Submitted by Adriana Martinez (amartinez@unoeste.br) on 2017-07-06T19:28:28Z No. of bitstreams: 1 Camila Pinaffi.pdf: 3431594 bytes, checksum: e5d36d386908f87bb76dcd0ea731d043 (MD5) / Made available in DSpace on 2017-07-06T19:28:28Z (GMT). No. of bitstreams: 1 Camila Pinaffi.pdf: 3431594 bytes, checksum: e5d36d386908f87bb76dcd0ea731d043 (MD5) Previous issue date: 2017-04-05 / The expansion of swine activity has provided an increase in the volume of waste, and its disposal without a treatment leads to problems of contamination of soil and surface water and groundwater. Aquatic plants are one of the alternatives that can be used in the treatment of these effluents. The objective of this study was to evaluate the potential of aquatic plants (Eichhornia crassipes), water lettuce (Pistia stratiotes) and salvinia (Salvinia auriculata) in improving the chemical and physicochemical characteristics of liquid swine manure (DLS). The experiment was conducted in an open environment in Campus II/UNOESTE. For the composition of the treatments was used liquid swine manure (DLS) of the zootechnical center diluted in water, being distributed in 16 boxes (0,32 m³) of PVC and characterized as: T1 = Witness - only 50% DLS; T2 = 50% DLS + E. crassipes; T3 = 50% DLS + P. stratiotes; T4 = 50% DLS + S. auriculata. In each treatment small, visually similar plants were inserted. The experiment was structured in a randomized complete block design (DBC), with four treatments, in subdivided plots, with four replications. Effluent samplings were performed weekly in the months of Oct/Nov/Dec 2015 and Mar/Apr/May/Jun/Aug/Sep 2016, and a sample of each treatment and repetition was collected, totaling 16 samples per week. In the effluent, the parameters were: electrical conductivity (EC), pH, dissolved oxygen (OD), turbidity, chemical and biochemical oxygen demand (COD e BOD), ammonium (N-NH4+), nitrate (N-NO3-) and total phosphorus (P total). The N-NH3 volatilization rates of the system were also evaluated. To obtain the content of the elements in the plant tissue, the plants were collected monthly and submitted to chemical analysis of the elements: N-NH4+, N-NO3-, P total, as well as the determination of total biomass of dry matter (BMS) of plants. The results were submitted to analysis of variance and to the comparison test of Tukey averages at the 5% probability level. The results obtained indicate that the E. crassipes provided a higher reduction of EC, turbidity, COD, BOD, NH4+ and P total of the effluent, lower NH3 volatilization, as well as the higher total P content present in its plant tissue and The highest production of BMS. P. stratiotes followed by E. crassipes showed higher NH4+ content in their plant tissues. Therefore, among the macrophytes studied, E. crassipes stands out as the most profitable in the cleaning of liquid swine manure. / A expansão da atividade da suinocultura tem proporcionado aumento no volume de dejetos, sendo que seu descarte sem um tratamento acarreta em problemas de contaminação do solo e das águas superficiais e subterrâneas. As plantas aquáticas são uma das alternativas que podem ser utilizadas no tratamento destes efluentes. Desta maneira, o estudo tem como objetivo avaliar o potencial das plantas aquáticas aguapé (Eichhornia crassipes), alface d’água (Pistia stratiotes) e salvínia (Salvinia auriculata) na melhoria das características químicas e físico-químicas dos dejetos líquidos de suinocultura (DLS). O experimento foi conduzido em ambiente aberto no Campus II/UNOESTE. Para composição dos tratamentos foi utilizado o DLS do centro zootécnico diluído em água, sendo distribuídos em 16 caixas (0,32 m³) de PVC e caracterizados como: T1 = Testemunha - apenas 50% DLS; T2 = 50% DLS + E. crassipes; T3 = 50% DLS + P. stratiotes; T4 = 50% DLS + S. auriculata. Em cada tratamento foram inseridas plantas de pequeno porte, semelhantes visualmente. O experimento foi estruturado em delineamento em blocos casualizados (DBC), com quatro tratamentos, em parcelas subdivididas, com quatro repetições. As amostragens do efluente foram realizadas semanalmente, nos meses de Out/Nov/Dez de 2015 e Mar/Abr/Mai/Jun/Ago/Set de 2016, sendo coletada uma amostra de cada tratamento e repetição semanalmente. Foram analisados no efluente os parâmetros: condutividade elétrica (CE), pH, oxigênio dissolvido (OD), turbidez, demanda química e bioquímica de oxigênio (DQO e DBO), amônio (N-NH4+), nitrato (N-NO3-) e fósforo total (P total). Também foram avaliadas as taxas de volatilização de amônia (N-NH3) do sistema. Para obter o teor dos elementos no tecido vegetal, as plantas foram coletadas mensalmente e submetidas à análise química dos elementos: N-NH4+, N-NO3-, P total, bem como a determinação da biomassa de matéria seca (BMS) total das plantas. Os resultados foram submetidos à análise de variância e ao teste de comparação de médias Tukey ao nível de 5% de probabilidade. Os resultados obtidos indicam que a espécie E. crassipes proporcionou maior redução de CE, turbidez, DQO, DBO, NH4+ e P total do efluente, menor volatilização de NH3, assim como o maior teor de P total presente em seu tecido vegetal e a maior produção de BMS. A P. stratiotes seguida da E. crassipes apresentaram maior teor de NH4+ em seus tecidos vegetais. Sendo assim, dentre as macrófitas estudadas, destaca-se à E. crassipes como a mais profícua na limpeza dos dejetos líquidos de suínos.

Orientador: Edivaldo Domingues Velini / Banca: Dagoberto Martins / Banca: Robinson Antonio Pitelli / Resumo: O objetivo deste trabalho foi avaliar a composição química, bromatológica e a decomposição de Egeria densa, E. najas e Ceratophyllum demersum, três espécies de plantas aquáticas imersas provenientes do reservatório de Jupiá da Usina Hidrelétrica Souza Dias, para determinar a melhor estratégia para descarte e/ou aproveitamento da biomassa coletada em operações mecânicas de controle. O estudo foi realizado em duas épocas do ano, verão e inverno. Amostras de plantas foram coletadas em nove pontos do trecho Tietê do reservatório, envolvendo quatro lagoas marginais e o leito do rio em questão. Estas foram desidratadas, pesadas para determinação de matéria seca, moídas e encaminhadas aos respectivos laboratórios para análise. Os maiores teores de água encontrado nas plantas foi para a espécie C. demersum, a qual obteve também a menor relação C/N, em comparação às demais espécies estudadas. Para as três espécies, a maior concentração dos elementos analisados, foi encontrada durante o período de verão, apresentando decréscimo nas concentrações no inverno. As espécies amostradas apresentam boa opção para uso em dietas animal, porém deve-se levar em conta o alto teor de água, necessitando prévia secagem para que possa ser inserida na dieta alimentar de animais. Referente ao descarte da biomassa em solo, ficou claro a necessidade de se efetuar tal procedimento em época seca do ano, haja visto a grande dificuldade de secagem e incorporação do material em solo úmido...(Resumo completo, clicar acesso eletrônico abaixo). / Abstract: The purpose of this work was to evaluate the chemical and bromatological compositions and the decomposition of Egeria densa, Egeria najas and Ceratophyllum demersum residues, three submerged aquatic plants, importants in Jupia reservoir. These data will be useful to determine a better strategy for discharge and/or utilization the plant biomass harvested by the mechanical control. The study was carried out in two seasons, summer and winter. Plants samples were collected in nine points in the Tiete river, including four marginal lakes and in the river body. Samples were dried, weighted, grounded and sent to laboratories for chemical analysis. Higher water level in plants were observed in the C. demersum species, in which were observed the smaller C/N relationship too, in comparison in the other species studied. For the three species, higher concentration of elements analyzed, was observed during the summer, decreasing in the winter. The species are good option to use in animal feeding, even it should be considered the high level of water, requiring a drying before to be inserted in feeding of animals. Considering to the discharge of the plant biomass in the soil, it was clear that need to make such procedure in dry season of the year, have seen that the great difficult in evaporate and incorporation of material in humid soil. However, the probable discard it should happen in the areas with irrigation systems, facilitating the degradation process of the incorporated material in the wet soil. / Mestre

Orientador: Raoul Henry / Resumo: As lagoas marginais são habitats lênticos, laterais ao rio, que podem manter comunicação permanente ou não com o rio. Nesses ecossistemas é encontrada elevada biodiversidade aquática, inclusive de zooplâncton. O objetivo deste estudo foi verificar diferenças na estrutura da comunidade zooplanctônica em lagoas marginais com diferentes níveis de conectividade hidrológica, por meio dos atributos ecológicos (riqueza, abundância, diversidade beta e funcional). Foi analisada a influência da conectividade hidrológica na comunidade de Cladocera e Rotifera em seis lagoas marginais antes e após um pulso de inundação do rio Paranapanema. Os resultados mostram que a estrutura da comunidade de Cladocera e Rotifera tende a ser mais distinta após o pulso de inundação. A diversidade beta foi mais elevada nas lagoas isoladas e na lagoa conectada que possui alta compartimentalização. Outro tema abordado diz respeito à analise da distribuição de Rotifera em um gradiente longitudinal da zona litorânea e envolvendo também a zona pelágica de uma lagoa marginal colonizada por macrófitas, por meio da diversidade taxonômica e funcional. A diversidade taxonômica foi maior na região de ecótono (transição da zona pelágica e litorânea) enquanto a diversidade funcional foi mais elevada na zona litorânea da lagoa. Neste estudo, também foi descrito como os microcrustáceos estão distribuídos em um transecto horizontal da zona litorânea e pelágica de uma lagoa marginal. A comunidade de microcrustáceos foi div... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The marginal lakes are lentic habitats, lateral to the river, that can maintain permanent communication or not with the river. High aquatic biodiversity is found in these ecosystems, including zooplankton. The aim of this study was to o verify differences in the structure of the zooplankton community in marginal lakes with different levels of hydrological connectivity, through ecological attributes (richness, abundance, beta and functional diversity). The influence of hydrological connectivity in the community of Cladocera and Rotifera in six marginal lakes was analyzed before and after the Paranapanema River pulse flood. The beta diversity was higher in isolated lakes and in connected lakes, which has high compartmentalization. Another topic addressed concerns the analysis of the distribution of Rotifera in a longitudinal gradient of the littoral zone and also involving the pelagic zone of a marginal lake colonized by macrophytes, through taxonomic and functional diversity. Taxonomic diversity was greater in the ecotone region (transition from the pelagic and littoral zone) while the functional diversity was higher in the littoral zone of the lake. In this study, it was also described how microcrustaceans are distributed in a horizontal transect of the littoral and pelagic zone of a marginal lake. The microcrustacean community was divided into six functional groups, with a predominance of the G2 group (bosminids) in the lake. Macrophytes had a strong influence on variations ... (Complete abstract click electronic access below) / Doutor

Orientador: Ciro Cesar Zanini Branco / Banca: Rosana Marta Kolb / Banca: Régis de Campos Oliveira / Resumo: Vários estudos observacionais sobre macrófitas de ecossistemas lóticos têm contribuído com o aumento do conhecimento ecológico destes organismos nestes ambientes. Entretanto, ainda persistem lacunas importantes neste conhecimento, entre as quais estão as relações de causa e efeito que potencialmente existem entre perturbações provocadas pela atividade antrópica e aspectos da fisiologia e da ecologia destes organismos. Com o objetivo de superar, obviamente em parte, esta lacuna, o presente estudo propõe, através de experimentos laboratoriais, avaliar os efeitos de resíduos de herbicidas usados nas lavouras agrícolas, em especial aqueles a base de glifosato (Roundup®) e seu metabólito (AMPA), sobre parâmetros fotossintéticos de espécies de angiospermas aquáticas típicas de ecossistemas lóticos tropicais. As avaliações das taxas fotossintéticas e de respiração no escuro foram realizadas através da evolução do oxigênio dissolvido, aplicando-se a técnica das garrafas claras e escuras e da fluorescência de clorofila a, que foi avaliada com o fluorômetro subaquático Diving-PAM. Os valores dos parâmetros fotossintéticos medidos/calculados para cada tratamento avaliado foram submetidos à estatística descritiva e as eventuais diferenças entre eles foram avaliadas através da análise de variância utilizando o teste de Scott-Knott e o t-Student. Foram observados alguns poucos efeitos fitotóxicos associados às espécies de macrófitas estudadas, porém, quase nenhuma diferença... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Even with many observational studies regarding lotic ecosystems, macrophytes that have contributed with great knowledge about the ecology of these organisms in these environments. However, there are still important gaps in this knowledge, among which are the cause and effect relationships that potentially exist between disturbances caused by anthropic activity and aspects of the physiology and ecology of these organisms. With the objective of overcoming, in part, this gap, the present study proposes, through laboratory experiments, to evaluate the effects of herbicide residues used in agricultural crops, especially those based on glyphosate (Roundup®) and your metabolite (AMPA) on photosynthetic parameters of aquatic angiosperm species typical of tropical lotic ecosystems. The evaluation of photosynthetic rates and respiration in the dark were performed through the evolution of dissolved oxygen, applying the light and dark bottle technique and chlorophyll a fluorescence, which was evaluated with the Diving-PAM underwater fluorometer. The values of the photosynthetic parameters measured / calculated for each evaluated treatment were submitted to descriptive statistics and any differences between them were evaluated through analysis of variance using the Scott-Knott and t-Student test. In spite of this global pattern, species responded specificially to exposure to Roundup® and AMPA, and Egeria densa was the one that registered the greatest susceptibility to the loss of... (Complete abstract click electronic access below) / Mestre

Exotic invasive plant species can alter aquatic habitats potentially influencing the macroinvertebrate community and foraging fishes. Therefore, I investigated the hypothesis that Hydrilla verticillata will alter habitat important to macroinvertebrate community structure and bluegill foraging efficiency. Studies were conducted in ponds and aquaria. At the pond level, macroinvertebrate abundance, richness, and biomass in a hydrilla-dominated habitat did not differ significantly from a diverse plant habitat. Indicator taxa did differ significantly between respective treatments. The data suggest hydrilla beds may not provide increased macroinvertebrate abundance and richness compared to diverse plant beds as previously thought. In aquaria, habitat complexity (Ihv) and light transmittance were influenced by increasing the homogeneity of hydrilla in an aquatic bed habitat. In addition, bluegill foraging efficiency was affected negatively by increasing spatial complexity of a hydrilla dominated habitat. Therefore, a shift to a monotypic hydrilla habitat can alter macroinvertebrate community composition and impact bluegill foraging success.

Dammar har använts till många saker genom århundrandena, bland annat energiutvinning, reglering av vattennivå och transport av timmer. När dammar inte längre är i bruk och inte är ekonomiskt gynnsamma är dammutrivning en vanlig restaureringsmetod för att återställa ekosystemen. Dammar påverkar generellt ekosystemen negativt då det blir en begränsad konnektivitet inom och mellan vattendragen och sjöarna. Fiskars migration av och spridning av fröer från växter hindras av dammarna. Genom att riva ut dammar öppnas vägar för organismer att förflytta sig. Med utrivning av dammarna sker även en vattennivåsänkning som leder till att undervattensväxter kan bli mer utsatta. Undervattensväxter (makrofyter) som lever i det grunda vattnet bidrar med skydd och habitat för både fisk och bentisk fauna, samt zooplankton. Syftet med min undersökning är att undersöka om täckningsgraden av makrofyter förändras av dammutrivning. Även koncentrationen av fosfor i vattnet samt ljustillgången (mätt som siktdjup) förväntades ha en påverkan på täckningsgraden av makrofyter i sjöarna. Resultaten visade att det inte fanns ett signifikant samband mellan täckningsgraden och dammutrivning. Ett samband mellan täckningsgrad och siktdjup kunde inte heller bevisas. Däremot fanns ett positivt samband mellan täckningsgrad och koncentration fosfor i vattnet. Den här studien visar att makrofyter inte påverkas negativt av dammutrivning vilket är positivt då makrofyter har en viktig roll i ekosystemen. / Dams have been used for many things throughout history, such as an energy source, for regulation of water levels and timber transport. When dams are no longer economically viable, dam removal is a common method of restoring the ecosystem. Dams generally effect the ecosystems negatively, as they limit the connectivity in and between rivers, streams, and lakes. For example, fish migration and the spread of seeds are typically disrupted by the dams. When dams are removed, the water levels are normally reduced, which can lead to aquatic plants becoming more vulnerable. Aquatic plants (macrophytes) that grow in shallow parts of a lake provide habitat for fish, bentic invertebrate fauna and zooplankton and they thus form an important part of the limnic ecosystems. The purpose of my study was to investigate if the coverage of macrophytes changes after dam removal in lakes. Also, the concentration of phosphorus in the water and the light availability (measured with Secchi depth) were predicted to influence the coverage of macrophytes. The results showed that there was not a significant effect of dam removal or Secchi depth on the coverage of macrophytes. The concentration of phosphors had a positive significant effect of on macrophyte coverage. My study indicates that dam removal does not affect macrophytes negatively, which may be important due to macrophytes’ important role in the ecosystem.

Georgian Bay (GB) coastal wetlands are unique in their geomorphology and quality. Though not pollution impaired, these wetlands are currently threatened by regional climate change, and its influence on their water level (WL) regime. Recently, GB coastal wetlands experienced 14-years of prolonged low WLs, followed by an eight-year increase in WLs, which was a departure from the eight-year oscillations modelled from 1865-2007. To conserve these ecosystems, it is critical to understand how these wetlands responded to these atypical WL patterns. First, we compared scores from three wetland health indicators between periods of low and high WLs. We determined that abiotic indicators became falsely inflated during high waters, through the dilution of concentration-dependent parameters. We also established that biotic indicators were unaffected by changing WLs, but masked significant changes in plant and fish communities. During initial low WLs, emergent and rosette basal macrophytes, and certain fish species (blackchin, blacknose, and common shiner, bluntnose minnow, longnose gar, rock bass, and smallmouth bass) that showed a preference for shallow, low-density vegetation dominated. During high WLs, unrooted submergents and canopy macrophyte species, along with fish species (bluegill, bowfin, largemouth bass, and northern sunfish), which were positively associated with dense and deep vegetation, dominated coastal wetlands. Based on these results, I developed 14 macrophyte and 10 fish Indicator Species of low and high WLs. Using independent data, all Indicator Species were supported, although only one macrophyte and two fish species were statistically confirmed. Since the fyke nets I used throughout the two decades of WL fluctuations could not be deployed effectively, due to the development of dead tree zones (DTZs), I developed a camera array, which was not depth or substrate dependent. This research advances our understanding of coastal wetlands’ responses to changes in WLs, and highlights tools to use in similar conditions. / Dissertation / Doctor of Science (PhD) / Coastal wetlands provide critical habitat for a variety of wildlife. Starting in 1999, climate change caused Lake Huron water levels (WLs) to remain low for 14-years, rather than fluctuating periodically as it has in the past century. Then, from 2015-2022, WLs rose and stayed high for another eight-years. The key goal of this thesis was to determine if, and how these two decades of atypical WLs impacted Georgian Bay (GB), Lake Huron coastal wetlands. First, I compared the mean of three wetland health indices to see if WLs impacted their scoring. Then, I identified and validated aquatic plant and fish Indicator Species of low or high WLs. Finally, I developed a method using underwater cameras and volunteers, to survey fish in a wider range of conditions. My thesis provides patterns and methods for stakeholders to better understand and monitor coastal wetlands impacted by regional climate change and altered WLs.

Les mollusques sont des indicateurs de perturbations anthropiques et environnementales. Ce groupe de macroinvertébrés représente en outre une source importante de nourriture pour les poissons et les oiseaux aquatiques du littoral. Les hypothèses de cette étude sont que la communauté de mollusques est influencée indirectement par les tributaires agricoles et/ou par des variables environnementales (comme la dessiccation et l'exposition aux vagues) puisque ces perturbations sont susceptibles de modifier leurs sources alimentaires et leur habitat. Les indicateurs de la réponse des mollusques aux agents perturbateurs sont la composition, la diversité, la densité, ainsi que la biomasse des espèces. En septembre 2013, des mesures de paramètres physico-chimiques de l'eau ont été réalisées, et des échantillons de mollusques et de végétation aquatique ont été prélevés à 14 sites le long des rives du lac Saint-Pierre (Fleuve Saint-Laurent, Québec, Canada). Le long de la rive nord, les sites fortement exposés à l'action du vent, situés à de plus grandes élévations, affichaient une plus faible densité, biomasse et richesse spécifique de mollusques que les sites de la rive sud, en milieu plus abrité et profond. Les sites physiquement perturbés étaient caractérisés par de faibles biomasses en macrophytes submergés. Les sphaeriidae apparaissent comme des exceptions à ces patrons, montrant une abondance plus élevée aux sites presque dépourvus de macrophytes. Bien que les variables physiques et l'habitat exercent une influence déterminante sur les communautés de mollusques, les gastéropodes et les moules unionidés étaient également affectés par la dégradation de la qualité de l'eau dans le panache des tributaires agricoles. La richesse, la densité et la biomasse des gastéropodes étaient négativement influencées par des teneurs élevées de matières en suspension et de fer dissous. Les résultats de notre étude montrent que la communauté de mollusques du lac Saint-Pierre est directement affectée par l'émersion périodique, l'exposition au vent, et indirectement par l'effet de ces variables physiques sur les macrophytes qui constituent leur habitat. / Molluscs are indicators of anthropogenic and environmental disturbances and constitute an important food source for littoral fish and aquatic birds. The main hypotheses put forward for our study are that the mollusc community is impacted by the agricultural tributaries and/or by physical variables (desiccation, exposure to waves) through changes in food and habitat. The indicators used were mollusc species composition, diversity, density, and biomass. Over the course of two weeks in September 2013, we sampled physical/chemical water variables, collected aquatic vegetation and molluscs at 14 sites on both shores of Lake Saint-Pierre (St. Lawrence River, Quebec, Canada). Sites located at higher elevations, subjected to recent water level fluctuations, and exposed to wind fetch along the north shore, had lower gastropod and unionid mussel richness, density, and biomass than less-exposed sites located at lower elevations along the south shore. These physically disturbed sites were characterized by low biomasses of submerged macrophytes. Sphaerid clams appeared to be notable exceptions to these patterns, showing their highest abundances at sites almost devoid of macrophytes. In spite of the fact that physical and habitat variables exerted a strong effect on mollusc communities, gastropod and unionid mussels were additionally affected by degraded water quality originating from agricultural tributaries. Gastropod richness, density, and biomass were negatively influenced by high levels of total suspended matter and dissolved iron. Our results show that the mollusc community in Lake Saint-Pierre was primarily affected by the direct influence of periodic emersion, wind exposure, and indirectly through the effect of these physical variables on macrophyte habitat.

En raison de leur importante capacité de réponse aux changements environnementaux, les producteurs primaires sont depuis longtemps utilisés comme indicateurs biologiques de la qualité des milieux aquatiques. La Directive Cadre Européenne sur l’Eau (2000/60/CE) préconise ainsi l’utilisation du phytoplancton, du phytobenthos et des macrophytes afin de mesurer l’état écologique des écosystèmes lacustres. Dans cette étude, ces trois compartiments ont été utilisés pour déterminer l’état écologique de cinq lacs localisés dans la région Aquitaine (Sud-Ouest de la France), lacs ayant la particularité de présenter des niveaux trophiques différents. Les résultats ont montré qu’au niveau intra-lac la composition floristique dépend fortement des variables physiques dans la plupart des systèmes tandis qu’au niveau inter-lac celle-ci dépend du niveau trophique. Le phytoplancton s’est révélé être l’indicateur de qualité le plus performant et le seul utilisable dans les eaux ouvertes, et le plus précis dans les systèmes où les macrophytes submergés étaient absents. Cependant, dans les lacs humiques, les assemblages phytoplanctoniques semblent répondre davantage à la turbidité et aux brassages fréquents de la colonne d’eau qu’aux nutriments. Dans de telles conditions, afin de mieux caractériser la qualité de l’eau, l’utilisation complémentaire du phytobenthos et des macrophytes se révèle plus pertinente. En conclusion, considérant les trois compartiments biologiques, la présente étude permet une approche complémentaire de l’état écologique des systèmes lacustres. Certaines des méthodes appliquées ici représentent un outil potentiel de détermination de la qualité de l’eau selon les exigences de la DCE, mais elles nécessitent d’être affinées pour une meilleure évaluation de l’état écologique des lacs français. Une attention particulière a été portée aux taxa exotiques observés dans ces lacs tempérés, et cet aspect doit être pris en considération lors de l’évaluation écologique. En effet, ces espèces sensiblement avantagées par les conséquences du changement climatique, peuvent altérer la structure et le fonctionnement des écosystèmes aquatiques en place, et aboutir à une perte de diversité. / Due to their important ability to respond to environmental changes, primary producers have been used for a long time as biological indicators of water quality. The Water Framework Directive (2000/60/EC) recommends the use of the phytoplankton, phytobenthos (diatoms) and macrophytes in the ecological status assessment of lakes. In this study, these three compartments have been used to determine the ecological status of five lakes located in the Aquitaine region (southwest of France) with different trophic status. The results showed that within lakes, the floristic composition in most of the systems strongly depends on physical parameters whereas among lakes it depends on the trophic status. The phytoplankton proved to be the most powerful indicator of quality in open-water areas as well as in systems where submerged macrophytes are absent. However, in the humic lakes, the phytoplankton assemblages seem to respond more to turbidity and mixing than to nutrient load. Under such conditions, water quality could be underestimated and the complementary use of phytobenthos and macrophytes appears more appropriated. In conclusion, considering the three biological elements, the present study allows a complementary approach of the ecological status of the lakes. Some of the methods applied here represent a potential tool for the assessment of the ecological status in the context of WFD, but they need to be refined to assess more properly the ecological status of French lakes. A special attention was paid to exotic taxa observed in these temperate lakes, and this aspect must be taken into account in the ecological assessment. Indeed, these species favoured by the consequences of the climate change, can modify the structure and functioning of the aquatic ecosystems, and lead to a loss of diversity.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work evaluated, throught techniques of Remote Sensing and geoprocessing, the influence of hydrological conditions in the dynamics of emergent aquatic macrophytes in Taim Wetland (TW), important wet area in Rio Grande do Sul. The TW covers about 53% of the entire area of Taim s Ecological Station, a Federal Protected Area, which has its uses shared, mainly between biodiversity protection and irrigation. The irrigation is an important economical activity for the region, however, it changes the hydrological regime of TW, a fundamental feature for the maintenance of local biodiversity. Thus, the understanding of how the hydrological regime impacts TW s biodiversity is an important tool for the management of water resources in the region. In this context, three species of emergent aquatic macrophytes (EAM), Z.bonariensis, S. californicus and S. giganteus, were selected, both considered as biological indicators of TW. In order to evaluate how the water levels impact the three EAM, some analyses on the relationship among the hydrological condition, maps of vegetation occurrence, index for normalized difference (IND) and index of habitat suitability (IHS) were carried out. For the identification of the occurrence areas and determination of IND of EAM, Landsat images from TM and ETM sensors were used, comprising the period between 1984 and 2003, while the IHS and the hydrological regime were obtained from previous studies (Tassi, 2008; Xavier, 2015). The employed methodology showed that the EAM Z.bonariensis and S. californicus are more sensitive to larger water levels (representatives of flood conditions); in this situation, reductions in the occurrence areas of these species were indentified. For smaller water levels (drought conditions), there was an increasing in the occurrence areas of the three species. The IND showed an effective index for the understanding of EAM s response to the hydrological conditions, although in many cases there was so much difficulty in the differentiation of vegetation and water. Generally, good coefficients of determination were found between the IND and the average IHS of three months (month of image + two months previous to the image date), and between the IND and the hydrological condition (water level) of two months previous to the image date. These results are the evidence that the effects of hydrological conditions on the studied EAM are not readily detected, and that anthropic actions can produce long-term effects. / O presente trabalho avaliou, por meio de técnicas de Sensoriamento Remoto e geoprocessamento, a influência das condições hidrológicas na dinâmica de macrófitas aquáticas emergentes no Banhado do Taim (BT), importante área úmida do Rio Grande do Sul. O BT ocupa cerca de 53% da área total da Estação Ecológica do Taim, uma Unidade de Conservação Federal, que tem seus usos compartilhados, principalmente entre conservação da biodiversidade e irrigação. A irrigação é uma importante atividade econômica para a região, no entanto, altera o regime hidrológico do BT, característica fundamental para a manutenção da biodiversidade local. Assim, o entendimento de como o regime hidrológico impacta a biodiversidade do BT constitui-se em uma importante ferramenta para o gerenciamento dos recursos hídricos da região. Neste contexto, foram selecionadas três espécies de macrófitas aquáticas emergentes (MAE), Z. bonariensis, S. californicus e S. giganteus, consideradas indicadores biológicos do BT. Para avaliar como os níveis de água impactam as três MAE, foram realizadas análises da relação entre condição hidrológica, mapas de ocorrência da vegetação, índice por diferença normalizada (NDVI) e índice de adequabilidade de habitat (IAH). Para a identificação das áreas de ocorrência e determinação do NDVI das MAE, foram utilizadas imagens Landsat dos sensores TM e ETM, compreendidas entre os anos de 1984 e 2003, enquanto o IAH e o regime hidrológico foram obtidos a partir de estudos prévios (Tassi, 2008; Xavier, 2015). A metodologia empregada mostrou que as MAE Z. bonariensis, S. californicus são mais sensíveis a níveis d água maiores (representativos de condições de cheia); nesta situação, foram identificadas reduções nas áreas de ocorrência destas espécies. Para níveis de água menores (condições de seca), houve um aumento nas áreas de ocorrência das três espécies. O NDVI se mostrou um índice eficaz no entendimento da resposta das MAE às condições hidrológicas, mesmo apresentando muita dificuldade na diferenciação de vegetação e água sob condições de cheia. De modo geral, foram encontrados bons coeficientes de determinação entre o NDVI e o IAH médio de três meses (mês da imagem + dois meses anteriores à data da imagem), e entre o NDVI e a condição hidrológica (nível d água) de dois meses anteriores à data da imagem. Esses resultados são indícios de que os efeitos das condições hidrológicas sobre as MAE estudadas não são prontamente detectados, e que ações antrópicas podem produzir efeitos a longo prazo.