillata (Linnaeus, 1758), the most common frugivorous bats in the study region , inside and between forests remnants with the combined use of different habitat attributes (fragments, agropecuary matrix, orchards, rivers, etc.). So, the regional agropecuary matrix does not seem to inhibit the movement of the species, which is an important behavior for seed dispersal and for the efficacy of the tool used for restoration of degraded areas.

Made available in DSpace on 2014-12-17T15:36:35Z (GMT). No. of bitstreams: 1 KellyCAP.pdf: 2804234 bytes, checksum: e14a879efe151d80522174c9403f357e (MD5) Previous issue date: 2009-02-13 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / This study investigated factors that influence the group size during the behavior foraging of estuarine dolphin Sotalia guianensis in the coast south of the state Rio Grande do Norte (RN), it also characterized the diet of estuarine dolphins and elaborated an otoliths catalog for aid in the identification of the preys found in the stomach contents. In relation to the group size during behaviour foraging, inside of the Curral Bay, larger frequency of solitary hunt was observed. Factors as tide variation, group composition and seasons didn't present correlation with the number of animals observed during a feeding episode. Capture success for participant was shown significantly larger when the animals hunted alone, what possibly explains the largest frequency of solitary hunt inside of the Curral Bay. About diet, were identified 18 bone fishes species, with predominance of species the families Haemulidae and Sciaenidae and five cephalopods species, including two new species in the diet of Sotalia guianensis in Brazil. Our results indicated that estuarine dolphin in the coast oriental from Rio Grande do Norte (RN) feeds predominantly of fish that form shoal, of habitat estuarino and producing of sounds. The analysis of the images, otoliths of 43 species of coastal fish of the coast of the state of Rio Grande do Norte (RN), aided by the offered descriptions, demonstrated to be an effective methodology for the knowledge of those structures, as well as it represented a form of reducing the subjectivity in the identification of the bone fishes found in stomach content / Esse trabalho investigou os fatores que influenciam o tamanho de grupo durante o comportamento alimentar do boto cinza Sotalia guianensis no litoral sul do estado do Rio Grande do Norte (RN), tamb?m caracterizou a dieta dessa esp?cie na regi?o e elaborou um cat?logo de ot?litos para auxiliar ? identifica??o das presas encontradas nos conte?dos estomacais dos animais analisados. Em rela??o ao tamanho de grupo durante o forrageio, dentro da enseada do curral, foi observado maior freq??ncia de ca?a solit?ria. Fatores como varia??o de mar?, composi??o de grupo e esta??es do ano n?o apresentaram correla??o com o n?mero de animais observados durante um epis?dio de alimenta??o. Contudo, o sucesso de captura por participante mostrou-se significativamente maior quando os animais ca?avam sozinhos, o que possivelmente explica a maior freq??ncia de ca?a solit?ria dentro dessa enseada. Sobre a caracteriza??o da dieta, foram identificadas 18 esp?cies de tele?steos, com predomin?ncia de esp?cies pertencentes ?s fam?lias Haemulidae e Sciaenidae e cinco esp?cies de cefal?podes, incluindo duas esp?cies ainda n?o registradas na dieta de Sotalia guianensis no Brasil. De acordo com as informa??es sobre a dieta, o boto cinza no litoral oriental do Rio Grande do Norte (RN) alimenta-se predominantemente de peixes que formam cardume, de habitat estuarino e produtores de sons. A an?lise das imagens dos ot?litos de 43 esp?cies de peixes costeiros do litoral do estado do Rio Grande do Norte (RN) demonstrou ser uma metodologia eficaz, bem como representou uma forma de diminuir a subjetividade na identifica??o dos tele?steos encontrado em conte?do estomacal

Made available in DSpace on 2014-12-17T15:36:35Z (GMT). No. of bitstreams: 1 LeonardoBR_TESE_Cap_II_III.pdf: 677404 bytes, checksum: 247b1251f8d1d16cb41bf4f8ec2f3c18 (MD5) Previous issue date: 2010-03-19 / Universidade Federal do Rio Grande do Norte / This study evaluated the spatial, time and alimentary niches of Tropidurus hispidus and Tropidurus semitaeniatus in sympatry in a caatinga of Rio Grande do Norte, Brazil, as well as their foraging and termoregulatory behaviors, the activity body temperature and their reproductive and fat body cycles. Monthly excursions, from October 2006 to May 2008, were conducted at the Ecological Station of the Serid? (ESEC Serid?), Serra Negra do Norte municipality, using specific methodology for investigation of the aforementioned objectives. The two species presented similarities in space niche use, mainly in rocky habitat, however they differed in vertical microhabitat use with T. hispidus using a larger vertical microhabitat range. In the dry season the time of activity of both species was bimodal. In the wet season T. semitaeniatus showed a unimodal activity period, while T. hispidus maintained an bimodal activity period. In terms of importance in the diet, to both species, Hymenoptera/Formicidae and Isoptera predominated during the dry season. In the wet season, although Hymenoptera/Formicidae had larger importance among the prey items, lizards opportunistically predated on Lepidoptera larvae, Coleoptera larvae/adults and Orthoptera nymphs/adults. The foraging intensity revealed differences between the species, mainly in the wet season, when T. semitaeniatus was more active than T. hispidus. The mean activity body temperature of T. semitaeniatus was significantly higher than that of T. hispidus. The thermoregulatory behavior showed that during the dry season T. hispidus and T. semitaeniatus spent more time in shade or under filtered sun. In the wet season, T. hispidus did not show differences in the amount of time spent among the light exposure locations, however T. semitaeniatus spent most of their time exposed to direct sun or filtered sun. The reproductive cicle of T. hispidus and T. semitaeniatus occurred from the middle of the dry season to the beginning of the wet season. In both species, female reproductive activity was influenced by precipitation, whereas males exhibited spermatozoa in their testes throughout the year, and their reproductive activity was not related with any of the climatic variables analysed. In the two species, the fat storage varied inversely with reproductive activity, and there was no difference in fat body mass between females and males. We concluded that the segregation between T. hispidus and T. semitaeniatus in this caatinga area occurs in vertical space use, in the largest vagility of T. hispidus in microhabitat use and larger range size of their alimentary xviii items. Additionally, significant seasonal differences in relation to the activity period, body temperature, and foraging and termoregulatory behaviors between these two Tropidurus species facilitate their coexistence. / Este estudo avaliou o uso dos recursos espacial, temporal e alimentar por Tropidurus hispidus e Tropidurus semitaeniatus em simpatria em uma caatinga do Rio Grande do Norte, Brasil, bem como seus comportamentos de forrageamento e termorregulat?rio, suas temperaturas corp?reas em atividade e seus ciclos reprodutivos e de gordura corp?rea. Excurs?es mensais, de outubro de 2006 a maio de 2008, foram realizadas ? Esta??o Ecol?gica do Serid? (ESEC Serid?), munic?pio de Serra Negra do Norte, com utiliza??o de metodologia espec?fica para a investiga??o dos objetivos acima mencionados. As duas esp?cies apresentaram similaridades no uso do nicho espacial, especialmente no h?bitat rochoso; contudo, elas diferiram no uso vertical do micro-h?bitat com T. hispidus usando uma faixa vertical maior do micro-h?bitat. Na esta??o seca o per?odo de atividade de ambas as esp?cies foi bimodal. Na esta??o chuvosa, a atividade de T. semitaeniatus mostrou um per?odo unimodal, enquanto T. hispidus manteve uma atividade bimodal. Em termos de import?ncia na dieta, para ambas as esp?cies, os Hymenoptera/Formicidae e Isoptera predominaram na esta??o seca. Na esta??o chuvosa ainda que os Hymenoptera/Formicidae continuaram a ter maior import?ncia entre os itens alimentares, os lagartos predaram oportunisticamente larvas de Lepidoptera, larvas/adultos de Coleoptera e ninfas/adultos de Orthoptera. A medida de intensidade de forrageamento revelou diferen?as entre as esp?cies, especialmente na esta??o chuvosa, quando T. semitaeniatus foi mais ativo do que T. hispidus. A temperatura corp?rea m?dia em atividade de T. semitaeniatus foi significativamente superior a de T. hispidus. O comportamento termorregulat?rio mostrou que, durante a esta??o seca, T. hispidus e T. semitaeniatus gastaram mais tempo expostos ? sombra ou sob sol filtrado. Na esta??o chuvosa, T. hispidus n?o mostrou diferen?as no tempo gasto entre os locais de exposi??o ? luz, contudo T. semitaeniatus esteve a maior parte de seu tempo exposto ao sol ou sob sol filtrado. A reprodu??o de T. hispidus e T. semitaeniatus ocorreu entre a metade da esta??o seca e o in?cio da esta??o chuvosa. Em ambas as esp?cies, a atividade reprodutiva das f?meas foi influenciada pela precipita??o, enquanto os machos apresentaram espermatoz?ides nos test?culos ao longo de todo o ano, e sua atividade reprodutiva n?o foi relacionada com nenhuma das vari?veis clim?ticas analisadas. O estoque de gordura corp?rea variou inversamente com a atividade reprodutiva nas duas esp?cies, e n?o houve diferen?a entre f?meas e machos quanto a massa dos corpos adiposos. Conclu?mos que xvi a segrega??o entre T. hispidus e T. semitaeniatus nesta ?rea de caatinga ocorre no uso vertical do espa?o, na maior vagilidade de T. hispidus na utiliza??o de micro-h?bitats e maior amplitude de tamanho de seus itens alimentares. Adicionalmente, diferen?as sazonais significativas em rela??o ao per?odo de atividade, temperatura corp?rea, e comportamentos de forrageamento e termorregulat?rio entre essas duas esp?cies de Tropidurus, possibilitam a coexist?ncia.

The microbiome plays a key symbiotic role in maintaining host health and aids in acquiring nutrients, supporting development and immune function, and modulating behavior. However, more research is needed to elucidate the potential impact of environmental pollutants on host microbial communities and how microbiomes can modulate the toxicity of contaminants to the host. Through a literature review of 18 studies that assessed the impacts of various anthropogenic chemicals on fish-associated microbiomes, we found that toxicants generally decrease microbial diversity, which could lead to long-term health impacts if chronically stressed, and can increase the host’s susceptibility to disease as well as the chemical resistance of certain microbes. These findings led us to explore the impacts of one of the reviewed contaminants, polycyclic aromatic hydrocarbons (PAHs), typically found in oil. The Deepwater Horizon disaster of April 2010 was the largest oil spill in U.S. history and had catastrophic effects on several ecologically important fish species in the Gulf of Mexico (GoM). This study tested the hypotheses that exposure to weathered oil would cause significant shifts in fish gut-associated microbial communities, with taxa known for hydrocarbon degradation increasing in abundance and that foraging behavior would decrease, potentially due to microbial dysbiosis via the gut-brain axis. We characterized the gut microbiome (with 16S rRNA gene sequencing) of a native GoM estuarine species, the sheepshead minnow (Cyprinodon variegatus). Fish were exposed to High Energy Water Accommodated Fractions (HEWAF; tPAH = 80.99 ± 12.5 μg/L) of oil over a 7-day period and whole gastrointestinal tracts were sampled for microbiome analyses. A foraging behavioral assay was used to determine feeding efficiency before and after oil exposure. The fish gut microbiome did not experience any significant changes in alpha or beta diversity but known hydrocarbon degrading taxa were noticeably present in oil-exposed communities and were absent in controls. We found the order Pseudomonadales, the family Paenibacillaceae, and Pseudomonas pachastrellae to be among these, with Pseudomonadales increasing in abundance. Foraging behavior was not significantly affected by oil exposure. This work highlights the need for further research to elucidate the functional metagenomic responses of the fish gut-microbiome under oil spill conditions.

During the summers of 2007-2009, I studied the population growth and reproductive and foraging ecology of the Razorbill (Alca torda) at Matinicus Rock (MR), Maine. This medium-sized marine bird in the family Alcidae (auks) was extirpated from the Gulf of Maine in the late 19th century by hunting, collecting, and colony disturbance. Following legislation protecting seabirds and their nesting habitats, the Razorbill has recolonized probable former nesting habitat in the Gulf of Maine during the past several decades. Six small colonies comprise the Maine population, which is listed as threatened and forms the southern extension of the species breeding distribution. In Chapter 1, I present a population model of the MR breeding colony, based on studies of population growth and reproductive success, and supplemented with previously collected data from the National Audubon Society Seabird Restoration Program (Project Puffin), with whom I collaborated. I also describe chick diet (supplemented with Project Puffin data) and draw connections between diet and reproductive success. I found that reproductive success was too low to account for the observed population growth rate, and conclude that the colony is a sink population supported by substantial immigration. Because annual fledging success was positively associated with prey quality, I suggest that substandard chick diet may contribute to the sink population dynamic via diet-driven depressed fledging success. In Chapter 2, I report on the foraging behavior of chick-rearing Razorbills fitted with bird-borne data-loggers at MR in 2008-2009. I describe diving behavior including depth, duration, and profile shape of dives, as well as diel patterns. Diving activity was restricted to daylight hours, and dives were shallowest and most frequent in the evening. Though generally similar to diving behavior reported at four European and Canadian colonies, Razorbills at MR performed three times as many dives per day as at the Gannet Islands, Labrador, and the mean dive depth was greater than three of four previous studies. Deeper and more frequent dives may indicate higher foraging effort and lower prey availability. Reproductive success would suffer if parents cannot buffer chicks against the effects of low prey availability through increased foraging effort or other behavioral modifications. Together, the pieces of our research indicate that prey availability may be negatively affecting reproduction and population growth at MR. Rapid colony growth cannot be explained by local reproductive success, and is likely the result of substantial immigration from other colonies. Chick diet is varied and includes multiple high-quality forage fish species, yet chicks also consume poor-quality prey (larval fish and euphausiids) that may signal periods of very poor prey availability. Frequency and depth of dives made by chick-provisioning adults are also suggestive of parents allocating extra effort to foraging, relative to other colonies.

Body size explains much of the interspecific variation in the physiology, behavior, and morphology of birds, such as metabolic rate, diet selection, intake rate, gut size, and bill size. Based on mass-specific metabolic requirements and relative energetic costs of activities, being a certain body size has both advantages and disadvantages. In particular, avian herbivores such as geese possess a relatively simple digestive system, consume foods with low digestibility and poor nutrient content, and have increased energetic demands compared to other bird taxa; therefore, any effects of body size on foraging strategies should be readily apparent in this foraging guild. The influence of body size on the behavior and management of Canada Geese (Branta canadensis) and Cackling Geese (B. hutchinsii) as avian herbivores has not been well studied. My dissertation explores the role of body size in comparative foraging behavior, habitat selection, and winter conservation planning for two congeneric geese, the Dusky Canada Goose (B. c. occidentalis; hereafter Duskys) and the Cackling Goose (B. h. minima; hereafter Cacklers). These two taxa share the same over-winter foraging environment (grass seed fields) in the same restricted geographic area (the Willamette Valley) during winter. Duskys and Cacklers differ by more than a factor of two in body size and have different relative bill sizes and social organization. Because of smaller body size, Cacklers have greater relative energy demands and less fasting endurance compared to Duskys; however, Cacklers have comparatively low energetic costs for flight and transport. Duskys, however, have higher total energy requirements than Cacklers. Additionally, Cacklers form large, high-density flocks and have a total over-wintering population size in the study area of about 200,000. Duskys occur in relatively small family groups and have a total over-wintering population size of about 13,000. My study demonstrated that interspecific differences in body size between Cacklers and Duskys was associated with differences in foraging behavior, movements, and habitat selection. Cacklers foraged a greater percentage of time (30%) in all habitats and across the entire winter compared to Duskys. Cacklers had higher peck rates (up to 100 pecks min⁻¹ greater) than Duskys in all foraging habitats expect pasture. The pecking rate of Cacklers was greatest in fields of young grass (200 pecks min⁻¹), which may indicate that Cacklers had relatively high intake rates in this foraging habitat. Based on differences in foraging behavior among habitats, Cacklers may have the foraging strategy of energy intake maximizers, whereas the foraging strategy of Duskys is more towards time-energy expenditure minimizers, at least for part of the winter. Cacklers moved across the landscape very differently from Duskys, exhibiting less site fidelity and greater commuting distances to foraging areas. Cacklers showed a preference for young grass during all periods of the winter, reaffirming that Cacklers are specialized grazers on short green forage, whereas Duskys preferred young grass and pasture. Fields of young grass were the preferred foraging habitat of Cacklers, had less standing crop biomass, and may have enabled higher foraging efficiencies, which may have led to higher intake rates. The ability of the landscape to support wintering geese changed across the winter because total available plant biomass fluctuated with the rate of grass regrowth. The estimated carrying capacity of the landscape for geese decline by almost one-half during mid-winter (mid-December to mid-February) compared to early winter or late winter periods. Although Cacklers have lower individual energy requirements compared to Duskys, due to a much larger target population size, Cacklers required 89% more foraging habitat than Duskys. Forage requirements encountered a bottleneck during mid-winter, when grass regrowth rates were low and day length was short. Commensurate with this pattern of forage availability, goose body condition declined during the mid-winter period. To support Pacific Flyway target populations for geese, approximately 18,000 ha of total grazing habitat in young and mature grass is needed in the Willamette Valley to support a total over-wintering population composed of 340,000 geese belonging to four subspecies. The role of body size in influencing the foraging behavior and decisions of over-wintering geese has important implications for conservation planning of goose populations. Small-bodied Cacklers are selective in field choice, yet more likely to redistribute across the landscape. Disturbances (e.g., hunting, hazing, or predation) will have a disproportionate effect on the movements of smaller-bodied geese compared to larger geese. These characteristics of Cacklers will make conservation planning to retain geese on public land more difficult. Coordinated management with private landowners and farming practices that maximize preferred goose foraging habitat on public lands may attract geese to utilize protected areas and minimize conflicts with agriculture in the Willamette Valley. Availability of resources during critical periods in winter is an important factor affecting the distribution of geese, but may affect small and large bodied geese differently. Management could be targeted during these critical time periods. By considering the role of body size in the context of life history characteristics, foraging behavior and habitat selection, appropriate management strategies can be developed and implemented to reduce the effects of agricultural depredation by geese, while promoting the future conservation of wintering geese in the Willamette Valley. / Graduation date: 2013