In the past, educators and policy makers believed that by providing more resources they could directly improve student-learning outcomes. To their frustration, this turns out not to be entirely true. Resources may be necessary but they are not sufficient. Resources themselves are not self-enacting, that is, they do not make change inevitable. Differences in their effects depend on differences in their use. This is also true in the case of educational technologies. As developers of these technologies we need to understand how resources fit within the classroom environment as enacted and how they can be effectively used to increase student learning. I report on four case studies conducted within the context of the Scaling-Up SimCalc study. In the study, "treatment" teachers were given a set of new resources to use: a combination of curriculum, educational software, and teacher professional development. "Delayed treatment" (control) teachers were asked to use their usual curriculum. Year-one study results demonstrated by randomized controlled testing the successful use of technology in class settings; however, there was little information on how the students and teachers actually interacted with the resources. Case study classrooms were selected to examine the effects of variation of computational resource arrangements: one utilized a computer lab, two used mobile laptop carts, and one used a laptop connected to a projector. The first round coding and analysis shows that the observed classrooms varied not only in their classroom set-ups but also in how teachers and students interacted with the software, the workbooks, and with one another. The variety of resource interaction points to the robustness of the SimCalc project: students and teachers can interact with the SimCalc resources in a variety of ways and still achieve student-learning gains. However, through subsequent review and analysis of the observation data five themes emerged. These themes suggest commonalities in classrooms practices surrounding the use of resources. Two new theoretical constructs, "socio-physical resource richness" and "resource use withitness" help describe (1) physical and social arrangements of resources and (2) how teachers and students manage resource use. / Ph. D.

A escassez de trabalhos acerca dos impactos causados por mosaicos agrícolas sobre a biodiversidade dificulta a criação de estratégias de conservação, havendo necessidade de informações acerca da ecologia e comportamento de espécies da fauna. Nesse contexto o presente estudo objetivou: 1) determinar a composição e estrutura de assembleias de mamíferos de médio e grande em uma paisagem agrícola de Mata Atlântica; 2) avaliar o padrão de alimentação da onça-parda (Puma concolor) por meio da análise de isótopos estáveis (SIA) em dois mosaicos agrícolas; 3) analisar por meio da diversidade funcional (FD) assembleias de mamíferos em remanescentes florestais distribuídos nas principais regiões biogeográficas da Mata Atlântica, e identificar limiares ecológicos para a conservação. Para o inventário, foram selecionados oito remanescentes florestais na Região Metropolitana de Campinas (RMC), São Paulo. Os dados foram coletados por busca ativa (visualizações e vestígios), resultando no registro de 34 espécies de mamíferos, sendo 27 de médio e grande porte, quatro de pequeno porte, e três exóticas. Sete espécies se encontram ameaçadas de extinção, com registros inéditos de Myrmecophaga tridactyla e Lycalopex gymnocercus. A riqueza e a composição de espécies registradas apontaram a RMC como importante para a conservação da mastofauna. Foram analisados isotopicamente (carbono e nitrogênio) pelos de onças-pardas, obtidos a partir de amostras fecais coletadas por busca ativa em remanescentes florestais inseridos em paisagens agrícolas no interior do estado de São Paulo. Houve maior consumo de presas C3 (~47% dos indivíduos) na área com maior proporção de vegetação nativa, e maior consumo de presas C4 (~40% dos indivíduos) para a área onde é predominante a matriz agrícola. Foi constatado o consumo de presas com dieta baseada em itens alimentares dos remanescentes e da matriz agrícola, sugerindo alta plasticidade comportamental das onças-pardas e de suas presas ocupando áreas fortemente impactadas pelo homem. A ferramenta isotópica apresentou informações pioneiras sobre ecologia trófica, podendo contribuir na elaboração estratégias de conservação em áreas antropizadas. Para a análise da FD e identificação dos limiares foi utilizado um banco de dados composto por 49 assembleias de mamíferos, criado a partir de dados primários e secundários de inventários, sendo selecionadas 38 características das espécies para o cálculo. A existência de limiares foi verificada utilizando a função \"segmented\", disponível no programa R. A FD apresentou-se diferente para assembleias com o mesma riqueza de espécies, indicando que filtros ambientais podem influenciar nos valores. O incremento gradual na FD devido ao aumento da área dos remanescentes mostrou uma relação positiva, possivelmente ligada a maior complexidade e heterogeneidade de áreas maiores. Foram identificados dois limiares (52 e 1244 ha), criando três situações funcionalmente distintas, tanto críticas quanto mais estáveis, permitindo definir e propor formas de ação específicas. Assembleias presentes entre os limiares apresentaram incremento funcional significativo entre FD e o aumento da área dos remanescentes, e ações visando à restauração e melhorias na configuração da paisagem devem ser incentivadas. Conclui-se, portanto, que tanto a SIA quanto a FD, podem ser consideradas importantes ferramentas para delinear estratégias e ações em prol da conservação da mastofauna. / The scarcity of studies regarding the impacts of agricultural mosaics on biodiversity hinders the creation of conservation strategies and a need for information concerning the ecology and behavior of wildlife species. In this context, the present study aimed to: 1) determine the composition and structure of mammal assemblages of medium and large sized in an agricultural landscape at Atlantic Forest; 2) evaluate the puma (Puma concolor) feeding pattern through analysis of stable isotopes (SIA) in two agricultural mosaics; 3) analyze mammal assemblages by functional diversity (FD) in forest remnants distributed in major biogeographic regions of the Atlantic Forest, and identify ecological thresholds for conservation. For mammal\'s inventory, eight forest remnants were selected in Campinas Metropolitan Region (RMC), São Paulo state. Data were collected through active search (visualizations and tracks), resulting in the record of 34 mammal species, 27 medium and large size, four of small size, and three exotic. Seven species are threatened with extinction, with novel records of Myrmecophaga tridactyla and Lycalopex gymnocercus for this region. The species richness and composition pointed RMC as an important area for mammal\'s conservation. Carbon and nitrogen stable isotopes were analyzed in pumas hair, obtained from fecal samples collected by active search in forest remnants embedded in agricultural landscapes in São Paulo state. There was a higher consumption of C3 prey (~ 47% of individuals) in the area with the highest proportion of forest coverage, and greater consumption of C4 prey (~ 40% of individuals) where the agricultural matrix was predominant. Was observed the consumption of prey with diet based on food items from both forest remnants and agricultural matrix, suggesting high behavioral plasticity of puma\'s and their prey\'s occupying areas heavily impacted by man. Stable isotopes contributed with pioneer information on trophic ecology, aiming the development of new conservation strategies in anthropogenic areas. A database consisting of 49 mammal\'s assemblages, created from primary and secondary data of inventories, was used for FD analysis and threshold\'s identification. 38 specie\'s traits were selected for FD calculation. The thresholds existence was verified using the \"segmented\" function, available on R program. FD was different between mammal assemblages with the same species richness, indicating that environmental filters may affect its values. The gradual increment in FD, due to the increase in forest remnants area, presented a positive relationship, possibly linked to the increased complexity and heterogeneity of large areas. Two thresholds (52 and 1244 ha) were identified, creating three functionally distinct situations, both critical as more stable, allowing to define and propose for each one specific ways of action. Mammal\'s assemblages found between the thresholds showed significant functional increment considering the relationship between FD and forest remnants area, and actions aiming biological restoration and improvements in the landscape configuration should be encouraged. It was concluded, therefore, that both SIA as the FD can be considered important tools to outline strategies and actions for mammal\'s conservation.

This is a qualitative study examining conservation attitudes and resource use of 63 individuals in Kasigau, Kenya. Community members described their perceptions of conservation, the resources that they use, the location and availability of these, their support for the protection of Mt. Kasigau, their likes and dislikes of plant and animal species, and their support of ecotourism in Kasigau. All individuals listed conservation behaviors and agreed that protecting Mt. Kasigau is important. Many recognized the mountain as the only source of water. Some resources were limited, especially at certain times of the year. All interviewed community members except one would like tourists to visit Kasigau and are interested in cultural exchange. There is an apparent difference between conservation and ecotourism attitudes in Makwasinyi and the other six villages which could be because Makwasinyi has a lower level of education and is isolated on the northeastern side of the mountain. Gender differences between males and females were also present as each gender uses different resources coupled with a division of labor. The main theory that evolved was rational choice theory. People of Kasigau are trying to sustain their livelihoods and will pick conservation activities due to their benefits and chance they will increase income. When developing a community-based conservation model, these attitudes, education level, and gender differences must be considered to make a plan the whole community can agree on and from which it will benefit.

Submitted by Valquíria Barbieri (kikibarbi@hotmail.com) on 2018-04-09T21:08:02Z No. of bitstreams: 1 DISS_2014_Angélica Francisca Mendes Mamede.pdf: 690362 bytes, checksum: 992dd831bb86f670485b28ddc3c8df3c (MD5) / Approved for entry into archive by Jordan (jordanbiblio@gmail.com) on 2018-04-26T16:45:41Z (GMT) No. of bitstreams: 1 DISS_2014_Angélica Francisca Mendes Mamede.pdf: 690362 bytes, checksum: 992dd831bb86f670485b28ddc3c8df3c (MD5) / Made available in DSpace on 2018-04-26T16:45:41Z (GMT). No. of bitstreams: 1 DISS_2014_Angélica Francisca Mendes Mamede.pdf: 690362 bytes, checksum: 992dd831bb86f670485b28ddc3c8df3c (MD5) Previous issue date: 2014-03-13 / CNPq / A variação no uso de recurso é muito comum e pode ocorrer de diferentes formas dentro de uma população natural. Dentre essas se destacam a exploração de recursos diferenciada entre machos e fêmeas, jovens e adultos, ou pode estar relacionada à mudança na morfologia em resposta ao uso de recurso e especialização individual (essa por sua vez pode ser afetada pela competição intra ou interespecífica). Desse modo o objetivo desse trabalho é descrever o padrão de uso de recurso alimentar dentro de uma população do peixe jeju (Hoplerythrinus unitaeniatus), um peixe predador comum em ambientes lênticos, na planície de inundação do Pantanal. As coletas foram realizadas na planície de inundação localizada na região do Pantanal de Poconé nos anos de 2009, 2010 e 2011. De cada indivíduo foram tomadas medidas morfológicas, tiveram seu sexo determinado e o estomago retirado. Os itens alimentares de H. unitaeniatus e seu possível competidor Hoplias malabaricus foram identificados. Para quantificação foi utilizado o método numérico. Verifiquei se machos e fêmeas, e/ou jovens e adultos (classificados segundo estimativa de primeira maturação) e/ou variações na morfologia estavam relacionadas à composição da dieta dentro dessa população através de uma PERMANOVA. Então calculei o grau de especialização individual na população (IS) e o aninhamento (NODF), separadamente para grupos que diferiam na dieta. Utilizei uma PCA para reduzir a dimensionalidade dos dados de cobertura vegetal, para então saber se existiu efeito da competição intra ou interespecífica e cobertura vegetal no IS através de uma regressão multipla. Foram analisados os conteúdos estomacais de 145 exemplares de H. unitaeniatus: 56 machos (CP variando entre 49,02 e 200,22 mm) e 89 fêmeas (CP variando entre 64,13 e 204,50mm). O comprimento médio da primeira maturação estimado foi de 105,8 mm. Desta forma, 82 indivíduos foram classificados como jovens e 53 como adultos. Os itens alimentares foram divididos em 22 categorias. Machos e fêmeas não diferiram na composição de recursos utilizados (pseudo-F1,143=1,46; p= 0,14). No entanto, a composição da dieta diferiu entre jovens e adultos (pseudo-F1,143= 5,26; p<0,01). Quando confrontados com a composição da dieta, encontramos relação entre a variação na dieta relacionada à morfologia (eixo 2, pseudo-F1,142=2,07, p<0,01; eixo 3, pseudo-F1,142= 0,57, p=0,87). De forma geral, a amplitude de especialização individual dentro desta população variou entre 0,22 e 0,62 e foi significativa somente na minoria dos casos. O aninhamento só foi significativo em dois casos, e variou entre 10 e 60,83. O modelo geral de regressão múltipla entre o IS e a abundância de jeju e de traíra e os eixos da PCA de cobertura vegetal, representou 12,6% da variação encontrada no IS e não foi significativo (F4,9= 1,47; R²ajustado=0,126; p= 0,29). O IS não foi afetado pela abundância de jejus (p= 0,12), pela abundância de traíra (p= 0,53) e nem pela cobertura vegetal (eixo 1, p= 0,94; eixo 2, p= 0,6). Em síntese, a população de Hoplerythrinus unitaeniatus da planície de inundação do Pantanal apresentou uma tendência em ter especialização individual em poucos casos, esta por sua vez não foi influenciada por interações competitivas. Também encontrei variação intrapopulacional no uso do recurso explicada pela ontogenia e por variações morfológicas. / The variation in resource usage is very common and can occur in different ways in a natural population. Among these, I highlight the differentiated exploitation of resources between males and females, young and old, or can be related to change in morphology in response to resource usage and individual specialization (that in turn can be affected by intra-or interspecific competition). Thus the aim of this study is to describe the standard of food resources usege within a population of jeju fish (Hoplerythrinus unitaeniatus), a predator fish common in lentic environments) on the floodplain of the Pantanal. The collections were made in the floodplain located in the Pantanal region of Poconé in the years 2009, 2010 and 2011. The measures of morphology of each individual were taken and they had their sex determined and their stomach removed. The food itens of H. unitaeniatus and its possible competitor Hoplias malabaricus were identified. To quantify the numerical method was used. I checked if males and females, and/or adults (classified according to estimate of first maturity), and/or variations in morphology were related to the composition of the diet within that population through a PERMANOVA. Then I calculated the degree of individual specialization in the population (IS) and nestedness (NODF), separately for groups that differed in the diet. I used a PCA to reduce the dimensionality of the data of vegetation cover, and then whether there was effect of intra and interspecific competition or vegetation cover in IS through a multiple regression. The food itens of 145 especims of H. uniteniatus were analized: 56 males (Standard Length between 49.02 and 200.22 mm) and 89 females (SL between 64.13 and 204.50mm). The average length of the first maturation estimated is 105.8 mm. Thus, 82 individuals were classified as young and 53 as adults. The food itens were divided into 22 categories. Males and females did not differ in the composition of resource used (pseudo-F1.143=1.46; p= 0.14). However, diet composition differed between young fishes and adults (pseudo-F1.143= 5.26; p<0.01). When confronted with the composition of the diet, we found relashionship between variation in diet linked to morphology (axis 2, pseudo-F1.142=2.07, p<0.01; exis 3, pseudo-F1.142= 0.57, p=0.87). In general, the amplitude of individual specialization within this population ranged from 0.22 and 0.61 and was significant only in a minority of cases. The nestedness was significant only in two cases, and range between 10 and 60.83. The general model of multiple regression between the IS and the abundance of jeju and traíra and the PCA axes of vegetal cover, represented 12.6% of the variation found in the IS and was not significant (F4.9= 1.47; R²adjusted=0.126; p= 0.29). The IS was not affected by the abundance of jeju (p= 0.12), by the abundance of traíra (p= 0.53) and not by the vegetation cover (axis 1, p= 0.94; axis 2, p= 0.6). In summary, the population of Hoplerythrinus unitaeniatus of floodplain of Pantanal, presented a tendency to have individual specialization in a few cases, this turn was not influenced by competitive interactions. I also found intrapopulation variation in resource use explained by ontogeny and morphological variations.

A escassez de trabalhos acerca dos impactos causados por mosaicos agrícolas sobre a biodiversidade dificulta a criação de estratégias de conservação, havendo necessidade de informações acerca da ecologia e comportamento de espécies da fauna. Nesse contexto o presente estudo objetivou: 1) determinar a composição e estrutura de assembleias de mamíferos de médio e grande em uma paisagem agrícola de Mata Atlântica; 2) avaliar o padrão de alimentação da onça-parda (Puma concolor) por meio da análise de isótopos estáveis (SIA) em dois mosaicos agrícolas; 3) analisar por meio da diversidade funcional (FD) assembleias de mamíferos em remanescentes florestais distribuídos nas principais regiões biogeográficas da Mata Atlântica, e identificar limiares ecológicos para a conservação. Para o inventário, foram selecionados oito remanescentes florestais na Região Metropolitana de Campinas (RMC), São Paulo. Os dados foram coletados por busca ativa (visualizações e vestígios), resultando no registro de 34 espécies de mamíferos, sendo 27 de médio e grande porte, quatro de pequeno porte, e três exóticas. Sete espécies se encontram ameaçadas de extinção, com registros inéditos de Myrmecophaga tridactyla e Lycalopex gymnocercus. A riqueza e a composição de espécies registradas apontaram a RMC como importante para a conservação da mastofauna. Foram analisados isotopicamente (carbono e nitrogênio) pelos de onças-pardas, obtidos a partir de amostras fecais coletadas por busca ativa em remanescentes florestais inseridos em paisagens agrícolas no interior do estado de São Paulo. Houve maior consumo de presas C3 (~47% dos indivíduos) na área com maior proporção de vegetação nativa, e maior consumo de presas C4 (~40% dos indivíduos) para a área onde é predominante a matriz agrícola. Foi constatado o consumo de presas com dieta baseada em itens alimentares dos remanescentes e da matriz agrícola, sugerindo alta plasticidade comportamental das onças-pardas e de suas presas ocupando áreas fortemente impactadas pelo homem. A ferramenta isotópica apresentou informações pioneiras sobre ecologia trófica, podendo contribuir na elaboração estratégias de conservação em áreas antropizadas. Para a análise da FD e identificação dos limiares foi utilizado um banco de dados composto por 49 assembleias de mamíferos, criado a partir de dados primários e secundários de inventários, sendo selecionadas 38 características das espécies para o cálculo. A existência de limiares foi verificada utilizando a função \"segmented\", disponível no programa R. A FD apresentou-se diferente para assembleias com o mesma riqueza de espécies, indicando que filtros ambientais podem influenciar nos valores. O incremento gradual na FD devido ao aumento da área dos remanescentes mostrou uma relação positiva, possivelmente ligada a maior complexidade e heterogeneidade de áreas maiores. Foram identificados dois limiares (52 e 1244 ha), criando três situações funcionalmente distintas, tanto críticas quanto mais estáveis, permitindo definir e propor formas de ação específicas. Assembleias presentes entre os limiares apresentaram incremento funcional significativo entre FD e o aumento da área dos remanescentes, e ações visando à restauração e melhorias na configuração da paisagem devem ser incentivadas. Conclui-se, portanto, que tanto a SIA quanto a FD, podem ser consideradas importantes ferramentas para delinear estratégias e ações em prol da conservação da mastofauna. / The scarcity of studies regarding the impacts of agricultural mosaics on biodiversity hinders the creation of conservation strategies and a need for information concerning the ecology and behavior of wildlife species. In this context, the present study aimed to: 1) determine the composition and structure of mammal assemblages of medium and large sized in an agricultural landscape at Atlantic Forest; 2) evaluate the puma (Puma concolor) feeding pattern through analysis of stable isotopes (SIA) in two agricultural mosaics; 3) analyze mammal assemblages by functional diversity (FD) in forest remnants distributed in major biogeographic regions of the Atlantic Forest, and identify ecological thresholds for conservation. For mammal\'s inventory, eight forest remnants were selected in Campinas Metropolitan Region (RMC), São Paulo state. Data were collected through active search (visualizations and tracks), resulting in the record of 34 mammal species, 27 medium and large size, four of small size, and three exotic. Seven species are threatened with extinction, with novel records of Myrmecophaga tridactyla and Lycalopex gymnocercus for this region. The species richness and composition pointed RMC as an important area for mammal\'s conservation. Carbon and nitrogen stable isotopes were analyzed in pumas hair, obtained from fecal samples collected by active search in forest remnants embedded in agricultural landscapes in São Paulo state. There was a higher consumption of C3 prey (~ 47% of individuals) in the area with the highest proportion of forest coverage, and greater consumption of C4 prey (~ 40% of individuals) where the agricultural matrix was predominant. Was observed the consumption of prey with diet based on food items from both forest remnants and agricultural matrix, suggesting high behavioral plasticity of puma\'s and their prey\'s occupying areas heavily impacted by man. Stable isotopes contributed with pioneer information on trophic ecology, aiming the development of new conservation strategies in anthropogenic areas. A database consisting of 49 mammal\'s assemblages, created from primary and secondary data of inventories, was used for FD analysis and threshold\'s identification. 38 specie\'s traits were selected for FD calculation. The thresholds existence was verified using the \"segmented\" function, available on R program. FD was different between mammal assemblages with the same species richness, indicating that environmental filters may affect its values. The gradual increment in FD, due to the increase in forest remnants area, presented a positive relationship, possibly linked to the increased complexity and heterogeneity of large areas. Two thresholds (52 and 1244 ha) were identified, creating three functionally distinct situations, both critical as more stable, allowing to define and propose for each one specific ways of action. Mammal\'s assemblages found between the thresholds showed significant functional increment considering the relationship between FD and forest remnants area, and actions aiming biological restoration and improvements in the landscape configuration should be encouraged. It was concluded, therefore, that both SIA as the FD can be considered important tools to outline strategies and actions for mammal\'s conservation.

Dieser Beitrag gibt einen Überblick über ökonomisch und ökologisch orientierte Messansätze des nachhaltigen Wohlstands. Besondere Aufmerksamkeit wird dabei dem Bruttoindlandsprodukt (BIP) und dem Index of Sustainable Economic Welfare gewidmet. Die Debatte um die Folgeschäden von Wachstumsprozessen hat gezeigt, dass das BIP ein unzulänglicher Wohlstandsindikator ist, der systematisch verzerrte Informationen über die Nachhaltigkeit der Wohlstandsentwicklung liefert. Trotzdem sind bisher keine auf ökologische und soziale Nachhaltigkeit ausgerichteten Indikatorensysteme implementiert, um das BIP als zentralen Wohlstandsindikator zu ersetzen. Die Diskussion in der Wirtschaftswissenschaft und ökologisch orientierte Debatten scheinen sich eher auseinander entwickelt zu haben.

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Sustainable development as our joint global goal is consensus in the mainstream international arena, in the name of long-term well-being for all living creatures. However economic constraints often limit the choices available to local communities, forcing them to make trade-offs between immediate socioeconomic gains and the long-term sustainability of natural resources. Thus, economic interests parallel with biodiversity conservation create difficult positionings for individuals, which becomes even clearer in developing areas and biodiversity hotspots. Despite this conflict of interest, there is currently insufficient empirical evidence on how communities on microlevels – in areas of both environmental and developmental interests – understand and reason about this potential dilemma. A discrepancy between assumptions and empirics motivates an investigation of discourses from local perspectives. This thesis will therefore highlight local development and environmental discourses of forest and land use. The region of North Sumatra, Indonesia, functions as a paradigmatic case study on how community members reason who are appointed to two forceful narratives – resource extraction and biodiversity conservation. Through conducting semi-structured interviews and using discourse analysis, two environmental discourses and four development discourses were identified in the local understandings of forest and land use. This gives us indications of how the jungle is understood and valued from a bottom-up perspective. Exploring local perspectives of land use is essential for informed decision-making, promoting sustainable development, ensuring social equity, and fostering community engagement. Further research on the relationship and interactions between local communities and the natural world is called upon.

Comparés aux monocultures, les systèmes agroforestiers (SAF) sont censés permettre une meilleure efficience d'utilisation de la ressource et améliorer les services écosystémiques. Cependant, la complexité des interactions se produisant dans les SAF rend délicate la quantification et la décomposition des effets des arbres d'ombrage sur la productivité primaire nette (NPP) de la culture principale. Peu de modèles sont capables d'analyser les effets des interactions entre culture principale et arbres d'ombrage sur les échanges de CO2 et d'eau. En effet, les interactions pour la lumière, l'eau et la chaleur se produisant entre culture et arbres d'ombrage peuvent produire des effets contre-intuitifs sur la photosynthèse, l'efficience d'utilisation de la lumière (LUE), l'efficience de transpiration et le microclimat. Nous montrons que MAESPA, un modèle 3D mécaniste, peut-être utilisé pour étudier la variabilité de ces processus à des échelles allant de la plante à la parcelle, et de la demi-heure à l'année entière. MAESPA a simulé de manière satisfaisante l'interception de la lumière dans un SAF à base de caféier composé de 2 couches hétérogènes. Des variables modélisées par MAESPA ont été utilisées pour produire de puissantes variables explicatives dans un dispositif expérimental étudiant les déterminants de la NPP aérienne (ANPP) du caféier. Il a été démontré que LUE était deux fois plus élevée pour les caféiers poussant à l'ombre ce qui compensait totalement la diminution de leurs budgets lumineux, résultant en une absence de différence de ANPP entre caféiers de plein soleil et caféiers d'ombrage. MAESPA a aussi simulé de manière satisfaisante les échanges de CO2 à l'échelle du caféier et à l'échelle de la parcelle, lorsque comparés à des mesures d'échanges gazeux dans des chambres plantes entières ou à des enregistrements de flux turbulents au-dessus de la canopée, respectivement. Nous avons utilisé MAESPA pour simuler la variabilité spatiale de la photosynthèse et de LUE. MAESPA a démontré être un modèle robuste pour quantifier les interactions spatiales dans un SAF. Le prochain développement pertinent de cette approche serait de coupler MAESPA avec un modèle d'allocation du carbone dans les organes des plants de caféiers / Compared to monocultures, agroforestry systems (AFS) are expected to provide enhanced resource-use efficiency and larger ecosystem services. However, due to the complexity of the interactions occurring in AFS, it is challenging to quantify and decompose the effects of shade trees on the main crop net primary productivity (NPP). Few process-based models are able to analyze the interactions between crop and shade trees for carbon and water. Interactions for light, water and energy occurring between tree and crops might have counterintuitive effects on photosynthesis, light use efficiency (LUE), transpiration efficiency and microclimate. We showed that a 3D process-based model, MAESPA, was able to quantitatively describe the spatial variability of those processes from the plant to the plot, and from hourly to yearly timescales. MAESPA simulated satisfactorily light interception in a 2-layer heterogeneous coffee AFS. It was used to produce powerful explanatory variables in AFS experiments and to analyze the determinants of coffee plant NPP. LUE displayed a 2-fold increase for shaded coffee plants totally compensating the expected decrease of local irradiance interception, and coffee plant ANPP was the same below shade trees or in the open. MAESPA also simulated satisfactorily carbon exchange at whole plant and plot scales, when compared to gas exchange records in a whole-plant chamber, or with eddy-covariance records above the canopy. We used MAESPA to simulate the spatial variability of photosynthesis and LUE. Overall, MAESPA proved to be a relevant model to quantify spatial interactions. The next very relevant development would be to couple it to a model of carbon allocation among organs in the coffee plants

A invasão por gramíneas africanas é uma das principais ameaças à diversidade biológica e funcional das formações savânicas do cerrado. Uma questão central em invasões por plantas é entender como espécies oriundas de sistemas com diferentes pressões seletivas são capazes de adquirir e utilizar recursos em um novo ambiente. O objetivo deste estudo foi de comparar os padrões de uso luz e água de gramíneas nativas e invasoras em duas condições de cobertura arbórea ao longo de um gradiente de invasão em uma área de cerrado localizada no Parque Estadual do Juquery - SP. O efeito da presença da cobertura sobre os indivíduos foi investigado através de amostragens em fisionomia de campo (dossel ausente) e de campo cerrado (dossel presente). A hipótese de que o desempenho no uso de recursos de invasoras supera o de nativas em presença de cobertura arbórea foi testada através da medição de aspectos ligados à capacidade de interceptação da luz e ao desempenho de uso da luz e água associado ao potencial de ganho de carbono. As gramíneas africanas apresentaram padrões de arranjo espacial das folhas e estrutura foliar que diferem dos de nativas. As copas das invasoras apresentaram maior grau de sobreposição entre as folhas. As folhas das invasoras exibiram menores inclinações, menor espessura e menor razão de massa seca por área. A presença do dossel arbóreo favoreceu o transporte fotoquímico de elétrons de invasoras e desfavoreceu o de nativas. As principais diferenças nas dinâmicas de trocas gasosas entre nativas e invasoras foram observadas quando as razões foram expressas por massa seca foliar. Diferenças nas relações entre as variáveis indicam que a relação do padrão de investimento em tecidos foliares com o potencial fotossintético pode implicar em respostas contrastantes de nativas e invasoras aos regimes de irradiância nas fisionomias de campo sujo e campo cerrado / Invasions by African grasses constitutes one of the greatest threats to the biological and functional diversity of the cerrado savannas. A central question to understand plant invasions is how species originating from systems with distinct selective pressures are able to acquire and utilize resources in their new environments. The objective of this study was to compare native and invasive grasses with respect to their light and water use patterns in two sites with differing canopy tree cover along an invasion gradient in a cerrado area in the Juquery State Park, SP. The effect of the canopy tree cover on the grass individuals was investigated through sampling in the cerrado physiognomies of \'campo sujo\' (tree cover absent) and \'campo cerrado\' (tree cover present). The hypothesis that invaders outperform natives under the presence of canopy tree cover in terms of resource-use was tested through field measurements of traits related to light interception capacity and to the performance in light and water use associated with carbon gain potentials. Invasive African grasses showed distinct patterns of crown architecture and leaf structure when compared to natives. Invaders showed a greater degree of leaf overlapping in the crown. Invaders leaves were thinner, relatively more planophile, and showed smaller leaf dry mass per area ratios. The presence of canopy tree cover favored the invaders photochemical electron transport while disfavored natives. The main differences concerning native and invaders gas-exchange dynamics were observed on a leaf dry mass basis. The relation between patterns of leaf tissue investment and photosynthetic potentials could imply in contrasting responses of native and invasive grasses to the irradiance regime in differing cerrado vegetation types