Sustainability has become a major concern for society, adding pressure on companies to become more sustainability-driven, while at the same time attending to the questions of economic growth and financial performance. Although the existing literature has provided frameworks that highlight the need for balancing environmental, social, and economic impact, there is still limited knowledge about how company representatives perceive and deal with the implicit trade-offs. In this study, we approach this issue by exploring how owners and managers of start-up companies, which operate under constant resource and capital constraints, perceive and deal with the potential trade-offs between sustainability, growth, and profitability. A qualitative research design with semi-structured interviews is used to explore how in their decision-making, owners, and managers of start-ups talk about and attempt to resolve these trade-offs. The primary findings from the study are that: (1) start-up representatives have limited knowledge about sustainability concepts, (2) they do not perceive a trade-off between sustainability and growth, but (3) they do recognize and contend with the trade-off between sustainability and profitability.

No description available.

A lógica do business case em que as organizações consideram aspectos sociais e ambientais apenas se trazem retorno econômico, historicamente, tem sido predominante e praticamente não questionada tanto na literatura quanto na prática. Recentemente, contudo, diante da piora de questões sociais e ambientais complexas, tem havido a conclamação para que as empresas adotem uma postura de não somente reduzir o impacto que geram como também tomar ações no sentido de que contribuam efetivamente com soluções para tanto. Ao assumirem tal postura, porém, as empresas precisam tomar decisões no cotidiano organizacional que envolvem lidar com paradoxos, isto é, situações em que ocorrem simultaneamente elementos contraditórios, ainda que relacionados. Isto porque, no caso da sustentabilidade corporativa, frequentemente, não é possível alinhar os três pilares da sustentabilidade, conciliar objetivos de curto, médio e longo prazo e atender simultaneamente o interesse de diversos stakeholders. Diante de tamanho desafio à prática organizacional, pesquisadores da área da sustentabilidade corporativa começaram a investigar a adoção de uma perspectiva integrativa da sustentabilidade, que pressupõe reconhecer a existência desses trade-offs, de forma a tentar gerenciá-los e acomodá-los. A presente pesquisa contribui para a literatura de sustentabilidade corporativa no que tange ao gerenciamento desses trade-offs ao propor como objetivo entender como as empresas significam e lidam com os trade-offs relacionados à sustentabilidade corporativa. Para atender tal objetivo, empregou-se uma estratégia de pesquisa baseada em estudos de casos múltiplos de dez empresas com modelos de negócios sustentáveis de dois setores diferentes. Como lente teórica de análise, adotou-se a perspectiva do sensemaking. A partir da análise das dez empresas estudadas, identificou-se 65 incidentes que envolviam um ou mais trade-offs em relação à sustentabilidade corporativa. Analisou-se, então, os incidentes com uma abordagem indutiva, gerando-se três resultados principais. Primeiro, identificou-se 13 vetores diferentes que abrangem os trade-offs relacionados à sustentabilidade corporativa, agrupados em quatro diferentes categorias. Segundo, propôs-se um modelo que ajuda a explicar como é o processo de construção de significado pelo qual as empresas passam ao se engajarem na acomodação dos trade-offs relacionados à sustentabilidade corporativa. Por fim, identificou-se 14 estratégias que as empresas podem se utilizar para acomodar os trade-offs agrupados em seis diferentes categorias. / The logic of business case in which organizations consider social and environmental aspects only if they bring economic returns has historically been predominant and practically unquestioned in both literature and practice. Recently, however, faced with the worsening of complex social and environmental issues, there has been a call for companies to struggle not only to reduce the impact they generate but also to take actions in order to effectively address solutions. When assuming such a position, however, companies need to make decisions in the organizational practice that involve dealing with paradoxes, that is, situations in which contradictory, yet related, elements occur simultaneously. This is because, in the case of corporate sustainability, it is often not possible to align the three pillars of sustainability, to reconcile short-, medium- and long-term objectives while simultaneously meeting the interests of various stakeholders. Faced with such a challenge to organizational practice, researchers in the area of corporate sustainability have begun to investigate the adoption of an integrative perspective of sustainability, which presupposes recognizing the existence of these trade-offs in order to accommodate and manage them. This research contributes to the corporate sustainability literature regarding the management of these trade-offs by proposing as aim to understand how companies make sense and deal with the trade-offs related to corporate sustainability. In order to achieve this, a research strategy based on multiple case studies of ten companies with sustainable business models from two different sectors was employed. As a theoretical lens of analysis, the sensemaking perspective was adopted. From the analysis of the ten companies studied, 65 incidents that involved one or more trade-offs in relation to corporate sustainability were identified. The incidents were then analyzed with an inductive approach, producing three main results. First, 13 different vectors that encompass trade-offs related to corporate sustainability were identified, grouped into four different categories. Second, a model has been proposed that helps to explain how the process of sensemaking occurs in companies engaged in the accommodation of trade-offs related to corporate sustainability. Finally, 14 strategies that companies can use to accommodate trade-offs were identified, grouped into six different categories.

A lógica do business case em que as organizações consideram aspectos sociais e ambientais apenas se trazem retorno econômico, historicamente, tem sido predominante e praticamente não questionada tanto na literatura quanto na prática. Recentemente, contudo, diante da piora de questões sociais e ambientais complexas, tem havido a conclamação para que as empresas adotem uma postura de não somente reduzir o impacto que geram como também tomar ações no sentido de que contribuam efetivamente com soluções para tanto. Ao assumirem tal postura, porém, as empresas precisam tomar decisões no cotidiano organizacional que envolvem lidar com paradoxos, isto é, situações em que ocorrem simultaneamente elementos contraditórios, ainda que relacionados. Isto porque, no caso da sustentabilidade corporativa, frequentemente, não é possível alinhar os três pilares da sustentabilidade, conciliar objetivos de curto, médio e longo prazo e atender simultaneamente o interesse de diversos stakeholders. Diante de tamanho desafio à prática organizacional, pesquisadores da área da sustentabilidade corporativa começaram a investigar a adoção de uma perspectiva integrativa da sustentabilidade, que pressupõe reconhecer a existência desses trade-offs, de forma a tentar gerenciá-los e acomodá-los. A presente pesquisa contribui para a literatura de sustentabilidade corporativa no que tange ao gerenciamento desses trade-offs ao propor como objetivo entender como as empresas significam e lidam com os trade-offs relacionados à sustentabilidade corporativa. Para atender tal objetivo, empregou-se uma estratégia de pesquisa baseada em estudos de casos múltiplos de dez empresas com modelos de negócios sustentáveis de dois setores diferentes. Como lente teórica de análise, adotou-se a perspectiva do sensemaking. A partir da análise das dez empresas estudadas, identificou-se 65 incidentes que envolviam um ou mais trade-offs em relação à sustentabilidade corporativa. Analisou-se, então, os incidentes com uma abordagem indutiva, gerando-se três resultados principais. Primeiro, identificou-se 13 vetores diferentes que abrangem os trade-offs relacionados à sustentabilidade corporativa, agrupados em quatro diferentes categorias. Segundo, propôs-se um modelo que ajuda a explicar como é o processo de construção de significado pelo qual as empresas passam ao se engajarem na acomodação dos trade-offs relacionados à sustentabilidade corporativa. Por fim, identificou-se 14 estratégias que as empresas podem se utilizar para acomodar os trade-offs agrupados em seis diferentes categorias. / The logic of business case in which organizations consider social and environmental aspects only if they bring economic returns has historically been predominant and practically unquestioned in both literature and practice. Recently, however, faced with the worsening of complex social and environmental issues, there has been a call for companies to struggle not only to reduce the impact they generate but also to take actions in order to effectively address solutions. When assuming such a position, however, companies need to make decisions in the organizational practice that involve dealing with paradoxes, that is, situations in which contradictory, yet related, elements occur simultaneously. This is because, in the case of corporate sustainability, it is often not possible to align the three pillars of sustainability, to reconcile short-, medium- and long-term objectives while simultaneously meeting the interests of various stakeholders. Faced with such a challenge to organizational practice, researchers in the area of corporate sustainability have begun to investigate the adoption of an integrative perspective of sustainability, which presupposes recognizing the existence of these trade-offs in order to accommodate and manage them. This research contributes to the corporate sustainability literature regarding the management of these trade-offs by proposing as aim to understand how companies make sense and deal with the trade-offs related to corporate sustainability. In order to achieve this, a research strategy based on multiple case studies of ten companies with sustainable business models from two different sectors was employed. As a theoretical lens of analysis, the sensemaking perspective was adopted. From the analysis of the ten companies studied, 65 incidents that involved one or more trade-offs in relation to corporate sustainability were identified. The incidents were then analyzed with an inductive approach, producing three main results. First, 13 different vectors that encompass trade-offs related to corporate sustainability were identified, grouped into four different categories. Second, a model has been proposed that helps to explain how the process of sensemaking occurs in companies engaged in the accommodation of trade-offs related to corporate sustainability. Finally, 14 strategies that companies can use to accommodate trade-offs were identified, grouped into six different categories.

[pt] O processo decisório na logística humanitária compreende diversos tipos de prioridades que por vezes estão relacionados com situações de vida ou morte. Neste grau de importância, os objetivos a serem perseguidos pelos tomadores de decisão na situação de um desastre e as restrições do problema devem ser estabelecidos para se alinhar com os anseios das vítimas e com as limitações existentes. Este estudo visa analisar de que maneiras as prioridades conflitantes num problema repleto de incertezas como em um desastre podem impactar o resultado do atendimento humanitário no que tange à sua eficiência, efetividade e equidade (3E). A dissertação apresenta o papel de alguns objetivos e restrições conflitantes (trade-offs) na tomada de decisão durante a fase de preparação para um desastre. Para tal, modelos de otimização estocástica são propostos utilizando-se dos conceitos de desempenho via 3E e sensibilidade ao risco, através da medida CVaR. Os resultados sugerem que a inclusão da aversão ao risco pode levar a um sistema mais efetivo em média. Outro ponto importante é que o modelo de minimização de custos incluindo o custo da falta forneceu uma resposta com melhor desempenho do que na maximização de equidade ou de cobertura de forma independente. Além disso, a restrição de orçamento (eficiência) quando mal dimensionada pode tornar um problema de maximização de cobertura (efetividade) desnecessariamente ineficiente. Conclui-se que a priorização da maximização conjunta da eficiência e da efetividade com restrição de inequidade e sensibilidade ao risco torna o modelo mais preciso quanto ao atendimento das vítimas do desastre. / [en] The decision-making process in humanitarian logistics comprises several types of priorities that are sometimes related to life or death situations. In this degree of importance, the objectives to be pursued by decision-makers in the event of a disaster as well as the constraints of the problem must be established to align both with the needs of the victims and with the existing limitations. This study aims at analyzing how conflicting priorities in an uncertainty-filled problem such as a disaster can impact the performance of the solution with respect to its efficiency, effectiveness and equity (3E). The dissertation presents the role of some decision-making trade-offs within disaster preparedness phase. For this, stochastic optimization models are proposed using the concept of 3E-performance and risk sensitivity, through the measure CVaR. Results indicate that the inclusion of risk aversion may lead to a more effective system on average. Another important point is that the cost minimization model including the shortage penalty provided a better performing response than in equity or coverage maximization independently. In addition, budget constraint (efficiency) when poorly dimensioned can make a problem of maximizing coverage (effectiveness) unnecessarily inefficient. It is concluded that the prioritization of the joint maximization of efficiency and effectiveness with restriction of inequity and risk sensitivity makes a model more precise as regards the care of the disaster victims.

Les systèmes d’élevage répondant aux principes de l’agroécologie doivent pouvoir s’adapter aux variations de leur environnement, en particulier parce qu’ils sont pensés pour maximiser l’utilisation des ressources locales et minimiser l’utilisation d’intrants. La composante animale des systèmes d’élevage peut dans ce contexte représenter un levier d’adaptation aux perturbations de l’environnement et contribuer à la pérennité des systèmes. Ainsi, produire des connaissances qui permettront de sélectionner des animaux robustes c’est-à-dire capables de se maintenir et de maintenir leurs performances dans un environnement changeant est actuellement un objectif prioritaire de la recherche en zootechnie. Peu de méthodes d’évaluation scientifique de la robustesse des animaux d’élevage ont été développées, et la seule méthode opérationnelle à ce jour, basée sur l’étude statique d’une seule fonction (l’approche norme de réaction) est remise en question. L’objectif de cette thèse est de proposer un cadre d’évaluation opérationnel de la robustesse, c’est-à-dire utilisable en élevage. Dans ce but, nous nous sommes focalisés sur le modèle vache laitière et avons mené deux démarches complémentaires, l’une basée sur l’analyse de données issues de fermes expérimentales de l’INRA et visant à évaluer les aptitudes biologiques des vaches à gérer les compromis (trade-offs) entre fonctions biologiques (lactation, reproduction et survie) en environnement stable puis perturbé. La seconde démarche est basée sur des enquêtes auprès d’éleveurs laitiers en vue de caractériser les stratégies de conduite (objectifs et seuils de performances) qui relèvent de la recherche d’adéquation animal-système et contribue à la robustesse des animaux. Enfin un travail de synthèse a permis d’intégrer les contributions respectives des deux approches dans la conception du cadre d’évaluation de la robustesse, ceci afin qu’il puisse être manipulable par l’ensemble des acteurs de la recherche, du terrain et du développement. Ce cadre opérationnel propose que la robustesse des vaches laitières soit évaluée en confrontant les aptitudes biologiques des animaux exprimées dans un environnement donné, aux stratégies de conduite des éleveurs. Pour ce faire, il convient 1/ de caractériser les trajectoires productives des vaches laitières sur la base de l’expression des compromis entre fonctions biologiques en situation stable et perturbée, 2/ de les confronter aux objectifs et les seuils de performances des éleveurs, 3/ d’analyser l’adéquation entre les profils de performances exprimés par l’animal et les profils de priorisation des performances des éleveurs, 4/ de prendre en compte les complémentarités entre animaux pour passer au niveau troupeau. Des indicateurs de fitness des animaux (longévité, nombre de descendants dans le troupeau) permettent de valider cette analyse. / Agroecological livestock farming systems have to be able to adapt to environmental variability because they are designed to maximize the use of local resources and minimize the use of inputs. The animal component of livestock farming systems could represent a lever to adapt to environmental disturbances and contribute to systems durability. Thus, producing scientific knowledge allowing the selection of robust animals, able to maintain and maintain their performances in a fluctuating environment is one main stake for farming system research. Few methods have been developed to assess robustness in farm animals, and the only operational measurement (reaction norm) that relies only on the analysis of one function at a given time is currently turned into question. This thesis objective is to propose an operational assessment framework of robustness, that is to say, usable on the field. To that end, we focused on the dairy cow model and carried two complementary approaches, one based on the analysis of data collected from INRA experimental units, aiming at assessing biological aptitudes of dairy cows to manage trade-offs between function (lactation, reproduction and survival) in stable and disturbed environments. The second approach is based on data collected during interviews with dairy farmers in order to characterize their management strategies (objectives and performance thresholds) associated with the search of the animal-system balance contributing to animals’ robustness. Finally, a synthesis integrated the respective inputs of the two approaches in the assessment framework of robustness, in order to make it usable by actors from research, farms and development. This operational framework suggests that robustness of dairy cows should be assessed by comparing biological aptitudes of the animals expressed in a given environment, with the management strategies of farmers. It requires, 1/ to characterized productive trajectories of dairy cows including trade-offs between function in stable and disturbed environment, 2/ to compare them with performance objective and thresholds of farmers, 3/ to analyze the balance between the performances profiles expressed by the animal and the profiles of performances prioritization of farmers, 4/ account for complementarities between animals to step up to the herd level. Animals’ fitness indicators (longevity, number of descendants) are used to validate the analysis

Ecological communities along gradients of environmental stress are thought to be structured by trade-offs between resisting biotic interactions in physically benign habitats and successfully exploiting physically stressful habitats. However, these trade-offs are likely to be affected by the predictability of abiotic stressors, and variation in the strength of biotic interactions. I investigated community assembly and food web interactions in ponds across an unpredictable gradient of water inundation (pond permanence) in Canterbury, New Zealand. Pond community composition and species richness were strongly influenced by pond permanence. However, species in temporary ponds were a nested subset of generalists that were also found in permanent ponds, rather than a unique assemblage of temporary pond specialists. Subsequent experiments indicated predator impact decreased with pond permanence, partially due to the foraging suppression of predatory invertebrates in permanent ponds by fish. Weak predation in permanent ponds combined with unpredictable drying regimes likely selected for generalist traits, and resulted in community assembly being driven by a gradient of drying stress rather than trade-offs between biotic interactions and drying. Furthermore, predator impact increased over time in temporary ponds. In predictable snow-melt ponds in the Colorado Rocky Mountains, seasonal windows of weak predation were exploited by vulnerable species, leading to increased diversity within habitats. However in unpredictable systems like Canterbury, temporal increases in predation risk that depend on drying history are likely to increase variability in the spatial arrangement of suitable habitats for particular species. This should further favour the evolution of generalist traits and reduce the importance of trade-offs between predation and drying in the assembly of communities. Considering the predictability of disturbance regimes and the spatial and temporal variation in biotic interactions will greatly enhance understanding and management of communities in heterogeneous landscapes.

Oxidative stress has recently been highlighted as a potential physiological mechanism underpinning life-history trade-offs in animals. While the role of oxidative stress in mediating such trade-offs is receiving increasing attention, its importance in wild populations remains poorly understood. In this thesis, I use a wild population of cooperatively breeding white-browed sparrow weavers (Plocepasser mahali) to investigate the role that oxidative stress plays in mediating the costs of reproduction and immune defence. Cooperative animal societies offer a unique opportunity to investigate the costs of reproduction, because dominants frequently monopolise breeding opportunities (exhibiting higher reproductive effort than subordinates), and subordinate cooperative contributions frequently lighten reproductive workloads. My findings reveal, first, that dominants’ reproductive monopolies do not arise because they exhibit superior oxidative balance, as no such rank-related differences in oxidative state exist prior to breeding (Chapter 2). However, the higher reproductive effort of dominant females may underpin their differential declines in antioxidant protection after the breeding season (Chapter 2). Second, experimental manipulation of reproductive effort reveals marked oxidative damage and body mass costs incurred during reproduction. However, these costs are entirely mitigated in large social groups, suggesting that the cooperative contributions of helpers may offset the costs of reproduction for all group members (Chapter 3). While this represents rare evidence of an oxidative stress cost of reproduction in the wild, longitudinal data suggests that these costs do not endure after the breeding season (Chapter 4), highlighting that circulating markers of oxidative balance are unlikely to mediate long-term costs of reproduction. Finally, an immune activation experiment reveals that, while mounting an immune response causes no net change in oxidative balance, the scale of the response can be adjusted according to baseline antioxidant protection in an oxidative-condition-dependent manner (Chapter 5). Together my results provide support for the role of oxidative stress in shaping life histories in the wild. Furthermore, evidence of rank-related disparities in oxidative balance and the avoidance of reproductive costs in large social groups may have important implications for our understanding of both the evolution of cooperative breeding and the patterns of health and ageing in societies.

Effective visualization of graphs is a powerful tool to help understand the relationships among the graph's underlying objects and to interact with them. Several styles for drawing graphs have emerged over the last three decades. Polyline drawing is a widely used style for drawing graphs, where each node is mapped to a distinct point in the plane and each edge is mapped to a polygonal chain between their corresponding nodes. Some common optimization criteria for such a drawing are defined in terms of area requirement, number of bends per edge, angular resolution, number of distinct line segments, edge crossings, and number of planar layers. In this thesis we develop algorithms for drawing graphs that optimize different aesthetic qualities of the drawing. Our algorithms seek to simultaneously optimize multiple drawing aesthetics, reveal potential trade-offs among them, and improve many previous graph drawing algorithms. We start by exploring probable trade-offs in the context of planar graphs. We prove that every $n$-vertex planar triangulation $G$ with maximum degree $\Delta$ can be drawn with at most $2n+t-3$ segments and $O(8^t \cdot \Delta^{2t})$ area, where $t$ is the number of leaves in a Schnyder tree of $G$. We then show that one can improve the area by allowing the edges to have bends. Since compact drawings often suffer from bad angular resolution, we seek to compute polyline drawings with better angular resolution. We develop a polyline drawing algorithm that is simple and intuitive, yet implies significant improvement over known results. At this point we move our attention to drawing nonplanar graphs. We prove that every thickness-$t$ graph can be drawn on $t$ planar layers with $\min\{O(2^{t/2} \cdot n^{1-1/\beta}), 2.25n +O(1)\}$ bends per edge, where $\beta = 2^{\lceil (t-2)/2 \rceil }$. Previously, the bend complexity, i.e., the number of bends per edge, was not known to be sublinear for $t>2$. We then examine the case when the number of available layers is restricted. The layers may now contain edge crossings. We develop a technique to draw complete graphs on two layers, which improves previous upper bounds on the number of edge crossings in such drawings. / October 2016

A presente dissertação teve como objetivo investigar se padrões presentes nas comunidades arbóreas adultas podem ser gerados por diferenças em aspectos relacionados ao nicho de regeneração das espécies. Nosso modelo de estudo foram duas florestas de restinga localizadas na Ilha do Cardoso, litoral sul do estado de São Paulo. A floresta de restinga alta (RA) é uma formação geologicamente mais antiga e possui dossel mais fechado que a floresta de restinga baixa (RB). No Capítulo 1, investigamos se as inversões de abundância das árvores adultas entre RA e RB podem ser geradas devido ao desempenho diferenciado destas espécies ainda na fase de plântula, devido à atuação do filtro ambiental luminosidade. Hipotetizamos que as espécies apresentem pior desempenho no estágio de plântula na floresta em que são menos abundantes como adultos, devido a uma demanda conflitante entre crescimento e sobrevivência. Esperávamos também que a mortalidade por patógenos fosse a principal causa de mortalidade das plântulas na floresta mais sombreada. Realizamos um experimento manipulativo em campo com seis espécies arbóreas, no qual plântulas com um mês após a germinação foram transplantadas nas duas florestas e no viveiro. Acompanhamos o desempenho destas plântulas durante nove meses. Não houve diferenças no desempenho das espécies entre as duas florestas estudadas, exceto na sobrevivência de Clusia criuva (no sentido esperado) e de Tapirira guianensis (sentido oposto ao esperado). Diferente do esperado, a principal causa de mortalidade de todas as espécies foi a herbivoria severa e não foi observado um conflito entre crescimento e sobrevivência. No Capítulo 2 investigamos se as diferenças de tamanho de semente entre as espécies arbóreas zoocóricas podem gerar diferenças nos padrões da comunidade adulta e essas diferenças ocorrem devido à atuação do filtro ambiental da luminosidade ou apenas devido às diferenças de capacidade de dispersão das espécies. Acompanhamos a chuva de sementes das espécies zoocóricas arbóreas durante quatro anos nas duas florestas e verficamos que a capacidade de dispersão ativa está negativamente relacionada ao tamanho de sementes, como é previsto por ambas as hipóteses (filtro ambiental e capacidade dispersão). Além disso, a relação entre a produção média de sementes e o tamanho de sementes apresentou um padrão triangular, de modo que as espécies de sementes grandes apresentam sempre baixas produções. Comparamos os tamanhos médios de sementes e a amplitude de tamanhos de sementes dos indivíduos e espécies estabelecidos como adultos nas duas florestas (DAP>= 5cm). Verificamos que a RA apresenta tamanho médio de semente e amplitude de tamanhos de sementes maiores que a RB. Além disso, a composição florística da RB está aninhada na composição da RA. Assim, hipotetiamos que as diferenças na capacidade de dispersão das espécies, aliadas às diferenças de idade das florestas são responsáveis pela distribuição de tamanho de sementes dos adultos estabelecidos nas duas florestas. Por fim, no capítulo 3, realizamos uma revisão bibliográfica sobre o papel dos microorganismos do solo no nicho de regeneração das espécies arbóreas tropicais. Foram encontrados estudos que abordam apenas a atuação de fungos, seja em interações positivas (fungos micorrízicos) ou negativas (fungos patogênicos). Discutimos os principais fatores e características associadas à mortalidade por patógenos do solo, bem como relações levantadas pelos estudos pioneiros que não foram corroboradas ou testadas / The objective of the current research was to investigate if the existing patterns in the adult tree communities can be generated by differences in the aspect related to the regeneration niche of species. Our model of study were two restinga\'s forests located at the Cardoso Island, on the South coast of São Paulo state. The tall resting forest (TRF) is an older formation, geologically speaking, and it hás closer canopies than the short resting forest (SRF). In the first chapter, we investigated if the abundance inversions of adult trees existing between the TRF and the SRF could be generated due to the differentiated performances of these species at the stage of the seedling, due to the action of the environmental light filter. We assumed as a hypothesis that the species show a worst performance in the stage of seedling in the forest where they are less abundant as adult, due to a trade-off between growth and survival. We expected that the mortality by pathogens was the main cause for the mortality of plants in the more shaded forest. We achieved a manipulative experiment in field with six tree species, in which one-month-old seedlings after germination were transplanted in the two forests and in the nursery. We followed the performance of the species in the two studied forests for nine months. There were no differences in the performance of the two species, except the survival of the Clusia criuva (in the expected way) and of the Tapirira guianensis (opposite to the expected way).Different from what was expected, the main cause of the mortality of all the species was the severe herbivory, and it was not possible to observe a conflict between the growth and the survival of them. In the second chapter, we investigated if the differences in the size of the seeds among the zoochoric tree species can generate differences in the patterns of the adult community and if those differences occur due to an action of the environment lighting filter or only by the differences of the dispersion capacity of the species. We followed the seed rain of the zoochoric tree species for four years in both forests and we could check that the active dispersion capacity of them is negatively related to the size of the seeds, as it can be predicted by both the hypothesis (environmental filter and dispersion capacity). Besides, the relationship between the average production of seeds and the size of the seeds presented a triangular pattern, as species with big seeds always provide low productions. We compared the seeds average sizes and the range of the seeds sizes of the individual plants and of the adult species in both forests (DAP_> 5 cm. We could verify that the TRF presents average size of seeds and range of the seeds\'s sizes that were bigger than in SRF. Furthermore, the SRF floristic composition is nested in the TRF composition. Therefore, we assumed as a hypothesis that the differences in the dispersal capacity of species, plus the age differences of the forests, are responsible for the distribution of the seeds sizes of the adult plants present in both forests. Finally, in chapter 3, we made a literature review about the role of the soil microorganisms in the specific site of the regeneration of the tropical tree species. We found studies that focus only on the action of the fungi as far in positive interactions (mycorrhizal fungi) as in negative ones (pathogenic fungi). We discussed the main factors and the characteristics associated to the mortality caused by the soil pathogens, as well as the relationship proposed by the pioneer studies which were not confirmed nor tested