Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-06-14T15:05:54Z No. of bitstreams: 1 ANDRÉ AIRES DE FARIAS - TESE (PPGRN) 2016.pdf: 5737610 bytes, checksum: 24b094da2cef8f2db3a8552a03764f80 (MD5) / Made available in DSpace on 2018-06-14T15:05:54Z (GMT). No. of bitstreams: 1 ANDRÉ AIRES DE FARIAS - TESE (PPGRN) 2016.pdf: 5737610 bytes, checksum: 24b094da2cef8f2db3a8552a03764f80 (MD5) Previous issue date: 2016-02-26 / Capes / Objetivou-se identificar e analisar os períodos de secas na sub-bacia hidrográfica do Rio Taperoá (SBHRT) e os impactos sociais, econômicos e ambientais e ações de convivência com a seca de 2012-2014 no município de Taperoá - PB. Dados pluviométricos, série 19632014, foram utilizados para analisar o regime de precipitação da sub-bacia; e a severidade dos anos secos, por meio do Índice padronizado de precipitação. A identificação dos impactos foi realizada utilizando-se o método de listagem descritiva check-list, questionários, dados bibliográficos e documentais. Para analisar as variáveis socioeconômicas e as ações de convivência foram utilizados os mesmos materiais dos impactos, exceto o check-list. O período chuvoso dos municípios da sub-bacia ocorre de janeiro a maio, precipitações menores do que a média nesses meses causaram graves impactos. Verificou-se que a maioria das secas que ocorreram na SBHRT se enquadram na categoria moderada, seguido por severa e extrema. A SBHRT foi atingida por secas severas e extremas durante todas as décadas analisadas, no entanto, o maior número delas ocorreu nas décadas de 1980, 1990, 2000 e 2010. A seca mais grave foi a de 1998-2000, seguido pela de 1979-1985. A seca de 20122014 não foi a mais grave porque a precipitação foi acima da ocorrida no período de 19982000 e 1979-1985, houve também maior investimento em ações de convivência com as secas e programas sociais implantados pelos governos. Os impactos sociais, econômicos e ambientais da seca de 2012-2014 no município de Taperoá-PB foram: problemas de saúde relativos à baixa disponibilidade hídrica, desigualdade na distribuição de recursos durante a seca, desgaste mental, reduções na alimentação da população, conflitos entre usuários de água, aumento da pobreza, migrações populacionais, redução da pecuária e da produção de culturas, aumento do desemprego, elevação dos custos para transportar água, indisponibilidade de alimentos para animais, perturbação dos ciclos de reprodução, redução de recreação e turismo, prejuízos à flora, à fauna e às espécies piscícolas, e redução da qualidade da água. Os impactos continuaram porque faltou recursos financeiros para implantar programas e as políticas públicas de convivência não foram efetivas, só aparecendo com maior intensidade quando a região estava prejudicada pela seca. Para redução dos impactos é necessário aumentar o número de cisternas, principalmente a calçadão. É necessário também perfurar poços e construir açudes, além de fazer manutenção nos que estejam com capacidade reduzida ou desativados, construir barragens subterrâneas e tanques naturais, terminar e colocar em funcionamento a Transposição do Rio São Francisco, incentivar a gestão dos recursos hídricos, criar programas que visem o fortalecimento da agricultura familiar, incentivando a fenação, silagem, meliponicultura, apicultura, criação de animais e plantas adaptados à região, dentre muitos outros. / This study aimed to identify and analyze the periods of droughts in sub-basin hydrographic of the Taperoá River (SBHTR) and the social, economic and environmental impacts and living actions with drought from 2012-2014 in the municipality of Taperoá - PB. Rainfall data, serie 1963-2014, were used to analyze the sub-basin rainfall regime; and the severity of the dry years, through the Standardized Precipitation Index. The identification of social, economic and environmental impacts was performed using the method of descriptive listing check-list, questionnaires, bibliographic and documentary data. To analyze the socioeconomic variables and of actions of living together were used same materials of the impacts, except the checklist. The rainy period in the municipalities of the sub-basin occurs from january to may, precipitations lower than average in these months caused severe impacts. It was found that most of droughts in SBHRT occurred into the category moderate, following by severe and extreme. The SBHRT was hit by severe and extreme dried for all analyzed decades, however, as many of them occurred in the decades of 1980, 1990, 2000 and 2010. The most severe drought was the from 1998-2000, followed by 1979-1985. The drought of 2012-2014 was not the more serious because the precipitation was above occurred in 1998-2000 and 1979-1985 period, there was also greater investment in coexistence actions with droughts and social programs implemented by governments. The social, economic and environmental impacts of the drought of 2012-2014 in the municipality of Taperoá-PB were: health problems of low flow, unequal distribution of resources during the drought, mental strain, reductions in food supply, conflicts water users, increasing poverty, population migration, reduction of livestock and crop production, rising unemployment, higher costs for transporting water, unavailability of feed, disruption of reproductive cycles, reduction of recreation and tourism, losses in flora, fauna and fish species, and reduced water quality. The impacts continued because they lack financial resources to implement programs and public coexistence policies were not effective, only appearing with greater intensity when the region was hampered by drought. To reduce the impacts is to increase the number of cisterns, especially the boardwalk. You also need to drill wells and build dams, in addition to maintenance on that are with reduced or deactivated capacity, building underground dams and natural ponds, finished and put into operation the Transposition of the São Francisco River, encourage the management of water resources, create programs aimed at strengthening family farming, encouraging haymaking, silage, beekeeping, meliponiculture, husbandry of animals and plants adapted to the region, among many others.

L’impact de l’homme sur l’environnement mondial et sur la diversité et le fonctionnement des écosystèmes terrestres fait l’objet d’une attention croissante. De nombreuses études ont évalué les effets de facteurs du changement global tels sur les processus de cycle de l'azote du sol dans les prairies. Cependant, ces études n'ont pas pris en compte le fait que la modification du régime de précipitations avait également une influence sur le régime de dépôt d'azote. En outre, la réponse du cycle de l'azote dans les sols des prairies à de multiples facteurs du changement global agissant ensemble et parfois en même temps que des perturbations telles que les incendies, doit encore être étudiée. Cela limite fortement notre capacité à comprendre et à prévoir les effets du changement global sur les prairies. Dans ce travail de doctorat, deux expériences ont été menées: (i) une expérience en mésocosme pour évaluer les effets combinés d'une augmentation des dépôts d'azote et de changements dans la quantité et la fréquence des précipitations sur le cycle de l'azote édaphique dans une prairie semi-aride; (ii) une expérience in situ pour évaluer les effets combinés de l'augmentation de la concentration en CO2, du réchauffement, d’une modification des précipitations, du dépôt d'azote et d’un feu sur le cycle de l'azote du sol dans une prairie méditerranéenne. Cela permet d'étudier les effets de la combinaison de plusieurs facteurs de changement global (et d’une perturbation feu) sur l'abondance des communautés microbiennes du cycle de l'azote.Les groupes microbiens étudiés étaient les bactéries et les archées oxydant l'ammoniac (AOB et AOA, respectivement), les réducteurs de nitrite porteuses des gènes nirK ou nirS, et les réducteurs de N2O porteurs des gènes nosZI- et nosZII, plus les bactéries oxydant le nitrite du genre Nitrobacter et Nitrospira pour la prairie méditerranéenne. Les principaux résultats et conclusions sont les suivants: 1) Les réactions des différents groupes de (dé)nitrifiants aux scénarios de changement global différaient fortement quel que soit le type de prairie. Les AOB étaient principalement dépendant de la disponibilité en azote En revanche, dans les deux prairies, les AOA étaient plus sensibles à la dynamique de l'eau du sol que la dynamique de l'azote. L'abondance des Nitrobacter étaient principalement affectée par les facteurs de changement global affectant l'abondance de l'AOB, tandis que l'abondance des Nitrospira était davantage liée aux changements d'abondance des AOA dans la prairie méditerranéenne. 2）Dans la prairie californienne où deux dépôts d'azote élevés avaient lieu chaque année, l'effet de l'azote dominait les effets du changement global. En revanche, dans la prairie chinoise, les dépôts d’azote simulés par des apports chroniques couplés aux événements de précipitation n’augmentaient pas l’abondance des dénitrifiants et ne faisaient que légèrement augmenter les émissions de N2O. 3） Pour les deux prairies, l'interaction entre les facteurs du changement global sur le cycle de l'azote du sol ne pouvait pas être prédite simplement en étudiant les effets d'un ou de deux facteurs. Ces effets interactifs ont pu être expliqués par des effets sur des variables environnementales clés telles que l'humidité du sol, la disponibilité de l'azote minéral, le pH et la croissance des racines. Ces résultats démontrent qu'il est impossible de prédire comment les (dé)nitrifiants et la (dé)nitrification répondent aux scénarios de changement global impliquant de multiples facteurs uniquement à partir de la connaissance d'effets de facteurs étudiés isolément. Cela nécessite donc des études plus approfondies dans le domaine de la biologie des changements globaux. La modélisation et l'évaluation de la généralité de ces effets d'interaction complexes constituent donc une priorité majeure pour les chercheurs qui veulent prédir les réponses du cycle de l'azote dans le sol au changement global et les rétroactions sur le climat. / The impact of global environmental changes on the diversity and functioning of terrestrial ecosystems has received increasing attention. Many studies evaluated the effects of single -and less often multiple- global change factors on soil N cycling processes in grasslands. However, these studies have not recognized that altered precipitation regime also has an influence on wet N deposition regime. Further, the response of grassland soil N cycling to co-occurring multiple global change factors and disturbance like fire, and how N cycling response to fire could differ under different global change scenarios, remains unclear. This strongly restricts our ability to understand and predict global change effect on grasslands. In this work, two experiments were conducted: (i) a mesocosm experiment to assess the combined effects of increased N deposition and changes in both the amount and frequency of rainfall on soil N cycling in a semi-arid Monsoon grassland; and (ii) an in situ experiment to assess the combined effects of elevated CO2, warming, increased precipitation, N deposition and fire on soil N cycling in a Mediterranean grassland. This allows studying the -possibly interactive- effects of several global change factors on the abundances of soil N-cycling microbial communities. The microbial groups studied were ammonia oxidizing bacteria and archaea (AOB and AOA, respectively), nirK- and nirS-nitrite reducers, nosZI- and nosZII-N2O reducers, plus Nitrobacter and Nitrospira for the Mediterranean grassland. The main results and conclusions are: 1）The responses of different groups of soil (de)nitrifiers to global change scenarios differed strongly regardless the grassland type. AOB were mostly driven by N. In contrast, AOA were more sensitive to soil water dynamics than N dynamics in both grasslands. Nitrobacter abundance was mostly affected by global change factors through their effects on AOB abundance, whereas Nitrospira abundance was more related to changes of AOA in the Mediterranean grassland. Similarly, nirK- and nirS-harboring nitrite reducers and nosZI-harboring N2O reducers were more sensitive to N deposition than nosZII-harboring N2O reducers, and nirK- and nirS-bacteria positively responded to reduced precipitation. This highlights niche differentiation between them and indicates that the balance between them may be altered in the future; 2）In the Mediterranean grassland, where high N deposition was simulated by two N addition events each year, the N effect dominated global change effects. In contrast, in the Monsson grassland, chronic wet N deposition did not increase denitrifier abundance and only weakly increased soil N2O emissions. This was explained by the efficient capture of added N by the dominant grass species and by the increased plant growth leading to increased transpiration and decreased soil moisture. 3）For both grasslands, the interaction between global change factors on soil N cycling could not be predicted simply by studying the effects of one or two factors. These interactive effects were explained by effects on key environmental variables like soil moisture, mineral N availability, pH and belowground plant growth.These results demonstrates the limitation of predicting how (de)nitrifiers respond to global change scenarios involving multiple factors only from studying single factor effects. Particularly, interactive effects were observed between N deposition, decreased precipitation amount and altered precipitation frequency in the Monsoon grassland; and between fire, N deposition, warming, elevated precipitation and elevated CO2 in the Mediterranean grassland. This calls for more comprehensive studies in the global change biology domain. Modelling and evaluating the generality of these complex interaction effects is thus a high priority for research to predict the responses of soil N cycling processes to global change and feedbacks on climate in the future