Whether species interactions are static or change over time has wide-reaching ecological and evolutionary consequences. However, species interaction networks are typically constructed from temporally aggregated interaction data, thereby implicitly assuming that interactions are fixed. This approach has advanced our understanding of communities, but it obscures the timescale at which interactions form (or dissolve) and the drivers and consequences of such dynamics. We address this knowledge gap by quantifying the within-season turnover of plant-pollinator interactions from weekly censuses across 3years in a subalpine ecosystem. Week-to-week turnover of interactions (1) was high, (2) followed a consistent seasonal progression in all years of study and (3) was dominated by interaction rewiring (the reassembly of interactions among species). Simulation models revealed that species' phenologies and relative abundances constrained both total interaction turnover and rewiring. Our findings reveal the diversity of species interactions that may be missed when the temporal dynamics of networks are ignored.

Changes of habitats are amongst the main drivers of evolutionary processes. Corresponding shifts in the behaviour and life history traits of species might in turn also alter ecosystem attributes. The reproduction of Western European fire salamanders (Salamandra salamandra), in small pond habitats instead of first order streams, is one example of a recent local adaptation. Since fire salamander larvae are important top-predators in these fish free habitats, their presence likely changes various aspects of ecosystem functioning. Here, it was analysed how the ecological performance of salamander larvae in ponds in the Kottenforst in Western Germany changed in comparison to sympatric stream populations. Further, it was analysed how their presence in ponds influenced key ecosystem attributes such as prey density and diversity and aquatic-terrestrial linkage. To assess the impact of the life cycle shifts in salamanders on the pond functioning, detailed investigations of salamander larvae population dynamics, phenology, and macroinvertebrate community development in ponds were combined with experimental manipulations of the salamander presence. In the first part of this study, the impact of pond presence of fire salamanders in terms of ecosystem functioning focussing on aquatic terrestrial subsidy transfer was calculated. The study could show, that the adaptation of fire salamanders to breed in pools led to strong increases of animal-mediated import of terrestrial matter into the aquatic habitats. The hypothesis about the impact on macroinvertebrate communities derived from these calculations was then tested experimentally. It was shown, that presence of salamander larvae could influence some taxa of macroinvertebrates but they had only limited effects on the food web structure in their aquatic habitats. Yet, a high relevance of the subsidy exchange from aquatic to terrestrial and its high relevance for the predator persistence in the system could again be confirmed. Moreover, it was demonstrated, that the larval behaviour and performance could have a high inter-annual variability as a reaction to contrasting ecosystem constraints in comparison to the stream habitats. A fact that integrally separates the pond ecotype from stream ecotype conspecifics.

A memória é considerada por muitos pesquisadores como um dos produtos mais fascinantes da evolução biológica, justamente por proporcionar aos animais a vantagem adaptativa de se utilizar de uma experiência prévia para a solução de problemas necessários para a sobrevivência. Os animais se utilizam de processos mnemônicos durante o forrageamento, a seleção de parceiros sexuais, seleção de habitat e a preferência alimentar. As aranhas são um modelo interessante em estudos de memória e há evidências do uso de experiências passadas na otimização do forrageio: a teia permite que as aranhas capturem e armazenem mais de um item alimentar. Há carência na literatura de estudos comparativos evolutivos da memória, o que dificulta identificar as possíveis pressões seletivas. O primeiro objetivo deste trabalho foi fazer um estudo comparativo de aspectos da memória predatória em aranhas do grupo Orbiculariae. Este grupo é monofilético e tem como principal sinapomorfia a construção de teia orbicular. Porém, ao longo da evolução, o padrão de teia foi se modificando desde uma estrutura plana até uma tridimensional. Tais modificações podem ter gerado diferenças comportamentais e no sistema de memória dessas aranhas. Por este motivo, o outro objetivo, foi traçar a evolução da memória dentro do grupo. Delinearam-se três grupos de estudo com sete espécies. Na condição natural, observou-se a captura de duas presas sucessivas. Na condição experimental I, ofereceu-se uma primeira presa (p1) à aranha e, em seguida, ofereceu-se uma segunda (p2); durante o deslocamento da aranha até p2, retirou-se p1 da teia. Na condição II, ao invés de se oferecer p2, a aranha foi atraída à periferia (simulando a queda de p2). No deslocamento da aranha até a fonte de vibração removeu-se p1. O indício de memória é observado quando, na supressão da presa, a aranha executa um comportamento denominado Busca. Neste, a aranha executa sacudidas/detecções dos fios no centro/refúgio da teia. A busca por p1 roubada foi observada em todas as espécies estudadas, exceto em Z. geniculata no grupo I. A presença de p2 parece interferir na expressão da memória de p1; deixar p2 na teia enquanto busca por p1, aumenta as chances de p2 também ser roubada por ação dos cleptoparasitas. Zosis apresenta algumas peculiaridades, entre elas a ausência de veneno. Dessa forma, o tempo gasto durante a imobilização de p2 parece ser suficiente para causar o esquecimento de p1. Todas as espécies buscaram por p1 quando não houve oferta de p2, inclusive Zosis. O tempo de busca, na condição I, diminui da base de Araneoidea até as famílias mais derivadas. No grupo II, há uma aparente inversão do sinal filogenético e o tempo de busca aumenta na família mais derivada. A estrutura da teia tridimensional parece ser mais complexa e, por este motivo, exigiria um sistema de navegação espacial também mais complexo quando comparado às aranhas orbitelas. A construção da teia parece ter sido crucial para a captura e armazenamento de presas excedentes, e tal comportamento, juntamente com a diversificação das teias, favoreceu a variação e evolução da memória na Ordem Araneae / Memory is one of the most fascinating products of biological evolution, because it endows animals with the adaptive use a prior experiences to solve survival problems. Animals use mnemonic processes during foraging, selection of sexual partners, habitat selection, and feeding preference. Spiders are an interesting model for studies of memory, and there is evidence of their using of past experiences in optimizing foraging: the web allows the spiders to capture and store more than one food item. In literature, there are few comparative studies, and no one about the evolution of memory, making it difficult to identify the possible selective pressures on memory. The first objective here was to make a comparative study on the aspects of predatory memory in spiders of the group Orbiculariae. This group is monophyletic and its main synapomorphy is building an orbicular web. However, during evolution, the web pattern changed from a flat to a three-dimensional structure. Such changes may have caused differences in behavior and memory. For that reason, another goal was to trace the evolution of memory within the group. We used three experimental groups with seven species each. In natural conditions, there was an observation of the capture of two successive preys. In the experimental condition I, a first prey (p1) was offered to the spider and, subsequently, another prey (p2) was offered; during the locomotion of the spider towards p2, p1 was removed from the web. In condition II, instead of offering p2, the spider was attracted to the periphery (simulating the fall of p2). As the spider moved towards the source of vibration, p1 was removed. The evidence of memory is observed when, in the suppression of the prey, the spider performs a behavior called search behavior: the spider runs plucking on threads in the web hub/retreat. The search for stolen p1 was observed in all species studied, except for Zosis geniculata in group I. The presence of p2 appears to interfere with the expression of p1 memory, and also leaving p2 on the web while searching for p1, increases the chances of having p2 stolen by the action of kleptoparasites. Zosis presents some peculiarities, including the absence of poison glands, leading to a prolonged immobilization of p2, in a time lag that could then be sufficient forget p1. All species sought by p1 when there was no offer of p2, including Zosis. The search time, in condition I, decreases from the base of Araneoidea until the most derived families. In group II, there is an apparent reversal of the phylogenetic signal and the search time increases in the most derived family. The three-dimensional structure of the derived webs seems to be more complex and, therefore, it would require a spatial navigation system also more complex if compared to the flat orbweb. The construction of the web seems to have been crucial for prey capture and storage of surpluses, and such behavior, along with the diversification of the webs, favored the variation and evolution of memory in the Order Araneae

Made available in DSpace on 2015-03-03T19:30:55Z (GMT). No. of bitstreams: 0 Previous issue date: 30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A criação do município de São Sebastião do Caí, em 1875, implicou a estruturação de um aparelho burocrático-administrativo e a atuação política de uma elite local que passou a ocupar os postos de poder na Câmara Municipal recém-criada. Tomando como ponto de partida a primeira eleição municipal realizada em São Sebastião do Caí, a presente Dissertação apresenta, num primeiro momento, as condições que favoreceram a emancipação política de São Sebastião do Caí, destacando o dinamismo econômico decorrente da exportação de excedentes para a capital da Província, o crescimento demográfico derivado do processo imigratório – tanto de alemães, quanto de italianos – e o desejo de ampliação dos poderes de decisão por parte das lideranças locais. A análise destaca as disputas políticas entre facções locais, identificando a existência de uma elite local anterior à própria fundação do município, bem como o papel desempenhado pela Câmara Municipal na conjuntura de transição política do Império para a República. Em seguida, / The creation of the county of São Sebastião do Caí, in 1875, implied the structuration of a bureaucratic-administrative device and the political action of the local elite which began to take the places of power in the newly-founded City Council. Starting with the first county election that took place in São Sebastião do Caí, this Dissertation presents, firstly, the conditions that helped the political emancipation of São Sebastião do Caí, highlighting the economic dynamism developed from the exportation of the exceedance to the Province capital, the demographic growth derivated from the immigratory process – Germans as well as Italians – and the local leaderships’ want to enlarge the decision powers. The analysis emphasizes the political disputes between local factions, identifying the existence of a local elite preceding the very foundation of the county, as well as the role played by the City Council in the juncture of political transition from the Empire to the Republic. Secondly, attention is paid to the

Diante da descoberta de petróleo na camada Pré-Sal, o país se viu diante de uma oportunidade única para investir em um projeto específico e claro de desenvolvimento. Com a ideia de incentivar a indústria naval há anos sucateada, o governo do Partido dos Trabalhadores decidiu que iria incentivar a abertura de novos e inúmeros estaleiros espalhados pela costa do país, com estratégias que giravam em torno de índices de nacionalização e licitações encomendadas pela maior empresa estatal do país junto a grandes consórcios formados por diferentes empreiteiras. Rio Grande torna-se, assim, um dos alvos privilegiados deste novo ciclo de pujança e investimentos bilionários. De forma inicial, proponho nesta tese entender as dinâmicas desta política desenvolvimentista adentrando nas suas redes e teias, assumindo assim intensificar o projeto antidualista da análise pós-estruturalista entre desenvolvimento e impactados, para pensar como se tramam, por meio de diversas agências, novas interpretações e ações diante de um cenário extremamente novo e inédito para grande parte dos atores envolvidos. Se pergunta, antes de tudo, de que forma os discursos e práticas ligados ao desenvolvimento são tecidos e agenciados através de diferentes redes de diferentes escalas. Seguindo tais indagações, a tese questiona se há ou não unidades ou contradições quando se pensa localmente sobre impactos e benfeitorias da indústria naval em um contexto e um momento especifico. A metáfora tese pela plataforma enquanto objeto fractal reforça essa nova postura diante de teorias do desenvolvimento, onde o trabalho, em suas mais diversas expressões e formas, é a liga metálica e suporte principal para as conexões parciais comuns na etnografia contemporânea. / After the oil and gas detection at the pre-sault layer, Brazil saw a unique opportunity to invest in a specific and unambiguous development project. Idealizing to encouraging the shipbuilding industry trashed by a long time ago, the Work Party government decided to institute the opening and settlement a large number of shipyards along the Brazilian coast, with strategies based around industrial nationalization and bids ordered by the largest Brazilian statement company nigh huge contractor’s consortiums. Thus, Rio Grande became one of the main targets of this new strength cycle and billionaires investments. Initially, I try in these work to understand the dynamics of this new development policy entering in its networks, web and scales, assuming with that reinforce the anti-dualist project from the poststructuralist between development and the affected population, to rethink how the actors maneuver their expectations trough a diverse number of agencies, new interpretations and actions in front of a extremely rare and new scenario to them. The main question goes direct to ask how the discourses and development practices are woven and intermediated trough a series of networks and webs between different scales. Thus, this thesis question if whether or not there contradictions when think the improvement and impacts of development in a local site situated in a specific moment. The platform metaphor as a fractal object reinforce this new position against development theories where the labor, in their most diverse expressions and forms is the metal who connect and support the ordinary partial connections at ethnography.

Some of the major problems we face today are human induced changes to the nitrogen (N), phosphorus (P) and carbon (C) cycles. Predicted increases in rainfall and temperature due to climate change, may also increase dissolved organic matter (DOM) inflows to freshwater ecosystems in the boreal zone. N, P, C and light, are essential resources that most often limit phytoplankton (PPr) and bacterial production (BP) in the pelagic zone of lakes. PPr and BP not only constitute the total basal C resource for the pelagic aquatic food web, but also influence ecosystem function and biogeochemical cycles. In this thesis I studied how N, P, C and light affect the relative and absolute rates of PPr and BP, along a wide latitudinal and trophic gradient using published data, and in two in situ mesocosm experiments in a clear water oligotrophic lake. In the experiments I manipulated bottom-up drivers of production and top-down predation to examine how these factors interact to affect pelagic food web structure and function. The most important predictors of PPr globally (Paper I) were latitude, TN, and lake shape. Latitude alone explained the most variation in areal (50%) and volumetric (40%) PPr. In terms of nutrients PPr was primarily N-limited and BP was P-limited. Therefore bacteria and phytoplankton were not directly competing for nutrients. BP:PPr was mostly driven by PPr, therefore light, N, temperature and other factors affecting PPr controlled this ratio. PPr was positively correlated with temperature, but not BP, consequently, higher temperatures may reduce BP:PPr and hence the amount of energy mobilised through the microbial food web on a global scale. In papers II and III interaction effects were found between C-additions and top-down predation by young-of-the-year (YOY) perch. Selective predation by fish on copepods influenced the fate of labile C-addition, as rotifer biomass increased with C-addition, but only when fish were absent. Interaction effects between these top-down and bottom-up drivers were evident in middle of the food web, which is seldom examined in this type of study. Although the energy pathway from bacteria to higher consumers is generally longer than from phytoplankton to higher trophic levels, increased BP still stimulated the biomass of rotifers, calanoid copepods and YOY fish. However, this appeared to be mediated by intermediate bacterial grazers such as flagellates and ciliates. Light was an important driver of crustacean zooplankton biomass (paper IV), but the light:nutrient hypothesis was inadequate to predict the mechanisms behind the decrease in zooplankton biomass at low light. Instead, it appeared that reduced edibility of the phytoplankton community under low light conditions and reduced BP most strongly affected zooplankton biomass. Thus, the LNH may not apply in oligotrophic lakes where PPr is primarily N-limited, Daphnia is rare or absent and mixotrophic phytoplankton are abundant. N, P, C and light manipulations have very different effects on different parts of the pelagic food web. They influence the relative rates of PPr and BP, affect phytoplankton community composition, alter the biomass of higher trophic levels and change pathways of energy transfer through the pelagic food web. This thesis adds valuable information as to how major changes in these resources will affect food web structure and function under different environmental conditions and future climate scenarios. / Lake ecosystem response to environmental change

Ecological communities are collections of species bound together by their influences on one another. Community structure, therefore, refers to the way in which these influences are organised. As a result, ecologists are mainly interested in the factors driving the structure, functioning, and persistence of communities. The traditional focus, however, has been on the feeding relationships among species (direct trophic interactions), whereas relationships mediated by a third species or the environment (indirect interactions) have been largely overlooked. I investigated the role of indirect interactions in structuring communities through a series of field experiments in a diverse assemblage of arthropods living on a Brazilian shrub species. I experimentally reduced the abundance of the commonest galler on the shrub and found that the perturbation resonated across the food web, affecting its structure and robustness. Since there was no potential for these effects to be propagated directly or indirectly via the documented trophic links, the effects must have spread non-trophically and/or through trophic links not included in the web. Thus, I investigated non-trophic propagation of effects in the system. I demonstrate that hatched galls of the commonest galler, which serve as habitat for other species, can mediate non-trophic interactions that feedback to the galler modifying its interactions with parasitoids and inquiline aphids. I performed further manipulative experiments, excluding ants, live galls and hatched galls, to reveal mechanisms for the non-trophic interaction modifications observed in this system. Finally, I explored how non-trophic interaction modification could affect the structure and stability of a discrete ecological community in the field. I investigated how the densities of certain pairs of groups relate to each other, and how their relationship changes in relation to a third group. Then, I assembled an "effect network" revealing, for the first time in an empirical community, a hidden web of non-trophic indirect interactions modifying the direct interactions and modifying each other. Overall, the thesis presents evidence that communities are strongly interconnected through non-trophic indirect interactions. This is one of the first empirical demonstrations of the context-dependent modification of interactions via non-trophic interactions. However, determining the mechanisms behind such interaction modifications may be unfeasible. Understanding how the observed effects relate to community structuring requires shifting our focus from bipartite interaction networks to a more holistic approach.

Diante da descoberta de petróleo na camada Pré-Sal, o país se viu diante de uma oportunidade única para investir em um projeto específico e claro de desenvolvimento. Com a ideia de incentivar a indústria naval há anos sucateada, o governo do Partido dos Trabalhadores decidiu que iria incentivar a abertura de novos e inúmeros estaleiros espalhados pela costa do país, com estratégias que giravam em torno de índices de nacionalização e licitações encomendadas pela maior empresa estatal do país junto a grandes consórcios formados por diferentes empreiteiras. Rio Grande torna-se, assim, um dos alvos privilegiados deste novo ciclo de pujança e investimentos bilionários. De forma inicial, proponho nesta tese entender as dinâmicas desta política desenvolvimentista adentrando nas suas redes e teias, assumindo assim intensificar o projeto antidualista da análise pós-estruturalista entre desenvolvimento e impactados, para pensar como se tramam, por meio de diversas agências, novas interpretações e ações diante de um cenário extremamente novo e inédito para grande parte dos atores envolvidos. Se pergunta, antes de tudo, de que forma os discursos e práticas ligados ao desenvolvimento são tecidos e agenciados através de diferentes redes de diferentes escalas. Seguindo tais indagações, a tese questiona se há ou não unidades ou contradições quando se pensa localmente sobre impactos e benfeitorias da indústria naval em um contexto e um momento especifico. A metáfora tese pela plataforma enquanto objeto fractal reforça essa nova postura diante de teorias do desenvolvimento, onde o trabalho, em suas mais diversas expressões e formas, é a liga metálica e suporte principal para as conexões parciais comuns na etnografia contemporânea. / After the oil and gas detection at the pre-sault layer, Brazil saw a unique opportunity to invest in a specific and unambiguous development project. Idealizing to encouraging the shipbuilding industry trashed by a long time ago, the Work Party government decided to institute the opening and settlement a large number of shipyards along the Brazilian coast, with strategies based around industrial nationalization and bids ordered by the largest Brazilian statement company nigh huge contractor’s consortiums. Thus, Rio Grande became one of the main targets of this new strength cycle and billionaires investments. Initially, I try in these work to understand the dynamics of this new development policy entering in its networks, web and scales, assuming with that reinforce the anti-dualist project from the poststructuralist between development and the affected population, to rethink how the actors maneuver their expectations trough a diverse number of agencies, new interpretations and actions in front of a extremely rare and new scenario to them. The main question goes direct to ask how the discourses and development practices are woven and intermediated trough a series of networks and webs between different scales. Thus, this thesis question if whether or not there contradictions when think the improvement and impacts of development in a local site situated in a specific moment. The platform metaphor as a fractal object reinforce this new position against development theories where the labor, in their most diverse expressions and forms is the metal who connect and support the ordinary partial connections at ethnography.

Les écosystèmes lacustres sont de plus en plus soumis à de multiples perturbations mais leur réponse est encore trop rarement considérée de façon globale. En effet, au travers d'un jeu d'interactions complexes, chaque perturbation peut moduler l'intensité de l'impact des autres sur les lacs, et de ce fait, leur réponse. Dans ce contexte, ce travail doctoral est axé sur l'approfondissement de notre compréhension de la réponse des lacs à un contexte de perturbations multiples, sur le long terme. Pour cela, trois grands lacs profonds (le lac Léman, du Bourget et d'Annecy), soumis à une perturbation régionale similaire (i.e., le réchauffement climatique) et à deux perturbations locales (i.e., les changements dans le statut trophique et dans les pratiques de gestion piscicole) d'intensités différentes, ont été choisis. La réponse de ces lacs à ces changements a été abordée au travers d'une approche paléolimnologique, basée sur les cladocères. En effet, la capacité de ceux-ci à intégrer les changements temporels dans le réseau trophique pélagique en réponse aux trois perturbations environnementales en fait un modèle adéquat pour reconstruire les changements à l'échelle de la communauté pélagique. Plus précisément, nous avons abordé (i) les changements dans les communautés de cladocères, au cours du siècle dernier, en réponse aux trois perturbations environnementales et (ii) l'impact de ces perturbations sur les stratégies de reproduction des Daphnies. Cependant, le manque de connaissance dans les grands lacs profonds sur la représentativité des communautés sources de cladocères par les assemblages de restes archivés dans les sédiments a tout d'abord conduit à faire un point méthodologique. Ce dernier a abouti à la mise en évidence de différences dans le niveau de représentation de communautés sources de cladocères selon le type de restes utilisés. La composition taxonomique et la structure en taille des restes parthénogénétiques (i.e., exosquelettes) reflètent relativement bien celle des communautés sources. Quant aux éphippies (œufs de dormance), elles se révèlent des indicateurs fiables pour reconstruire les comportements de reproduction. Suite à ces résultats, les reconstructions paléolimnologiques des communautés de cladocères montrent que leur trajectoire écologique était contrôlée par des interactions complexes entre les trois pertubations différentes, selon les périodes de temps et entre les lacs. De plus, la réponse des communautés de cladocères au climat était différente entre les trois lacs comme une fonction de l'intensité des forçages locaux. Ces observations suggèrent qu'il est important d'inclure le rôle des perturbations locales dans la prédiction de l'impact futur des changements climatiques sur les lacs. L'impact des perturbations environnementales sur le comportement de reproduction des Daphnies est tel que des évènements d'hybridation interspécifique ont été observés. Cependant, ces évènements d'hybridation sont issus de sensibilité aux trois perturbations environnementales différentes entre les espèces de Daphnies. / Lake ecosystems are increasingly subjected to multiple perturbations but their response is too rarely considered in overall. But, though a complex set of interactions, each perturbation can modulate the intensity of the impact of each other on lakes, and thus their response. In this context, this work is focused on deepening our understanding of the response of lakes in a context of multiples perturbations, over the long-term. We studied this response performing a paleolimnological approach (based on cladoceran) on three large, deep lakes (Lakes Geneva, Bourget and Annecy) submitted to a similar regional perturbation (i.e., climate warming) and varying intensities of two local perturbations (i.e., changes in nutrient inputs and fisheries managment practices). The ability of cladoceran to integrate the temporal changes in the pelagic food web in response to three environmental perturbations makes them a suitable model to reconstruct changes in the whole pelagic community. Specifically, we addressed (i) changes in cladoceran communities, during the last century, in response to three environmental perturbations and (ii) the impact of these perturbations on reproductive behavior of Daphnia. However, the lack of knowledge in large, deep lakes on the representativity of source cladoceran communitites by fossil assemblages in sediments firstly led to a methodological calibration. This last showed that the represention level of source communities was different according to the type of remain. Parthenogenetic remain assemblages (i.e., exoskeleton) reflect accurately the taxonomical and size structure of source communities in contrast to ephippia which are reliable proxy to reconstruct reproductive behavior. Following these results, the paleolimnological reconstructions of cladoceran communities showed that their ecological trajectories are controlled by complex interactions between the three perturbations, according to time periods and lakes. Moreover, the response of cladoceran communties to climate was different between the three lakes as a function of the intensity of local forcings. These observations suggest that it is important to include the role of local perturbations in predicting the future impact of climate change on lakes. The impact of environmental perturbations on the reproductive behavior of Daphnia is such that interspecific hybridization events were observed. However, these hybridization events were the result of different sensitivity to perturbations among Daphnia species.

A food web comprises exchanges of matter and energy that occur among species and between biotic and abiotic environment. Given that abiotic components form the basal resources, the approach of this work consists of evaluating the effects of nutrients input in strategic models that describe food web and chain dynamics. Its focus lies on the determination of the nature of equilibrium populations as well as on their dynamics for different functional responses. Strategic models that describe the behavior of interactive populations under nutrient inputs are an important basis for outlining general phenomena that occur in community dynamics. / Uma rede trófica reúne as trocas de matéria e energia que ocorrem entre as espécies e entre o meio biótico e abiótico. Visto que os componentes abióticos formam a fonte de recursos basais, a abordagem deste trabalho consiste na avaliação dos efeitos da entrada de nutrientes alóctones em modelos estratégicos que descrevem a dinâmica de redes e cadeias tróficas, concentrando-se na determinação das características das populações de equilíbrio e das dinâmicas das espécies com diferentes respostas funcionais. Modelos estratégicos que contêm informações acerca do comportamento de populações interativas frente à entrada de nutrientes são uma base importante no delineamento de fenômenos gerais que podem ocorrer dentro da dinâmica de comunidades.