The paper presents a simulation and parameter-estimation approach for evaluating stochastic patterns of population growth and spread of an annual forest herb, Melampyrum pratense (Orobanchaceae). The survival of a species during large-scale changes in land use and climate will depend, to a considerable extent, on its dispersal and colonisation abilities. Predictions on species migration need a combination of field studies and modelling efforts. Our study on the ability of M. pratense to disperse into so far unoccupied areas was based on experiments in secondary woodland in NE Germany. Experiments started in 1997 at three sites where the species was not yet present, with 300 seeds sown within one square meter. Population development was then recorded until 2001 by mapping of individuals with a resolution of 5 cm. Additional observations considered density dependence of seed production. We designed a spatially explicit individual-based computer simulation model to explain the spatial patterns of population development and to predict future population spread. Besides primary drop of seeds (barochory) it assumed secondary seed transport by ants (myrmecochory) with an exponentially decreasing dispersal tail. An important feature of populationpattern explanation was the simultaneous estimation of both population-growth and dispersal parameters from consistent spatio-temporal data sets. As the simulation model produced stochastic time series and random spatially discrete distributions of individuals we estimated parameters by minimising the expectation of weighted sums of squares. These sums-ofsquares criteria considered population sizes, radial population distributions around the area of origin and distributions of individuals within squares of 25*25 cm, the range of density action. Optimal parameter values, together with the precision of the estimates, were obtained from calculating sums of squares in regular grids of parameter values. Our modelling results showed that transport of fractions of seeds by ants over distances of 1…2 m was indispensable for explaining the observed population spread that led to distances of at most 8 m from population origin within 3 years. Projections of population development over 4 additional years gave a diffusion-like increase of population area without any “outposts”. This prediction generated by the simulation model gave a hypothesis which should be revised by additional field observations. Some structural deviations between observations and model output already indicated that for full understanding of population spread the set of dispersal mechanisms assumed in the model may have to be extended by additional features of plant-animal mutualism.

La production porcine européenne fait face à des enjeux économiques et environnementaux. Les outils d’aide à la décision peuvent aider les éleveurs à tester les effets des facteurs d’élevage sur leur système de production. Nous avons développé un modèle individu-centré de l’atelier d’engraissement porcin, qui intègre la variabilité des performances entre individus, la conduite d’élevage, et estime les résultats technico-économiques (ECO) et les impacts environnementaux (ENV) de l’atelier. L’analyse de sensibilité a montré que le comportement du modèle est cohérent et que les variables d’entrée les plus influentes sont les caractéristiques des porcs. La comparaison des valeurs prédites et observées nous a permis de construire un processus de paramétrage et a montré que le modèle fournit des estimations fiables des résultats ECO et ENV de l’atelier.Une expérimentation virtuelle a été effectuée pour évaluer les effets combinés des pratiques d’alimentation, du statut sanitaire du troupeau, et des infrastructures. Le statut sanitaire a un impact majeur sur les résultats ECO et ENV, pouvant être atténué par le choix de la conduite en bandes et de la stratégie d’alimentation. S’approcher au plus près des besoins nutritionnels individuels des porcs semble être une solution appropriée pour améliorer le revenu de l’élevage et réduire ses impacts quel que soit son statut sanitaire. Ce modèle sera inclus dans un outil d’aide à la décision construit en accord avec les résultats de l’analyse de sensibilité et le processus de paramétrage développé. / European pig production is facing economic and environmental challenges. Decision support tools can help farmers testing the effects of rearing factors on their production system. For this purpose, we developed an individual-based model of the pig fattening unit which includes farmers’ practices, individual variability in performance among pigs and, and estimates economic results (ECO) and environmental impacts (ENV) of the unit. Global sensitivity analysis has shown that the model behavior is consistent and that the most influent input variables are related to the pigs’ characteristics. Formal comparison of predicted with observed data has enabled us to produce a process for parameterisation of the model and has shown that the model provides reliable estimates of ECO and ENV.A virtual experiment using the model was designed in order to evaluate the combined effects of feeding practices, health status of the pig herd, and infrastructure on technical performance, ECO and ENV of the unit. Health status has the major impact on unit performance but this effect can be reduced through batch management and feeding strategies. Approaching more closely the individual pigs’ nutritional requirements seems to be an appropriate solution to increase farm income and to reduce environmental impacts regardless the health status. The model will be included into a decision support tool designed according to the influent inputs resulting from the sensitivity analysis and the parameterisation process

No description available.

In this paper we endeavor to test the controversial ideas that exist about the role of fragmentation in a conservation context. In line with earlier understanding, we find that habitat fragmentation alone results in a strong detrimental effect (especially for the predator population). Connecting the fragmented habitats facilitates predator survival and hence prey survival as compared to the unconnected fragmented case. Our main result is counterintuitive: in the presence of a high quality predator, connected fragmented habitats ensure a better chance for coexistence than does even the unfragmented case. We explain why a connected fragmented habitat might thus be beneficial for the stabilization of the system, and how connections between sub-habitats are able to protect prey population from over-exploitation. In the model, habitat fragmentation is separated from the effects of habitat destruction, in order to better understand how populations react to habitat transformation.

White-tailed deer (Odocoileus virginianus) dispersal and excursion movements impact gene flow, population dynamics, and disease spread. Knowledge of movement characteristics and habitat selection during dispersal could provide the ability to predict how deer may relocate themselves within the landscape while providing managers valuable information regarding corridors for gene flow and disease spread. My objectives were to 1) test the hypothesis that extra-home-range movements occur as a strategy to broaden mating opportunities or as a means of searching for higher quality resources in this fragmented landscape, 2) compare occurrence rates and path movement metrics for dispersal and excursion movements to determine if underlying differences in behavior exist that would allude to mechanisms for accepting the risk of leaving a home range, 3) create and test the performance of expert opinion and step selection function resistance models at predicting deer dispersal movements, and 4) fit single and multiple random walk models to dispersal path data to determine movement states occurring within this behavior. During 2011-2014, I placed GPS collars programmed to take hourly locations on 49 fawn and yearling white-tailed deer in agricultural east-central Illinois to record dispersal and excursion movement paths. Linear mixed effects models were used to test for differences in path characteristics between sexes and ages (e.g., distance, straightness, duration, and speed). I used known-fate models, with demographic, temporal, and home range variables as covariates, to obtain dispersal and excursion occurrence rate estimates. Ten dispersal and 54 excursion movement paths were recorded during the study. Dispersal paths were longer and straighter (P < 0.001), and trended toward being longer in duration (P = 0.080) and faster in speed (P = 0.085), than excursion paths. Dispersal rates differed by sex (annual estimate ± SE with ages pooled: males 0.81 ± 0.12, females 0.16 ± 0.15) and were greatest during the breeding season (14-day estimates for males: winter 0.00 ± 0.01, fawning 0.02 ± 0.1, prebreeding 0.01 ± 0.01, and breeding 0.31 ± 0.15, and females: winter 0.00 ± 0.01, fawning 0.01 ± 0.1, prebreeding 0.01 ± 0.01, and breeding 0.04 ± 0.03). In contrast, I found no evidence that excursion rates were influenced by demographic, temporal, or home range variables (annual: 0.78 ± 0.06). I compared 2 methods of resistance modeling for predicting deer dispersal paths. I created an expert opinion survey and calculated a dispersal step selection function (SSF) to rank habitat variables and create 2 types of resistance maps to dispersal movements. I created least-cost paths with the starting and ending points coinciding with recorded dispersal paths within these 2 resistance maps. I compared the created paths to actual paths and a null straight line path using a path deviation index (PDI), path straightness, and path cost/m as variables of interest. Experts ranked land cover variables differently by season, applying a lower resistance value to agriculture cover during the summer/fall period, so 2 versions of the expert opinion resistance maps were created. For the SSF, I found that both forest cover and streams had significant nonlinear effects on deer dispersal movements. Assuming that all other factors remained constant, deer were more likely (≥ 0.50 probability) to move toward forested habitat when located < 335 m and when > 2795 m away. Deer dispersal movement behavior relating to streams followed a similar trend but with deer always having > 0.56 probability to move toward a stream than away. For least-cost path comparison, I conducted 3 ANOVAs (α = 0.05 throughout) to test for mean differences in calculated path metrics for all paths with path type as a within-subjects effect. I found no difference between the expert opinion survey model, the SSF model, and the null straight line model at predicting dispersal paths. PDI values were similar among all models (F1,9 = 0.004, P = 0.99). The SSF paths (0.91 ± 0.02) were significantly straighter then both the expert opinion (0.57 ± 0.03) and actual deer paths (0.44 ± 0.06; F1, 9 = 32.65, P < 0.001), but the expert opinion path did not differ from the actual path (P = 0.08). Path costs differed within the expert opinion survey resistance map (F1, 9 = 14.21, P < 0.001) with the expert opinion least cost paths (23.64 ± 3.14) having lower resistance/m than both the actual (46.15 ± 3.85) and straight line paths (48.74 ± 3.94; P < 0.001 for both). However, the actual and straight line paths did not differ (P = 0.872). There were no difference in path costs between the actual, SSF least-cost path, and straight line paths within the SSF resistance map (F1, 9 = 0.454, P = 0.64). I constructed and attempted to fit single and multiple random models to collected dispersal locations using WinBUGS v. 1.4.3. I was able to fit a single random walk model to deer dispersal paths but the more complex random walk models did not converge. I used the average parameter values derived from the single model to simulate deer dispersal paths and compared them to observed Net Squared Displacement. My simulated paths underpredicted deer displacement for 0.90 of individuals. Deer in east-central Illinois are very mobile and commonly make excursion movements throughout the year. The fact that I recorded differing dispersal rates within the same study area over a temporally short period from a previous study highlight the need for managers to obtain recent estimates of population parameters when making management decisions. The frequency of excursion movements should not be overlooked by managers as it is a behavior that can influence gene flow and potentially spread disease across the landscape at a localized scale. The preference for forest and stream habitats during dispersal can allow managers to focus surveillance or culling efforts around these types of habitats. The application of the least-cost path modeling technique appears to be ineffective at predicting deer dispersal paths, which emphasizes the importance of validating these types of models with actual data. The results from the random walk analysis highlight the need to collect as many locations as possible during temporally-short movements to understand the mechanisms acting upon them.

No description available.

Uma efetiva ação de conservação depende de um claro entendimento de como as espécies respondem às características ambientais, em particular à cobertura, configuração espacial e qualidade do habitat. No entanto, nem sempre esses dados estruturais da paisagem estão disponíveis em extensão e escala compatíveis com o planejamento ambiental. Ademais, a obtenção de dados empíricos sobre as respostas das espécies à estrutura da paisagem é longa e custosa, o que exige abordagens alternativas para o entendimento destas relações. Esta tese teve dois objetivos principais: i. gerar informações atualizadas sobre as características espaciais dos remanescentes de Mata Atlântica, estimando a quantidade e distribuição de mata existente ao longo de todo o Domínio fitogeográfico, além de avaliar a distribuição da floresta em relação a características do relevo; ii. avaliar, através de modelos de simulação, o efeito da estrutura da paisagem, qualidade de habitat e atributos das espécies, em processos associados à movimentação de aves. A Mata Atlântica é uma das florestas com maior biodiversidade do planeta, mas está também entre as mais ameaçadas, dado o avançado estágio de perda e fragmentação do hábitat, o que a coloca entre os principais hotspots do planeta. Na primeira parte desta tese, estimamos que a cobertura da Mata Atlântica está entre 12 a 16% (em função de erros de mapeamento), o que representa um valor intermediário em relação às estimativas anteriores (7-8%, ou 22-23%). Os dados de configuração mostram uma situação pouco favorável para conservação das espécies. Mais de 80% dos fragmentos remanescentes são menores que 50 hectares, tamanho extremamente reduzido e incapaz de preservar a maioria das espécies florestais. Ademais, quase a metade da floresta existente está a menos de 100 m de ambientes antropizados, sendo que as áreas mais distantes da borda ficam a aproximadamente 12 km da matriz. Outro fato alarmante é a grande distância média entre os remanescentes de mata (1.440 m), o que torna difícil a movimentação de indivíduos entre fragmentos. A quantidade de unidades de conservação é extremamente reduzida, correspondendo apenas a aproximadamente 1% da Mata Atlântica original, bem abaixo dos 10% sugeridos como mínimo para a manutenção de espécies. As faixas de altitude acima de 1200 m mantêm mais de 20% da cobertura original, enquanto as faixas mais baixas conservam somente 10% da floresta. Algumas diretrizes de conservação e restauração por sub-regiões biogeográficas foram propostas, porém tais regiões apresentaram-se muito extensas para a definição de ações de manejo. Este fato nos levou a sugerir a subdivisão do domínio em 55 novos compartimentos, considerando características de clima e relevo, além dos aspectos biogeográficos. Na segunda parte desta tese, foi desenvolvido o BioDIM (Biologically scaled dispersal model), um modelo baseado em indivíduos que simula a movimentação de aves florestais calibradas para espécies encontradas na Mata Atlântica. O BioDIM inclui vários perfis (i.e. sensibilidades) de espécies, permitindo simular desde espécies muito sensíveis (preferência pelo interior dos fragmentos), até espécies moderadamente generalistas (cruzam até 120 m através de ambientes abertos). Além da sensibilidade a ambientes abertos ou de borda, a área de vida (i.e. requerimento de habitat), e o deslocamento máximo diário ou explorativo (i.e. quando o indivíduo está dispersando) também foram considerados. As simulações com o BioDIM foram feitas para 10.000 paisagens simuladas, apresentando grande variação de porcentagem (de 5 a 70%), agregação e qualidade do habitat, o que nos permitiu estudar uma ampla gama de paisagens, o que não seria viável em estudos empíricos. Os resultados sugerem as características das espécies e a estrutura da paisagem foram igualmente importantes para explicar os processos ecológicos analisados, porém a qualidade de habitat foi pouco influente. A sensibilidade das espécies foi o fator mais importante para explicar a mortalidade de indivíduos e a taxa de dispersão, sendo um fator de efeito secundário para o custo de movimentação e para a taxa de encontros entre indivíduos. A porcentagem de cobertura foi o fator mais influente para custo de movimentação, enquanto para a taxa de encontros o efeito primário foi o tamanho da área de vida. Uma surpresa foi que, ao se avaliar os efeitos para cada perfil de espécie, observou-se que a agregação de habitat foi tão importante quanto a quantidade de habitat para explicar alguns processos, independente da quantidade de habitat, oposto do que tem sido sugerido na literatura. Isto sugere que as variáveis de paisagem são importantes ao longo de todo o processo de conversão do habitat, e devem ser cuidadosamente consideradas na tomada de decisão voltada ao manejo para a conservação de espécies. / Effective conservation actions depend on a clear understanding of how species respond to environmental factors, particularly to the amount of habitat and the spatial arrangement and quality of this habitat. However, landscape structure information is not always available to the extent and scale needed to promote effective conservation planning. Additionally, acquiring biological information of how species respond to landscape structure is particularly expensive in time and money. This thesis has two main goals: i. to generate updated information about the amount and spatial distribution of the remnants of the Brazilian Atlantic Forest, combining information on the remaining forest and landscape relief; ii. untangle the effects of landscape structure, habitat quality, and species traits on ecological processes related to the movements of Atlantic Forest bird species, using simulation models. The Atlantic Forest is one of the most biodiverse regions on the planet, but is also among the most threatened because of the high degree of habitat loss and fragmentation, which confer the status of biodiversity \"hotspot\" on the region. In the first part of the thesis, I estimated that the remaining Brazilian Atlantic Forest occupies between 12-16% of its original extent (considering mapping errors), which is an intermediate estimate compared to previous ones (7-8%, or 22-23%). The spatial distribution of this forest indicates poor conditions for species conservation. More than 80% of the remaining forest is distributed in patches smaller than 50 ha, which is extremely reduced in size and incapable of preserving most of the forest species. Additionally, half of the remaining forest is less than 100 m distant from any edge, and the farthest point within any forest is about 12 km from the surrounding matrix. Another critical point is the high degree of isolation between patches (mean 1 440 m), which impedes the movement of individuals between forest fragments. Protected areas are extremely small, approximately 1% of the original extent, which is below the 10% suggested as the minimum amount for species maintenance. Higher-altitude areas (> 1200 m) retain more than 20% of the original cover; whereas in lower altitudes, such as from 400 to 800 m, only about 10% of the original forest still exists. Some conservation and restoration measures for the entire region and within biogeographical sub-regions are suggested, but I consider the subregions too extensive for defining appropriate management actions. Thus, I refined the subdivision of the entire region into 55 new sub-regions, considering climate and relief characteristics, as well as biogeographical aspects. In the second part of this thesis I developed a program called BioDIM (Biologically scaled dispersal model), an individual-based model calibrated to simulate the movement of Atlantic Forest bird species in fragmented landscapes. Five species profiles (i.e., species sensitivity) are already available in BioDIM, which allows us to simulate movements from highly sensitive species (which avoid forest edges), to moderately generalist ones (capable of crossing 120 m of open matrix). Home-range size (a surrogate for habitat amount requirement) and maximum routine and explorative distances per day can also be set. I generated 10 000 simulated landscapes, varying in habitat amount (5 to 70%), aggregation, and quality, which made it possible to evaluate landscape variability to a degree that would not be possible in real conditions. The results suggest that species traits and landscape structure were both important to explain the ecological processes, but habitat quality contributed relatively little. Species sensitivity was the prime factor in explaining dispersal rate and mortality, and had a secondary effect on movement cost and encounter rate. Habitat amount was the most influential factor to explain movement cost, and home-range size was the prime factor for encounter rate. Astonishingly, we observed that, within species profiles, habitat aggregation was as important as habitat amount to explain several ecological processes, independently of the percentage of forest amount. This is the opposite of what has been observed in the literature. These results indicate that landscape variables are important for all habitat conversion processes, and that they must be carefully considered in decision-making for species conservation management.

Orientador: Miguel Petrere Júnior / Banca: Claudio José Von Zuben / Banca: Carlos Edward de Carvalho Freitas / Banca: Ronaldo Angelini / Banca: Angelo Antonio Agostinho / Resumo: Um modelo baseado no indivíduo para história de vida e interações tróficas de peixes é proposto nesta tese. Ele integra teorias sobre fisiologia, crescimento, reprodução e alimentação num mesmo arcabouço dinâmico. As comunidades são formadas por um processo seqüencial de assembleamento que seleciona espécies com melhor ajuste às condições locais. No capítulo 1, experimentos computacionais foram feitos para avaliar a resposta seletiva de 10 características bionômicas em gradientes de produtividade, taxas de ataque por predadores, distribuição do tamanho corporal no conjunto regional de espécies, e a presença/ausência de assimetrias nas habilidades dos peixes em consumir presas e em evitar predação. Este último fator inclui conflitos funcionais entre a eficiência de captura versus generalidade de dieta e intensidade de forrageamento versus defesa contra predadores. As comunidades resultantes foram fortemente afetadas pelos gradientes. Picos de riqueza ocorrem em produtividades moderadamente baixas, associadas a baixas taxas de ataque, o que pode estar relacionado ao efeito estabilizador de respostas funcionais menos saturadas e às características emergentes das espécies. Com alta disponibilidade de recursos, espécies de rápido crescimento e tamanhos variados dominaram, promovendo rápida depleção dos recursos durante a formação das comunidades e ocasionando fortes efeitos de prioridade. As assimetrias de consumo aumentaram a coexistência onde ela tende a ser mais difícil, mas a diminuíram em seus pontos de pico. Mas seu principal efeito foi o de modificar a composição ao longo dos gradientes, modulando o formato das associações emergentes entre as características biológicas das espécies bem sucedidas. No capítulo 2 foram realizados experimentos de invasão e exclusão, para avaliar como as características das espécies... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: An individual-based model for fish life history and trophic interactions is here proposed. It integrates theories for individual physiology, growth, reproduction, and feeding in the same dynamical framework. Communities are formed by a sequential assembly process which selects for species best adjusted to local conditions. Simulation experiments were carried out to evaluate the distribution of diversity and selective response of 10 bionomic features along gradients of resource productivity, predators maximum attack rates, body size distribution in species pool, and the presence/absence of asymmetries in both the abilities of fish to consume prey and to avoid being consumed. This last factor includes tradeoffs concerning capture efficiency versus diet generality and foraging intensity (associated to growth rate) versus defense against predators. The resulting communities were strongly affected by the gradients. Richness peaks are localized at moderately low productivities associated to low maximum attack rates, which might be related to the stabilizing effect of less saturated functional responses and to the emergent features of selected species. At high resource availability, fast growing species with variable sizes dominated, promoting early fast resource depletion during assembly and leading to strong priority effects. The hierarchical consumption asymmetries increased coexistence where it tends to be more difficult, but diminished it at its points of peak. But its main effect was modifying species trait composition along other gradients, modulating the shape of emergent associations among biological features of successful species. Additional invasion and deletion experiments were carried out to evaluate how species and community features are related invasion success and native extinctions. Successful invaders tend to possess similar life-history features to invaded community, but low... (Complete abstract click electronic access below) / Doutor

Two types of mathematical models incorporating several types of competition between two species of African carnivores were constructed and analysed. The heuristic model focuses on population dynamics of both carnivores and their shared prey. The individual-based model focuses on the role of habitat heterogeneity and unique features of ecology of one of the predators, using the African wild dogs and hyaenas as a case study.

Uma efetiva ação de conservação depende de um claro entendimento de como as espécies respondem às características ambientais, em particular à cobertura, configuração espacial e qualidade do habitat. No entanto, nem sempre esses dados estruturais da paisagem estão disponíveis em extensão e escala compatíveis com o planejamento ambiental. Ademais, a obtenção de dados empíricos sobre as respostas das espécies à estrutura da paisagem é longa e custosa, o que exige abordagens alternativas para o entendimento destas relações. Esta tese teve dois objetivos principais: i. gerar informações atualizadas sobre as características espaciais dos remanescentes de Mata Atlântica, estimando a quantidade e distribuição de mata existente ao longo de todo o Domínio fitogeográfico, além de avaliar a distribuição da floresta em relação a características do relevo; ii. avaliar, através de modelos de simulação, o efeito da estrutura da paisagem, qualidade de habitat e atributos das espécies, em processos associados à movimentação de aves. A Mata Atlântica é uma das florestas com maior biodiversidade do planeta, mas está também entre as mais ameaçadas, dado o avançado estágio de perda e fragmentação do hábitat, o que a coloca entre os principais hotspots do planeta. Na primeira parte desta tese, estimamos que a cobertura da Mata Atlântica está entre 12 a 16% (em função de erros de mapeamento), o que representa um valor intermediário em relação às estimativas anteriores (7-8%, ou 22-23%). Os dados de configuração mostram uma situação pouco favorável para conservação das espécies. Mais de 80% dos fragmentos remanescentes são menores que 50 hectares, tamanho extremamente reduzido e incapaz de preservar a maioria das espécies florestais. Ademais, quase a metade da floresta existente está a menos de 100 m de ambientes antropizados, sendo que as áreas mais distantes da borda ficam a aproximadamente 12 km da matriz. Outro fato alarmante é a grande distância média entre os remanescentes de mata (1.440 m), o que torna difícil a movimentação de indivíduos entre fragmentos. A quantidade de unidades de conservação é extremamente reduzida, correspondendo apenas a aproximadamente 1% da Mata Atlântica original, bem abaixo dos 10% sugeridos como mínimo para a manutenção de espécies. As faixas de altitude acima de 1200 m mantêm mais de 20% da cobertura original, enquanto as faixas mais baixas conservam somente 10% da floresta. Algumas diretrizes de conservação e restauração por sub-regiões biogeográficas foram propostas, porém tais regiões apresentaram-se muito extensas para a definição de ações de manejo. Este fato nos levou a sugerir a subdivisão do domínio em 55 novos compartimentos, considerando características de clima e relevo, além dos aspectos biogeográficos. Na segunda parte desta tese, foi desenvolvido o BioDIM (Biologically scaled dispersal model), um modelo baseado em indivíduos que simula a movimentação de aves florestais calibradas para espécies encontradas na Mata Atlântica. O BioDIM inclui vários perfis (i.e. sensibilidades) de espécies, permitindo simular desde espécies muito sensíveis (preferência pelo interior dos fragmentos), até espécies moderadamente generalistas (cruzam até 120 m através de ambientes abertos). Além da sensibilidade a ambientes abertos ou de borda, a área de vida (i.e. requerimento de habitat), e o deslocamento máximo diário ou explorativo (i.e. quando o indivíduo está dispersando) também foram considerados. As simulações com o BioDIM foram feitas para 10.000 paisagens simuladas, apresentando grande variação de porcentagem (de 5 a 70%), agregação e qualidade do habitat, o que nos permitiu estudar uma ampla gama de paisagens, o que não seria viável em estudos empíricos. Os resultados sugerem as características das espécies e a estrutura da paisagem foram igualmente importantes para explicar os processos ecológicos analisados, porém a qualidade de habitat foi pouco influente. A sensibilidade das espécies foi o fator mais importante para explicar a mortalidade de indivíduos e a taxa de dispersão, sendo um fator de efeito secundário para o custo de movimentação e para a taxa de encontros entre indivíduos. A porcentagem de cobertura foi o fator mais influente para custo de movimentação, enquanto para a taxa de encontros o efeito primário foi o tamanho da área de vida. Uma surpresa foi que, ao se avaliar os efeitos para cada perfil de espécie, observou-se que a agregação de habitat foi tão importante quanto a quantidade de habitat para explicar alguns processos, independente da quantidade de habitat, oposto do que tem sido sugerido na literatura. Isto sugere que as variáveis de paisagem são importantes ao longo de todo o processo de conversão do habitat, e devem ser cuidadosamente consideradas na tomada de decisão voltada ao manejo para a conservação de espécies. / Effective conservation actions depend on a clear understanding of how species respond to environmental factors, particularly to the amount of habitat and the spatial arrangement and quality of this habitat. However, landscape structure information is not always available to the extent and scale needed to promote effective conservation planning. Additionally, acquiring biological information of how species respond to landscape structure is particularly expensive in time and money. This thesis has two main goals: i. to generate updated information about the amount and spatial distribution of the remnants of the Brazilian Atlantic Forest, combining information on the remaining forest and landscape relief; ii. untangle the effects of landscape structure, habitat quality, and species traits on ecological processes related to the movements of Atlantic Forest bird species, using simulation models. The Atlantic Forest is one of the most biodiverse regions on the planet, but is also among the most threatened because of the high degree of habitat loss and fragmentation, which confer the status of biodiversity \"hotspot\" on the region. In the first part of the thesis, I estimated that the remaining Brazilian Atlantic Forest occupies between 12-16% of its original extent (considering mapping errors), which is an intermediate estimate compared to previous ones (7-8%, or 22-23%). The spatial distribution of this forest indicates poor conditions for species conservation. More than 80% of the remaining forest is distributed in patches smaller than 50 ha, which is extremely reduced in size and incapable of preserving most of the forest species. Additionally, half of the remaining forest is less than 100 m distant from any edge, and the farthest point within any forest is about 12 km from the surrounding matrix. Another critical point is the high degree of isolation between patches (mean 1 440 m), which impedes the movement of individuals between forest fragments. Protected areas are extremely small, approximately 1% of the original extent, which is below the 10% suggested as the minimum amount for species maintenance. Higher-altitude areas (> 1200 m) retain more than 20% of the original cover; whereas in lower altitudes, such as from 400 to 800 m, only about 10% of the original forest still exists. Some conservation and restoration measures for the entire region and within biogeographical sub-regions are suggested, but I consider the subregions too extensive for defining appropriate management actions. Thus, I refined the subdivision of the entire region into 55 new sub-regions, considering climate and relief characteristics, as well as biogeographical aspects. In the second part of this thesis I developed a program called BioDIM (Biologically scaled dispersal model), an individual-based model calibrated to simulate the movement of Atlantic Forest bird species in fragmented landscapes. Five species profiles (i.e., species sensitivity) are already available in BioDIM, which allows us to simulate movements from highly sensitive species (which avoid forest edges), to moderately generalist ones (capable of crossing 120 m of open matrix). Home-range size (a surrogate for habitat amount requirement) and maximum routine and explorative distances per day can also be set. I generated 10 000 simulated landscapes, varying in habitat amount (5 to 70%), aggregation, and quality, which made it possible to evaluate landscape variability to a degree that would not be possible in real conditions. The results suggest that species traits and landscape structure were both important to explain the ecological processes, but habitat quality contributed relatively little. Species sensitivity was the prime factor in explaining dispersal rate and mortality, and had a secondary effect on movement cost and encounter rate. Habitat amount was the most influential factor to explain movement cost, and home-range size was the prime factor for encounter rate. Astonishingly, we observed that, within species profiles, habitat aggregation was as important as habitat amount to explain several ecological processes, independently of the percentage of forest amount. This is the opposite of what has been observed in the literature. These results indicate that landscape variables are important for all habitat conversion processes, and that they must be carefully considered in decision-making for species conservation management.