xiv, 219 p. : ill. (some col.) A print copy of this title is available through the UO Libraries. Search the library catalog for the location and call number. / This dissertation examines popular responses to property rights reforms in Mexico by comparing two ejidos in the southeastern state of Yucatan. As part of a series of neoliberal reforms enacted in the 1980s and 1990s in Mexico, the federal government altered the existing property rights regime to enable the division and privatization of previously protected communal land. I argue that the responses to the reforms were contingent on the historical development of institutional rules, political and economic practices, and cultural values. In the first case study, Mani­, ejidatarios accepted the new rules while simultaneously expressing concern over changes in the process of becoming an ejidatario, a rights holder making land tenure decisions. Community members used the new rules to guarantee access to land and the ejido system by purchasing individualized parcelas of ejido land in part because they gained material benefits, such as secure access to state-funded irrigation systems. The rise in the remittance-economy and population pressures increased local demand for land and provided the income for local buyers. In Hunucma, the other case study, ejidatarios contested the state-imposed rules as violations of their traditional usos y costumbres. They fought against land sales for the construction of a new airport, rejecting the legitimacy of the formal property system because the new rules had been manipulated by state officials and land speculators. In doing so the ejidatarios revived and re-deployed historical cross- ejido alliances and habits of militancy and mobilization. Both cases reveal that property rights regimes are more than institutions but rather political configurations of control over resources, whereby the distribution of rights and subjective interpretation of the rules and practices determine local responses. / Adviser: Dennis Galvan

In Spanish Colonial America, as well as in the Iberian Peninsula at the same time, different jurisdictions intertwined in the same space. By way of consequence, the complex political organization of the New World was composed, at the local level, by the Indian and Spanish Councils, the doctrines, and the provincial structures called corregimientos. Although the officials of those institutions received precise instructions, in which the Spanish Crown defined and limited their functions, tensions were common between the Indian governors, the clergymen, the Spanish Councils’ officeholders, and the Spanish provincial magistrates, or corregidores. The present article will analyze a series of lawsuits that occurred in sixteenth century Yucatan and in which those authorities were implicated, in order to highlight not only the nature of the jurisdictional conflicts, but also the modalities of their resolution at stake in the Spanish Empire’s courts of justice. Special emphasis will be put on the jurisdiction of the Maya Councils with the objective of better understanding the scope of indigenous agency in Spanish Colonial America. We argue that the local control on the one hand, and the legal representation on the other, were key elements in these processes. / Al igual que en la península ibérica, en la América colonial se superpusieron distintas jurisdicciones en el mismo espacio, de modo que el complejo entramado político del Nuevo Mundo estaba conformado, a nivel local, por los cabildos indígenas y españoles, las doctrinas y los corregimientos. Aunque los representantes de aquellas instituciones recibieron detalladas instrucciones en las que la Corona española definía y limitaba sus funciones y prerrogativas, fueron frecuentes las tensiones entre los gobernadores indígenas, los alcaldes ordinarios, los curas beneficiados y los corregidores. A partir de una serie de pleitos en los que estuvieron involucradas estas autoridades, el presente trabajo analiza tanto la naturaleza de los conflictos jurisdiccionales que tuvieron lugar en el Yucatán del siglo XVI como las modalidades de su resolución en los foros de justicia de la Monarquía hispana. Se presta especial atención a la jurisdicción de los cabildos mayas con el fin de esclarecer el alcance de la participación indígena en el sistema político del Imperio hispánico. Consideramos que el control local, por un lado, y la representación legal, por otro, resultan fundamentales para comprender aquellos fenómenos.

La présente recherche étudie le déploiement de la domination hiérarchique de l’Etat mexicain dans ses espaces territoriaux au niveau local. Elle se concentre sur le cas de l’état fédéré du Yucatán. Dans l’ordonnancement politico-administratif des états fédérés du Mexique, on insère progressivement une figure intermédiaire entre le gouverneur et les municipalités, le jefe político, insertion parachevée dans le dernier quart du XIXème siècle. Celui-ci est, d’une part, l’agent de l’autorité étatique au niveau départemental (partidos) et, d’autre part, l’intermédiaire formel entre l’exécutif, les municipalités et la société, caisse de résonance des demandes locales. La bipolarité de la charge et sa nature foncièrement relationnelle permettent d’examiner l’imbrication, plutôt que l’opposition entre déploiement étatique et réalités non étatiques dans la construction de l’Etat mexicain au niveau local, afin d’élucider la spécificité de cet Etat et d’expliciter les mécanismes par lesquels le régime porfirien a pu se pérenniser en s’adaptant aux réalités socio-politiques existantes tout en les mettant à son service. / This research studies the establishment of the hierarchical power of the Mexican State in its territories on the local scale. It focuses on the case study of the federated state of Yucatán. An intermediary civil official, the jefe político is introduced step by step between the governor and the municipal powers, this institution is achieved during the last quarter of the 19th century. He is, on the one hand, the agent of the state authority in the partidos (districts) and, on the other hand, the official intermediary between the executive power, the municipal authorities and the society, as the voice of the local requests. This double-acting office, essentially based on public relations, enables us to analyze the imbrications rather than the contrasts between the State establishment and the non-state powers in the Mexican State building, in order to clear up the specific character of the Mexican State and to explain the mechanisms by which the porfirian government could last in time by adapting to the existent socio-political actors and by using them into its service.

Background: Coastal ecosystems in Mexico remain understudied in spite of their ecological, economic and conservation value and are being impacted by human activities along the coast. Knowledge on spatial patterns of plant species distribution that helps preserve these fragile ecosystems is crucial. Aims: We evaluated differences in species richness, species diversity and species dominance patterns in 16 plant communities as well as the degree to which differences were driven by climatic conditions in sandy dunes in Yucatán. We evaluated the importance of invasive species in mediating patterns of species diversity and species dominance patterns. Results: We found wide variation in plant species richness, species diversity and species dominance patterns among communities that stems from broad climatic differences along dune systems. Invasive plants represent almost one-third of total species richness and seem to be drastically changing the species dominance patterns in these communities. Conclusions: Regional climatic differences along the Yucatán north coast seems to be a major driver of plant diversity and species composition. Our findings suggest that invasive plants have successfully colonised and spread along the coast over the past 30 years. Even though invasive species do not alter spatial patterns of species diversity, they are becoming more dominant with potential detrimental consequences for native plants.

The disintegration of the Classic Maya throughout the Terminal Classic (750-900 C.E.) is a complex loss of human population that has presented many questions about climate change and its impact on humanity. With droughts proposed as a prominent cause, understanding the quality and availability of groundwater resources at the time is pivotal to further determining the spatial and temporal distributions of population deterioration. The Yucatan aquifer consists of karstic cave systems, with a small number of inland lakes, which have previously been termed closed to the aquifer. It is important to understand how both of these types of water bodies react to long- and short-term forcing mechanisms such drying climate, sea-level rise and precipitation events. Using a variety of spatial and temporal records to determine aquifer evolution, changes and connectivity throughout the Holocene it will further understanding of how the aquifer reacts to changes in climate and the implications this may have had on the Classic Maya. Four sediment cores from Pac Chen Lake and two sediment cores from Carwash Cenote were collected to investigate Holocene paleoclimatic trends on the Yucatan Peninsula in Mexico. Records of past climate, groundwater conditions and flooding history at both sites were determined through microfossil and micro X-Ray fluorescence data. In Pac Chen Lake, elevation and timing of flooding of the lake coincided with sea-level rise. Using Ti, Fe and K records to determine wet vs dry conditions, dry periods through the terminal classic coincided with other paleoclimate records, but with no evidence of draw-down within the lake. Both of these observations imply connection of the lake to the aquifer. The Cl record from Carwash was used alongside a core from the Yax Chen cave system to observe spatial and temporal potability of the aquifer. An overall freshening trend in the coastal groundwater occurred throughout the Holocene. The largest amount of this freshening transpired through the Terminal Classic. At this time, populations inland were experiencing deterioration, while coastal populations along the coast continued to survive. Comparing Cl records at various depths and distances from the coast proved that Cl is impacted by proximity to the halocline. / Thesis / Master of Science (MSc)

Harmful Algal Blooms (HABs) in the Gulf of Mexico (GOM) are natural phenomena that can have negative impacts on marine ecosystems on which human health and the economy of some Gulf States depends. Many of the HABs in the GOM are dominated by the toxic dinoflagellate Karenia brevis. Non-toxic phytoplankton taxa such as Scrippsiella sp. also form intense blooms off the Mexican coast that result in massive fish mortality and economic losses, particularly as they may lead to anoxia. The main objectives of this dissertation were to (1) evaluate and improve the techniques developed for detection of Karenia spp. blooms on the West Florida Shelf (WFS) using satellite remote sensing methods, (2) test the use of these methods for waters in the GOM, and (3) use the output of these techniques to better understand the dynamics and evolution of Karenia spp. blooms in the WFS and off Mexico. The first chapter of this dissertation examines the performance of several Karenia HABs detection techniques using Moderate Resolution Imaging Spectroradiometer (MODIS) satellite images and historical ground truth observations collected on the WFS from August 2002 to December 2011. A total of 2323 in situ samples collected by the Florida Fish and Wildlife Research Institute to test for Karenia spp. matched pixels with valid ocean color satellite observations over this period. This dataset was used to systematically optimize variables and coefficients used in five published HAB detection methods. Each technique was tested using a set of metrics that included the F-Measure (FM). Before optimization, the average FM for all techniques was 0.47. After optimization, the average FM increased to 0.59, and false positives decreased ~50%. The addition of a Fluorescence Line Height (FLH) criterion improved the performance of every method. A new practical method was developed using a combination of FLH and Remote Sensing Reflectance at 555 nm (Rrs555-FLH). The new method resulted in an FM of 0.62 and 3% false negatives, similar to those from more complex techniques. The first chapter concludes with a series of recommendations on how to improve the detection techniques and how to take these results a step further into a Gulf wide observing systems for HABs. In chapter two, ocean color techniques were used to examine the extension, evolution and displacement of four Karenia spp. events that occurred in the WFS between 2004 and 2011. Blooms were identified in the imagery using the new Rrs-FLH method and validated using in situ phytoplankton cell counts. The spatial extension of each event was followed in time by delineating the blooms. In 2004 and 2005, the WFS was affected by a series of hurricanes that led to high river discharge and intense sediment resuspension events. Both processes had an impact on HAB occurrence. For example, I tracked a Karenia spp. bloom found in late December 2004 approximately 40-80 km offshore Saint Petersburg, which then expanded reaching an extension of >8000 km2 in February 2005. The bloom weakened in spring 2005 and intensified again in summer reaching >42,000 km2 after the passage of hurricane Katrina in August 2005. This bloom covered the WFS from Charlotte Harbor to the Florida Panhandle. Two other cases were studied in the WFS. The results of the Hybrid Coordinate Ocean Model from the U.S. Navy aid understanding the dispersal of the blooms. During fall 2011, three field campaigns to study HABs in Mexico were conducted to do an analysis of optical properties and explore the possibility of using ocean color techniques to distinguish between the main phytoplankton blooms in that region. Three main bloom scenarios were observed in the Campeche Bank region: massive diatom blooms, blooms dominated by Scrippsiella spp., and Karenia spp. blooms. The normalized specific phytoplankton absorption spectra were found to be different for Karenia spp. and Scrippsiella sp. blooms. A new technique that combines phytoplankton absorption derived from MODIS data and the new technique developed in Chapter One showed potential for a detection technique that can distinguish between Karenia and Scrippsiella blooms. Additional work is needed to improve the new technique developed for Mexican waters, but results show potential for detection techniques that can be used Gulf-wide. This will help better understand the dynamic and possible connectivity of phytoplankton blooms in the GOM.

Background: Tropical sand dunes are ideal systems for understanding drivers of community assembly as dunes are subject to both deterministic and stochastic processes. However, studies that evaluate the factors that mediate plant community assembly in these ecosystems are few. Aims: We evaluated phylogenetic community structure to elucidate the role of deterministic and stochastic processes in mediating the assembly of plant communities along the north of the Yucatan Peninsula, Mexico. Methods: We used plastid genetic markers to evaluate phylogenetic relationships in 16 sand-dune communities. To evaluate the role of climate in shaping plant community structure we carried out linear regressions between climatic variables and mean phylogenetic distance. We estimated the Net Relatedness Index and Nearest Taxon Index to identify ecological processes mediating community assembly. Results: Observed phylogenetic structure was not different from random, suggesting that stochastic processes are the major determinants of community assembly. Climate was slightly correlated with phylogenetic diversity suggesting that abiotic environment plays a minimal role in community assembly. Conclusions: Random assembly appears to be the primary factor structuring the studied sand dune plant communities. Environmental filters may represent a secondary factor contributing to the observed phylogenetic structure. Thus, both processes may act simultaneously to mediate the assembly of sand-dune plant communities.

No description available.

Bahia de la Ascension (BA) is a pristine, shallow, karst bay located in the Mexican Caribbean, a region experiencing rapid population growth stimulated by intense tourism development. The overall objective of this study was to address the natural hydrographic variability of this inherently vulnerable ecosystem and assess its influence on a key habitat, the seagrass. The chapters follow the three-branched nature of the study which tackled the connected ecosystem issues of coastal hydrology, physical dynamics of flow and circulation, and the ecological dynamics of the seagrass species Thalassia testudinum in BA. Freshwater input to BA is primarily by submerged groundwater discharges and surface runoff; both sources are derived from fissures in the aquifer but feature distinct water quality due to the interaction with adjacent wetlands. Hurricanes explain 36 percent of the interannual precipitation variability in the region. The water balance indicates a persistent net outflow from BA to the adjacent shelf, suggesting an intense exchange across inlets. Both diurnal and semidiurnal tidal frequencies are attenuated in the inner bay, where a meteorologically-induced subtidal water level increase may occur during four-day southeasterly winds. A clear SW-NE salinity gradient was established during dry and rainy seasons, with a strong tidally-driven marine influence throughout the central basin, and a perennial mesohaline ambient in the southwestern-most bay, where hydrodynamics are primarily controlled by wind stress. Thalassia testudinum is the dominant seagrass species in BA, occupying ~90 percent of the substrate, including the freshwater-influenced inner bay. High nutrient inputs, including phosphorus which might have limiting effects in karst environments, along with the wind-driven circulation controlling water residence times are associated with the successful development of T. testudinum (up to 1,461.23 g DW m-2) within the SW bay. Farthest into the central basin, Thalassia consistently exhibited an inverse correlation between abundance and density of shoots. This pattern was enhanced under exceptional precipitation and inputs of denuded organic matter resulting from hurricanes making landfall on this region. The relationship between nutrient distribution and the above/belowground ratio suggested that Thalassia growing in BA favors the development of the aerial component as nutrients availability increases. This study provides a basic understanding of the most important processes molding the patterns of variability exhibited by T. testudinum in Bahia de la Ascension. The salinity gradient and external nutrient supply, along with the hydrodynamic component, define the spatial scale at which the connectivity between the adjacent wetland, the bay, and the shelf may occur.

No description available.