Dissertations / Theses on the topic 'Ecosystems'

The declines of fish populations in ecosystems around the globe have triggered considerable interest in marine ecosystem restoration. In addition to focusing on individual fish populations, there is increased emphasis on understanding inter-species interactions and on understanding the human relationships with the ecosystems. My thesis approaches marine restoration from (a) practical aspects of considering multispecies interactions in the ecosystem (Ecopath with Ecosim models), estimating unreported and illegal catches (influence tables) and policy that considers the concerns of multiple stakeholders (Bayesian influence diagram modeling); (b) theoretical aspects of carrying capacity and fish life history analyzed using life history parameters (Population dynamics modeling). I begin my thesis by exploring the technological, socio-economic, and political history of Raja Ampat in Eastern Indonesia (my geographical focus) to understand resource management challenges and to calculate the trends in relative misreporting of fisheries catch. The unreported fish catch exceeds the reported fish catch by a factor of 1.5. My next chapter explores the ecological benefits of establishing marine protected areas for coral reef ecosystems in Raja Ampat using Ecopath, Ecosim and Ecospace models. I estimate an ideal minimum size of no-take areas— the size of no-take area at which the biomass density of reef fish reached an asymptote—to be 16 to 25 km². Analysis of biomass density of reef fish in MPAs led to questions about ecosystem carrying capacity. To explore carrying capacity, I reconstruct ancient snapper population biomass using archaeological data obtained from fish middens using equilibrium age structure model. The results show that the ancient snapper population was about 2 to 4 times higher than the modern population biomass. To model the differing utilities of different stakeholders, in the next chapter, I develop a bayesian influence diagram model. The results indicate that restricting net fisheries and implementing 25% fisheries closure are robust scenarios favored under several combinations of the modeled variables and utility functions. The final chapter explores how the life history parameters of fish species affect the population response to restoration. It is expected that slow growing species would show a greater response to protection than fast growing species.

Experimental studies, in temperate grasslands, assessing the role of biodiversity and its effects on ecosystem functioning have generally shown that a decline in species number has negative effects on ecosystem functioning. Even though, this relationship has been intensively studied in the last ten years, little is known about it in complex and hyperdiverse tropical ecosystems and where species diversity is not manipulated. My research examines the relationship between biodiversity and ecosystem functioning in natural tropical forests with a special focus on scale. This research centers on field studies. The field studies address the relationship between natural tree biodiversity and aboveground biomass, as the ecosystem function of interest, in forest plots of similar physiognomy but different species composition. Specifically, I explored the following questions: (1) How can the relationship between biodiversity and ecosystem functioning be detected in a naturally varying environment and space?, (2) How can different measures of diversity (species versus function) explain tree carbon stocks?, (3) Can we confound the effect of species diversity on tree carbon storage with that of forest structure?, (4) How does this relationship change with different spatial scales?, and (5) Can we extrapolate the results of biodiversity-ecosystem functioning found in experimental plantations to natural forests? Overall, my thesis has found that environmental factors related to topography, soil physical factors, and nutrients have little effect on aboveground biomass in tropical ecosystems. Species richness alone cannot be used as a predictor for aboveground biomass, however, if reduced to functional types, its explanatory power increases. Functional traits can be useful to unveil the relationship of aboveground biomass and tree diversity, by reducing species to functional types. Forest structure correlates strongly with aboveground biomass independently of scale, but forest structure is interlinked with species functional traits. Finally, we have to be cautious in extrapolating results found in experimental plantations to natural forests.<br>Des études expérimentales qui ont été effectuées dans des systèmes expérimentaux herbacés du milieu tempéré afin d'évaluer le rôle de la diversité biologique et ses effets sur le fonctionnement de l'écosystème ont généralement pu montrer que le déclin dans le nombre d'espèces a un effet négatif sur le fonctionnement de l'écosystème. Même si cette relation a été étudiée de façon intensive au cours des dix dernières années, très peu est encore connu à ce propos dans les écosystèmes tropicaux, beaucoup plus complexes et mégadiversifiés. Mes travaux de recherche examinent la relation entre diversité biologique et fonction de l'écosystème dans les forêts naturelles tropicales, en mettant l'emphase sur la question d'échelle. Cette recherche est basée sur une approche de terrain, en opposition avec une approche théorique. L'approche de terrain aborde la relation entre la diversité biologique à l'état naturel et les fonctions d'écosystème dans des parcelles forestières de physionomies similaires mais d'une composition en espèces différente. De façon plus spécifique, j'explore les questions suivantes : (1) Comment la relation entre diversité biologique et fonction d'écosystème peut-elle être détectée dans un environnement et un espace naturel changeant?, (2) Comment différentes mesures de diversité (espèces vs fonction) expliquent-elles les stocks de carbone dans les arbres?, (3) Pouvons-nous confondre l'effet de la diversité en espèces sur l'entreposage du carbone dans les arbres avec l'effet de la structure de la forêt? (4) Comment cette relation change-t-elle avec différentes échelles spatiales? (5) Pouvons-nous extrapoler les résultats obtenus dans des plantations expérimentales aux forêts naturelles dans les tropiques en ce qui a trait à la relation entre biodiversité et fonction d'écosystème? Ainsi, ma thèse montre que pour les écosystèmes tropicaux, les facteurs environnementaux tels que ceux reliés à la topographie, les facteurs physiques et les nutriments des sols ont peu d'effet sur l'entreposage du carbone dans les arbres. De plus, la richesse en espèces ne peut pas à elle prédire de l'entreposage de carbone dans les arbres, cependant lorsque celle-ci est divisée par types fonctionnels, sa puissance explicative augmente. Les traits fonctionnels peuvent donc être utiles pour révéler une relation entre le stockage du carbone et la diversité en arbres en réduisant les espèces en des types fonctionnels. La structure de la forêt est le moteur principal du stockage arboricole du carbone indépendamment de l'échelle, par contre cette dernière est reliée aux traits fonctionnels des espèces. Finalement, nous avons pu montrer que la prudence est de mise en ce qui concerne toute possible extrapolation de résultats provenant de plantations expérimentales à des forêts naturelles dans les tropiques.

The rapid and ubiquitous spread of information technologies (IT) is creating unprecedented effects that challenge traditional fundamentals of the business world. Platform-mediated ecosystems are increasingly attracting the attention of practitioners from diverse industries, from telecommunications to video consoles, as well as academics from different fields ranging from management to economics, and information systems (IS) and innovation management. A platform-mediated ecosystem can be defined broadly as an industrial architecture with an infrastructure in the center that facilitates value co-creation among different agents (platform owners, and providers and users of complementary products) and a set of rules governing their interdependencies. The speed and the magnitude at which platforms diffuse are inspiring numerous analyses from diverse perspectives, mainly focused on drivers of success and ecosystem interdependencies in different contexts. This thesis highlights the importance of detangling the different interdependencies within platform-mediated ecosystems, while building a comprehensive approach based on the ecosystem as a whole. The wide range of platform types and their rapid evolution makes it difficult to establish a consensual categorization of platforms. A common aspect among most of them is that platform-mediated ecosystems usually present network effects that is the value of products depend on the number of peers within the ecosystem. In this sense, the number of adopters, known also as the size of the installed base, in a market has traditionally had a central importance in the literature. The platform-mediated ecosystems, however, are becoming more and more complex due to rising competition. Thus, there is a need for advancing understanding of the fundamentals of platform-mediated ecosystems and the management alternatives inherent in designing such systems which would enable a comprehensive platform approach to be built. Consequently, the main purpose of this thesis is to advance the understanding of the strategic management of platform-mediated ecosystems. Specifically, this thesis aims to unravel the ecosystem interdependencies and to identify strategic choices as a source of competitive advantage. To achieve this aim, different methodologies are applied in this thesis. Specifically, Paper I was based on a structured literature review of relevant papers in platform-mediated ecosystems for the period 2000 through 2014. The empirical analyses conducted in Papers II, III, and IV use different secondary samples from the video console ecosystem. Finally, the results in Paper V were based on a qualitative, multiple case study of global manufacturing firms implementing product-service systems (PSS) through a platform architecture. Overall, the findings within this thesis present the following main theoretical contributions. First, the thesis presents a comprehensive approach toward platform mediated ecosystems covering new ways of value creation and value capture, new governance regimes, and new agents making interdependent choices. Precisely, platform ecosystems offer unprecedented efficiencies and innovation enhancements, and the possibility of establishing rules for new role participation and interaction. Thus, the findings shed light on the fundamentals and future trends in the platform approach. Second, different ecosystem interdependencies may increase the platform adoption and performance. Specifically, the thesis highlights the importance of the positive effects from different agents in the complementary product markets. Accordingly, the findings contribute on unraveling the interdependencies within platform ecosystems. Third, platform performance can be enhanced by exploiting complementarities among strategies and regions. Precisely, the findings show significant complementarities from the joint management of different activities related to the complementary products and the platform, and from the presence in several countries. Consequently, the findings provide strategic choices as a source of competitive advantage. Finally, transformation toward global PSS may be guided by a platform approach, which may be helpful to explain the origins in building a platform ecosystem. In this respect, the findings shed light on how platform-mediated ecosystems are created. In sum, these findings have important implications for researchers in strategic management, economics, and information systems as well as managers from highly innovative industries and traditional sectors under structural transformation. This thesis concludes with the limitations that should be considered when interpreting the findings and some suggestions for future researchers.<br>Godkänd; 2015; 20150917 (javcen); Nedanstående person kommer att disputera för avläggande av teknologie doktorsexamen. Namn: Javier Cenamor Gómez Ämne: Entreprenörskap och innovation/Entrepreneurship and Innovation Avhandling: Managing Platform-Mediated Ecosystems: Investigating Ecosystem Interdependencies and strategic Choises Opponent: Biträdande professor Andreas Larsson, Institutionen för maskinteknik, Blekinge tekniska högskola, Karlskrona. Ordförande: Biträdande professor Vinit Parida, Avd för innovation och design, Institutionen för ekonomi, teknik och samhälle, Luleå tekniska universitet, Luleå. Tid: Tisdag 10 november, 2015 kl 13.00

The purpose of this study was to find out the progress in the research of technology ecosystems and digital business ecosystems and to combine that information for business purposes by the utilization of information about business ecosystems. The need for this information emerged at the Department of Information Processing Science in the context of European Union research projects. The information gained is expected to assist to increase possibilities both for the research and for the personal competence to work with enterprises in new kinds of technology environments. The main research question to be answered in this study was: How are technology ecosystems and digital business ecosystems for business perceived and approached in the literature? Instead of a systematic review, a method of systematic mapping was selected to structure the selected research areas for getting a broad overview over the two streams of research, and for identification the possible research evidence. To answer the main question the following subquestions were set for both systematic mapping studies: RQ1 Which journals include papers on technology ecosystems / digital business ecosystems for business? RQ2 What are the most investigated topics of technology ecosystems / digital business ecosystems and how have these changed over time? RQ3 What are the most frequently applied research approaches and methods, and in what study context? Based on structuring the selected research areas according to the set subquestions, broad overviews were established presenting findings. Based on the identification and evaluation of publication channels the forums for discussion were exposed. Based on the identification of topics and their evolution the trends of discussion were exposed. Based on the identification of research types the non-empirical and the empirical research were exposed. Found research evidence and found solution proposals (from non-empirical research) were discussed and the need for further research was considered. The main contribution of this mapping study was the identification of different perceptions of two vague concepts, technology ecosystem and digital business ecosystem, and notion of their convergence and interlace over time (especially in relation to the exposed scarce research evidence). The recommendations for future research were set based on the found empirical research and solution proposals, as well as limitations of this study.

It is an emerging phenomenon that the leading multinational companies are studying how to use the engagement experiences of customers and communities as the foundation of value co-creation. To achieve this, the business leaders have increasingly adopted an ecological organizational form, namely business ecosystem. Google, Amazon and Microsoft are the real world examples and pioneers in this field. However, in the academic research, it is addressed by a number of researchers that there is significant lack of empirical studies that examines the emergence and formation of business ecosystem, especially in ICT industry. In essence, this study takes Cloud as the context to develop concepts on the emergence of business ecosystem and examine the manifestation of such evolution in the emerging business field. Through extensive literature reviews and empirical interviews, the current study developed answers to the research question, “How do new business ecosystems emerge, in the context of Cloud computing?” at qualitative level. In general, it is considered in the study that business ecosystem is a type of more advanced business form emerged recently. It has the characteristics as follow: provision of value, integration with external partners, requiring multiple participants, shifting from individual to collaborative thinking, interdependence of the participants, value co-creation, co-petition, open innovation and shared fate of success or failure. From a macro level viewpoint, the emergence of business ecosystem is the result of the continuous evolution of business forms, from linear type towards a more complex networked type. At a micro level, for an ecosystem to emerge in a given industry, it involves strategic design and appropriate execution. Furthermore, a set of critical elements need to be in the right place for a business ecosystem to emerge, which including: prerequisite conditions for ecosystem to emerge, external environmental and resource, shared vision, leadership of the ecosystem, common platform, mechanisms of the ecosystem, ecosystem healthiness, and IT infrastructure. The study further suggests that the emergence of business ecosystem as a new business form is not out of luck or probability. It is a natural path that under governance of the evolution forces existing in the social-economic contexts, just as the evolution of all the living creatures in the natural environment. For this broader perspective, the emergence of ecosystem is inevitable due to the social-economic and technological driving forces.

One of the greatest challenges for sustaining the ecosystem services that we, as a society, derive from marine ecosystems is to minimize the knowledge gap relating to marine ecosystem values. That is, identifying, eliciting and understanding the economic value of the ecosystem services that marine systems provide for societies world-wide is key to ensuring sustainable resource use and environmental management of these ecosystems. This is particularly problematic for the ecosystem services derived from the deep sea as a tremendous knowledge gap exists for the many marine ecosystems that comprise the deep sea. Addressing this gap in knowledge may, directly and indirectly, facilitate actionable strategies for successful climate change adaptation and reduce the degradation of these important marine ecosystems. Estimating values for certain types of marine ecosystem services in particular the deep sea is imperative for understanding the economic trade-offs associated with human actions and resource use of marine resources. Identifying, exploring and understanding the economic benefits and costs associated with the human resource use of marine systems is also crucial for circumventing irreversible damage to ecosystems, and for addressing the growing problem of ecosystem degradation of marine ecosystems. However, a knowledge gap remains in terms of eliciting and understanding how vulnerable marine ecosystems, such as coral reefs and the deep-sea, generate economic value to local economies, and for societies on a global scale. By employing a variety of quantitative and qualitative methodologies, this thesis explores the economic value of the ecosystems of coral reefs and the deep-sea, respectively. The thesis investigates various aspects of the economic contribution of these ecosystems, namely: (i) the local economic contribution of ) Fiji's coral reefs to tourism; and ii) the economic value of the deep- sea's ecosystems to human societies, globally. Moreover, it discusses the importance of exploring the social and non-monetary value of coral reefs to human well-being in the South Pacific Island Countries (SPICs). The research of this thesis therefore constitutes a genuine contribution to understanding how changes in these marine ecosystems impact on economies and human well-being, now and in the future. Although the full extent to which ecosystem degradation of marine ecosystems will impact economies and societies globally remains uncertain, its impacts are already being witnessed, e.g. through ocean acidification, sea-level rise, reduced fish stocks and changing environmental conditions. In turn, these impacts affect human survival and well-being by negatively impacting fishery incomes, food security and coastal protection in many countries around the world. Action and investment plans for reducing the ecosystem degradation of marine systems are urgently needed to protect the value of those ecosystem services to human societies. Deepening our understanding of marine ecosystems' economic contributions constitutes a crucial component of facilitating action plans and investments for sustainable resource use and development. Valuation of vulnerable marine ecosystems is important for several reasons. First, valuation of an ecosystem's contribution to society demonstrates the importance of that ecosystem for social stability, economic growth and human well-being, thereby improving public awareness of that ecosystem's significance. Second, ecosystem valuation can inform policy and decision-making for future conservation programs and legislation pertaining to the human use of marine resources. Third, ecosystem valuation creates important incentives to invest in the protection of marine systems as it outlines the connection between the ecological functioning of marine systems on the one hand, and economic output and stability on the other hand. Fourth, ecosystem valuation can also raise awareness about the importance of protecting biodiversity. Finally, ecosystem valuation of marine ecosystems is especially important for supporting decision-making related to the resource-use of marine ecosystems for which very limited information exists on their economic contribution. The thesis starts with an introduction and a literature review of the main themes and concepts along with the problems, challenges and opportunities associated with the ecosystem valuation of coral reefs and the deep-sea. Subsequently, the research studies of this thesis, which constitutes chapters 2, 3, 4 and 5 are presented. Specifically, chapter 2 explores the economic impacts of future (hypothetical) deep-sea mining activities on Fiji's tourism industry, through a contingent behaviour study; chapter 3 discusses the need for developing non-monetary and social ecosystem valuation methodology in order to elicit marine ecosystems' importance for human well-being in the SPICs; chapter 4 explores current knowledge about the deep-sea's economic value through a systematic review and meta-analysis; and chapter 5 identifies the four main priorities for future ecosystem valuation, policy-making and research pertaining to the deep-sea. This thesis makes a small but significant contribution to the knowledge base of the economic value of the ecosystems of coral reefs and the deep-sea, respectively, and to developing future ecosystem valuation by means of introducing the social willingness-to commit (Social WTCommit) technique. Finally, this thesis can contribute to policy-making, decision-making and legislation pertaining to the deep-sea and coral reefs, locally and globally.<br>Thesis (PhD Doctorate)<br>Doctor of Philosophy (PhD)<br>Dept Account,Finance & Econ<br>Griffith Business School<br>Full Text

We view Digital Ecosystems to be the digital counterparts of biological ecosystems, which are considered to be robust, self-organising and scalable architectures that can automatically solve complex, dynamic problems. So, this work is concerned with the creation, investigation, and optimisation of Digital Ecosystems, exploiting the self-organising properties of biological ecosystems. First, we created the Digital Ecosystem, a novel optimisation technique inspired by biological ecosystems, where the optimisation works at two levels: a first optimisation, migration of agents which are distributed in a decentralised peer-to-peer network, operating continuously in time; this process feeds a second optimisation based on evolutionary computing that operates locally on single peers and is aimed at finding solutions to satisfy locally relevant constraints. We then investigated its self-organising aspects, starting with an extension to the definition of Physical Complexity to include the evolving agent populations of our Digital Ecosystem. Next, we established stability of evolving agent populations over time, by extending the Chli-DeWilde definition of agent stability to include evolutionary dynamics. Further, we evaluated the diversity of the software agents within evolving agent populations, relative to the environment provided by the user base. To conclude, we considered alternative augmentations to optimise and accelerate our Digital Ecosystem, by studying the accelerating effect of a clustering catalyst on the evolutionary dynamics of our Digital Ecosystem, through the direct acceleration of the evolutionary processes. We also studied the optimising effect of targeted migration on the ecological dynamics of our Digital Ecosystem, through the indirect and emergent optimisation of the agent migration patterns. Overall, we have advanced the understanding of creating Digital Ecosystems, the self-organisation that occurs within them, and the optimisation of their Ecosystem-Oriented Architecture.

The idea of Terraformation comes from the science fiction literature, where humans have the capability of changing a non-habitable planet to an Earth-like one. Nowadays, Nature is changing rapidly, the poles are melting, oceans biodiversity is vanishing due to plastic pollution, and the deserts are advancing at an unstoppable rhythm. This thesis is a first step towards the exploration of new strategies that could serve to change this pernicious tendencies jeopardising ecosystems. We suggest it may not only be possible by adding new species (alien species), but also engineering autochthonous microbial species that are already adapted to the environment. Such engineering may improve their functions and capabilities allowing them to recover the (host) ecosystem upon their re-introduction. These new functionalities should make the microbes be able to induce a bottom-up change in the ecosystem: from the micro-scale (microenvironment) to the macro-scale (even changing the composition of species in the entire the ecosystem). To make this possible, the so-called Terraformation strategy needs to fuse many different fields of knowledge. The focus of this thesis relies on studying the outcome of the interactions between species and their environment (Ecology), on making the desired modifications by means of genetic engineering of the wild-type species (Synthetic Biology), and on monitoring the evaluation of the current ecosystems’ states, testing the possible changes, and predicting the future development of possible interventions (Dynamical Systems). In order to do so, in this thesis, we have gathered the tools provided by these different fields of knowledge. The methodology is based on loops between observation, designing, and prediction. For example, if there is a lack of humidity in semiarid ecosystems, we then propose to engineer e.g. Nostoc sp. to enhace its capability to produce extracellular matrix (increasing water retention). With this framework, we perform a model to understand the different possible dynamics, by means of dynamical equations to evaluate e.g. when a synthetic strain will remain in the ecosystem and the effects it will produce. We have also studied spatial models to predict their ability to modify the spatial organization of vegetation. Transient dynamics depend on the kind of transition underlying the occurring tipping point. For this reason, we have studied different systems: vegetation dynamics with facilitation (typical from drylands), a cooperator-parasite system, and a trophic chain model where different human interventions can be tested (i.e. hunting, deforestation, soil degradation, habitat destruction). All of these systems are shown to promote different types of transitions (i.e. smooth and catastrophic transitions). Each transition has its own dynamical fingerprint and thus knowing them can help monitoring and anticipating these transitions even before they happen, taking advantage of the so-called early warning signals. In this travel, we have found that transients can be an important phenomena in the current changing world. The ecosystems that we observe can be trapped into a seemingly stable regime, but be indeed in an unstable situation driving to a future sudden collapse (Fig 1) For this reason, we need to investigate novel intervention methods able to sustain the current ecosystems, for instance: Terraformation.

This thesis investigates processes of ecosystem emergence. Ecosystem research has thus far focused on understanding the structure and dynamics of already existing ecosystems. However much less attention has been devoted to the emergence of ecosystems. I first theoretically develop an institutional approach to ecosystems, arguing that the ecosystem is an organisational field which has value co-creation as its recognised area of institutional life. Synthesising the theories of dominant design, social movements, and institutional entrepreneurship, I identify four activities that drive the processes of ecosystem emergence: resource, technological, institutional and contextual activities. Empirically, I compare the emergence sequences of six digital service ecosystems – Amazon, eBay, Facebook, Google, Salesforce and Wikipedia – using a narrative explanation methodology, applying event colligation, optimal matching, direct inspection, frequency analysis and an innovative statistical bootstrapping technique. I find that emergence sequences of each case are significantly dissimilar and that there are three phases of emergence – Initiation, Momentum, Control. The first of these phases is similar across cases, but subsequent phases exhibit increasing dissimilarity as the ecosystem evolves and takes on idiosyncratic characteristics. To explain these findings, I develop an ecosystem perspective that explicitly integrates value co-creation processes as an important regulator of the evolution of ecosystems. I suggest that idiosyncratic logics of value co-creation result in differing value creation processes. I show that the three distinct phases of ecosystem emergence form a coherent, distinctive whole when considered from the perspective of value co-creation. Emphasising that value appropriated must first be co-created, I propose the ‘ecosystem model’ as an analytic tool to better conceptualise value co-creation and appropriation in ecosystems. I discuss the implications of these contributions for ecosystem research, institutional theory, and strategic management practice.

Biodiversity loss is one of the major threats to humanity. This has led to an increasing amount of research on biodiversity on genetic and species levels. Studies of diversity at the ecosystem level has however been neglected. An important aspect of ecosystems is food webs that describe the predation-prey interactions between species. Properties explaining the topological structure of food webs can be used to compare and highlight differences between ecosystems. In the present study, topological network properties are used to compare the diversity of network structures between groups of empirical food webs. Differences between 45 aquatic and 45 terrestrial food webs are compared as well as the effects of species richness on lake network structure diversity. Network structure diversity is measured as the average Euclidean distance from food webs to their group centroid in a multidimensional space of network properties. While the average network structure differs between aquatic and terrestrial food webs, no significant difference in variation is found. For 128 Swedish and 48 North American lake food webs, increasing species richness is shown to decrease network structure diversity. A higher diversity of network structures could potentially indicate a more ways to cope with disturbances or provisions of a higher variety of ecosystem services. Preliminary tests of ecosystem diversity effects on stability were conducted but proved inconclusive.

In this thesis, a philosophy and lexicon for the engineering of biosystems are established. The focus is on a specific class of biosystems ( ecocyborgs) created by combining ecosystems and technological Components. This work is part of the EcoCyborg Project, a highly interdisciplinary research program which concerns the development of a general theory for biosystems engineering, with an emphasis on system autonomy as a design goal. In the short term, the objective is to develop computational models and simulations for use in the study of ecocyborgs as representative instances of substantially autonomous biosystems. Accordingly, in this thesis an explicit conceptual basis is established for the EcoCyborg Project, as well as for biosystems engineering in general.<br>First, in the body of the thesis, a biosystem is defined as a coherent assemblage of entities that is alive to some degree as a whole. The sole criterion for life is considered to be comportment that is somewhat autopoietic , whereby local interactions among the components combine to Continually renew the overall system. Next, concepts related to autonomy, or the formulation and pursuit of proprietary goals, are elaborated. The degree of autonomy of a system is seen to depend on its consciousness, or ability to reason using a model of itself. Hence, a substantially autonomous system requires an ensemble of information storage and processing devices (mind) of the type and sophistication (intelligence ) appropriate for this. The approach that is taken here to the creation of ecocyborgs with such minds is described, and a specific mental architecture is delineated, comprising functionally semidifferentiated, intermediate-scale components arranged according to a semihierarchical control organization. Finally, the characterization of such systems is scrutinized as an epistemic process in which knowledge is generated by an observer, but in which only a limited degree of objectivity is possible. A paradigm appropriate to the engineering of ecocyborgs is defined as an illustration, and associated archetypal concepts and descriptive procedures (such as measures) are given that are useful in this context. Such tools are required by significantly autonomous ecocyborgs because they must characterize themselves. They are also necessary to observers with scientific and engineering agendas.

The main topic of this thesis concerns the study of how conflicting interests of software agents within an information ecosystem may cause cooperative behavior. Since such agents act on the behalf of their human owners, which often act in their own interest, this will sometimes result in malignant acts. Different types of models, often inspired by biological theories such as natural selection, will be used to describe various aspects of such information ecosystems. We begin by adopting a game theoretic approach where a generous and greedy model is introduced. Different agent strategies for iterated games are compared and their ability to cooperate in conflicting games are evaluated in simulation experiments. The conclusion is that games like the chicken game favor more complex and generous strategies whereas in games like the prisoner’s dilemma, the non-generous strategy tit-for-tat often is the most successful. We then use models based on a surplus value concept to explain antagonistic group formations. The focus is on systems that consist of exploiter agents and agents being exploited. A dynamic protection model of access control is proposed, where a chain of attacks and countermeasures concerning the access are measured. This process can be described as an arms race. It is argued that arms race is a major force in the interaction between antagonistic agents within information ecosystems. Examples of this are given in several contexts such as peer-to-peer tools concerning anonymity and non-censorship, using agents for sending or filtering out mass distributed advertisement e-mails, and finally for describing the fight against viruses or spywares.<br>Avhandlingen tar upp hur konflikter mellan agenter på individnivå i ett informationsekosystem kan leda till samverkande effekter på grupp eller systemnivå. Biologiska och ekonomiska modeller inom spelteori, naturligt urval, mervärde och kapprustning mellan olika grupper används för att förklara dynamiken som uppstår mellan användare och agenter som uppför sig själviskt. Exempel på sådana områden är: ”peer-to-peer” nätverk, skyddssystem mot virus och andra intrång samt oönskad massreklam (spam) och ”spionprogram”. Ett önskvärt och möjligt slutresultat är ett informations ekosystem med robusta, samverkande egenskaper mot attacker utifrån.

Industry 4.0 ha transformado rápida y significativamente la industria AEC a nivel mundial desde principios de la década de 2000. La profesión profesional de la arquitectura alográfica hasta finales de la década de 1990 ha visto un cambio de paradigma hacia una práctica más autográfica después de la inclusión del algoritmo en el desarrollo tradicional de la forma construida a través de los medios del diseño. Este advenimiento del algoritmo en la industria AEC viene con un sólido soporte de infraestructura del aumento sin precedentes del diseño computacional y la fabricación digital. Al observar la tasa de progreso tecnológico, es muy probable que el diseño computacional se vuelva más autónomo y la fabricación digital se vuelva más impulsada por los datos. Debido a esta mayor probabilidad en la ubicuidad del algoritmo, el diseño como herramienta para la racionalización de la forma, el espacio y el cerramiento y el diseño como herramienta para la creación de un documento de construcción se encuentra en el umbral de volverse redundante. La investigación y esta tesis se basan en el supuesto de que el diseño sería reemplazado por una lógica comunicacional entre la forma construida y el algoritmo

The thesis investigates the role played by green roofs in urban areas by reviewing the existing literature and by developing a numerical platform. For this purpose, the FAO-56 dual crop coefficient method (FAO-56 method) has been adopted to evaluate evapotranspiration taking place in some green infrastructure (GI) practices, i.e. green roofs. The Tew Extension was incorporated into the FAO-56 method to achieve more accurate estimates. Modifications were also made to the FAO-56 method with the Tew Extension for the application to agricultural green roofs. The findings relating to the test green roofs’ functions of annual rainfall retention, peak flow rate reduction and runoff delay reveal that green roofs can greatly help mitigate urban runoff volume and rate problems. Regarding the impact on runoff quality, the test green roofs, in most cases, deteriorated the incoming water. The FAO-56 method was applied to urban agriculture and agricultural green roofs, based on which evapotranspiration and irrigation needs of the ten annual crops grown in fields and on rooftops in Australia’s five major cities were estimated. In both field and rooftop cases, different crops planted in the same city resulted in significantly different irrigation needs. In all five cities, all the crops grown on rooftops evapotranspired more water than the crops grown in fields. Nearly in all cases, crops grown on rooftops demanded more irrigation than these crops grown in fields. Most of the water lost through evapotranspiration was transpiration in both field and rooftop cases; however, the percentages of transpiration to evapotranspiration on rooftops were smaller when compared with these in the field case for all the crops in all five cites. In general, a city that is more irrigation water dependent is likely to use a larger portion of total water beneficially. Crops grown on rooftops are likely to take up smaller portions of total delivered water than the same crops grown in fields.

Self-organising pervasive ecosystems of devices are set to become a major vehicle for delivering infrastructure and end-user services. The inherent complexity of such systems poses new challenges to those who want to dominate it by applying the principles of engineering. The recent growth in number and distribution of devices with decent computational and communicational abilities, that suddenly accelerated with the massive diffusion of smartphones and tablets, is delivering a world with a much higher density of devices in space. Also, communication technologies seem to be focussing on short-range device-to-device (P2P) interactions, with technologies such as Bluetooth and Near-Field Communication gaining greater adoption. Locality and situatedness become key to providing the best possible experience to users, and the classic model of a centralised, enormously powerful server gathering and processing data becomes less and less efficient with device density. Accomplishing complex global tasks without a centralised controller responsible of aggregating data, however, is a challenging task. In particular, there is a local-to-global issue that makes the application of engineering principles challenging at least: designing device-local programs that, through interaction, guarantee a certain global service level. In this thesis, we first analyse the state of the art in coordination systems, then motivate the work by describing the main issues of pre-existing tools and practices and identifying the improvements that would benefit the design of such complex software ecosystems. The contribution can be divided in three main branches. First, we introduce a novel simulation toolchain for pervasive ecosystems, designed for allowing good expressiveness still retaining high performance. Second, we leverage existing coordination models and patterns in order to create new spatial structures. Third, we introduce a novel language, based on the existing ``Field Calculus'' and integrated with the aforementioned toolchain, designed to be usable for practical aggregate programming.

Self-organising pervasive ecosystems of devices are set to become a major vehicle for delivering infrastructure and end-user services. The inherent complexity of such systems poses new challenges to those who want to dominate it by applying the principles of engineering. The recent growth in number and distribution of devices with decent computational and communicational abilities, that suddenly accelerated with the massive diffusion of smartphones and tablets, is delivering a world with a much higher density of devices in space. Also, communication technologies seem to be focussing on short-range device-to-device (P2P) interactions, with technologies such as Bluetooth and Near-Field Communication gaining greater adoption. Locality and situatedness become key to providing the best possible experience to users, and the classic model of a centralised, enormously powerful server gathering and processing data becomes less and less efficient with device density. Accomplishing complex global tasks without a centralised controller responsible of aggregating data, however, is a challenging task. In particular, there is a local-to-global issue that makes the application of engineering principles challenging at least: designing device-local programs that, through interaction, guarantee a certain global service level. In this thesis, we first analyse the state of the art in coordination systems, then motivate the work by describing the main issues of pre-existing tools and practices and identifying the improvements that would benefit the design of such complex software ecosystems. The contribution can be divided in three main branches. First, we introduce a novel simulation toolchain for pervasive ecosystems, designed for allowing good expressiveness still retaining high performance. Second, we leverage existing coordination models and patterns in order to create new spatial structures. Third, we introduce a novel language, based on the existing ``Field Calculus'' and integrated with the aforementioned toolchain, designed to be usable for practical aggregate programming.

Ecosystem-based management (EBM) is increasingly seen as the new paradigm for managing the use of marine resources and ecosystems. Although EBM has been defined in theory, its implementation has faced challenges worldwide. This research aims to examine two approaches to contribute to the operationzalization of EBM by incorporating stakeholder values in the decision-making process, and by better representing ecosystem dynamics in ecosystem models. First, I illustrate a decision-making framework for EBM rooted in structured decision-making (SDM), a well-known systematic approach for planning and stakeholder-consultation processes. SDM helps to identify the values of the constituents and define objectives and indicators that are consistent with those values. I demonstrate how SDM can enable managers to evaluate the performance of management alternatives using indicators specifically chosen to reflect values. This can help managers make more systematic, transparent and informed decisions with respect to the use of marine resources. As a case study, I apply SDM to the marine planning process on the west coast of Vancouver Island (WCVI). Second, as ecosystem models play an important role in EBM, I strive to improve the representation of marine ecosystems using ecosystem models in Ecopath with Ecosim (EwE). I focus on incorporating mediating effects and species reintroductions, both common situations that can strongly influence ecosystem dynamics. These considerations are essential when applying holistic approaches to management but they are not generally included in EwE. I use EwE to model the reintroduction of sea otters (Enhydra lutris) and the mediating effects provided by kelp forests in nearshore ecosystems of the WCVI. Because EwE does not have the functionality to represent reintroductions, I created two scenarios to work around the assumptions of Ecospace on the initial state of the ecosystem. In addition, I demonstrate how mediating effects can be represented using the ‘mediation’ function in Ecosim. These methods and results can contribute to advance EBM on the WCVI and offer insights to other marine planning processes. Both strengths and limitations of this work are presented and analyzed.

<p> Methylmercury (MeHg) is a toxic and bioaccumulative form of mercury that can be produced by bacteria living in water saturated soils, including those found in flooded rice fields. In the Sacramento Valley, California, rice is grown on 240,000 hectares, and mercury is a concern due to a history of mining in the surrounding mountains. </p><p> Using unfiltered aqueous MeHg data from MeHg monitoring programs in the Sacramento River watershed from 1996 to 2007, the MeHg contribution from rice systems to the Sacramento River, was assessed. AgDrain MeHg concentrations were elevated compared to upstream river water during November through May, but were not significantly different during June through October. June through October AgDrain MeHg loads (concentration &times; flow) contributed 10.7&ndash;14.8% of the total Sacramento River MeHg load. Missing flow data prevented calculation of the percent contribution of AgDrains in November through May. </p><p> Field scale MeHg dynamics were studied in two commercial rice fields in the Sacramento Valley. The Studied fields had soil total mercury concentrations of 25 and 57 ng g^-1, which is near the global background level. Surface water and rice grain MeHg and THg concentrations were low compared to previously studied fields. An analysis of surface water drainage loads indicates that both fields were net MeHg importers during the growing season and net MeHg exporters during the fallow season. </p><p> Since the microbes that produce MeHg prefer flooded environments, management that dries the soil might reduce MeHg production. Conventional continuously flooded (CF) rice field water management was compared to alternate wetting and drying, where irrigation was stopped twice during the growing season, allowing soil to dry to 35% volumetric moisture content, at which point plots were re-flooded (AWD-35). Compared to CF, AWD-35 resulted in a significant reduction of MeHg concentration in soil, surface water and rice grain.</p><p>

Water motion has been shown to influence almost every aspect of the ecology of seagrass communities; seagrass communities have likewise been shown to significantly influence water movement around them. This thesis examines the important role of water motion on seagrass ecosystems by integrating field and laboratory studies of several aspects of seagrass ecology influenced by water motion. To facilitate the study of hydrodynamics of seagrass ecosystems, a solid state electronic current meter was designed and developed, using thermistors as flow sensing devices. Important characteristics of the meters include: no moving parts, compact size, high sensitivity (resolution better than ± 0.5 cm s-1), and high sampling rate (greater than 0.2 Hz). Deployment of the meters in field measurements provided reliable and meaningful results of flow conditions through seagrass canopies, and they show great potential for use in many studies of marine ecology. Field studies of water velocity profiles revealed significant differences between the shapes of profiles of different seagrass species, particularly between species of Posidonia and Amphibolis. Of particular note is the observation of a region of high water velocity beneath the leafy canopy of Amphibolis, which was not present in the Posidonia plants. Water velocity profile measurements, sediment grain size analyses and standing stock measurements were conducted across an exposure gradient in a Posidonia sinuosa meadow. These studies revealed that, while the exposed location experienced a higher ambient water velocity than the sheltered site, the baffling influence of the seagrass canopy reduced the water velocity to approximately the same at both sites, within the meadow, although the effects varied seasonally. It was also observed that the seagrass meadow produced apparent skimming flow under the low flow conditions measured at the sheltered location; this phenomenon reflects the capacity for flow redirection over the canopy, and has important implications for the sub-canopy ecosystem and the protective role of seagrasses on the seabed. Field and laboratory studies on the role of seagrass density on the hydrodynamic nature of seagrass ecosystems revealed that water velocity profiles through meadows of reduced densities, and different shoot arrangements, were markedly different to “natural” profiles, implying the existence of a “critical density” (approximately 25 % of natural meadow density) with regard to canopy hydraulics. The role of water motion at an individual leaf scale was investigated with a series of laboratory flume studies of photosynthetic rates of seagrass and algae. The results show that the response of photosynthetic rate to water velocity depends very much on the plant species, with the algae markedly more productive (on a unit chlorophyll basis) than the seagrasses tested. Increases in photosynthetic rate were observed at water velocities above approximately 2.5 cm s-1; negligible photosynthetic activity was observed below this velocity. Calculation of P v. I curves indicated that the Posidonia species had high Ik values at low velocities (1360 :mol quanta m-2 s-1 for P. australis and 250.8 :mol quanta m-2 s-1 for P. sinuosa at 1.58 cm s-1), which decreased with increasing water velocity (to 138.9 and 24.77 :mol quanta m-2 s-1 for P. australis and P. sinuosa respectively), while the algal species had relatively constant values of Ik across all water velocities (85.42 to 312.7 :mol quanta m-2 s-1 for Ulva lactuca and 169.7 to 573.9 :mol quanta m-2 s-1 for Laurencia cruciata). Dye visualization studies showed that the algae remained quite rigid at all the velocities tested, while the seagrass leaves compressed as velocity increased. This resulted in an increased rate of turbulence creation by the algae, which is believed to enhance photosynthetic rates, through improved nutrient exchange rates across the boundary layer adjacent to the thallus. Further dye visualization studies revealed the significance of blade morphology on the creation of microscale turbulence at the surface of seagrass leaves. Epiphytic growth on seagrass leaves was observed to play an important role in breaking up water flow across the leaf surface, thereby enhancing the creation of microscale turbulence. From these studies, it is clear that water motion influences all aspects of the functioning of all components of seagrass communities, playing a role in nutrient supply, reproduction, physical stability, temperature and metabolic functions. The influence of seagrass meadows on coastal hydrodynamics is also apparent, with potential impacts on sediment stability, recruitment of benthic species and coastal erosion. This thesis has clearly demonstrated that water motion is an important parameter in seagrass ecology, and requires serious consideration in seagrass research, conservation and rehabilitation programmes.

Conventional wisdom in ecotoxicology predicts reductions in organismal fitness to follow from exposure-related physiological effects. This expectation may be appropriate for controlled laboratory environments, but may not necessarily reflect what is likely to take place in the wild. In an extensive review of the ecotoxicology literature, it was revealed that fish condition factor (an index of energetic fitness) is just as likely to respond favourably to pollutant exposure as it is to respond negatively. The remainder of this thesis examines some of the ecological reasons for this apparent paradox. One possible cause of altered energetic status in wild, pollutant-exposed fish is variable food availability. Addressing this possibility, I showed that consumption rates (estimated using a 137Cesium mass-balance approach) were not related to growth reductions in hormonally-impaired yellow perch ( Perca flavescens) from metal-contaminated lakes. Another possibility is that fish forage less efficiently in metal-polluted lakes as a result of lowered prey choice. In this thesis, I develop an enzymatic and individual-based biomarker for fish activity costs (muscle lactate dehydrogenase, LDH, activity) and show, through the use of this tool that the cost of fish activity is intimately tied to prey type and the ability to make normal ontogenetic diet shifts. Through the application of LDH measurements, as well as through bioenergetic modelling, diet and prey community analyses, a link between decreased prey choice and high perch activity costs leading to zero growth efficiency (energetic bottlenecks) was demonstrated in yellow perch from metal-contaminated lakes. This finding provided one of the first examples in ecotoxicology of a mechanistic link between community and organismal endpoints. The findings of this thesis emphasize the need for ecotoxicology to consider ecology when looking for and interpreting ecologically relevant endpoints. The final chapter of this thesis ex

Ecologists would like to understand how complexity persists in nature. In this thesis I have taken two fundamentally different routes to study ecosystem stability of model ecosystems: classical community ecology and classical population ecology. In community ecology models, we can study the mathematical mechanisms of stability in general, large model ecosystems. In population ecology models, fewer species are studied but greater detail of species interactions can be incorporated. Within these alternative contexts, this thesis contributes to two consuming issues concerning the stability of ecological systems: the ecosystem stability-complexity debate; and the causes of cyclic population dynamics. One of the major unresolved issues in community ecology is the relationship between ecosystem stability and complexity. In 1958 Charles Elton made the conjecture that the stability of an ecological system was coupled to its complexity and this could be a “wise principle of co-existence between man and nature” with which ecologists could argue the case for the conservation of nature for all species, including man. The earliest and simplest model systems were randomly constructed and exhibited a negative association between stability and complexity. This finding sparked the stability-complexity debate and initiated the search for organising principles that enhanced stability in real ecosystems. One of the universal laws of ecology is that ecosystems contain many rare and few common species. In this thesis, I present analytical arguments and numerical results to show that the stability of an ecosystem can increase with complexity when the abundance distribution is characterized by a skew towards many rare species. This work adds to the growing number of conditions under which the negative stability - complexity relationship can been inverted in theoretical studies. While there is growing evidence that the stability-complexity debate is progressing towards a resolution, community ecology has become increasingly subject to major criticism. A long-standing criticism is the reliance on local stability analysis. There is growing recognition that a global property called permanence is a more satisfactory definition of ecosystem stability because it tests only whether species can coexist. Here I identify and explain a positive correlation between the probability of local stability and permanence, which suggests local stability is a better measure of species coexistence than previously thought. While this offers some relief, remaining issues cause the stability-complexity debate to evade clear resolution and leave community ecology in a poor position to argue for the conservation of natural diversity for the benefit of all species. In classical population ecology, a major unresolved issue is the cause of non-equilibrium population dynamics. In this thesis, I use models to study the drivers of cyclic dynamics in Scottish populations of mountain hares (Lepus timidus), for the first time in this system. Field studies currently favour the hypothesis that parasitism by a nematode Trichostrongylus retortaeformis drives the hare cycles, and theory predicts that the interaction should induce cycling. Initially I used a simple, strategic host-parasite model parameterised using available empirical data to test the superficial concordance between theory and observation. I find that parasitism could not account for hare cycles. This verdict leaves three options: either the parameterisation was inadequate, there were missing important biological details or simply that parasites do not drive host cycles. Regarding the first option, reliable information for some hare-parasite model parameters was lacking. Using a rejection-sampling approach motivated by Bayesian methods, I identify the most likely parameter set to predict observed dynamics. The results imply that the current formulation of the hare-parasite model can only generate realistic dynamics when parasite effects are significantly larger than current empirical estimates, and I conclude it is likely that the model contains an inadequate level of detail. The simple strategic model was mathematically elegant and allowed mathematical concepts to be employed in analysis, but the model was biologically naïve. The second model is the antipode of the first, an individual based model (IBM) steeped in biological reality that can only be studied by simulation. Whilst most highly detailed tactical models are developed as a predictive tool, I instead structurally perturb the IBM to study the ecological processes that may drive population cycles in mountain hares. The model allows delayed responses to life history by linking maternal body size and parasite infection to the future survival and fecundity of offspring. By systematically removing model structure I show that these delayed life history effects are weakly destabilising and allow parameters to lie closer to empirical estimates to generate observed hare population cycles. In a third model I structurally modify the simple strategic host-parasite model to make it spatially explicit by including diffusion of mountain hares and corresponding advection of parasites (transportation with host). From initial simulations I show that the spatially extended host-parasite equations are able to generate periodic travelling waves (PTWs) of hare and parasite abundance. This is a newly documented behaviour in these widely used host-parasite equations. While PTWs are a new potential scenario under which cyclic hare dynamics could be explained, further mathematical development is required to determine whether adding space can generate realistic dynamics with parameters that lie closer to empirical estimates. In the general thesis discussion I deliberate on whether a hare-parasite model has been identified which can be considered the right balance between abstraction and relevant detail for this system.

The objective of this thesis was to better understand the mechanistic control of carbon (C) cycling in two terrestrial ecosystems (agricultural grasslands and Arctic tundra), with an aim to identify the contribution of microbial respiration to below-ground C cycling. Firstly, I evaluated different techniques for measuring CO2 evolution from soil. I found that different in-situ chamber-based CO2 gas analyzers gave comparable results across contrasting ecosystems. However, the addition of collars to the CO2 chamber induces variable flux estimates due to the disturbance created upon collar insertion, severing root and mycorrhizal networks. In subsequent studies, I showed that microbial breakdown of individual dissolved organic C (DOC) components demonstrated good reproducibility when performed under either in-situ and ex-situ conditions. After validating the experimental techniques, they were then used to study C turnover in two plant-soil systems. In Arctic tundra, soil temperature was identified as the key driver initiating microbial and vegetation response to snow melt, thereby driving early season CO2 efflux. However, as the growing season progressed, soil water content was hypothesized to become a more important regulator of C turnover with older C compounds becoming more susceptible to decomposition as soil water content increases. In a grassland soil I found that soil microbial community composition does not correlate with increased rates of mineralization across a wide pH gradient. This suggests that abiotic drivers of respiration may directly influence microbial metabolic processes independent of community structure. Further research involving advanced molecular techniques (metabolomics, proteomics, transcriptomics) will help disseminate how metabolic processes are being influenced by different respiration drivers. The application of mathematical models to respiration data provides a more quantitative and mechanistic understanding of processes involved in soil C cycling. I found the fitting of exponential models to respiration data is a reliable proxy for describing substrate mineralization; however, the correct choice of model is critically dependent on the number of measurement points and length of experiment. The modelling approach was subsequently used to quantify the turnover of functional microbial C pools. By combining modelling with experimental measures of soil solution C concentration, we estimated that the microbial contribution to total soil respiration is ea. 18%. This research provides a more detailed understanding of how C constituents are processed by the microbial decomposer community to drive soil respiration. This is crucial to accurately model global terrestrial C fluxes in different ecosystems and to predict how these fluxes are likely to respond to future changes from both natural (e.g. climate change) and anthropogenic (e.g. land-use change) sources.

Thesis (S.M. in Management Studies)--Massachusetts Institute of Technology, Sloan School of Management, 2013.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 101-103).<br>Entrepreneurship is a vehicle of growth and job creation. America has understood it and benefitted most from following this philosophy. Governments around the world need to build and grow their entrepreneurial ecosystems to support the economies and foster innovation. Approaches taken to encourage entrepreneurship vary around the world based on cultural norms, market conditions, and economic circumstances. Entrepreneurial ecosystems are generally comprised of the government, which builds rules and regulations to support entrepreneurship, the angel and venture capital industry, which provide necessary startup and growth capital to support entrepreneurship, the financial market, which provides financial incentives and exit routes for startups, and finally the entrepreneurs, who form teams and start companies. This thesis is an attempt to study and analyze the entrepreneurial ecosystems in the U.S, Europe, and Asia. Primarily relying on interviews with industry experts and supported by academic research, it draws qualitative comparisons of entrepreneurship processes among these regions to understand the differences in these environments.<br>by Anand R. Kumar.<br>S.M.in Management Studies

The innovation ecosystem’s online presence continues to grow with the emergence and maturation of ICT-based platforms. With these new channels, a diversity of actors, including firms, scientists, universities, media entities, and individuals, interact to satisfy their information needs and to access and mobilize network-based resources. This research is among a growing number of social science studies examining the advent of social media and its influence on the innovation process, asking, “How do different types of actors use social media to form network linkages, and what kinds of innovative outcomes will result?” To study this complex network activity, I turn to Twitter, the popular microblogging service, and focus on the case of graphene, a novel nanotechnology material consisting of a two-dimensional sheet of carbon atoms. Twitter is one of the world’s most often-used social networks, boasting over 500 million users (200+ million active). Graphene, on the other hand, is a relatively well-bounded area of scientific inquiry with ongoing, concurrent scientific and commercialization activity. The primary sample dataset derives from 34 graphene firms’ friend and followers relationships captured in early 2014. Nine interview transcripts supply qualitative data. The results show that network formation on Twitter is not random and that certain actor relationships predict following linkages. A series of network visualizations show that users agglomerate in communities; these communities exhibit greater density than the larger ecosystem network and a propensity to congeal in topically focused ways. That is, each community indicates a coherent topical focus, suggesting that graphene firms follow specific sets of users in ways that support their information and resource needs. At the micro-level, an unstructured text mining approach to operationalizing and computing information distance shows that increasing amounts of topical distance between any two users decreases the likelihood of a tie existing. Are innovation outcomes more likely to occur in strategically-developed and information-rich social media networks? Drawing on different sources of “behavioral additionality” – or changes in behaviors as a result of social media participation – I identify ex-ante several such plausible outcomes, which could include increased awareness, improved problem solving ability, community development, and greater sales. The qualitative results show that social media participation results in increased awareness of graphene and related ecosystem topics, but engagement is a key tactical maneuver that actors pursue, often in varying ways, to access and mobilize other resources. Policy implications are targeted at intermediary institutions and scientists, while management implications focus on high-technology SMEs. Limitations include alternative theories to explaining social media participation and engagement, methodological issues, and the continuing evolution of social media platforms and usage patterns. Future work is considered to address the temporal nature of network construction and topical growth (or constriction), as well as the ability to map areas of science and technology through social media data.

<p> Empirical studies of graphs have contributed enormously to our understanding of complex systems, growing into a more scientific exploration of communities spanning the physical, biological, and social called network science. As the quantity and types of networks have grown so has their heterogeneity in quality and specificity resulting in a wealth of datasets that are not matched by existing theoretical methods. This is especially true in ecology where the majority of interactions are indirect and unobservable even in well-studied systems. As a result ecologists continue to grapple with three fundamental questions: Most basically, (i) `How do ecosystems function?' I answered this question by comparing networks to each other such that poorly-studied systems can be understood through their similarity to well-understood ones and theoretical models. To do this I created the alignment algorithm netcom which recasts ecosystem processes as statistical dynamics of diffusion kernels originating from a network's constituent nodes. Using netcom I constructed a supervised classifier which can distinguish processes in both synthetic and empirical network data. While this kind of inference works on currently available network data, I have shown how causality can serve as a more effective and unifying currency of ecological interaction. Measures of causality are even able to identify complex interactions across organizational scales of communities, answering the longstanding question (ii) `Can community structure causally determine dynamics of constituent species?' Moreover, causal inference can be readily combined with existing modeling frameworks to quantify dynamic interactions at the same scale as the underlying data. In this way we can answer the question (iii) `Which species in an ecosystem cause which other species?' These tools are part of a paradigm shift in ecology that offers the potential to make more reliable management decisions for dynamic ecosystems in real time using only observational data.</p><p>

This study aims at finding out how ecosystems affect the development of startups. This is a current topic because startups are a prominent phenomenon, the development and growth of which studies have not been able to fully describe or explain so far. Furthermore, it has been noted that more research should be aimed at providing insights and guidelines for startup managers on how to grow their company, especially in the international markets. We are looking at the business ecosystem because it is a good way of describing the complex business environment of the startups today. By looking at the ecosystem that the startup is a part of, we can find out how the characteristics and interactions, as well as other actors and their actions can affect the development of a startup. Therefore, we need close observations on the ecosystem. The study approaches the startup development from a case study point of view and utilizes qualitative interview data as its primary source for analysis. The interviews are recorded and transcribed and the transcription coded. Within case analysis is utilized to get a more comprehensive and reliable understanding of the phenomenon. This study supports the view that ecosystems are important for startups and can offer them opportunities for development. It is noted that startups should take the ecosystem realities into consideration when strategizing and planning the activities and actions of the company. The specific ecosystem structures and ways of interaction and participation are important indicators on how a startup should participate in the ecosystem, what kind of information is available, what areas are to pursue and with what kind of strategies. It is also noted that different ecosystem actors, also other than for-profit companies, can be important for company development in the ecosystem. All, in all, the study offers support to the notion that business ecosystems are important these days, and that startups can benefit from knowing, participating in, and adjusting to these ecosystems. The results of this study can be used by startup managers to gain insights for planning and strategizing. The results can be used as guidance on what the managers should take into consideration when entering new international markets, but also point out the ways in which the ecosystem can affect the company development. The results can be generalized to some extent, even though this is a case study into a certain ecosystem and a certain startup as a part of that ecosystem.

Among the main issues we face today dynamics of changes and unpredictability of transformation trajectories should be definitely mentioned. As a result of even just these two our own lives are faster and working conditions are more and more demanding. From personal micro-level to socio-economic macro-level we can see human creativity and its innovative outcomes. And at all that levels different socio-economic systems obtain more and more self-organising potential. In addition, having much less material limits both intelligence and creativity are very promising in the context of sustainable development in times of our “information age” and “knowledge society”.

Water motion has been shown to influence almost every aspect of the ecology of seagrass communities; seagrass communities have likewise been shown to significantly influence water movement around them. This thesis examines the important role of water motion on seagrass ecosystems by integrating field and laboratory studies of several aspects of seagrass ecology influenced by water motion. To facilitate the study of hydrodynamics of seagrass ecosystems, a solid state electronic current meter was designed and developed, using thermistors as flow sensing devices. Important characteristics of the meters include: no moving parts, compact size, high sensitivity (resolution better than plus-minus 0.5 cm s-1), and high sampling rate (greater than 0.2 Hz). Deployment of the meters in field measurements provided reliable and meaningful results of flow conditions through seagrass canopies, and they show great potential for use in many studies of marine ecology. Field studies of water velocity profiles revealed significant differences between the shapes of profiles of different seagrass species, particularly between species of Posidonia and Amphibolis. Of particular note is the observation of a region of high water velocity beneath the leafy canopy of Amphibolis, which was not present in the Posidonia plants. Water velocity profile measurements, sediment grain size analyses and standing stock measurements were conducted across an exposure gradient in a Posidonia sinuosa meadow. These studies revealed that, while the exposed location experienced a higher ambient water velocity than the sheltered site, the baffling influence of the seagrass canopy reduced the water velocity to approximately the same at both sites, within the meadow, although the effects varied seasonally. It was also observed that the seagrass meadow produced apparent skimming flow under the low flow conditions measured at the sheltered location; this phenomenon reflects the capacity for flow redirection over the canopy, and has important implications for the sub-canopy ecosystem and the protective role of seagrasses on the seabed. Field and laboratory studies on the role of seagrass density on the hydrodynamic nature of seagrass ecosystems revealed that water velocity profiles through meadows of reduced densities, and different shoot arrangements, were markedly different to 'natural' profiles, implying the existence of a 'critical density' (approximately 25 % of natural meadow density) with regard to canopy hydraulics. The role of water motion at an individual leaf scale was investigated with a series of laboratory flume studies of photosynthetic rates of seagrass and algae. The results show that the response of photosynthetic rate to water velocity depends very much on the plant species, with the algae markedly more productive (on a unit chlorophyll basis) than the seagrasses tested. Increases in photosynthetic rate were observed at water velocities above approximately 2.5 cm s-1; negligible photosynthetic activity was observed below this velocity. Calculation of P v. I curves indicated that the Posidonia species had high Ik values at low velocities (1360 :mol quanta m-2 s-1 for P. australis and 250.8 :mol quanta m-2 s-1 for P. sinuosa at 1.58 cm s-1), which decreased with increasing water velocity (to 138.9 and 24.77 :mol quanta m-2 s-1 for P. australis and P. sinuosa respectively), while the algal species had relatively constant values of Ik across all water velocities (85.42 to 312.7 :mol quanta m-2 s-1 for Ulva lactuca and 169.7 to 573.9 :mol quanta m-2 s-1 for Laurencia cruciata). Dye visualization studies showed that the algae remained quite rigid at all the velocities tested, while the seagrass leaves compressed as velocity increased. This resulted in an increased rate of turbulence creation by the algae, which is believed to enhance photosynthetic rates, through improved nutrient exchange rates across the boundary layer adjacent to the thallus. Further dye visualization studies revealed the significance of blade morphology on the creation of microscale turbulence at the surface of seagrass leaves. Epiphytic growth on seagrass leaves was observed to play an important role in breaking up water flow across the leaf surface, thereby enhancing the creation of microscale turbulence. From these studies, it is clear that water motion influences all aspects of the functioning of all components of seagrass communities, playing a role in nutrient supply, reproduction, physical stability, temperature and metabolic functions. The influence of seagrass meadows on coastal hydrodynamics is also apparent, with potential impacts on sediment stability, recruitment of benthic species and coastal erosion. This thesis has clearly demonstrated that water motion is an important parameter in seagrass ecology, and requires serious consideration in seagrass research, conservation and rehabilitation programmes.

Water motion has been shown to influence almost every aspect of the ecology of seagrass communities; seagrass communities have likewise been shown to significantly influence water movement around them. This thesis examines the important role of water motion on seagrass ecosystems by integrating field and laboratory studies of several aspects of seagrass ecology influenced by water motion. To facilitate the study of hydrodynamics of seagrass ecosystems, a solid state electronic current meter was designed and developed, using thermistors as flow sensing devices. Important characteristics of the meters include: no moving parts, compact size, high sensitivity (resolution better than plus-minus 0.5 cm s-1), and high sampling rate (greater than 0.2 Hz). Deployment of the meters in field measurements provided reliable and meaningful results of flow conditions through seagrass canopies, and they show great potential for use in many studies of marine ecology. Field studies of water velocity profiles revealed significant differences between the shapes of profiles of different seagrass species, particularly between species of Posidonia and Amphibolis. Of particular note is the observation of a region of high water velocity beneath the leafy canopy of Amphibolis, which was not present in the Posidonia plants. Water velocity profile measurements, sediment grain size analyses and standing stock measurements were conducted across an exposure gradient in a Posidonia sinuosa meadow. These studies revealed that, while the exposed location experienced a higher ambient water velocity than the sheltered site, the baffling influence of the seagrass canopy reduced the water velocity to approximately the same at both sites, within the meadow, although the effects varied seasonally. It was also observed that the seagrass meadow produced apparent skimming flow under the low flow conditions measured at the sheltered location; this phenomenon reflects the capacity for flow redirection over the canopy, and has important implications for the sub-canopy ecosystem and the protective role of seagrasses on the seabed. Field and laboratory studies on the role of seagrass density on the hydrodynamic nature of seagrass ecosystems revealed that water velocity profiles through meadows of reduced densities, and different shoot arrangements, were markedly different to 'natural' profiles, implying the existence of a 'critical density' (approximately 25 % of natural meadow density) with regard to canopy hydraulics. The role of water motion at an individual leaf scale was investigated with a series of laboratory flume studies of photosynthetic rates of seagrass and algae. The results show that the response of photosynthetic rate to water velocity depends very much on the plant species, with the algae markedly more productive (on a unit chlorophyll basis) than the seagrasses tested. Increases in photosynthetic rate were observed at water velocities above approximately 2.5 cm s-1; negligible photosynthetic activity was observed below this velocity. Calculation of P v. I curves indicated that the Posidonia species had high Ik values at low velocities (1360 :mol quanta m-2 s-1 for P. australis and 250.8 :mol quanta m-2 s-1 for P. sinuosa at 1.58 cm s-1), which decreased with increasing water velocity (to 138.9 and 24.77 :mol quanta m-2 s-1 for P. australis and P. sinuosa respectively), while the algal species had relatively constant values of Ik across all water velocities (85.42 to 312.7 :mol quanta m-2 s-1 for Ulva lactuca and 169.7 to 573.9 :mol quanta m-2 s-1 for Laurencia cruciata). Dye visualization studies showed that the algae remained quite rigid at all the velocities tested, while the seagrass leaves compressed as velocity increased. This resulted in an increased rate of turbulence creation by the algae, which is believed to enhance photosynthetic rates, through improved nutrient exchange rates across the boundary layer adjacent to the thallus. Further dye visualization studies revealed the significance of blade morphology on the creation of microscale turbulence at the surface of seagrass leaves. Epiphytic growth on seagrass leaves was observed to play an important role in breaking up water flow across the leaf surface, thereby enhancing the creation of microscale turbulence. From these studies, it is clear that water motion influences all aspects of the functioning of all components of seagrass communities, playing a role in nutrient supply, reproduction, physical stability, temperature and metabolic functions. The influence of seagrass meadows on coastal hydrodynamics is also apparent, with potential impacts on sediment stability, recruitment of benthic species and coastal erosion. This thesis has clearly demonstrated that water motion is an important parameter in seagrass ecology, and requires serious consideration in seagrass research, conservation and rehabilitation programmes.

Business Administration/Management Information Systems<br>Ph.D.<br>Digital ecosystems are one of the most important strategic issues in the current digital economy. Digital ecosystems are dynamic and generative. They evolve as new firms join and as heterogeneous systems are integrated into other systems. These features digital ecosystems determine economic and technological success in the competition among digital platform systems. However, how these ecosystems evolve over time is not yet clearly known. I describe three empirical essays in order to understand the underlying mechanism of the evolution of a digital ecosystem: 1) the underlying architecture of a digital ecosystem, 2) the evolutionary pattern of a digital ecosystem, 3) and the co-evolution of a digital ecosystem. To explore these topics, I focus on the underlying generative structure of the ecosystem and its evolutionary pattern of WordPress, which is the world largest blog platform system. I collected a comprehensive set of information about the WordPress ecosystem including over 23,000 plug-ins from January 2004 to December 2014. To analyze the data, I apply a network approach to capture the generative nature of digital technology that assumes a fractal-like structure in which digital components such as Application Programming Interfaces (API) cluster into groups that generate other groups over time. As such, I can effectively capture the hierarchical structure of a network by exploring the topological structure of sub-networks that represent the fractal-like evolutionary dynamic system mechanism. The network approach, together with the conventional statistical approach, allows me to understand the unique nature of a digital ecosystem that is different from the boundary of a decomposable system, as the generative nature of system-agnostic digital components builds on a developmental combinable system. I also discuss underlying theory, methodology, data, result, and implications and conclude by highlighting the contributions of this study and the direction of future research to further explore the evolution of digital ecosystems.<br>Temple University--Theses

Abstract Streams and rivers have been extensively altered by humans. Channelization and land use have changed stream habitats and water quality with adverse effects on biota and ecosystem functions. Impacted streams have been targets for restoration, but there is considerable lack of understanding how streams should be restored in an ecologically effective way. In this doctoral thesis, I studied the impacts of channelization (for timber floating) and agricultural diffuse pollution on stream biota. I also studied the effectiveness of restorations of forestry impacted streams stressed by excessive sand sedimentation from catchment drainage. Finally, I also studied the effects of mosses, fine sediment and enhanced dispersal on stream macroinvertebrate communities and ecosystem functions. I found that channelization did not have effect on diatom, macrophyte, macroinvertebrate and fish assemblages, whereas diffuse pollution had strong effects, with no interactions between the two stressors. I showed that excessive sedimentation from forest drainage was harmful for stream biota but had no effect on leaf decomposition and algal accrual rate. Restoration with boulders reduced sand cover and was more beneficial for in-stream biodiversity, whereas restoration with wood tended to increase hydrological retention of stream channels, thereby altering riparian plant assemblages toward more natural composition. In a mesocosm experiment, I found mosses to have a strong impact on macroinvertebrate communities and ecosystem functions. Mosses increased organic matter retention and reduced algal accrual rate and leaf decomposition. The effect of mosses on macroinvertebrates was stronger than that of sand sedimentation, and mosses mitigated some of the negative effects of sand. Extensive dispersal had a distinct imprint on invertebrate community composition but did not blur the effect of mosses and sand on communities, suggesting strong local-scale environmental control of composition. My thesis emphasizes that priority in stream restoration should be in the mitigation of diffuse pollution rather than restoration of channel morphology, especially in streams where channel alteration has been fairly modest, as in the case of timber floating. Addition of both boulders and large wood likely yields the best biodiversity response in the restoration of forestry impacted streams. Mosses are a key component of boreal lotic ecosystems; therefore, the recovery of mosses may be a prerequisite for the full recovery of biodiversity and ecosystem integrity of boreal streams<br>Tiivistelmä Ihmisen toiminta on laajasti muokannut virtavesiä. Uomien kanavointi ja maankäyttö ovat muuttaneet virtavesien elinympäristöjä ja veden laatua, millä on ollut haitallisia vaikutuksia virtavesien luonnon monimuotoisuuteen ja ekosysteemin toimintaan. Huonokuntoisia virtavesiä on kunnostettu paljon, mutta ymmärrys siitä, kuinka virtavesiä tulisi kunnostaa parhaan ekologisen lopputuloksen saavuttamiseksi, on edelleen vajaata. Tutkin tässä väitöskirjassa uittoperkausten ja maatalouden hajakuormituksen merkitystä ja yhteisvaikutusta virtavesien eliöyhteisöihin. Tutkin myös kunnostusten vaikutusta hiekasta kärsivissä metsätalouden muokkaamissa puroissa, sekä vesisammalten, hiekan ja eliöiden levittäytymisen merkitystä purojen pohjaeläinyhteisöjen ja ekosysteemin toimintojen muovautumisessa. Havaitsin, että uoman perkauksilla ei ollut vaikutusta virtavesien eliöyhteisöihin, mutta hajakuormituksen vaikutus oli voimakas. Perkauksella ja hajakuormituksella ei ollut yhteisvaikutuksia eliöyhteisöihin. Osoitin, että metsäojituksista aiheutuva ylimääräinen hiekan sedimentaatio on haitallista virtavesien eliöille, mutta sillä ei ollut vaikutusta lehtikarikkeen hajotukseen tai päällyslevien tuotantoon. Kunnostukset joissa käytettiin kiveä vähensivät hiekan peittävyyttä ja olivat hyödyllisempiä uoman eliöstölle kuin kunnostukset, joissa tehtiin puurakennelmia. Puukunnostukset kuitenkin lisäsivät uoman vedenpidätyskykyä ja siten muokkasivat rantavyöhykkeen kasvillisuutta luonnontilaisemmaksi. Havaitsin, että vesisammalilla on voimakas vaikutus pohjaeläinyhteisöjen koostumukseen. Sammalet vaikuttivat ekosysteemin toimintoihin lisäämällä eloperäisen aineksen pidättymistä ja vähentämällä lehtikarikkeen hajotusta ja päällyslevien tuotantoa. Sammalten vaikutus pohjaeläimiin oli voimakkaampi kuin hiekan, ja sammalet kykenivät jopa lieventämään joitakin hiekan negatiivisia vaikutuksia. Eliöiden levittäytymisellä oli selvä vaikutus yhteisöjen koostumukseen, mutta se ei hävittänyt hiekan ja sammalen vaikutusta, mikä viittaa korkeaan ympäristötekijöiden merkitykseen yhteisöjen rakentumisessa. Tutkielmani korostaa, että maatalousjokien tilan parantamisessa hajakuormituksen hallinta tulisi olla ensisijainen kunnostustavoite uoman rakenteen kunnostamisen sijaan. Metsätalouden vaikutuksista kärsivissä puroissa kivi- ja puumateriaalin käyttö samanaikaisesti tuottaa luultavimmin laajimman vaikutuksen purojen monimuotoisuuteen. Sammalilla on merkittävä vaikutus muiden eliöiden yhteisökoostumukseen ja ekosysteemin toimintoihin, joten sammalten palautuminen on tärkeä kunnostustavoite virtavesissä, joissa on luonnostaan paljon sammalkasvustoa

Benthic algae a re one of the most important primary producers i n lotic ecosystems, and changes i n their community structure and function (e.g., metabolism) will influence other organisms at higher trophic levels or even the entire aquatic ecosystem through bottom-up effects. Since they are known to be sensiti ve to changes i n ambient conditions, benthic algae and especially diatoms have been widely used as i ndicators of environmental changes in aquatic ecosystems, particular ly i n E urope , through developi ng diatom-based indices. However, these indices have not been widely used i n other continents. Applications of such i ndices in Asia and Oceania first require testi ng to see whether the y can perform as reliable bioindicators across time and space, considering that aquatic systems are constantly changing in terms of their ambient environment such as water physical and chemical conditions. Nevertheless, few studies have been carried out to compare the environmental influences on benthic algal communities among different geographic regions, nor the influences at different spatial scales (e.g., catchment, reach, and habitat). F urthermore, few studies have considered how diatom indices perform compare with other commonly used bioindicators of aquatic ecosystem health.<br>Thesis (PhD Doctorate)<br>Doctor of Philosophy (PhD)<br>Griffith School of Environment.<br>Science, Environment, Engineering and Technology<br>Full Text

La plataforma i els ecosistemes representen models cada vegada més ubics per organitzar l’activitat econòmica en sectors empresarial i tecnològic. Aquesta tesi representa un avanç en l’explicació dels fenòmens observats en ecosistemes diferents: programes de màrqueting d’afiliació programari empresarial. L'objectiu empresarial pràctic i global per a cadascun dels ecosistemes és entendre com les empreses centrals de cada àmbit gestionen els esforços de centenars o fins i tot milers de col•laboradors la feina deis quals gira al voltant de la plataforma de l’empresa principal. Aquesta tesi pretén omplir diversos buits de la literatura existent. En primer lloc, les recerques prèvies sobre els límits organitzatius s’han basat principalment en teories aïllades, com l’economia de costos de transacció. En la tesi, complementem aquestes teories amb les teories més recents sobre plataformes i ecosistemes, i oferim més coneixements teòrics i l’ampliació del tema a partir de les nostres observacions empíriques. Suggerim que hi ha una compensació fonamental entre la creativitat i el control central en plataformes o ecosistemes tecnològics. La creativitat sense control pot conduir a una excessiva fragmentació i a una qualitat variable, cosa que podria crear una percepció general de l’ecosistema negativa, i podria afectar la capacitat dels contribuïdors per desenvolupar les seves activitats de manera rendible. A més, hi ha el risc que l’activitat no regulada de tercers parts pugui portar el desenvolupament de l’ecosistema en direccions incompatibles amb la visió del patrocinador central. D’altra banda, uns mecanismes de control excessius o mal dissenyats poden perjudicar la creativitat i la innovació, i també la salut i el creixement de l’ecosistema. En segon lloc, argumentem que la recerca sobre els mecanismes de govern i control està menys desenvolupada o madura que el discurs sobre les fases de creativitat, i cal parar-hi més atenció per entendre aquesta interdependència fonamental entre la creativitat i el control. En tercer lloc, sostenim que les recerques anteriors han tendit a considerar els ecosistemes tecnològics homogenis, i han assumit que la governança és uniforme per a totes les parts. Proposem que cal fer una recerca empírica que adopti un punt de vista més subtil de la governança d’ecosistemes tecnològics, que reconegui que els rols dels participants varien i, encara més important, que la governança ha d’abastar l’heterogeneïtat en tot l’ecosistema, fins i tot en aquells rols semblants. Finalment, una gran part de la literatura existent vinculada a les relacions entre empreses ha tendit a centrar-se o en la creació o en el control, però calen estudis empírics més detallats que tractin sobre la tensió entre aquestes dues forces. Aquesta tesi fa diverses contribucions a la teoria existent, incloses unes importants observacions empíriques en dos ecosistemes empresarials grans i complexos, i el desenvolupament teòric referent als esforços de les empreses principals en aquests ecosistemes per encoratjar la generativitat de terceres parts mantenint un grau de control sobre les seves contribucions a la plataforma central.<br>Las plataformas y los ecosistemas representan modelos cada vez más ubicuos para organizar la actividad económica en sectores empresarial y tecnológico. Esta tesis representa un avance en la explicación de los fenómenos observados en dos ecosistemas distintos: programas de marketing de afiliación y software empresarial. El objetivo empresarial práctico y global para cada uno de los ecosistemas es entender cómo empresas centrales en cada ámbito gestionan los esfuerzos cientos o incluso miles de colaboradores cuyo trabajo gira en torno a la plataforma de la compañía principal. Esta tesis pretende llenar varios vacíos de la literatura existente. En primer lugar, las investigaciones previas sobre los límites organizativos se han basado principalmente en teorías aisladas, como la economía de costes de transacción. En la tesis, complementamos estas teorías con las teorías más recientes sobre plataformas y ecosistemas, y ofrecemos más nociones teóricas y la ampliación del tema basándonos en nuestras observaciones empíricas. Sugerimos que existe una compensación fundamental entre la creatividad y el control central en plataformas o ecosistemas tecnológicos. La creatividad sin control puede llevar a una fragmentación excesiva y a una calidad variable, lo que podría crear una percepción general del ecosistema negativa, y podría afectar la capacidad de los contribuidores para desarrollar sus actividades de manera rentable. Además, existe el riesgo de que la actividad no regulada de terceras partes pueda llevar el desarrollo del ecosistema en direcciones incompatibles con la visión del patrocinador central. Por otro lado, unos mecanismos de control excesivos o mal diseñados pueden dañar la creatividad y la innovación, así como la salud y el crecimiento del ecosistema. En segundo lugar, argumentamos que la investigación sobre los mecanismos de gobierno y control está menos desarrollada o madura que el discurso sobre las fases de creatividad, y es necesario prestarle atención para entender esta interdependencia fundamental entre la creatividad y el control. En tercer lugar, sostenemos que las investigaciones anteriores han tendido a considerar los ecosistemas tecnológicos como homogéneos, asumiendo que la gobernanza es uniforme para todas las partes. Proponemos que existe la necesidad de realizar una investigación empírica que adopte un punto de vista más sutil de la gobernanza de ecosistemas tecnológicos, que reconozca que los roles de los participantes varían y, lo más importante, que la gobernanza debe abarcar la heterogeneidad en todo el ecosistema, incluso aquellos roles parecidos. Por último, gran parte de la literatura existente vinculada a las relaciones entre empresas ha tendido a centrarse o en la creación o en el control, pero son necesarios estudios empíricos más detallados que traten sobre la tensión entre estas dos fuerzas. Esta tesis realiza varias contribuciones a la teoría existente, incluidas unas importantes observaciones empíricas en dos ecosistemas empresariales grandes y complejos, y el desarrollo teórico referente a los esfuerzos de las empresas principales en dichos ecosistemas para alentar la generatividad de terceras partes manteniendo un grado de control sobre sus contribuciones a la plataforma central.<br>Platforms and ecosystems represent increasingly ubiquitous models for organizing economic activity in business and technology. This thesis represents an effort to explain observed phenomena in two distinct ecosystems: affiliate marketing programs and business software. The overall practical business objective for each is to understand how the core firm(s) in each domain manage the efforts of hundreds or even thousands of contributors whose work centers around the core company's platform. This thesis addresses several gaps in the literature. First, prior research on organizational boundaries has relied primarily on single theories such as transaction cost economics. We complement TCE with the more recent theories of platforms and ecosystems, offering further theoretical grounding and extension based on our empirical observations. We suggest that there is a fundamental tradeoff between creativity and control salient in technology platforms or ecosystems. Creativity without control can lead to excessive fragmentation and variable quality, which could create a negative overall perception of the ecosystem, and could affect the ability of niche contributors to profitably develop their activities. In addition, there is the risk that unregulated third-party activity may take ecosystem development in directions inconsistent with the vision of the core sponsor. On the contrary, excessive control or poorly designed control mechanisms can hurt creativity and innovation, also damaging the health and growth of the ecosystem. Second, we argue that research on governance and control mechanisms is less developed or mature than discourse on creativity phases, and therefore warrants attention in order to understand this critical interdependence between creativity and control. Finally, we contend that prior research has tended to view technology ecosystems as homogeneous, assuming that governance is uniform for all parties. We propose that there is a need for empirical research which adopts a more subtle view of technology ecosystem governance, acknowledging that participant roles vary, but more importantly, governance across the ecosystems must embrace heterogeneity, even for similar participant roles. Finally, much of the extant literature related to relationships between firms has tended to focus on either creation or on control, but there is a need for more detailed empirical studies which address the tension between these two forces. This thesis makes several contributions to extant theory, including substantial empirical observations in two large and complex business ecosystems, and theoretical development pertaining to efforts of core firms in such ecosystems to encourage third-party generativity while maintaining a degree of control over the third-party contributions to the core platform.