This thesis addresses the mechanisms regulating the evolution and maintenance of colour polymorphism in the shrimp Hippolyte obliquimanus. It includes four chapters that illustrate, in an integrative approach, the ecological and behavioural consequences of different camouflage and habitat use strategies selected in main colour morphs. In the first chapter entitled Camouflage through colour change: mechanisms, adaptive value, and ecological significance, the physiological and structural mechanisms underpinning colour change, and hence camouflage, in different species were detailed within a general framework. Also in this section, both the adaptive value and the ecological and evolutionary implications of these processes were discussed. In the second chapter entitled Shape, colour plasticity, and habitat use indicate morph-specific camouflage strategies in a marine shrimp morph-specific colour change and habitat selection were investigated as potential mechanisms affecting camouflage efficiency and the natural distribution of H. obliquimanus colour morphs between macroalgal habitats formed by Sargassum furcatum and Galaxaura marginata. Moreover, morph-specific morphology and behavioural traits were also assessed. Shrimp showing a homogeneous coloration (H) changed colour when placed in colour-mismatching backgrounds and also exhibited a more robust shape associated to high substrate fidelity and specialization. On the other hand, striped translucent shrimp (ST) were not capable of colour change and showed high mobility, consistent with a more streamlined shape and a generalised use of algal habitats. In the third chapter entitled The adaptive value of camouflage and colour change in a polymorphic shrimp visual models and predation trials were used to test the adaptive value of camouflage and colour change of H. obliquimanus colour morphs against colour-contrasting macroalgae, which provide different levels of colour concealment. The low colour discrimination predicted by a visual model of a seahorse predator for pink shrimp against the red weed Galaxaura was directly translated to lower detection and consumption rates on this morph by captive seahorses in a laboratory experiment, demonstrating the high adaptive value of camouflage in this species. Finally, in the fourth chapter entitled Habitat-dependent niche partitioning between colour morphs of the algal-dwelling shrimp Hippolyte obliquimanus the trophic ecology of H and ST morphs when using Sargassum and Galaxaura habitats were assessed through stable isotope analysis. Morphs showed different isotopic signatures only in Galaxaura, where the supply of food resources are limiting, leading to a tropic niche diversification between H and ST shrimp and a probable relaxation of intra-specific competition. Conversely, in Sargassum, where resources are abundant, morphs coexistence is possible even without niche partitioning. Altogether, the results of this thesis contributed to a better understanding of the adaptive value and the underlying mechanisms controlling for the maintenance of colour polymorphism in H. obliquimanus. From both an ecological and evolutionary perspective, morph-specific strategies of camouflage and habitat use likely promote the stability of shrimp populations in a spatially heterogeneous and markedly seasonal habitat. / Esta tese aborda os mecanismos que regulam a evolução e manutenção do polimorfismo de cor no camarão Hippolyte obliquimanus ao longo de quatro capítulos que ilustram de forma integrada as consequências ecológicas e comportamentais das distintas estratégias de camuflagem e de uso do habitat selecionadas nos principais morfótipos da espécie. No Capítulo 1, intitulado Camouflage through colour change: mechanisms, adaptive value, and ecological significance, são detalhados de maneira geral os mecanismos fisiológicos e estruturais responsáveis pelo processo de mudança de cor e obtenção de camuflagem em diferentes espécies de animais. Nessa seção também é detalhado o valor adaptativo e as implicações ecológicas e evolutivas desses processos. No Capítulo 2, intitulado Shape, colour plasticity, and habitat use indicate morph-specific camouflage strategies in a marine shrimp, são investigados os processos de mudança de cor e de seleção de habitat como possíveis mecanismos reguladores dos padrões de camuflagem e de distribuição dos morfótipos de cor de H. obliquimanus entre os bancos das algas Sargassum furcatum e Galaxaura marginata. Além disso, também são avaliadas diferenças morfológicas e comportamentais entre os morfótipos na utilização dos habitats vegetados. Camarões caracterizados por uma coloração homogênea (H) mudam de cor quando em contato com substratos de coloração diferente à sua, exibindo também uma morfologia mais robusta e um comportamento de alta fidelidade e especialização aos substratos de macroalgas. Por outro lado, camarões transparentes listrados (TL) não mudam de cor e apresentam elevada mobilidade, consistente com uma morfologia mais hidrodinâmica e com uso mais generalizado dos habitats estudados. No Capítulo 3, intitulado The adaptive value of camouflage and colour change in a polymorphic shrimp, são utilizados modelos visuais e experimentos de predação para testar o valor adaptativo da camuflagem e mudança de cor em diferentes morfótipos do camarão H. obliquimanus quando estes estão associados a macroalgas que fornecem diferentes graus de semelhança cromática. O baixo grau de discriminação cromática previsto para camarões rosa em associação à alga vermelha Galaxaura através da modelagem visual de um predador (cavalo-marinho) resultou em baixas taxas de detecção e predação desse morfótipo por cavalos-marinhos em um experimento de laboratório, demonstrando um alto valor adaptativo da camuflagem nessa espécie. Por fim, no Capítulo 4, intitulado Habitat-dependent niche partitioning between colour morphs of the algal-dwelling shrimp Hippolyte obliquimanus, a ecologia trófica dos morfótipos de cor H e TL na utilização dos bancos de Sargassum e Galaxaura é avaliada através de análises de isótopos estáveis. Os morfótipos de cor mostraram diferenças nas razões isotópicas apenas em Galaxaura, onde a abundância de recursos alimentares é limitante, levando à diversificação de nicho trófico entre camarões H e TL e uma provável redução da competição intraespecífica. Por outro lado, em Sargassum, onde há abundância de recursos, a coexistência entre os morfótipos é possível mesmo sem partição de nicho ecológico. Em conjunto, os resultados obtidos nessa tese detalham tópicos centrais sobre os mecanismos reguladores e o valor adaptativo do polimorfismo cromático em H. obliquimanus. Dentro de uma abordagem ecológica e evolutiva, as diferentes estratégias de camuflagem e de uso de habitat dos morfótipos de cor parecem ser essenciais para o equilíbrio populacional da espécie, uma vez que os bancos de macroalgas utilizados como habitat pelos indivíduos são bastante heterogêneos e sua disponibilidade varia sazonalmente.

As aves de rapina, assim como os outros grupos animais, não estão distribuídas de maneira uniforme nos diferentes hábitats que compõem a paisagem terrestre. Conhecer e entender os fatores (e as implicações) que levam as espécies a escolher um determinado hábitat é questão essencial nos estudos de ecologia. Esse tema ganha ainda mais importância não só pela escassez de informações sobre a ecologia e história natural das aves de rapina na região Neotropical, mas também, pelo atual cenário de alteração dos hábitats. Estes são modificados rapidamente sem que haja um conhecimento básico da relação espécie/hábitat e dos efeitos provocadas por tais alterações. Dessa maneira, a presente tese teve como objetivo principal verificar o uso e a seleção de hábitat por aves de rapina diurnas em uma paisagem heterogênea (151. 866 ha) na região central do Estado de São Paulo (22° 15′ S; 47° 49′ W), onde a Estação Ecológica de Itirapina (EEI) foi considerada como área núcleo. Ainda, foi também alvo desse estudo estimar a área de vida de três espécies de rapineiros (Falco femoralis, Rupornis magnirostris e Heterospizias meridionalis) por meio de rádio-telemetria; verificar a eficiência de captura das aves de rapina frente a dois tipos de armadilhas, bal-chatri e goshawk; e elaborar um mapa de uso/ocupação do solo da área em questão, bem como analisar a paisagem no entorno da EEI. Entre setembro de 2005 e fevereiro de 2007 foram registradas 19 espécies de Falconiformes (Pandionidae n =1, Falconidae n = 5, Accipitridae n = 13) em uma paisagem essencialmente ocupada por monoculturas (cana-de-açúcar 22 %, laranja 14 %, eucalipto 13 %) e pastagens (21%). A riqueza média dos Falconiformes em áreas de monoculturas foi de 4,6 espécies e nas áreas naturais 10,3. A composição de espécies da taxocenose se mostrou mais relacionada às outras de área abertas sob influência do Cerrado. Um total de 48 indivíduos, pertencentes a cinco espécies, foram capturados pelos dois tipos de armadilhas. O sucesso de captura geral foi de 15,3 % (n = 33) para a armadilha bal-chatri e de 1 captura a cada 11,8 dias (8,5 %) para goshawk trap (n = 15). Implicações e limitações referentes à captura das aves de rapinas em áreas abertas foram também discutidas. A média da área de vida pelo método Kernel adaptativo (KA) 95 % foi de 1.329 ± 780 ha para F. femoralis, 129 ± 140 ha para R. magnirostris e de 1.883 ha para o indivíduo de H. meridionalis. A média da área de vida de F. femoralis foi 2,8 maior em áreas alteradas quando comparada a áreas naturais. De maneira geral, a qualidade do hábitat parece ter influenciado nos diferentes valores de requerimento de área apresentado pelos indivíduos e, também, na seleção/rejeição dos diferentes hábitats. Na maioria dos casos, as monoculturas foram rejeitadas, enquanto as áreas naturais foram selecionadas pelas aves de rapina. Cana-de-açúcar foi rejeitada por todas as aves de rapina. O único ambiente alterado utilizado em maior proporção que o esperado foi pastagem, selecionada por quatro das 10 espécies analisadas. Em contrapartida, três espécies evitaram este hábitat. Este é o primeiro estudo a avaliar a seleção de hábitat por Falconiformes no Brasil e demonstra que o intensivo incremento de áreas para agricultura pode afetar negativamente até mesmo as espécies mais abundantes e generalistas, contrário a algumas generalizações da literatura. A interação entre estrutura do hábitat, disponibilidade de presas, morfologia e comportamento de caça parece explicar tanto o tamanho da área de vida requerida quanto a utilização diferenciada dos diferentes tipos de hábitats. / Raptors, similarly to other animal groups, are not randomly distributed in the different habitats in the terrestrial landscape. Knowing and understanding the factors (and implications) influencing these species to chose a certain habitat are essential in ecological studies. This subject has become even more important not only because of the lack of information on the ecology and natural history of raptors of the Neotropics, but also because of current scenario of habitat changes. Areas are being rapidly modified without a basic knowledge of the species/habitat relationship and the effects it may cause. Thus, the main goal of this thesis was to examine habitat use and selection by diurnal birds of prey in a heterogeneous landscape (151. 866 ha) in the central region of state of São Paulo (22° 15′ S; 47° 49′ W), where the Estação Ecológica de Itirapina (EEI) was considered the central area. Also, this study aimed at estimating the home range size of three raptor species (Falco femoralis, Rupornis magnirostris and Heterospizias meridionalis) through radio-telemetry; examining the efficiency of capture of birds of prey using two types of traps, bal-chatri and goshawk; and mapping land use/occupation of the study area and making the landscape analysis around the EEI. Between September 2005 and February 2007, 19 species of Falconiformes (Pandionidae n = 1, Falconidae n = 5, Accipitridae n = 13) were observed in a landscape basically occupied by monocultures (sugar cane 22 %, orange 14 %, eucalyptus 13 %) and pastures (2 1%). The average richness of Falconiformes in areas occupied by a monoculture was 4,6 species and 10,3 in natural areas. The species composition of the assemblage was more similar to those of other open areas influenced by Cerrado. Forty-eight individuals from five species were captured in the two types of traps. The general capture success was 15.3 % (n = 33) for the bal-chatri trap and 1 capture every 11,8 days (8,5 %) for the goshawk trap (n = 15). Implications and limitations of the capture of birds of preys in the areas were also discussed. The average home range obtained with the 95 % adaptive Kernel method (AK 95%) was 1.329 ± 780 ha for F. femoralis, 129 ± 140 ha for R. magnirostris and 1.883 ha for the individual of H. meridionalis. The average home range of F. femoralis was 2.8 higher in altered areas when compared to natural ones. In general, habitat quality seems to have influenced the different values of home range requirement of individuals, and also, in the selection/rejection of the different habitats. In most cases, monocultures were rejected, while natural areas were selected by raptors. Sugar cane plantations were rejected by all raptors. The only altered habitat used more than expected was pastures, selected by four of ten species analyzed. However, three species avoided this habitat. This is the first study to evaluate habitat selection by Falconiformes in Brazil and demonstrate that the increase of areas for agriculture may negatively affect even the most abundant and generalist species, contrary to some generalizations described in the literature. The interaction among the habitat structure, prey availability, morphology and hunting behavior seems to explain home range size requirements as well as the differential use of the various types of habitats.

A Ilha de São Sebastião está localizada em um dos remanescentes de Mata Atlântica e, apesar de sua importância, o conhecimento sobre as taxocenoses da herpetofauna ainda é fragmentado. Assim, considerando a inexistência de dados, este trabalho teve como objetivo o estudo da ecologia da herpetofauna, enfocando os seguintes aspectos: composição, riqueza, dominância, abundância relativa, uso do ambiente e uso do substrato. Para a amostragem de campo, foram utilizados os métodos armadilha de interceptação e queda, armadilha de funil, procura visual limitada por tempo, procura de carro e encontro casual. Os dados de campo foram complementados por dados de coleções científicas e literatura. Foram registradas 34 espécies de anfíbios anuros, um anfíbio gimnofiono, um anfisbenídeo, dez lagartos, 26 serpentes e um quelônio. Serapilheira, arbusto e solo foram os substratos mais utilizados pela herpetofauna. A maioria das espécies é especialista. A distribuição das espécies indica que ocorre estruturação das taxocenoses, com maior diversidade na altitude intermediária. / The ilha de São Sebastião is located in one of the most representative remnants of the Atlantic forest, and although its great importance, the knowledge of herpetofaunal assemblages remain poorly known, mainly in ecology. Thus, considering the data or quantitative studies absence, this work goal the herpetofaunal ecology, focusing: composition, richness, dominance, relative abundance, habitat use and macrobabitat use. Fieldwork included pitfall traps with drift fences, funnel traps, time constrained search, sampling by car and incidental encounters. The fieldwork data was complemented by herpetological collections and literature records. We recorded 34 species of anuran amphibians, one gymnophiona, one amphisbenid, ten lizards, 26 species of snakes and one turtle. There were many differences on macrohabitat use, and the main were litter, shrub and ground. The most of species is specialist in the macrohabitat use. In the habitat use, the species distribution shows that the assemblage structure is complex, with superior diversity in the intermediate altitude.

Os estudos sobre a relação habitat-espécie são importantes para a conservação, pois geram conhecimento sobre características de habitat essenciais para uma população. A incorporação destas informações em planos de conservação permite um manejo mais inteligente tanto da fauna como das áreas a serem preservadas. O presente estudo teve como objetivo estudar o uso e a seleção de habitat de Saltator atricollis e Cypsnagra hirundinacea na Estação Ecológica de Itirapina, região central do estado de São Paulo, Brasil. Ambas espécies são aves endêmicas do Cerrado e ameaçadas de extinção no Estado de São Paulo. O estudo foi desenvolvido entre setembro e dezembro de 2007 e setembro de 2008. O habitat foi analisado em duas escalas: o macro-habitat e o micro-habitat. Para analisar o habitat foram dispostos sistematicamente 84 pontos de amostragem na área de estudo. Na análise do macro-habitat foram utilizadas informações sobre o uso-disponibilidade das diferentes fisionomias sendo comparadas por meio do intervalo de confiança de Bailey. No estudo de micro-habitat foram medidas 11 características estruturais da vegetação ao redor de cada ponto de contato com S. atricollis, com C. hirundinacea e nos 84 pontos de amostragem. Para analisar as associações entre as características estruturais e as aves foi utilizado modelos de regressão logística selecionados pelo Critério de Informações de Akaike (AIC). Saltator atricollis selecionou áreas de campo cerrado, utilizou na mesma proporção que o esperado as áreas campestres e utilizou menos que o esperado o cerrado sensu stricto. Cypsnagra hirundinacea utilizou na mesma proporção que o esperado as áreas campestres e o campo cerrado enquanto o cerrado sensu stricto foi utilizado menos que o esperado. Quanto ao micro-habitat os melhores modelos para explicar a presença de S. atricollis incluíram maior densidade de árvores maiores que 2 m de altura e menor densidade de Syagrus petrea e de arbustos com até 1 m de altura. A presença de árvores é importante para a espécie, pois são utilizadas como poleiros durante o comportamento de sentinela. As altas densidades de Syagrus petrea e arbustos baixos (< 1m) podem diminuir a quantidade de moitas de gramíneas (utilizadas para a construção de ninhos) já que ambos ocupam o mesmo estrato. Assim, indiretamente, a presença de Syagrus petrea e arbustos baixos (< 1m) podem diminuir a disponibilidade de sítios reprodutivos. Além disso, podem atrapalhar o forrageamento por dificultar a utilização do estrato herbáceo. Os modelos que explicaram melhor a presença de C. hirundinacea foram representados por uma maior densidade de arbustos e árvores intermediárias e altas (entre 1 e 2 m, entre 2 e 4 m e maiores que 4 m de altura), maior densidade de braquiária e menor densidade de Attalea geraensis e de solo exposto. A presença de árvores é importante, pois a espécie as usa para forragear, construir ninhos e vigiar contra predadores. A relação positiva com a braquiária pode estar relacionada ao fato da espécie não utilizar o estrato herbáceo e ao mesmo tempo a invasão dessa gramínea, possivelmente, ainda não deve ter alterado a estrutura da vegetação lenhosa. Já a relação inversa entre a presença de C. hirundinacea e a densidade de solo exposto e de A. geraensis deve ocorrer, pois em ambientes com alta densidade dessas variáveis provavelmente há um baixo número de árvores o que diminui a disponibilidade de sítios de forrageamento e reprodutivos. Portanto para a manutenção dessas espécies é importante preservar as fisionomias abertas do Cerrado, as quais estão desaparecendo no estado de São Paulo, além disso recomenda-se manter nessas fisionomias a presença de algumas árvores e evitar a dominância de palmeiras rasteiras. / Studies about habitat-species relationships are important for conservation, because they generate knowledge about the essential characteristics of a habitat for a population. Incorporation of such information in conservation plans allows for a more intelligent management of both fauna and habitats that should be preserved. The aim of this study was to investigate the habitat use and selection by Saltator atricollis and Cypsnagra hirundinacea at Estação Ecológica de Itirapina in central State of São Paulo, Brazil. Both species are endemic birds of the Cerrado (Brazilian Savannah) and they are considered threatened with extinction in the State of São Paulo. The study was developed from September to December of 2007 and in September 2008. Habitat was analyzed in two scales: macrohabitat and microhabitat. To analyze the habitat 84 sampling points had been distributed at the study area. Macrohabitat selection was analyzed based on use-availability data of physiognomy and performing Baileys confidence interval. To investigate the use of the microhabitat there were estimated eleven structural characteristics of vegetation. These characteristics were described in each exact point that S. atricollis and C. hirundinacea had seen and in the 84 sampling points. The associations between the structural characteristics and the birds were identified by logistic regression models selected by Akaike Information Criteria (AIC). Saltator atricollis selected campo cerrado physiognomies (grassland savannah), it use campos (grasslands) at the expected proportion and cerrado sensu stricto (woodland savannah) less than expected proportion. Cypsnagra hirundinacea used both campos and campo cerrado areas at expected proportions while cerrado sensu stricto was used less than expected proportion. At the microhabitats level, the best models to explain the presence of S. atricollis included greater density of trees higher than 2 meters, lesser density of Syagrus petrea, and lesser density of bushes of to up to 1 meter height. The presence of trees is important to this specie, because the trees are used as perches during sentinel behavior. The high density of Syagrus petrea should diminish the amount of grassy because they use the same space on the habitat. Birds use the grassy to make its nest and the presence of Syagrus petrea and short bushes (< 1m) should indirectly reduce places for reproductive sites and might make foraging more difficult. The best models to explain the presence of C. hirundinacea were the one represented by a greater density of bushes and, trees of intermediate to greater height (between 1 and 2 meters, between 2 and 4 meters, and higher than 4 meters), greater density of Brachiaria grasses and lesser density of Attalea geraensis and exposed ground. The presence of trees is important because the species use them to forage, build nests and watch against predators. The positive relation with Brachiaria grasses might be occurs because C. hirundinacea dont use the herb layer. Possibly, the invasion of the Brachiaria grasses not having changed the structure of the vegetation yet. The inverse relation between the bird specie and the presence of exposed ground and A. geraensis, should occur because in habitats with high density of exposed ground and A. geraensis there are few places to feed and to reproduction. Therefore, to the maintenance of these birds species it is important preserving the open physiognomies of the Cerrado, which are disappearing from the State of São Paulo. Its also necessary to keep in theses physiognomies the presence of a few bushes and trees and also avoid the dominance of A. geraensis and Syagrus petrea.

A perda de habitats é, atualmente, a grande ameaça à diversidade de vertebrados terrestres (Crooks, 2002). Muito pouco resta da vegetação nativa no estado de São Paulo, uma vez que é o estado mais desenvolvido do Brasil. Embora sua porção litorânea ainda possua uma grande faixa de Floresta Atlântica, o que restou da vegetação de cerrado em seu interior são pequenos fragmentos, cercados de agricultura e silvicultura. Entretanto, este mosaico de vegetação ainda abriga espécies de médios e grandes mamíferos. Este estudo foi desenvolvido numa área com fragmentos de cerradão, cerrado sensu stricto, floresta semidecídua, além de cultivos de eucalipto e cana-de-açúcar, nos municípios de Santa Rita do Passa-Quatro e Luiz Antônio. Registraram-se 22 espécies de mamíferos de médio e grande porte por meio de armadilhamento fotográfico, canteiro de pegadas, identificação de fezes, vestígios e avistamentos diretos. Dessas 22 espécies, dez eram carnívoros os quais exploravam o ambiente independentemente de sua cobertura vegetal. Numa abordagem mais espacializada notou-se alguma diferença no uso dos habitats da área de estudo, inclusive do eucaliptal, que se mostrou um habitat importante na dinâmica das populações de carnívoros do local. Dessa forma concluiu-se que ambientes modificados pelas culturas humanas podem representar habitats efetivamente utilizados pela mastofauna de uma região antropizada. Diferentes métodos podem ser usados para monitorar populações ou comunidades faunísticas. O armadilhamento fotográfico e o registro em canteiro de pegadas são bastante utilizados para médios e grandes mamíferos. Os dois métodos possuem viéses na sua amostragem, além de custos e eficiências bem distintos, no entanto o uso conjunto desses dois métodos parece registrar de forma adeqüada a riqueza da mastofauna de uma determinada região. / Habitat\'s loss is the great jeopardy to the diversity of terrestrial vertebrates nowadays (Crooks, 2002). There\'s too little left from the native vegetation in São Paulo State, since it\'s the most developed state in Brazil. Although its coastal area still has a large tract of the Atlantic Forest, just small patches of Brazilian savanna (cerrado) vegetation are found in it, surrounded by agriculture and silviculture. However this vegetation mosaic still shelters both medium and large mammals\' species. This study was held in an area with remnant fragments of woodland savanna (cerradão), cerrado sensu stricto, semideciduous forest as well the cultivation of eucalyptus and sugar-cane in Santa Rita do Passa-Quatro e Luiz Antônio - Brazil. Twenty-two species of large and medium sized mammals were reported by the use of camera trapping, track plots recording, identification of dungs, vestiges and sights. Among these 22 species, ten were carnivore which exploit the environment regardless its vegetation coverage. During a more spatial approach, some difference in the use of the habitats was noted, concerning the study area, including the eucalyptus plantation, which turned out to be an important habitat on the dynamics of the carnivore population of the region. Thus one realizes that environments which were altered by human cultures can represent habitats actually used by mammals from an anthropogenic region. Different procedures can be applied to observe faunal populations or communities. The camera trapping and the track plot recording are often used for medium and large-sized mammals. Both methods present bias in their showing, besides these 2 methods seem to be suitable to the register the wealth of the mammals of a specific region.

Bottlenose dolphins (Tursiops spp.) are a widely studied species in marine habitats, however, information on estuarine populations in Australia is very limited. To fully understand the importance of estuaries as habitats for dolphins there needs to be clear quantitative data on dolphin populations and their habitat use in estuaries. This study provides the first published data on Indo-Pacific bottlenose dolphins (Tursiops aduncus) abundance estimates, site fidelity, individual ranging patterns, habitat use, flood impacts and sexual segregation patterns over a 3- year period in the Clarence River (CR) and Richmond River (RR) estuaries in northern New South Wales, Australia.The results indicate that, at present, the CR estuary is sustaining a larger dolphin community with a predominantly resident population compared to the RR estuary, which supports a smaller community with lower site fidelity. The CR estuary dolphin abundance estimate of 71 (62-81 95% CI, CV = 0.07) is more than twice the size of the RR estuary abundance estimate of 34 (19- 49 95% CI, CV = 0.23). Differences in site fidelity were observed between the estuaries with 60% and 37% of identified dolphins determined as residents, 26% and 21% as occasional visitors, and 14% and 42% as transients for the CR and RR, respectively. Resource partitioning was apparent in both estuaries with the mean distance resident dolphins were found upstream from the River mouth being greater than for the occasional visitors and transients.Tursiops aduncus was seen all year round in the CR and RR estuaries, with peak sightings occurring in spring at both sites. In the CR the dolphin population showed consistent seasonal fluctuations, whereas this did not occur in the RR population. In the CR the largest spatial distribution of dolphins in the estuary was observed in spring and winter, while in summer they were primarily restricted to the main estuary channel. Different behaviours that were observed; feeding, socialising, travelling, and milling and resting, were found to be influenced by season, tidal phase and tidal range. In both estuaries the core habitat areas used by the population for feeding consisted of areas with considerable slope near the edge of tidal sand banks, adjacent to deeper channels at the entrances of canals, creeks or artificial breakwalls. In addition, the core habitat areas used by the population for milling and resting behaviour in both estuaries occurred in shallow, sheltered areas, often associated with seagrass beds. Socialising occurred more frequently in the CR throughout most of the deeper waters of the estuary, whereas in the RR it was primarily restricted to a small area of medium depth in the estuary.The major determinant of T. aduncus occupancy in the two estuaries was the flood events that occurred, which resulted in the dolphins abandoning the estuary. The mean predicted probabilities for sighting dolphins during non-flood periods were 0.87 and 0.71, during a flood 0.21 and 0.04, and during a post-flood recovery period 0.83 and 0.80 in the CR and RR, respectively. Principal Components Analysis (PCA) showed that when the dolphins were absent from the estuaries, three components were extracted from the water quality parameters in the CR, and two components in the RR. High loadings from the PCA were associated with the changing salinity, turbidity, pH, dissolved oxygen and temperature associated with the flood events. The return of the dolphins to the estuary following a flood depended on the length and severity of the flood event, but generally the dolphins seemed to prefer waters with salinity levels above 29 ‰. This could be associated with higher salinities being important for their physiological health, or because their prey returned to the estuaries during these higher salinity conditions, more likely a combination of both of these factors.Sexual segregation patterns were observed in T. aduncus populations with mixed gender and female groups mainly recorded in the CR, whereas in the RR female groups dominated the estuary. In the CR, significant differences occurred in sightings between the mixed and female groups in relation to water depth and behaviour. Mixed gender groups were sighted predominantly in deeper water and were involved in social behaviour including sexual behaviour and male herding of females. In contrast, the female groups were observed across all water depths, predominately feeding and also participating in more milling and resting behaviours.The high occurrence of aggressive herding behaviour by males in the CR was significantly different at varying depths, tides and seasons, occurring more often in deeper water, at higher tides and in non-breeding seasons. Female groups were found to utilise the small, shallow tributaries and travel for longer distances up these smaller tributaries than the mixed groups, which were concentrated in the deeper main channel of the estuary.The deeper water of the channels may facilitate the males in herding the females, while the female groups’ habitat selection of shallow estuary areas may provide a sanctuary from aggressive males, access to suitable prey items or prey density for mothers and their calves, or a combination of these factors.This study has provided the first detailed research on T. aduncus dolphin population dynamics, habitat use, occupancy and sexual segregation patterns in two Australian subtropical estuaries. To ensure the long-term survival of both of these dolphin populations, management of future increased anthropogenic disturbances from boat traffic, pollution, dolphin watching, industrial or urban development, over-fishing and habitat degradation of the catchment is needed. Good quality water conditions, the protection of the core feeding areas and small shallow tributaries for females and their calves, and sheltered areas for resting behaviour all need to be maintained for the continued conservation of these important dolphin populations.

No description available.

La variabilité spatiale et temporelle de l’écoulement en rivière contribue à créer une mosaïque d’habitat dynamique qui soutient la diversité écologique. Une des questions fondamentales en écohydraulique est de déterminer quelles sont les échelles spatiales et temporelles de variation de l’habitat les plus importantes pour les organismes à divers stades de vie. L’objectif général de la thèse consiste à examiner les liens entre la variabilité de l’habitat et le comportement du saumon Atlantique juvénile. Plus spécifiquement, trois thèmes sont abordés : la turbulence en tant que variable d’habitat du poisson, les échelles spatiales et temporelles de sélection de l’habitat et la variabilité individuelle du comportement du poisson. À l’aide de données empiriques détaillées et d’analyses statistiques variées, nos objectifs étaient de 1) quantifier les liens causaux entre les variables d’habitat du poisson « usuelles » et les propriétés turbulentes à échelles multiples; 2) tester l’utilisation d’un chenal portatif pour analyser l’effet des propriétés turbulentes sur les probabilités de capture de proie et du comportement alimentaire des saumons juvéniles; 3) analyser les échelles spatiales et temporelles de sélection de l’habitat dans un tronçon l’été et l’automne; 4) examiner la variation individuelle saisonnière et journalière des patrons d’activité, d’utilisation de l’habitat et de leur interaction; 5) investiguer la variation individuelle du comportement spatial en relation aux fluctuations environnementales. La thèse procure une caractérisation détaillée de la turbulence dans les mouilles et les seuils et montre que la capacité des variables d’habitat du poisson usuelles à expliquer les propriétés turbulentes est relativement basse, surtout dans les petites échelles, mais varie de façon importante entre les unités morphologiques. D’un point de vue pratique, ce niveau de complexité suggère que la turbulence devrait être considérée comme une variable écologique distincte. Dans une deuxième expérience, en utilisant un chenal portatif in situ, nous n’avons pas confirmé de façon concluante, ni écarté l’effet de la turbulence sur la probabilité de capture des proies, mais avons observé une sélection préférentielle de localisations où la turbulence était relativement faible. La sélection d’habitats de faible turbulence a aussi été observée en conditions naturelles dans une étude basée sur des observations pour laquelle 66 poissons ont été marqués à l’aide de transpondeurs passifs et suivis pendant trois mois dans un tronçon de rivière à l’aide d’un réseau d’antennes enfouies dans le lit. La sélection de l’habitat était dépendante de l’échelle d’observation. Les poissons étaient associés aux profondeurs modérées à micro-échelle, mais aussi à des profondeurs plus élevées à l’échelle des patchs. De plus, l’étendue d’habitats utilisés a augmenté de façon asymptotique avec l’échelle temporelle. L’échelle d’une heure a été considérée comme optimale pour décrire l’habitat utilisé dans une journée et l’échelle de trois jours pour décrire l’habitat utilisé dans un mois. Le suivi individuel a révélé une forte variabilité inter-individuelle des patrons d’activité, certains individus étant principalement nocturnes alors que d’autres ont fréquemment changé de patrons d’activité. Les changements de patrons d’activité étaient liés aux variables environnementales, mais aussi à l’utilisation de l’habitat des individus, ce qui pourrait signifier que l’utilisation d’habitats suboptimaux engendre la nécessité d’augmenter l’activité diurne, quand l’apport alimentaire et le risque de prédation sont plus élevés. La variabilité inter-individuelle élevée a aussi été observée dans le comportement spatial. La plupart des poissons ont présenté une faible mobilité la plupart des jours, mais ont occasionnellement effectué des mouvements de forte amplitude. En fait, la variabilité inter-individuelle a compté pour seulement 12-17% de la variabilité totale de la mobilité des poissons. Ces résultats questionnent la prémisse que la population soit composée de fractions d’individus sédentaires et mobiles. La variation individuelle journalière suggère que la mobilité est une réponse à des changements des conditions plutôt qu’à un trait de comportement individuel. / Spatiotemporal flow variability contributes to create a dynamic habitat mosaic sustaining ecological diversity. One of the most important topics in ecohydraulic research is to identify the relevant scales of flow variability affecting organisms at different life stages. The general objective of the thesis is to examine the links between habitat variability and the behaviour of juvenile Atlantic salmon. More specifically, three themes are addressed: turbulence as a fish habitat variable, the spatial and temporal scales of habitat selection and individual variability in fish behaviour. Through detailed field measurements incorporating a variety of sampling techniques and statistical analyses our objectives were to: 1) Quantify the causal links between standard habitat variables and flow turbulence at multiple scales; 2) Test a new in situ portable flume to analyse the effect of turbulent flow properties on the prey capture probability and foraging behaviour of juvenile Atlantic salmon; 3) Analyse the spatial and temporal scale dependence of fish-habitat associations within a reach during the summer and autumn; 4) Examine individual variation of seasonal and daily activity patterns and habitat use and their interaction; 5) Investigate the individual variation in seasonal daily movement behaviour in relation to environmental fluctuations. The thesis provides a detailed characterization of turbulence in pools and riffles and showed that the capacity of ‘standard’ fish habitat variables to explain turbulent properties was relatively low, especially at smaller spatial scales, but varied greatly between the units. From a practical point of view, this level of complexity suggested that turbulence should be considered as a ‘distinct’ ecological variable within this range of spatial scales. In a second experiment, using an in situ portable flume and underwater videotaping of fish, we did not conclusively confirm or rule out the effect of turbulence on prey capture probability, but observed a preferential selection of locations where flow velocity was downward and turbulence intensity was lower. The selection of lower turbulence habitat was also observed in natural habitat conditions in an observational field study, in which 66 PIT-tagged fish were tracked for three months in a river reach using a high resolution network of antennas buried in the bed. Juvenile salmon habitat selection was dependant on the scale of observations. Fish were associated with moderate depth micro-scale habitats, but also with higher depth patch-scale habitats. Furthermore, the range of habitat used by individuals increased asymptotically with the temporal scale. The scale of one hour was considered as optimal to describe the range of habitats used in a day and three days optimal to describe the range of habitat used in a month. Individual tracking revealed high inter-individual variability in activity patterns, as some individuals were predominantly nocturnal whereas others frequently changed their daily activity pattern. Changes in activity patterns were linked to environmental fluctuations, but also to individual habitat use patterns, which might signify that lower quality habitats require fish to increase daytime activity when food intake and the risk of predation are both high. High inter-individual variability was also observed in the fish movement behaviour. It appeared that most fish exhibited low mobility on most days, but also showed occasional bouts of high mobility. Between-individual variability accounted for only 12-17% of the variability in the mobility data. These results challenge the assumption of a population composed of a sedentary and mobile fraction. Individual variation on a daily basis suggested that movement behaviour is a response to changing environmental conditions rather than an individual behavioural trait.

Vom Herbst 2011 bis zum Herbst 2013 wurde das Verhalten und die Standortwahl einer Herde Exmoorponys unter seminatürlichen Bedingungen im Naturpark Solling-Vogler untersucht. Die zehn Fokustiere lebten auf einer rund 140 ha großen Fläche. Die Verhaltensweisen wurden für jedes Individuum mittels focal-animal-sampling notiert. Im Durchschnitt verbrachten die Exmoorponys im Solling 72,4% des gezeigten Gesamtverhaltens mit der Nahrungsaufnahme, 15,5% mit dem Ruhen, 6,5% mit der Lokomotion, 2,1% mit dem Komfortverhalten, 1,4% mit dem Stehen, 1,3% mit dem Sozialverhalten, 0,7% mit dem Defäkationsverhalten und 0,2% mit der Aufnahme von Flüssigkeiten. Die Verhaltensweisen unterlagen dabei einem Tages- sowie Jahresrhythmus. Der Grund für diese saisonalen Schwankungen waren die entsprechenden Vegetationsgegebenheiten sowie die klimatischen Bedingungen während der Jahreszeiten. Bei Gegenüberstellung der individuellen Verhaltensweisen war auffallend, dass die Tiere besondere Vorlieben und Charakterzüge zu haben schienen. Nach Auswertung der Habitatnutzung mittels des electivity-Index, welcher die Nutzung in Zusammenhang mit der Größe des Gebietes stellt, fiel auf, dass die Ponys vor allem die offenen Areale präferierten. Die Fichten- und Eichenforste wurden nur entsprechend der Verfügbarkeit genutzt und sogar teilweise gemieden. Zudem fiel eine Kopplung bestimmter Verhaltensweisen an ausgesuchte Areale auf. So wurden die offenen Flächen eher zum Grasen und die Wälder eher zum Ruhen genutzt. Bei abschließender Betrachtung des Sozialverhaltens fallen starke individuelle Unterschiede sowie eine Abhängigkeit des Sozialverhaltens von den Jahreszeiten auf. Im Frühling und im Winter wurde Sozialverhalten häufiger gezeigt als in den Herbstmonaten. Das vorgestellte Projekt kann ein guter Leitfaden für nachfolgende Projekte sein, welche eine Ganzjahresbeweidung in vorwiegend forstlich geprägten Bereichen anstreben. Erste Auswirkungen sind bereits abzusehen. So ist die Anwesenheit von Megaherbivoren beispielsweise förderlich für die großflächige Verjüngung von Eichen (Quercus robur und Q. petrea), da große Pflanzenfresser dazu tendieren, eher die jungen Pflanzen der Rotbuche (Fagus sylvatica) zu verbeißen. Dieser Verbiss fand vor allem im Winter sowie im Frühjahr statt, wenn den Ponys keine alternativen Nahrungsmittel zur Verfügung standen.

Bottlenose dolphins (Tursiops spp.) are a widely studied species in marine habitats, however, information on estuarine populations in Australia is very limited. To fully understand the importance of estuaries as habitats for dolphins there needs to be clear quantitative data on dolphin populations and their habitat use in estuaries. This study provides the first published data on Indo-Pacific bottlenose dolphins (Tursiops aduncus) abundance estimates, site fidelity, individual ranging patterns, habitat use, flood impacts and sexual segregation patterns over a 3- year period in the Clarence River (CR) and Richmond River (RR) estuaries in northern New South Wales, Australia.The results indicate that, at present, the CR estuary is sustaining a larger dolphin community with a predominantly resident population compared to the RR estuary, which supports a smaller community with lower site fidelity. The CR estuary dolphin abundance estimate of 71 (62-81 95% CI, CV = 0.07) is more than twice the size of the RR estuary abundance estimate of 34 (19- 49 95% CI, CV = 0.23). Differences in site fidelity were observed between the estuaries with 60% and 37% of identified dolphins determined as residents, 26% and 21% as occasional visitors, and 14% and 42% as transients for the CR and RR, respectively. Resource partitioning was apparent in both estuaries with the mean distance resident dolphins were found upstream from the River mouth being greater than for the occasional visitors and transients.Tursiops aduncus was seen all year round in the CR and RR estuaries, with peak sightings occurring in spring at both sites. In the CR the dolphin population showed consistent seasonal fluctuations, whereas this did not occur in the RR population. In the CR the largest spatial distribution of dolphins in the estuary was observed in spring and winter, while in summer they were primarily restricted to the main estuary channel. Different behaviours that were observed; feeding, socialising, travelling, and milling and resting, were found to be influenced by season, tidal phase and tidal range. In both estuaries the core habitat areas used by the population for feeding consisted of areas with considerable slope near the edge of tidal sand banks, adjacent to deeper channels at the entrances of canals, creeks or artificial breakwalls. In addition, the core habitat areas used by the population for milling and resting behaviour in both estuaries occurred in shallow, sheltered areas, often associated with seagrass beds. Socialising occurred more frequently in the CR throughout most of the deeper waters of the estuary, whereas in the RR it was primarily restricted to a small area of medium depth in the estuary.The major determinant of T. aduncus occupancy in the two estuaries was the flood events that occurred, which resulted in the dolphins abandoning the estuary. The mean predicted probabilities for sighting dolphins during non-flood periods were 0.87 and 0.71, during a flood 0.21 and 0.04, and during a post-flood recovery period 0.83 and 0.80 in the CR and RR, respectively. Principal Components Analysis (PCA) showed that when the dolphins were absent from the estuaries, three components were extracted from the water quality parameters in the CR, and two components in the RR. High loadings from the PCA were associated with the changing salinity, turbidity, pH, dissolved oxygen and temperature associated with the flood events. The return of the dolphins to the estuary following a flood depended on the length and severity of the flood event, but generally the dolphins seemed to prefer waters with salinity levels above 29 ‰. This could be associated with higher salinities being important for their physiological health, or because their prey returned to the estuaries during these higher salinity conditions, more likely a combination of both of these factors.Sexual segregation patterns were observed in T. aduncus populations with mixed gender and female groups mainly recorded in the CR, whereas in the RR female groups dominated the estuary. In the CR, significant differences occurred in sightings between the mixed and female groups in relation to water depth and behaviour. Mixed gender groups were sighted predominantly in deeper water and were involved in social behaviour including sexual behaviour and male herding of females. In contrast, the female groups were observed across all water depths, predominately feeding and also participating in more milling and resting behaviours.The high occurrence of aggressive herding behaviour by males in the CR was significantly different at varying depths, tides and seasons, occurring more often in deeper water, at higher tides and in non-breeding seasons. Female groups were found to utilise the small, shallow tributaries and travel for longer distances up these smaller tributaries than the mixed groups, which were concentrated in the deeper main channel of the estuary.The deeper water of the channels may facilitate the males in herding the females, while the female groups’ habitat selection of shallow estuary areas may provide a sanctuary from aggressive males, access to suitable prey items or prey density for mothers and their calves, or a combination of these factors.This study has provided the first detailed research on T. aduncus dolphin population dynamics, habitat use, occupancy and sexual segregation patterns in two Australian subtropical estuaries. To ensure the long-term survival of both of these dolphin populations, management of future increased anthropogenic disturbances from boat traffic, pollution, dolphin watching, industrial or urban development, over-fishing and habitat degradation of the catchment is needed. Good quality water conditions, the protection of the core feeding areas and small shallow tributaries for females and their calves, and sheltered areas for resting behaviour all need to be maintained for the continued conservation of these important dolphin populations.