The Tropical savannas of central Brazil (cerrado) and the Everglades wetland (Florida) ecosystems are ideal systems to study landscape spatial mosaics and their interactions. Both ecosystems show a variety of plant physiognomies distributed within small spatial scales and elevation gradients. Such variety of plant physiognomies provide an opportunity to investigate the roles of climate, topography, nutrient availability and water table dynamics as determinants of plant physiognomic distributions, and their role in shaping regional systems. South Florida Wetlands and the tropical savannas of central Brazil are examples of hydrologically-controlled ecosystems. In hydrologically-controlled ecosystems water sources, the availability of nutrients, and the patterns of water movement play important roles in determining vegetation structure and function. The main objective of this study was to understand ecosystem level processes that shape different physiognomies in two hydrologically-controlled ecosystems. I conducted field work at the IBGE ecological reserve, a field experimental station located in Brasilia, Brazil. I also worked at the Everglades National Park in an area located near the south entrance of the Park in Homestead, Florida. I carried out three interconnected studies investigating water and nutrient dynamics: (1) In a Brazilian savanna I manipulated levels of litter input and measured changes to soil properties, organic matter decomposition and tree growth. I found that changes in litter input affect soil physicochemical properties and soil biochemical processes. I also found that litter dynamics influence tree growth through their effects on soil physicochemical properties. (2) I also studied the effect of water table depth and its temporal variation on spatial patterns of vegetation distribution in the cerrado landscape. I monitored diurnal and seasonal changes in water table depth along two tree-density and topographic gradients. In addition, I measured woody species composition, growth rates of four tree species, litter production, soil nutrients, and nutrient resorption efficiency along those two gradients. I found that water table depth has an important role in determining the spatial distribution of cerrado physiognomies; it also affects tree growth, species composition and nutrient resorption efficiency. (3) In the Everglades I studied patterns of underground water uptake by two vegetation types. I monitored seasonal and diurnal changes in water table depth in a Hammock forest, in a stand dominated by the invasive woody species Schinus terebinthifolius, as well as the water level in an adjacent lake. I estimated stand level transpiration using two different approaches: with sap flow measurements and diurnal oscillations in water table levels. Then, I calculated the total quantity of groundwater withdrawn by evapotranspiration for the wet and dry seasons in the Hammocks and in the exotic invaded site and then compared the results. I found that water uptake by Everglades trees is well coupled to diurnal changes in water table depth and that the amount of water withdrawn from the groundwater was larger during the wet season than during the dry season. Finally, I detected hydrological feedbacks between different vegetation types and nearby bodies of water. Results of this study contributes to the current knowledge of ecosystem level processes in tropical and subtropical ecosystems where water circulation and water availability play a dominant role in shaping vegetation structure and function.

The Florida Everglades ecosystem is threatened by human development, increased pollution, freshwater scarcity, and invasive species; factors that have negatively impacted the Everglades and native species health and populations. Man-made canals and levies have redirected the natural flow of fresh water from Lake Okeechobee into the Florida Everglades, starving central and south Florida ecosystems of necessary fresh water and nutrients. Through the efforts of the Comprehensive Everglades Restoration Project (CERP), freshwater is being redirected back into central and south Florida, returning the sheet flow of water back into the Everglades. Monitoring species abundance in the Everglades is a beneficial conservational tool for assessing restoration efforts from CERP. As a semi-aquatic apex predator, river otters (Lontra canadensis) are a useful health bio-indicator for the Florida Everglades. In order to conduct future population studies of river otters in the Florida Everglades, it must first be ascertained where they can be found and what time of year they are most likely to be sighted. For this study, Moultrie infrared game cameras were used to photograph the presence or absence of river otters within the five main habitats in the Everglades; the pinelands, hardwood hammock, cypress swamp, marsh prairie, and mangrove estuary at two protected areas in the Florida Everglades (Big Cypress National Preserve and Fakahatchee Strand State Park). River otters were most frequently sighted in the hardwood hammock habitat, but were also found in the cypress swamp. The large majority of river otter sightings occurred during dry season, which is thought to be a function of restricted water availability and aquatic mobility. Future population studies of river otters would be most productive in the hardwood hammock and cypress swamp habitats during dry season. Game camera images along with field opportunistic sightings, resulted in a variety of species documented. This provided valuable information of species richness and distribution within and amongst the habitats. The hardwood hammock was found to be the most species rich habitat, having over half the species observed in the study in this habitat. The Aves class was the most abundantly observed in the Everglades, and was most frequently sighted during the dry season. As a refuge for migratory birds, the Everglades house the majority of bird species during the winter months, which occur during dry season. The Aves class was most frequently sighted in the pinelands habitat during dry season. This habitat, being the highest in elevation and therefore the driest, shows a stronger resemblance to most northern bird habitats then does the water-saturated wetlands found throughout the Everglades. The mangrove estuary was the most commonly occurring outlier, having the least species overlap when compared to the other habitats. All other habitats in the Everglades are freshwater wetlands, while the mangrove estuary is a brackish environment, which limits the species that are unable to tolerate saline conditions. Further studies of species abundance throughout the Everglades will aid in monitoring CERP restoration efforts over time.

SOUZA, Maria Rodrigues de. Traçando destinos, entrecruzando territórios: sociabilidade dos redeiros de Patos-PB. 2004. 163f. Dissertação (Mestrado em Sociologia) – Universidade Federal do Ceará, Departamento de Ciências Sociais, Programa de Pós-Graduação em Sociologia, Fortaleza-CE, 2004. / Submitted by Liliane oliveira (morena.liliane@hotmail.com) on 2011-12-06T11:16:22Z No. of bitstreams: 1 2004_DIS_MRSOUZA.pdf: 812716 bytes, checksum: 2f6721e1286fb2cb070dcb4f87a7f777 (MD5) / Approved for entry into archive by Maria Josineide Góis(josineide@ufc.br) on 2012-01-09T12:42:59Z (GMT) No. of bitstreams: 1 2004_DIS_MRSOUZA.pdf: 812716 bytes, checksum: 2f6721e1286fb2cb070dcb4f87a7f777 (MD5) / Made available in DSpace on 2012-01-09T12:42:59Z (GMT). No. of bitstreams: 1 2004_DIS_MRSOUZA.pdf: 812716 bytes, checksum: 2f6721e1286fb2cb070dcb4f87a7f777 (MD5) Previous issue date: 2004 / In this work I analyse forms of sociability among hammock sellers from Patos, PB, including living experiences with their marital partners, using the methodology of interviews and the direct observation of aspects of their daily lives. The theoretical perspective has as main founts: (1) contributions done by Marcel Mauss on the theme of sociability nets, which are built around structures of giving and reciprocity; (2) the contributions done by Bourdieu on the theme of honour among the Kabila; (3) the contributions done by Simmel, with his discussion on sociability forms. In order to understand the social organisation of hammock sellers and theirs wives in the context of hammocks and other sales and other craft-works sales, I used the ethnographic method and did semi-structured interviews. Besides it I made direct observation and participated in informal chats between hammock sellers I chose, in order to have some life stories. Among the main outcomes of my research I bring out the following: (1) the honour of the hammock sellers from Patos-PB is built with reference to the debt logic; (2) the sociability of hammock sellers is determined by the imposed reciprocity of debt, which helps them in building and make strong social links; (3) the hammock sellers honour expresses itself in varied forms according to the different places in which hammock sellers circulate. It varies as well as a function of social roles they play at the community. / Neste trabalho analiso as formas de sociabilidade dos redeiros de Patos-PB, incluindo as vivências com seus cônjuges, a partir da observação e mergulho nos aspectos do cotidiano de suas vidas. A perspectiva teórica adotada tem como principais matrizes:os conceitos de dádiva e reciprocidade na constituição de redes de sociabilidade (MarcelMauss0; a noção de honra (Bourdieu)e forma de sociabilidade (Simmel) (1) a contribuição de Marcel Mauss, com sua discussão relativa às redes de sociabilidade constituídas em torno das estruturas de dádiva e de reciprocidade; (2) a contribuição de Bourdieu, em seus estudos sobre a honra entre os Kabilia; (3) a contribuição de Simmel, com sua discussão a respeito das formas de sociabilidade. Para compreender a organização social dos redeiros-vendedores e das suas mulheres no contexto das vendas das redes, cangas e mantas, bem como as maneiras pelas quais eles constroem e reconstroem as mais diversas formas de sociabilidade e trabalho frente a outros sujeitos sociais nos múltiplos espaços por onde transitam ao efetivarem suas vendas, utilizei a etnografia como metodologia, realizando entrevistas semi-estruturadas, conversas informais, observação participante e sistematizando algumas histórias de vida. Dentre as principais conclusões do trabalho destaco as seguintes: (1) a honra entre os redeiros de Patos-PB é construída a partir da lógica da dívida; (2) a sociabilidade dos redeiros é determinada pela reciprocidade obrigatória da dívida, que favorece a construção e fortalecimento de laços sociais; (3) a honra se expressa de várias formas nos diferentes lugares e papéis sociais ocupados e desempenhados pelos redeiros na relação da dádiva