A pesquisa abordou o processo de uso e ocupação das terras nos municípios de Bodoquena, Bonito e Jardim, situados na borda leste do Parque Nacional da Serra da Bodoquena (PNSB), região sudoeste de Mato Grosso do Sul. Além disso, foi estudado o estado de conservação, em termos de estrutura e configuração da paisagem, dos remanescentes de cerrado e floresta contidos no interior do PNSB e em sua zona de amortecimento. O objetivo foi o de analisar a dinâmica de ocupaçao das terras nos municípios mencionados nos últimos 18 anos, com vistas à subsidiar estratégias de planejamento do uso e ocupação das terras ideal para a região. Objetivou-se também analisar a dinâmica espacial e temporal da paisagem que compõe o PNSB e sua zona de amortecimento, visando à conservação da biodiversidade local. Para isso, foi utilizado um sistema de informação geográfica (SIG) para elaboração de mapas temáticos e de um banco de dados georreferenciado. A determinação do grau de conservação do PNSB e da sua zona de amortecimento se deu mediante a utilização de métricas de paisagem, e da adoção dos preceitos da Teoria dos Grafos. O capítulo 1 demonstrou, por meio dos mapas gerados para os municípios de Bodoquena, Jardim e Bonito, dos anos de 1986 e 2004, que ocorreu uma perda de área nativa e um conseqüente crescimento da matriz antrópica composta por pastagens (principalmente) e culturas agrícolas. Apenas em Bodoquena os remanescentes vegetais tiveram maior porcentual que as áreas de pastagens e lavouras. Pode-se observar que a região estudada, passa por um processo de conversão de habitats naturais, outrora contínuos, para uma paisagem composta por fragmentos de cerrados, campos e florestas. O capítulo 2 mostrou que as fisionomias florestais e de cerrado, apresentaram-se em melhor estado de conservação em 1986 que em 2004. Além disso, foi possível observar que os remanescentes das formações vegetais acima citadas, apresentaram-se em melhor estado de conservação no interior do PNSB, que em sua zona de amortecimento. O mapa de relevância dos remanescentes de floresta, considerando as notas combinadas das métricas de forma e área das manchas indicou, quais são as áreas prioritárias para serem protegidas, por possuírem características adequadas para a persistência da biodiversidade florestal presente no PNSB e em sua zona de amortecimento. O setor norte se destacou por apresentar remanescentes com valores alto e extremamente alto com relação à relevância. O mesmo setor norte possui um maior número de pontos de sensibilidade à quebra de conectividade entre as manchas de floresta. Nesta região pode-se observar que a maior parte dos pontos com alta sensibilidade, merece alguma estratégia que retarde ou mesmo cesse o processo de conversão da floresta para pastagem ou agricultura. Com relação ao padrão de fragmentação dos remanescentes vegetais, conclui-se o seguinte: os remanescentes de cerrado e floresta, no intervalo de dezoito anos, ficaram menores, mais irregulares, mais distantes e mais numerosos, indicando uma piora no estado de conservação da paisagem entre 1986 e 2004. Isso compromete a manutenção da biodiversidade, a persistência de espécies, diminuindo suas populações mínimas viáveis. A diversificação das formas de uso das terras na matriz é recomendada, com a introdução da silvicultura (principalmente composta por espécies nativas), por exemplo, também poderá auxiliar na manutenção/surgimento da heterogeneidade espacial e da complexidade estrutural da paisagem. A Teoria dos Grafos, avaliada neste trabalho, apresentou-se como ferramenta eficiente para se calcular a conectividade em paisagens heterogêneas. / The research approached the process of use and occupation of lands in the cities of Bonito, Bodoquena and Jardim, situated in the edge east of the National Park of the Serra da Bodoquena (NPSB), southwestern region of Mato Grosso do Sul, Brazil. Moreover, the conservation state was studied, in terms of structure and configuration of the landscape, of the contained remainders of cerrado and forest in the interior of the NPSB and its buffer zone. The objective was to analyze the dynamics of occupation of lands in the cities mentioned in last the 18 years, with sights to subsidizing strategies of planning of the use and ideal occupation for the region. Also, it was objectified to analyze the space-temporal dynamics of the landscape that composes the PNSB and its buffer zone, aiming at to the conservation of local biodiversity. For this, geographic information system (GIS) for the classification of images of satellite and elaboration of thematic maps was used. The determination of the NPSB conservation degree and its buffer zone occurred by means of the use and of metrics of landscape ecology and the adoption of Graph Theory. Chapter 1 demonstrated, by the maps generated for the cities of Bonito, Bodoquena and Jardim, of the years of 1986 and 2004, that it occurred a loss of native area and a consequent growth of the composed matrix for pastures (mainly) and agriculture. Only in Bodoquena the vegetal remainders had percentual had been bigger than the areas of pastures and agriculture. It can be observed that the studied region passes for a process of conversion of natural habitats, long ago continuous, for a composed landscape for patches of cerrado and forests in a matrix predominantly represented by planted pasture and agriculture. Chapter 2 showed that the forest and cerrado physiognomy, had been presented in better conservation in 1986 that in 2004. Moreover, it was possible to observe that the remainders of the vegetal formations above cited, had been presented in better conservation in the interior of the NPSB, that in its buffer zone. The map of relevance of the remainders of forest, considering the agreed area and shape notes metric of the spots, had indicated which the priority areas to be protecting, for possessing characteristics adjusted for the persistence of present forest biodiversity in the NPSB and its buffer zone. The north sector had detached for presenting remainders with high and extremely high values to the relevance. The same north sector posses a bigger number of points of sensitivity to the break of connectivity between the forest spots. In this region it can be observed that most of the points with high sensitivity deserves some strategy that delays or stop the conversion process of the forest for pasture or agriculture. Regard the standard of spelling of the vegetal remainders, had been concluded that: the remainders of cerrado and forest, in the interval of eighteen years, had been lesser, more irregular, more distant and more numerous, indicating a worsening in the state of conservation of the landscape between 1986 and 2004. This compromises the maintenance of biodiversity, the species persistence, diminishing its viable minimum populations. The diversification of the forms of use of lands in the matrix is recommended, with the introduction of forestry (mainly composed for native species), for example, also it will be able to assist in the maintenance/sprouting of the space heterogeneity and the structural complexity of the landscape. The Graph Theory, evaluated in this work, was presented as efficient tool to calculate the connectivity in heterogeneous landscapes.

Das visuelle System erreicht enorme Verarbeitungsmengen, wenn wir unsere Augen auf ein Objekt richten. Mehrere Prozesse sind aktiv bevor unser Blick das neue Objekt erreicht. Diese Arbeit erforscht die räumlichen und zeitlichen Eigenschaften drei solcher Prozesse: 1. aufmerksamkeitsbedingte Steigerung der neuronalen Aktivität und sakkadische Suppression; 2. aufmerksamkeitsbasierte Auswahl des Zielreizes bei einer visuellen Suchaufgabe; 3. zeitliche Entwicklung der Detektiongenauigkeit bei der Objekt-Substitutionsmaskierung. Wir untersuchten diese Prozesse mit einer Kombination aus humaner Elektroenzephalografie (EEG), eye tracking und psychophysischen Verhaltensmessungen. Zuerst untersuchten wir, wie die neuronale Repräsentation eines Reizes von seiner zeitlichen Nähe zur Sakkade geprägt wird. Wir zeigten, dass direkt vor der Sakkade erscheinende Reize am meisten durch Aufmerksamkeit und Suppression geprägt sind. In Studie 2 wurde die Sichtbarkeit des Reizes mit der Objekt-Substitutionsmaskierung verringert, und wir analysierten das Verhältnis zwischen sakkadischen Reaktionszeiten und ihrer Genauigkeit. Dazu erfassten wir neuronale Marker der Aufmerksamkeitslenkung zum Zielreiz und eine subjektive Bewertung seiner Wahrnehmbarkeit. Wir stellten fest, dass schnelle Sakkaden der Maskierung entgingen und Genauigkeit sowie subjektive Wahrnehmbarkeit erhöhten. Dies zeigt, dass bereits in frühen Verarbeitungsstadien eine bewusste und korrekte Wahrnehmung des Reizes entstehen kann. Wir replizierten diesen Befund für manuelle Antworten, um eine Verfälschung der Ergebnisse durch sakkadenspezifische Prozesse auszuschließen. Neben ihrer theoretischen Bedeutung liefern diese Studien einen methodischen Beitrag zum Forschungsgebiet der EEG-Augenbewegung: Entfernung sakkadischer Artefakte aus dem EEG bzw. Erstellung eines künstlichen Vergleichsdatensatzes. Die Arbeit stellt mehrere Ansätze zur Untersuchung der Dynamik visueller Wahrnehmung sowie Lösungen für zukünftige Studien dar. / The visual system achieves a tremendous amount of processing as soon as we set eyes on a new object. Numerous processes are active already before eyes reach the object. This thesis explores the spatio-temporal properties of three such processes: attentional enhancement and saccadic suppression that accompany saccades to target; attentional selection of target in a visual search task; the timecourse of target detection accuracy under object-substitution masking. We monitored these events using a combination of human electrophysiology (EEG), eye tracking and behavioral psychophysics. We first studied how the neural representation of a visual stimulus is affected by its temporal proximity to saccade onset. We show that stimuli immediately preceding a saccade show strongest effects of attentional enhancement and saccadic suppression. Second, using object-substitution masking to reduce visibility, we analyzed the relationship between saccadic reaction times and response accuracy. We also collected subjective visibility ratings and observed neural markers of attentional selection, such as the negative, posterior-contralateral deflection at 200 ms (N2pc). We found that fast saccades escaped the effects of masking, resulted in higher response accuracy and higher awareness ratings. This indicates that early visual processing can trigger awareness and correct behavior. Finally, we replicated this finding with manual responses. Discovering a similar accuracy timecourse in a different modality ruled out saccade-specific mechanisms, such as saccadic suppression and retinal shift, as a potential confound. Next to their theoretical impact, all studies make a methodological contribution to EEG-eye movement research, such as removal of large-scale saccadic artifacts from EEG data and composition of matched surrogate data. In sum, this work uses multiple approaches to describe the dynamics of visual perisaccadic perception and offers solutions for future studies in this field.

En esta tesis se aborda la cuantificación, mediante censos visuales, de las pautas de variación espacial y temporal de los poblamientos de peces que viven en los fondos rocosos infralitorales del Mediterráneo occidental, a varias escalas espaciales, y se estima la importancia relativa de la estructura del hábitat rocoso para explicar dichas variaciones. En sucesivos estudios, utilizándose técnicas de análisis espacial, se muestra que riqueza, abundancia y diversidad de peces responden a las variaciones del hábitat estructural (distinguiéndose entre complejidad y heterogeneidad), tanto a escala local como a múltiples escalas espaciales jerarquizadas. Por otra parte, el poblamiento de peces muestra una notable estabilidad temporal, aunque ésta depende de las escalas taxonómica, espacial o analítica considerada, pudiendo esta estabilidad ser debida al efecto del hábitat sobre las poblaciones. La influencia de la estructura del hábitat rocoso puede enmascarar, e incluso contrarrestar, los beneficios esperados de la protección pesquera.

The objective of this work was to understand microbial population density and diversity, both spatially and temporally, in wetland mesocosms to gain a better fundamental understanding for use in the optimization and design of constructed wetlands (CWs). A standardized community level physiological profiling (CLPP) data analysis protocol was adapted and utilized for CW mesocosms. A new one-dimensional metric was developed to track community divergence using BIOLOGTM ECO plate data. The method proved easy to use, did not require a background in multivariate statistics, and accurately described community divergence in mesocosm systems. To study mesocosm biofilm-bound bacterial communities an appropriate detachment protocol was required. Various shaking protocols were evaluated for their effectiveness in the detachment of bacteria from mesocosm pea gravel, with a focus on detachment of viable and representative bacterial communities. A protocol based on mechanical shaking with buffer and enzymes was identified as an optimal approach and used further in this study. The bacterial communities associated with the interstitial water, pea gravel media, and rhizospheric regions from both planted and unplanted CW mesocosms were profiled using the CLPP method and compared. Vertical community stratification was observed for all mesocosm systems. Rhizospheric communities were found to be significantly more active than their gravel-associated counterparts, suggesting that although rhizospheric bacteria were less abundant in the mesocosms they may play a more significant role in the removal and fate of water born contaminants. The start-up dynamics of CW mesocosms was investigated using the CLPP and standard CW characterization methods over an eight month period. All mesocosms showed a steep increase in interstitial community divergence until day 75-100, at which point a steady-state was reached. The interstitial communities were also characterized in terms of similarity based on experimental design treatments (planted/unplanted and origin of seeding inoculum). Four stages were identified during the start-up consisting of an initial stage where mesocosm communities were differentiated based on origin of the inoculum, a period where adjustments and shifts occurred in all mesocosm, a time where all mesocosm communities were quite similar, and a final state where community differentiations were made based plant presence in the mesocosms.

The objective of this work was to understand microbial population density and diversity, both spatially and temporally, in wetland mesocosms to gain a better fundamental understanding for use in the optimization and design of constructed wetlands (CWs). A standardized community level physiological profiling (CLPP) data analysis protocol was adapted and utilized for CW mesocosms. A new one-dimensional metric was developed to track community divergence using BIOLOGTM ECO plate data. The method proved easy to use, did not require a background in multivariate statistics, and accurately described community divergence in mesocosm systems. To study mesocosm biofilm-bound bacterial communities an appropriate detachment protocol was required. Various shaking protocols were evaluated for their effectiveness in the detachment of bacteria from mesocosm pea gravel, with a focus on detachment of viable and representative bacterial communities. A protocol based on mechanical shaking with buffer and enzymes was identified as an optimal approach and used further in this study. The bacterial communities associated with the interstitial water, pea gravel media, and rhizospheric regions from both planted and unplanted CW mesocosms were profiled using the CLPP method and compared. Vertical community stratification was observed for all mesocosm systems. Rhizospheric communities were found to be significantly more active than their gravel-associated counterparts, suggesting that although rhizospheric bacteria were less abundant in the mesocosms they may play a more significant role in the removal and fate of water born contaminants. The start-up dynamics of CW mesocosms was investigated using the CLPP and standard CW characterization methods over an eight month period. All mesocosms showed a steep increase in interstitial community divergence until day 75-100, at which point a steady-state was reached. The interstitial communities were also characterized in terms of similarity based on experimental design treatments (planted/unplanted and origin of seeding inoculum). Four stages were identified during the start-up consisting of an initial stage where mesocosm communities were differentiated based on origin of the inoculum, a period where adjustments and shifts occurred in all mesocosm, a time where all mesocosm communities were quite similar, and a final state where community differentiations were made based plant presence in the mesocosms.

No description available.

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal

Le sol est une des composantes essentielles au soutien du fonctionnement de l’écosystème. Il est lesupport de la production primaire, un habitat pour la diversité biologique et remplit de nombreux processus écologiques. Les activités anthropiques, et parmi elles, les pratiques agricoles intensives, ont conduit à des déséquilibres au sein du sol causant un fort déclin de leur biodiversité. En réponse à ces effets, de nouvelles pratiques agricoles ont été développées pour préserver les sols et les services écosystémiques qu’ils fournissent. Ces pratiques dites innovantes s’appuient principalement sur la réduction du travail du sol, une gestion intégrée des résidus de culture, l’installation d’un couvert végétal permanent ou encore l’introduction de légumineuses dans les rotations de culture. C’est dans ce contexte de mutation des pratiques agricoles que s’inscrit ce sujet de thèse qui vise à mieux comprendre les effets de l’adoption de ces gestions innovantes sur (i) la diversité des communautés de la macro- et de la mésofaune du sol et (ii) sur le fonctionnement du sol en termes de stockage ducarbone organique (source de nourriture de base), de structure du sol et de distribution de la taille des pores (milieu de vie). Au cours des différents chapitres de ce travail, nous avons mis en évidence trois actions liées à des pratiques agricoles innovantes combinant des approches expérimentales in et ex situ. L’objectif de la première action visait à étudier l’effet combiné de l’introduction de légumineuse (féverole) et de la réduction du travail du sol sur le compartiment endogé. Pour y répondre, nous avons développé une conception expérimentale empirique faite avec la combinaison des situations rencontrées dans les fermes. Nos résultats ont montré que l’interaction entre les deux pratiques innovantes n’a pas entrainé d'augmentation significative de la diversité de la faune du sol. Les fonctions microbiennes ainsi que la dynamique du carbone (C) et de l’azote (N) ne semblent pas non plus être affectées par ces pratiques. Il s’avère que les effets bénéfiques de ces pratiques innovantes ne peuvent être envisagés sans prendre en compte la manière dont elles sont mises en oeuvre à l’échelle des rotations culturales et des itinéraires techniques. Cela nous a permis de valoriser une seconde action dont l’objectif était de suivre dans les mêmes conditions pédoclimatiques et mêmes itinéraires techniques, l'effet à long terme (quatre ans) de cinq régimes de gestion différents sur les communautés de faune du sol. Les traitements comprenaient des combinaisons de différentes cultures (annuelles, vivaces), de différents taux de fertilisation azotée (ajout d'azote, azote réduit),incorporation ou élimination de résidus de culture et différentes intensités de labour (labour vs. travail superficiel). Les résultats ont montré que la réduction de l’intensité du travail du sol a favorisé la diversité des collemboles et ses groupes fonctionnels grâce à l’amélioration des conditions de l’habitat à travers l’augmentation de la biomasse microbienne de carbone (source trophique). Par ailleurs, les autres composantes de la gestion, soit la « réduction des apports d’azote » et la « restitution / exportation des résidus de culture», n’ont pas eu d’effet sur les collemboles (abondance et richesse), notamment sur ceux vivants dans le sol, qu'ils soient hémi ou euédaphiques. Toutefois, cette étude démontre que la dissemblance dans la composition des assemblages de collemboles augmente avec la différenciation temporelle des pratiques agricoles et le travail du sol est le premier facteur responsable de cette trajectoire. Cette assertion a donné lieu à une troisième action dont l’objectif était de suivre sur une saison de végétation la conversion de la perturbation mécanique résultant du travail du sol sur la résistance et résilience fonctionnelle des assemblages biotiques édaphiques. / Soil is one of the essential components supporting the functioning of the ecosystem. It is the support of primary production; an habitat for biodiversity, and it fulfills many ecological processes. Human activities, including intensive agricultural practices, have led to impaired the soil causing a sharp decline in their biodiversity. In response to these effects, new agricultural practices have been developed to preserve the soils and the ecosystem services they provide. These so-called innovative practices rely mainly on the reduction of tillage, integrated management of crop residues, the installation of permanent plant cover or the introduction of legumes into crop rotations. It is in this context of changes in agricultural practices that this thesis topic lays. This thesis aims to better understand the effects of the adoption of these innovative management practices on (i) the diversity of the macro and mesofauna communities soil and (ii) soil functioning in terms of organic carbon storage (basic food source), soil structure and pore size distribution (living environment). During the different chapters of this work, we highlighted three actions related to innovative agricultural practices combining in situ and ex situ experimental approaches. The aim of the first action was to study the combined effect of the introduction of legume (faba bean) and the reduction of tillage on the endogenous compartment. To answer this question, we developed an empirical experimental design made with the combination of situations encountered on farms. Our results showed that theinteraction between the two innovative practices did not result in a significant increase in the diversity of soil fauna. Microbial functions and the dynamics of carbon (C) and nitrogen (N) also do not seem to be affected by these practices. It turns out that the beneficial effects of these innovative practices cannot be considered without taking into account how they are implemented at the scale of crop rotations and technical itineraries. This allowed us to promote a second action whose objective was to follow, under the same pedoclimatic conditions and the same technical itineraries, the long-term effect (four years) of five different management regimes on the communities of soil fauna. Treatments included combinations of different crops, different rates of nitrogen fertilization, incorporation or removal of crop residues and different plowing intensities. The results showed that the reduction of tillage intensity favored the diversity of Collembola and its functional groups by improving habitatconditions through the increase of microbial carbon biomass (trophic source). In addition, the other components of management, namely the "reduction of nitrogen inputs" and the "restitution / export of crop residues", had no effect on springtails (abundance and wealth), in particular on those living in the soil, whether hemi or euedaphic. However, this study demonstrates that the dissimilarity in the composition of Collembola assemblages increases with the temporal differentiation of agricultural practices, and tillage was the main factor responsible for this trajectory.

A pesquisa abordou o processo de uso e ocupação das terras nos municípios de Bodoquena, Bonito e Jardim, situados na borda leste do Parque Nacional da Serra da Bodoquena (PNSB), região sudoeste de Mato Grosso do Sul. Além disso, foi estudado o estado de conservação, em termos de estrutura e configuração da paisagem, dos remanescentes de cerrado e floresta contidos no interior do PNSB e em sua zona de amortecimento. O objetivo foi o de analisar a dinâmica de ocupaçao das terras nos municípios mencionados nos últimos 18 anos, com vistas à subsidiar estratégias de planejamento do uso e ocupação das terras ideal para a região. Objetivou-se também analisar a dinâmica espacial e temporal da paisagem que compõe o PNSB e sua zona de amortecimento, visando à conservação da biodiversidade local. Para isso, foi utilizado um sistema de informação geográfica (SIG) para elaboração de mapas temáticos e de um banco de dados georreferenciado. A determinação do grau de conservação do PNSB e da sua zona de amortecimento se deu mediante a utilização de métricas de paisagem, e da adoção dos preceitos da Teoria dos Grafos. O capítulo 1 demonstrou, por meio dos mapas gerados para os municípios de Bodoquena, Jardim e Bonito, dos anos de 1986 e 2004, que ocorreu uma perda de área nativa e um conseqüente crescimento da matriz antrópica composta por pastagens (principalmente) e culturas agrícolas. Apenas em Bodoquena os remanescentes vegetais tiveram maior porcentual que as áreas de pastagens e lavouras. Pode-se observar que a região estudada, passa por um processo de conversão de habitats naturais, outrora contínuos, para uma paisagem composta por fragmentos de cerrados, campos e florestas. O capítulo 2 mostrou que as fisionomias florestais e de cerrado, apresentaram-se em melhor estado de conservação em 1986 que em 2004. Além disso, foi possível observar que os remanescentes das formações vegetais acima citadas, apresentaram-se em melhor estado de conservação no interior do PNSB, que em sua zona de amortecimento. O mapa de relevância dos remanescentes de floresta, considerando as notas combinadas das métricas de forma e área das manchas indicou, quais são as áreas prioritárias para serem protegidas, por possuírem características adequadas para a persistência da biodiversidade florestal presente no PNSB e em sua zona de amortecimento. O setor norte se destacou por apresentar remanescentes com valores alto e extremamente alto com relação à relevância. O mesmo setor norte possui um maior número de pontos de sensibilidade à quebra de conectividade entre as manchas de floresta. Nesta região pode-se observar que a maior parte dos pontos com alta sensibilidade, merece alguma estratégia que retarde ou mesmo cesse o processo de conversão da floresta para pastagem ou agricultura. Com relação ao padrão de fragmentação dos remanescentes vegetais, conclui-se o seguinte: os remanescentes de cerrado e floresta, no intervalo de dezoito anos, ficaram menores, mais irregulares, mais distantes e mais numerosos, indicando uma piora no estado de conservação da paisagem entre 1986 e 2004. Isso compromete a manutenção da biodiversidade, a persistência de espécies, diminuindo suas populações mínimas viáveis. A diversificação das formas de uso das terras na matriz é recomendada, com a introdução da silvicultura (principalmente composta por espécies nativas), por exemplo, também poderá auxiliar na manutenção/surgimento da heterogeneidade espacial e da complexidade estrutural da paisagem. A Teoria dos Grafos, avaliada neste trabalho, apresentou-se como ferramenta eficiente para se calcular a conectividade em paisagens heterogêneas. / The research approached the process of use and occupation of lands in the cities of Bonito, Bodoquena and Jardim, situated in the edge east of the National Park of the Serra da Bodoquena (NPSB), southwestern region of Mato Grosso do Sul, Brazil. Moreover, the conservation state was studied, in terms of structure and configuration of the landscape, of the contained remainders of cerrado and forest in the interior of the NPSB and its buffer zone. The objective was to analyze the dynamics of occupation of lands in the cities mentioned in last the 18 years, with sights to subsidizing strategies of planning of the use and ideal occupation for the region. Also, it was objectified to analyze the space-temporal dynamics of the landscape that composes the PNSB and its buffer zone, aiming at to the conservation of local biodiversity. For this, geographic information system (GIS) for the classification of images of satellite and elaboration of thematic maps was used. The determination of the NPSB conservation degree and its buffer zone occurred by means of the use and of metrics of landscape ecology and the adoption of Graph Theory. Chapter 1 demonstrated, by the maps generated for the cities of Bonito, Bodoquena and Jardim, of the years of 1986 and 2004, that it occurred a loss of native area and a consequent growth of the composed matrix for pastures (mainly) and agriculture. Only in Bodoquena the vegetal remainders had percentual had been bigger than the areas of pastures and agriculture. It can be observed that the studied region passes for a process of conversion of natural habitats, long ago continuous, for a composed landscape for patches of cerrado and forests in a matrix predominantly represented by planted pasture and agriculture. Chapter 2 showed that the forest and cerrado physiognomy, had been presented in better conservation in 1986 that in 2004. Moreover, it was possible to observe that the remainders of the vegetal formations above cited, had been presented in better conservation in the interior of the NPSB, that in its buffer zone. The map of relevance of the remainders of forest, considering the agreed area and shape notes metric of the spots, had indicated which the priority areas to be protecting, for possessing characteristics adjusted for the persistence of present forest biodiversity in the NPSB and its buffer zone. The north sector had detached for presenting remainders with high and extremely high values to the relevance. The same north sector posses a bigger number of points of sensitivity to the break of connectivity between the forest spots. In this region it can be observed that most of the points with high sensitivity deserves some strategy that delays or stop the conversion process of the forest for pasture or agriculture. Regard the standard of spelling of the vegetal remainders, had been concluded that: the remainders of cerrado and forest, in the interval of eighteen years, had been lesser, more irregular, more distant and more numerous, indicating a worsening in the state of conservation of the landscape between 1986 and 2004. This compromises the maintenance of biodiversity, the species persistence, diminishing its viable minimum populations. The diversification of the forms of use of lands in the matrix is recommended, with the introduction of forestry (mainly composed for native species), for example, also it will be able to assist in the maintenance/sprouting of the space heterogeneity and the structural complexity of the landscape. The Graph Theory, evaluated in this work, was presented as efficient tool to calculate the connectivity in heterogeneous landscapes.

Abstract Describing how and why species composition of ecological communities varies across spatial and temporal scales is a primary objective for ecological research. A key challenge is to distinguish changes in community composition resulting from external factors from the natural background variability. In this thesis I aimed to study: 1) the level of temporal variation in community composition of stream macroinvertebrates, 2) the role of different environmental factors to temporal variability, 3) the effect of temporal variability on bioassessment outcomes, and 4) comparability of different approaches to study community variability through time. A majority of the studied macroinvertebrate communities showed lower level of inter-annual variation, i.e. temporal turnover, than expected by chance. The observation of high community stability was further supported by the low level of inter-annual variation in taxonomic completeness (quotient of observed and expected number of species, O/E). Despite the low absolute variation in O/E, ecological status assessments varied annually. Thus the use of one year data may bias management decisions. Macroinvertebrate communities experienced similar dynamics across several spatial extents, from riffles within a stream to streams among regions, suggesting that large-scale extrinsic factors are the major driver of community dynamics. Especially climatically exceptional years may have a strong imprint on community variability. However, at the within-stream scale, coherence was lower than expected, indicating that community dynamics may be driven by different processes at different spatial extents. Stream macroinvertebrate community dynamics were strongly related to in-stream vegetation, temporal variability decreasing with increasing macrophyte cover. Importantly, the effect of in-stream vegetation on temporal turnover of macroinvertebrate communities was masked by the stochastic effect of habitat connectivity, suggesting that unless stochastic effects are controlled for, the role of deterministic processes may be obscured, thus affecting our ability to understand and predict community changes through time. In addition, different approaches to study temporal variability may disagree on estimates for the level of temporal turnover and factors explaining it – a fact that should be taken into account when planning and comparing studies. / Tiivistelmä Yksi ekologisen tutkimuksen keskeisistä tavoitteista on kuvata, miten ja miksi eliöyhteisöjen koostumus muuttuu paikasta ja ajankohdasta toiseen. On tärkeää pystyä erottamaan erilaisten ulkoisten tekijöiden aiheuttamat muutokset luonnollisesta taustavaihtelusta. Väitöskirjani tavoitteena oli selvittää 1) miten paljon virtavesien pohjaeläinyhteisöissä tapahtuu ajallista vaihtelua 2) mitkä ympäristötekijät vaikuttavat yhteisöjen ajalliseen vaihteluun 3) miten ajallinen vaihtelu vaikuttaa ympäristön tilan arviointiin ja 4) kuinka vertailukelpoisia ovat eri lähestymistavat ajallista vaihtelua tutkittaessa. Valtaosa tutkituista pohjaeläinyhteisöistä vaihteli vuosien välillä vähemmän kuin olisi sattumalta odotettavissa osoittaen varsin suurta ajallista pysyvyyttä. Käsitystä yhteisöjen pysyvyydestä tuki myös vähäinen vuosittainen vaihtelu ekologista tilaa kuvaavassa taksonomisessa eheydessä (=havaitun ja odotetun lajiston suhde O/E). Huolimatta näennäisen pienestä vaihtelusta O/E suhteessa paikkakohtaiset tilaluokka-arviot saattoivat vaihtua vuodesta toiseen. Yhden vuoden aineistoon perustuvat tilan arvioinnit voivat siis johtaa virheellisiin johtopäätöksiin. Pohjaeläinyhteisöjen ajallinen vaihtelu oli samankaltaista eri mittakaavoilla niin peräkkäisten koskipaikkojen kuin eri alueilla sijaitsevien purojen välillä. Suuren mittakaavan ympäristötekijät näyttävät siis säätelevän eliöyhteisöjen ajallista vaihtelua. Erityisesti ilmastotekijöiltään poikkeukselliset vuodet säätelevät eliöyhteisöjä, ja niiden vaikutus voi näkyä vielä useiden vuosien kuluttua. Vaihtelun samankaltaisuus peräkkäisten koskipaikkojen välillä oli kuitenkin odotettua pienempää. Yhteisöjä voivat siis säädellä osittain eri tekijät eri mittakaavoilla. Tutkittujen pohjaeläinyhteisöjen ajallisen vaihtelun voimakkuus liittyi erityisesti vesikasvillisuuden määrään: vaihtelu väheni kasvillisuuden lisääntyessä. Kasvillisuuden määrän vaikutus peittyi kuitenkin satunnaisten tekijöiden alle. Jos satunnaisia tekijöitä ei huomioida, deterministiset syy-seuraussuhteet voivat jäädä huomaamatta heikentäen mahdollisuuksiamme ymmärtää ja ennustaa eliöyhteisöjen vaihtelua. Lisäksi eri lähestymistavat ajallista vaihtelua tutkittaessa voivat johtaa erilaisiin arvioihin vaihtelun suuruudesta ja siihen vaikuttavista tekijöistä, mikä tulisi ottaa huomioon tutkimuksia suunnitellessa ja niiden tuloksia vertailtaessa.