A recuperação de funções e processos ecossistêmicos, entre outros atributos, é um dos indicadores mais importantes no processo de retorno de um ecossistema à sua trajetória histórica. A ciclagem de nutrientes é um atributo fundamental do ecossistema, e relaciona-se diretamente à regulação do funcionamento e do desenvolvimento dos ecossistemas e inclui, em um modelo geral, as entradas de nutrientes, as transferências internas entre plantas e solo e as saídas do sistema. A compreensão das mudanças nos processos biogeoquímicos durante a sucessão secundária em áreas em restauração ecológica ainda é incipiente, principalmente em áreas de florestas tropicais. Esse estudo tem por objetivo elucidar a dinâmica do nitrogênio ao longo do processo de restauração ecológica em áreas reflorestadas com espécies nativas da Mata Atlântica. A questão norteadora deste estudo é a seguinte: A restauração florestal com alta diversidade de espécies e predominância de espécies arbóreas nativas regionais restaura a dinâmica original do nitrogênio? Esse estudo visa investigar o funcionamento da ciclagem de nutrientes, com foco no nitrogênio, que é um elemento limitante à sucessão secundária, especialmente em florestas tropicais. Para tal, alguns indicadores da ciclagem do nitrogênio foram mensurados em uma cronosequência florestal formada por uma floresta natural preservada e florestas restauradas de diferentes idades (21 e 52 anos) reflorestadas com alta diversidade de espécies e predominância de nativas regionais. Os indicadores utilizados foram: 15N e teor de N da vegetação, serrapilheira e solo; razão N:P da vegetação e da serrapilheira; taxas líquidas de mineralização e nitrificação; teor de amônio, nitrato, N mineral e razão nitrato:amônio. As florestas foram amostradas entre agosto de 2008 e abril de 2009, nas seguintes estações: seca, transição entre seca e chuvosa, chuvosa, e transição entre chuvosa e seca. Foram encontrados padrões claros de mudanças na ciclagem do N ao longo da cronosequência estudada, incluindo diferenças nos valores de 15N foliar, teor de N, razão N:P, N mineral e taxas líquidas de mineralização e nitrificação, caracterizadas por um aumento de valores médios dessas variáveis ao longo da cronosequência. Os resultados encontrados sugerem que as florestas em processo de restauração, mesmo a de 52 anos, ainda não possuem uma ciclagem de N característica de uma floresta madura e, portanto, a recuperação da ciclagem de N ainda não foi completamente atingida. Entretanto, é possível afirmar que as florestas em processo de restauração estudadas estão seguindo uma trajetória de desenvolvimento caracterizada por uma ciclagem de N cada vez mais parecida com a de uma floresta natural madura, como a da floresta natural madura utilizada como referência. Através dos modelos de restauração utilizados para as florestas da cronosequência estudada, os processos da ciclagem do N são recuperados à medida que a floresta desenvolve-se, com uma clara tendência de mudança na economia de N para economia de P típica de florestas tropicais maduras. / The recuperation of ecosystem processes and functions, among other attributes, is one of the most important indicators in the process of return of an ecosystem to its historic trajectory. Nutrient cycling is a fundamental ecosystem attribute, and relates directly to regulation of functioning and development of ecosystems and includes, in a general model, nutrients entering, being transferred internally between plants and soil, end leaving the system. The comprehension of changes in biogeochemical processes during secondary succession in areas in ecological restoration is still incipient, mainly in tropical forests. This study aims to elucidate nitrogen dynamics along the process of ecological restoration in areas reforested with Atlantic Forest native species. The question driving this study is: Does ecological restoration with high diversity of species and predominance of regional native tree species restore nitrogen original dynamics? This research investigated nutrients cycling functioning, focusing on nitrogen, which is a limiting nutrient in secondary succession, particularly in tropical forests. In order to do so, some indicators of nutrient cycling were assessed in a forest chronosequence formed by a preserved natural forest and restored forests of different ages (21 and 52 years) reforested using high species diversity and predominance of regional native species. The indicators used were: 15N and N content in green foliage, litter and soil; N:P ratio of green foliage and litter; net mineralization and net nitrification rates; content of ammonium, nitrate, inorganic N, and nitrate:ammonium ratio. The forests were sampled between August 2008 and April 2009, in the following seasons: dry, dry-rainy transition, rainy, rainy-dry transition. Clear patterns of change in the N cycling along the studied chronosequence were found, including differences in green foliage 15N values, N content, N:P ratio, inorganic N and net mineralization and nitrification rates, characterized by an increase in the mean values of these variables along the chronosequence. The results found suggest that the forests in restoration process, even the 52 years old one, still do not present a N cycling characteristic of a mature forest and, therefore, the recuperation of the N cycling was not completely reached yet. However, it is possible to state that the forests in restoration process studied here are following a development trajectory characterized by a N cycling progressively more similar to what is common to a mature native forest, as the one used as the reference ecosystem in this study. Through the restoration models used for the forests studied, the N cycle processes are recovered as the forests develop, as they present a clear tendency of changing from N economy to P economy, typical to mature tropical forests.

Utilizando-se materiais coletados durante qua-tro cruzeiros oceanográficos com o N/Oc .\"Prof. W. Besnard\", na região Sudeste do Brasil, compreendida entre Cabo Frio (RJ) e Florianópolis (SC), de janeiro de 1980 a março de 1982, foram realizados estudos quali quantitativos so-bre ocorrências de larvas de peixes, relacionando-as com fatores abióticos. Problemas concernentes aos processos de amostragem tambem foram verificadas. Realizaram-se dois tipos de arrastos: arrasto oblíquo com a rede Bongo usando-se malhagens de 0,333 mm (fina) e de 0,505 mm (regular), e arrasto horizontal de superfície com a rede de Neuston, de 0,333 mm de malhagem. Em cada estação oceanográfica, alem das amostras biologicas, efetuaram-se as medições de temperatura e coleta de água para determinação de salinidade. Um total de 35.090 larvas foram analisadas, incluíndo as coletas das redes fina e regular da Bongo e a rede de Neuston. Dentre estas, 61 grupos diferentes foram separados, chegando a níveis específicos em alguns casos.- Dois gêneros e quatro especies foram identificados pela primeira vez na região: Saurida spp, Hygophum spp, Trachinocephalus myops, Synodus foetens Bregmaceros can-tori e Maurolicus muelleri. As famílias predominantes foram Clupeidae, Engraulidae, Myctophidae e Gonostomatidae. De uma maneira geral, a região Sudeste apresentou grande riqueza em taxa, mas com o predomínio de poucos grupos, em termos de abundância. Análises da relação entre larvas de peixes e fatores abióticos revelaram a existência de padrões de ocorrência e distribuição próprios para cada espécie, dentro de uma determinada faixa de variaçao de temperatura e de salinidade. Estudos realizados durante uma estação fixa de 36 horas em Cabo Frio, mostraram uma situação típica da estrutura oceanográfica da região, notando-se mudanças de massas de água no local, devido ao fenômeno da ressurgiê-cia. Este fator, associado ao horário de coleta, deve ter exercido influência de maneira complexa sobre o componen-te biológico, induzindo mudanças na ocorrência de diferentes tipos de larvas. Dois transectos, um ao largo de Cabo Frio e ou-tro ao largo de paranaguá, foram analisados com o intuito de obter-se informações a respeito da ocorrência e distribuição de larvas de acordo com a distância da costa. Os dados hidrográficos comprovam a existincia de diferentes massas de água compondo a estrutura oceanográfica daregião, que por sua vez influenciam a ocorrência e distribuição de larvas. A família Gerreidae teve a maior abundância associada à massa costeira. Sardinella brasiliensis, Harenguia jaguna e Engraulis anchoita foram de distribuição tipicamente nerítica, assim como as famílias Sciaenidae, Bleniidae, Ophidiidae, Carangidae e Cynoglossidae. Por ou-tro lado, Myctophidae, Gonostomatidae, Paralepedidae e Scombridae ocorreram preferencialmente na região ocêanica, que sofre influência da Corrente do Brasil. Análise do material coletado com a rede de Neuston comprovam a importância deste tipo de amostragem su-perficial para os estudos relacionados com o ictioplâncton, uma vez que esta rede captura uma porcentagem da população que é subamostrada pela rede Bongo. Observou-se a tendência de estratificação na camada superficial, principalmete de formas jovens, como no caso de Sardinella brasiliensis. Um aspecto especialmente notável foi o caso das fa-mílias Mugilidae e Mullidae em que a captura se deu significativamente em maior número no arrasto de superfície do que no arrasto oblíquo. Comparando-se os materiais coletados com as re-des finas e regular da Bongo, pôde-se verificar dois pro-blemas relacionados com a seletividade: o entupimento da rede e o escape de larvas menores através da malhagem. Ecomparando-se os materiais coletados durante os períodos diurno e noturno, pôde-se verificar o outro problema importante de seletividade, que é a fuga da boca da rede de larvas maiores. As nossas amostragens parecem nao ter sido afetadas pelo problema de entupimento, como mostram as análises do volume de água filtrada. Já o escape de lar-vas menores foi constatado em vários grupos, tendo sido de terminado para três especies o tamanho a partir do qual este problema começa a se tornar evidente: 7,5 mm para Sardinella brasiliensis e 6,5 mm para Harengula jaguana e Engraulis anchoita. A fuga da boca da rede ocorreu em lar-vas maiores durante o dia, concluindo-se que este problema varia conforme a especie, o padrão de migração vertical e o desenvolvimento do sistema visual. / Four oceanographic cruises have heen carried out off the southeastern Brazilian coast from Cabo Frio (23ºS) to Florianópolis (27°S) during the period from January 1980 to March 1982 by the R/V\" Prof. W. Besnard ,\". Fish larvae taken during these cruises were analysed and influences of abiotic factors on their occurrence were discussed.Problems regarding the sampling process were also discussed. Two kinds of sampling gears were used: Bongo nets fitted with a 0.505 mm and 0.333 mm mesh nets for oblique tow and Neuston net with a 0.333 mesh net for surface horizontal tow. At each sampling station, hydrographic data were sampled in addition to biological data. Total of 35,090 larvae were analysed. Sixty one groups were classified and some dominant ones were identified to spec1es level. Larvae belonging to two genera and four species were identified for the first time in the region under observation, i. e. Saurida spp., Hygophum spp., Synodus foetens, Trachinocephalus myops, Bregmaceros cantori and Maurolicus muelleri. The most abundant families were clupeidae, Engraulidae, Myctophidae and Gonostomatidae. In general, the ichthyoplankton from the southeastern Brazilian coast showed a large variety of larvae, but just few groups were outstandingly abundant. Analysing the relations between occurrence of fish larvae and hydrographic parameters, we found specific distri-bution patterns for each species. At the fixed station off Cabo Frio (22°59\'S; 042º05\'7W), 36 hour observations have been done and biological and hydrographic data have been collected every two hours. A change in the local oceanographic structure during the survey period has been observed along with wind induced coastal upwelling. A change of the oceanographic conditions associated with sampling time, may have influenced the occurrence of fish larvae. In order to obtain information on the distribution patterns of fish larvae in relation to distance from the coast, the samples collected on two transects off Cabo Frio and paranaguá were analysed. The presence of four different water masses in this region was confirmed and the occurrence and distribution of larvae seems to have close relationship with those water masses. Larvae of the family Gerreidae were more abundant in the coas tal water mass and those of Sardinella braziliensis, Harengula jaguana and Engraulis anchoita showed typical neritic distribution. Larvae belonging to the families Sciaenidae, Blenniidae, Ophídiidae, Carangidae and Cynoglossidae also showed the same distribution pattern. On the other hand, larvae belonging to the families Myctophidae, Gonostomatidae, Paralepedidae and Scombridae occurred mainly in the oceanic region where the influence of the Brazil Current is eminent. The ichthyoplankton collected at surface layer with Neuston net showed quite different types and size composition of fish larvae, In comparison with those taken with Bongo nets. Clear tendency of stratification in size composition at the surface layer was observed on some species (e.g. S.braziliensis). Larvae belonging to the families Mugilidae and Mullidae seems to be more concentrated at the surface layer, since they were more frequently sampled with the Neuston neto Three problems related to selectivity of plankton net (clogging, extrusion and avoidance) can be studied compar1ng the materials collected with the Bongo ets fitted with different mesh size nets and sampled at different times of the day. As shown in Figs. 23 and 24, there is no evidence of clogging of the fine mesh net during this survey. On the other hand, the extrusion of smaller larvae was confirmed for many groups and it was observed at sizes smaller than 7.5 mm, 6.5 mm, and 6.5 mm, respectively for S.brasiliensis, H.jaguana and E. anchoita. The avoidance was more remarkeble during the day time for larger larvae, but this problem varies depending on spec1es, migration pattern, and development stage of the visual system of each larvae

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-06-01T14:33:12Z No. of bitstreams: 1 gustavomartinsstroppa.pdf: 1222382 bytes, checksum: 4ef99b2b99f409674d64468fbebf599f (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-07-02T12:59:41Z (GMT) No. of bitstreams: 1 gustavomartinsstroppa.pdf: 1222382 bytes, checksum: 4ef99b2b99f409674d64468fbebf599f (MD5) / Made available in DSpace on 2016-07-02T12:59:41Z (GMT). No. of bitstreams: 1 gustavomartinsstroppa.pdf: 1222382 bytes, checksum: 4ef99b2b99f409674d64468fbebf599f (MD5) Previous issue date: 2012-02-27 / A ocupação das paisagens naturais por atividades humanas é uma das maiores ameaças à biodiversidade local. As consequências desta ocupação são a remoção dos habitats naturais e a formação de fragmentos isolados e menores que aquele original. Estudos sobre a composição e padrões de distribuição da fauna de lagartos e anfisbenídeos em ambientes de Mata Atlântica no estado de Minas Gerais são escassos. O presente trabalho teve como objetivo realizar um inventário faunístico de lagartos e anfisbenídeos na Fazenda Fortaleza de Sant’Anna, na Zona da Mata mineira, e fornecer informações a fim de ampliar o conhecimento da distribuição e composição da fauna de répteis Squamata do estado de Minas Gerais. A região onde o estudo foi realizado está inserida em uma das áreas prioritárias para a conservação da herpetofauna do Estado. As amostragens foram feitas no período entre fevereiro e dezembro de 2011, totalizando 28475 dias/balde e 56950 dias/funil. Foram instalados conjuntos de armadilhas de interceptação e queda, e armadilhas de funil em nove pontos do fragmento, três localizados na matriz no entorno da mata, três na borda da mata e três em áreas centrais do fragmento. Foram registrados 47 espécimes pertencentes a 12 espécies, distribuídas em 10 famílias: Amphisbaenidae, Anguidae, Diploglossidae, Gekkonidae, Gymnophthalmidae, Leiosauridae, Phyllodactylidae, Scincidae, Teiidae e Tropiduridae, sendo que o filodactilídeo Gymnodactylus darwinii foi a espécie mais abundante (n = 15) e a única encontrada em todas as áreas de amostragem com armadilhas. A espécie que se destacou dentre as menos abundantes foi Diploglossus fasciatus (n = 1), pois seus hábitos solitários e a baixa densidade em suas populações tornam seu registro mais raro. Entre as 12 espécies registradas, as exclusivas do ambiente “Matriz” foram Amphisbaena microcephala, Diploglossus fasciatus e Ophiodes striatus, no de “borda” foram Mabuya dorsivittata e Placosoma glabellum e na “Central” foi Heterodactylus imbricatus. Não houve diferença significativa na frequência de ocorrência entre as áreas de matriz, borda e centro do fragmento (t = 0,1955; p= 0,8989). A análise de variância mostrou que não houve diferença significativa no número de espécimes amostrados por cada área (t = 0,5937; p = 0,6717). A curva de acumulação de espécies dos pontos de coleta indicou que não houve estabilização no acréscimo de espécies de lagartos e anfisbenídeos para a região, indicando a necessidade de continuidade do trabalho. / The occupation of the natural landscape by human activities is the major threat to local biodiversity. Its consequences are the removal of natural habitats and formation of isolated fragments smaller than the original ones. Studies on composition and distribution patterns of the lizards and amphisbaenians in environments of the Atlantic Forest in Minas Gerais state are scarce. This study conducted an inventory of lizards and amphisbaenians fauna at Fortaleza de Sant'Anna farm in Zona da Mata of Minas Gerais, and provided information to expand knowledge of the distribution and composition of Squamata reptile fauna of the state of Minas general. The region of study is one of the priority areas for conservation of the herpetofauna in the state. The samples were taken in the period between February and December 2011, totaling 28475 days / bucket and 56950 days / funnel. Were installed sets of pitfall traps, funnel and drop in nine points of the fragment, three located in the matrix surrounding the forest, three in the forest edge and three in central areas of the fragment. We recorded 47 specimens belonging to 12 species were registered, distributed in 10 families: Amphisbaenidae, Anguidae, Diploglossidae, Gekkonidae, Gymnophthalmidae, Leiosauridae, Phyllodactylidae, Scincidae, Teiidae and Tropiduridae, and the filodactilídeo Gymnodactylus darwinii was the most abundant species (n = 15) and the only found in all of the sampling areas with traps. The species that stood out among the least abundant ones was Diploglossus fasciatus (n = 1), because their lonely habits and the low density in their populations turn his/her rarer registration. Among the 12 registered species, the exclusive of the "Matriz" atmosphere were Amphisbaena microcephala, Diploglossus fasciatus and Ophiodes striatus, in the one of "border" they were Mabuya dorsivittata and Placosoma glabellum and in the "Centro" it was Heterodactylus imbricatus. There was not significant difference in the occurrence frequency among the head office areas, it embroiders and center of the fragment (t = 0,1955; p = 08989). The variance analysis showed that there was not significant difference in the number of specimens for each area (t = 0,5937; p = 06717). The curve of accumulation of species of the collection points indicated that there was not stabilization in the increment of species of lizards and anfisbenídeos for the area, indicating the need of continuity of the work.

Orientador: Marlies Sazima / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-23T01:09:15Z (GMT). No. of bitstreams: 1 Bugoni_Jeferson_M.pdf: 1779584 bytes, checksum: 28e75bbf88520708b08ce2dffeb7b431 (MD5) Previous issue date: 2013 / Resumo: Neutralidade, complementaridade nos fenótipos das espécies e restrições filogenéticas são alguns dos principais determinantes da estrutura das redes de interações entre espécies. Embora diversos padrões estruturais das redes tenham sido descritos, a importância relativa dos mecanismos que os geram permanece em discussão. Neste estudo, investigamos a importância relativa da abundância (neutralidade) e da complementaridade fenológica e morfológica (interações permitidas ou proibidas) na estruturação de uma rede de interações planta-beija-flor na Floresta Atlântica (SE Brasil). Encontramos que fenologia e morfologia juntas compõem o modelo que melhor prediz a frequência de interações entre pares de espécies, entretanto os modelos não foram capazes de predizer acuradamente a maioria das métricas agregadoras de redes (aninhamento, conectância, equitabilidade e assimetria na força de interação). Em contraste com os estudos prévios, nossos resultados mostram que a importância das interações proibidas pode sobrepujar a importância da abundância na determinação de quais interações ocorrem na comunidade. Os estudos prévios podem ter subestimado a importância das interações proibidas em detrimento das abundâncias relativas (neutralidade) devido à insuficiência amostral. Adicionalmente, discutimos que as métricas de redes, ainda que sejam úteis para descrever padrões de interações em comunidades, podem ser pouco informativas sobre os mecanismos geradores da estrutura das redes de interações / Abstract: Neutrality and complementarity in the phenotypes of species as well as phylogenetic constraints are the main determinants of the structure of interaction networks. Although several structural patterns of the networks have been described, the relative importance of the mechanisms that generate them remains under discussion. In this study, we investigated the relative importance of abundance (neutrality) and phenological and morphological complementarity (forbidden links) in the structure of a plant-hummingbird network in the Atlantic Forest (SE Brazil). We found that the combination of phenological and morphological matches of interacting species represents the best model that predicts the frequency of interactions between pairs of species. Nevertheless, models were not able to accurately predict most of the network metrics - nestedness, connectance, and interaction evenness and interaction asymmetry. In contrast to previous studies, our results highlight the importance of forbidden links that may overcome the importance of relative abundances (neutrality) in the structure of the interactions at the community level. Previous studies could have underestimated the importance of complementarity in the species phenotypes due to insufficient sampling effort, while neutrality was likely overestimated. Finally, although network metrics have been useful for describing network structures, we argue that these metrics can tell us little about the mechanisms that generate the structure of networks / Mestrado / Ecologia / Mestre em Ecologia

Coral reefs are one of the world’s most diverse yet heavily impacted marine ecosystems. As a result of many direct and indirect stressors, coral reefs have experienced major degradation over the last several decades. Declines in coral reefs in the Caribbean have been particularly acute and generally associated with the loss of key herbivores and an increase in algae. Herbivorous fishes such as parrotfishes can positively impact coral reefs by removing algae that compete with corals for light and space. However, many parrotfishes are also important coral predators. Predation on corals, known as corallivory, can adversely affect coral growth, reproduction and survivorship. In this time of changing environments and coral reef decline, understanding the context-dependent nature of parrotfish foraging behavior is of critical importance to scientists and managers. Knowledge of the responses of parrotfishes across a range of resource abundance will help scientists and managers better predict the impacts that these herbivores have on benthic communities as both herbivores and corallivores. In Chapter 1, we examined how six different species of coral reef herbivores (i.e. parrotfishes), all of which belong to a single feeding guild but represent a range of dietary specialization, respond to changes in the abundance of preferred food items. We conducted behavioral observations of parrotfishes in two regions of the Greater Caribbean, and compared consumption rates, diet preferences, and foraging territory size in relation to natural variation across sites in preferred resource abundance. We found that the more-specialized parrotfishes increased their dietary specialization, had smaller foraging territories, and increased their feeding rate with increased preferred resource abundance. In contrast, less-specialized species exhibited constant foraging traits regardless of the abundance of their preferred resources. This study suggests that differences in dietary preference, specialization, and subsequent nutritional demand may drive a differential response in foraging behavior by generalists and specialist herbivores to changes in resource abundance. Recognizing that generalists and specialists differ in the degree to which their foraging behaviors are context-dependent can allow researchers to better predict how herbivores shape the structure and function of marine and terrestrial ecosystems. In Chapter 2, we determined if and how corallivory rates and intensity by parrotfishes differ between two regions of the Greater Caribbean that vary in coral and parrotfish community composition and abundance. We found that more species of parrotfishes than previous studies suggest contribute to corallivory. However, corallivory rates and selectivity for coral species by parrotfishes were largely context-dependent, particularly with regards to the relative abundance of preferred corals and diversity of corallivores at a given site. Although we found that corallivory rates decrease with coral cover, it appears that areas of low coral cover may have high corallivory intensity and coral tissue loss, in part due to the relatively high abundance of corallivores in these areas. The impact of high corallivory intensity and tissue loss requires further knowledge regarding the fate of bite scars on corals.This information will help predict the positive and negative consequences of parrotfishes on coral persistence in the Caribbean. Evidence provided in this thesis furthers our understanding of the dual role of parrotfishes as herbivores and corallivores. Additionally, it reveals the implications of changing coral reef habitats on parrotfish behavior and subsequent coral reef health and resilience.

La mise en place d'objectifs de conservation adéquats repose sur la définition d'états de référence appropriés pour la distribution et l'abondance des espèces. Cependant, l'étendue des impacts cumulés de l'homme sur les écosystèmes est aujourd'hui largement sous-estimée. Dans ce projet, je m'intéresse aux opportunités qu'offre l'utilisation de données historiques combinées à différentes méthodes analytiques pour définir ces états de référence ainsi qu'aux défis posés par ce type d'approche. Des données de présence ont été recueillies pour sept espèces de cétacés et trois espèces de pinnipèdes à partir de sources archéologiques, historiques et industrielles, révélant des réductions dans la distribution et l'abondance des espèces depuis la préhistoire à nos jours. Des modèles de distribution d'espèces ont été développés pour cinq espèces de cétacés, combinant des données de chasse baleinière du 19ème siècle à des variables environnementales afin d'estimer la distribution historique des espèces avant qu'elles n'aient été chassées. J'ai obtenu pour la baleine franche de l'Atlantique Nord (Eubalena glacialis) une estimation détaillée de sa distribution et de son abondance avant qu'elle ne soit exploitée, en extrapolant des connaissances sur la distribution et l'abondance d'une espèce congénérique, la baleine franche du Pacifique Nord (E. japonica). Ces résultats suggèrent que la baleine franche de l'Atlantique Nord occupe une portion réduite de sa distribution historique, et que son abondance actuelle ne représente qu'une infime portion (<5%) de son abondance passée. Plus généralement, ces résultats soulignent l'importance de considérer des données historiques pour comprendre le niveau d'impact par l'homme sur les espèces, évaluer leur niveau de déplétion et renseigner leur potentiel de rétablissement dans l'avenir. / Relevant baselines on the historical distribution and abundance of species are needed to support appropriate conservation targets for depleted species, but the full scale of cumulative human impacts on ecosystems is highly underestimated. In this project, I investigated the challenges and opportunities of combining historical data with analytical methods to improve these historical baselines. Occurrence data from archaeological, historical and industrial sources were reviewed for seven cetacean and three pinniped species, revealing range contractions and population depletions from prehistorical times to today. For five whale species, I used species distribution modelling to combine 19th Century whaling records with environmental data, to estimate pre-whaling distributions. For the highly depleted North Atlantic right whale, (Eubalaena glacialis), I obtained a detailed estimate of pre-whaling distribution and abundance by inferring from the historical distribution and abundance of its congeneric North Pacific right whale (E. japonica). These results suggest that the North Atlantic right whale occupies a small fraction of its historical range and that its current population represents <5% of its historical abundance, with implications for the management, monitoring and conservation targets of this species. More generally, these results emphasize the utility of considering historical data to understand the extent to which species have been impacted by humans, assess their current level of depletion, and inform the options available for their future recovery.

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Seabirds are often used as indicator species for changes in marine ecosystems due to the species visibility and sensitivity to changing conditions, such as changes in prey abundance. They often reside in habitats affected by anthropogenic impacts such as large-scale fisheries and pollution. Understanding the connection between seabirds and their surrounding environment can give us important insight about the ecology of the ocean and how anthropogenic pressures affects it. Studying feeding habits, and foraging behavior especially, is useful for understanding seabird´s responses to changing environments. Feeding studies are commonly used in seabird monitoring and requires a lot of time and resources. Monitoring of seabirds are also logistically challenging, and the risk of disturbing bird colonies must be considered. It can be especially complicated when studying cliff nesting seabirds such as the common murre, Uria aalge, the study species for this thesis. Photography as a method for monitoring seabirds may limit the need of people on site, hence minimize disturbance and save time and resources. This study provides insight in whether it is a viable option to use photography instead of on-site field studies when monitoring sea birds. This was accomplished by installing cameras and monitor a feeding study at Stora Karlsö, Sweden, parallel with performing the usual monitoring in the field. This thesis makes it clear that a camera study very well could replace the field study without any larger concerns, although, improvements need to be considered if the study is to maintain a high quality and for results to be reliable.

The vegetation provides an ecological space for birds and its structure reflects the availability of this place and resources. What specific influence does the vegetation structure have on bird abundance and which vegetation parameters are the most essential for bird species are classic, but still topical questions. The aim of this work was to find an answer using a study focused on birds in floodplain forests and to determine whether microhabitat characteristics affect the distribution of bird species within a single habitat. The data of this work were collected by the point counting method in six floodplain forests of the Czech Republic and Slovakia and statistically evaluated using regression, correlation and redundancy analysis. The birds were observed on a larger and smaller spatial scale. It was also used the study of the saturation of the environment by bird species over time and for the first time the analysis of habitat photo documentation as an alternative way for describing the vegetation structure. Results show that the analysis of vegetation photographs can be used to explain and predict avian abundance and thus create a new suitable method for birds' studies. Some bird species such as the collared flycatcher (Ficedula albicollis) and the Eurasian blue tit (Cyanistes caeruleus) have...

Currently, most scientific attention focused on bird population trends is centred on birds in the agricultural landscape. Forest bird research, on the other hand, is given far less space, despite the fact that forests in Europe often form a substantial part of the landscape in some parts. Moreover, it is undergoing drastic changes throughout Europe, and especially in the Czech Republic. In the second half of the 20th century, their quality deteriorated due to air pollution, later regenerated, but other additional challenges have emerged, such as global climate change and epidemics of wood-destroying insects. It is therefore possible to assume their fundamental influence on forest bird populations. However, most of the work examining the effects of the forest environment and forest management on bird populations is only very local, limited to ecologically valuable, and therefore quite specific, habitats, or covering only a small number of bird species. However, data on the evolution of forest birds vary across Europe. In Finland, for example, forest birds are declining, while in neighbouring Sweden the trend is the opposite. In this study, I aim to better map what characteristics of forests affect specific species of birds, in research conducted throughout the Czech Republic. I decided to explore...