Dissertations / Theses on the topic 'National Park of Upper Niger'

La gestion des aires protégées en Guinée pose le problème de la cohabitation des politiques publiques et des systèmes traditionnels. Censée améliorer la gestion des aires protégées, cette cohabitation s'avère difficile et ne produit pas les résultats escomptés. Pour contribuer à la compréhension de cette difficile cohabitation, cette thèse propose une analyse de l'évolution de la politique de gestion des aires protégées en Guinée, de l'époque précoloniale à nos jours. La démarche utilisée fait appel à plusieurs approches méthodologiques : recueil et analyse de documents historiques et juridiques, recueil et analyses des traditions orales ancestrales relatives à la protection de la nature, observations de terrain, inventaires floristiques, estimations et analyses qualitatives, enquêtes par entretiens semi-directifs. Les résultats obtenus ont permis de retracer et de caractériser les différentes phases de la gestion des aires protégées en Guinée. La gestion des aires protégées précoloniales a connu diverses formes, allant de la sacralisation à la gestion clanique ; elle a varié en fonction des coutumes des populations autochtones de chacune des régions naturelles du pays. Pendant l'époque coloniale, 167 aires protégées ont été mises en place dont 157 forêts classées, 4 parcs de refuge de faune et une réserve naturelle intégrale. A son accession à l'indépendance en 1958, la Guinée a hérité des aires protégées coloniales et a appliqué, jusqu'en 1984, une politique fondée sur la législation forestière de l'administration coloniale. L'Etat s'est approprié les aires protégées dans leur contexte contemporain seulement à partir des années 1984, et a progressivement mis en place de nouveaux dispositifs (législatif et institutionnel) de gestion. Avec l'appui des bailleurs de fonds, il a mis en place plusieurs catégories d'aires protégées (parcs nationaux, réserves de biosphère, aires protégées transfrontalières, zone de conservation) dont la gestion qui se veut participative en associant les populations locales, soufre aujourd'hui essentiellement du manque de financements associé à l'insuffisance de la logistique nécessaire à une gestion opérationnelle et efficace. L'étude du cas du Parc National du Haut Niger révèle que, malgré la reconnaissance et la prise en compte du rôle des communautés traditionnelles (Waton), les populations locales adhèrent à la gestion participative sans grande conviction. Les structures publiques associées à cette gestion ne disposent pas de moyens suffisants pour intervenir de manière efficiente. L'exemple du PHNN illustre l'écart entre le discours dominant qui prône la gestion intégrée des aires protégées et les difficultés de l'Etat à mettre en œuvre une gestion participative. Ces difficultés ne devraient pas pour autant conduire à une remise en cause de la gestion participative, car nos observations et nos enquêtes suggèrent que la stratégie peut fonctionner et faire la preuve de son efficacité si des efforts sont entrepris dans l'appui au développement communautaire et dans la création d'activités génératrices de revenus pour les populations traditionnelles qui mettent leurs savoirs au service de la gestion des aires protégées.

A series of small mud mounds are exposed in the McConnell and Miette thrust sheets on the southern flank of the Miette reef complex. They occur on the southeastward inclined carbonate clinoforms of the late Frasnian Arcs Member. These mounds are rooted on marine, argillaceous lime mudstones and are surrounded by lime mudstones of several prograding clinoforms of the upper Arcs Member or dolomitic siltstones of the lower Ronde Member.
Mounds are approximately 17 to 36 m high and 32 to 81 m wide and columnar to domal in shape. The lower part of the mounds consists of sponge-rich wackestones and packstones, and locally laminar stromatoporoid boundstones. Calcareous green algae tend to predominate in the upper parts of the mounds.
Variable cavities occur and are filled with geopetal sediments, isopachous fibrous and blocky calcite cements. The most common cavity types, irregular and irregular stromatactoidal cavities, might be related to organic origins, possibly the decay of sponges in conjunction with submarine cementation.
Abrupt mound margins indicate that the mounds grew upwards more rapidly than the accumulation of the adjacent basin and clinoforming slope sediments. (Abstract shortened by UMI.)

The patch reefs located in Biscayne National Park (BNP) are some of the most northern reefs of the Florida reef system. The focus of my study is seven patch reefs that were first surveyed annually between 1977 and 1981, revealing 8% - 28% cover by scleractinian corals. An assessment of BNP patch reefs completed in 2000 reported that coral cover had decreased to approximately 0.4% - 10%. The once dominant species in the Florida reef tract, Acropora palmata and A. cervicornis, have rapidly declined over time and were not found in any transects during the 2000 survey. This study is a re-assessment of the BNP patch reefs surveyed in 1977-1981. In addition, one patch reef from BNP and three in upper keys region of the Florida Keys National Marine Sanctuary (FKNMS) have been included (a total of 11 patch reefs, all with historical data available). This study found 2% - 13% coral cover at these 11 reefs using a photographic survey (Point Count) and 4% - 21% coral cover using Atlantic and Gulf Rapid Reef Assessment (AGRRA) survey methods. These results are relatively similar to results reported for the same patch reefs in the 1990s and in 2002, indicating that the major changes occurred earlier with the extreme decline in Acropora spp. Montastraea annularis complex cover has also declined substantially at the BNP sites from 5.4% in 1977-81 to 1.3% in 2009. Although the number of species recoded on the seven resurveyed BNP patch reefs was only 23, compared with 28 recorded in the 1977-81 study, all species are still present in the region surveyed, indicating no actual loss of over all species richness.

Fossil plants in the Upper Triassic Chinle Formation are preserved in fluvial channel, overbank, and lacustrine deposits. Plant-bearing units in these deposits are classified into seven types based on these depositional environments or subenvironments. Taphonomic characteristics of these assemblages, and of individual plant fossils within them, indicate that most plant fossils have either not been transported far from their growth sites or are preserved in situ. One particular deposit in the central part of Petrified Forest National Park preserves fossil plants in three associations: (1) allochthonous logs in basal lags in a channel-fill/lateral accretion deposits; (2) autochthonous horsetail trunks and parautochthonous horsetail leaves in a crevasse-splay deposits; and (3) parautochthonous and autochthonous cycadaceous, fern and other types of leaves, and erect and prostrate trunks in a paludal/distal splay deposits. Exposures of contemporaneous high-sinuosity channel and overbank deposits in this area enabled the reconstruction of the local paleogeography, paleohydrology, and paleoecology at a high resolution. Fossil plant assemblages of the Upper Triassic Chinle Formation are concentrated in the lower members of the formation. The lower part of the Chinle Formation was deposited in an incised valley system. Depositional, hydrological, and near-surface geochemical conditions in the incised valley system were conducive to preservation of terrestrial organic material, even though regional conditions were characterized by seasonal/monsoonal precipitation and groundwater conditions. Fossil plant assemblages preserved in these types of fully terrestrial incised valley-fills are taphonomically biased towards riparian wetland environments.

Devonian Winterburn strata in the Boule and Bosche Ranges of eastern Jasper National Park consist of two unconformity bounded, 45 m thick carbonate dominated depositional sequences, the Arcs Member (Nisku) and the Ronde Member (Calmar/Blue Ridge). Earliest Famennian clastics of the Sassenach Formation directly overlie the Ronde and this contact forms the Frasnian/Famennian boundary. Sampling for conodont biostratigraphy in three sections indicates that the Arcs and Ronde are Upper rhenana in age.
Arcs, Ronde, and Sassenach strata were deposited on a gently sloping carbonate ramp to platform ranging from shallow subtidal to peritidal depositional environments. Argillaceous limestones and shales are the dominate lithotype of the Mount Hawk Formation. Shallow subtidal limestones consisting of floatstones and rudstones interbedded with packstones and wackestones comprise most of the Arcs Member. Arcs strata consist of at least 4 depositional cycles and represent a shallowing upward sequence from outer shallow slope fossiliferous limestones to back reef lagoonal grainstones. Two previously undocumented Arcs patch reefs were described, the limestone Brule reef or bank in the southern Boule Range and the dolomitized Moosehorn reef in the central region of the Bosche Range. The Ronde Member is comprised of shallow subtidal limestones and siltstones with intertidal silty limestones occurring less frequently and predominately at the top. The Ronde consists of two carbonate shallowing upward cycles. FA 6 A intertidal limestones and fine grained sandstones comprise the Sassenach Formation which consists of two main depositional cycles and ranges from 20 m thick in the Bosche Range to less than 5 m thick in the Boule Range. (Abstract shortened by UMI.)

Thesis (M.S.)--University of Nevada, Reno, 2008.
"August, 2008." Includes bibliographical references (leaves 142-149). Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2008]. 1 microfilm reel ; 35 mm. Online version available on the World Wide Web.

The distribution of animals across landscapes is driven by processes operating across a multitude of spatial scales. In essence, the spatial and temporal variability in nutrient availability characteristic of savanna ecosystems, superimposed on the spatial pattern of the distribution of predator risky areas, govern the herbivore foraging response. Thus studying the foraging behaviour of individual herds is a fundamental link in ultimately understanding demographic responses of entire populations. This study formed part of a broader research programme managed by the Centre for African Ecology (CAE) specifically focusing on the decline of rare antelope species in the Kruger National Park (KNP). Ultimately the aim was to contribute towards identifying the causal factors of a recent decline in sable antelope (Hippotragus niger) in the KNP. Specifically, this research was designed to span two levels of selection. Firstly to identify the forage resources that sable depend on by investigating the acceptability and dietary contribution of grass species and by examining the way in which the selection of particular species is influenced by changes in grass phenology and structure. In addition, with this study I attempted to describe the characteristics of sable foraging habitat and to identify the landscape features that distinguish areas suitable for feeding from those areas that remain unaccepted for feeding. I predicted at the level of the grass species that factors influencing the distribution and concentrations of nutrients between species and between tufts of the same species should influence the relative acceptance of a species by sable. Similarly, I expected sable’s use of foraging areas and feeding sites to be governed largely by nutrient distributions across the landscape, but to be restricted within safe areas with high visibility where the probability of the timely detection of predators is high. Four herds of sable were fitted with GPS/GSM collars and tracked from the early dry season to the start of the wet season for a total of two years during which characteristics of the foraging area and forage selection were recorded. The dietary contribution and the attributes of the foraging area remained largely descriptive and only involved analysis of seasonal and herd differences. Grass species and phenological and structural features influencing species acceptance were analysed using generalised linear models (GLM). A similar analysis technique was employed to identify the landscape attributes that played an important role in the distinction between feeding and non-feeding sites. The grass species that were consistently highly accepted by all four herds and contributed considerable proportions to the diet of each herd, included Panicum maximum, Heteropogon contortus, Hyperthelia dissoluta and Setaria sphacelata. Sable increased the dietary contribution of P. maximum and H. dissoluta during the dry season by feeding more frequently in areas where it was abundantly available. Regardless of the identity of the grass species, sable were more likely to feed from tufts that were green relative to the greenness available in that season. Sable also adjusted their acceptance of grass species based on the height of the tuft and were more likely to feed from tufts greater than 20 cm in height. The foraging area was mostly located on upper catena positions and a lack of a dry season increase in the use of bottomlands suggested that nutrients were either not accumulating in bottomlands as expected, or that sable were not responding to an accumulation of nutrients. Sable foraged and fed readily in low to high shrub cover and showed no response to the increased predation risk that would be expected to be associated with increased shrub cover. Sable were more likely to feed in areas with a relatively high tree canopy cover and more likely to feed in areas with a relatively green sward. However, sable still fed fairly frequently in open areas or areas with a predominantly brown sward. Overall, sable seemed unexpectedly tolerant of landscapes that would be predicted to range widely in nutrient distributions and forage quality as well as relative predation risk.

The relationships between woody cover and habitat use by sable antelope (Hippotragus niger) in Kruger National Park (KNP) are poorly documented. Previous studies of sable antelope habitat did not explicitly measure space use and its relationship to habitats attributes. Global positioning system (GPS) telemetry permits the accurate collection of animal locations, which can be used to estimate home ranges and utilisation distributions (UDs). Resource utilisation functions (i.e., functions regressing probabilistic space use by animals such as UDs on landscape attributes) were used to analyse relationships between habitat use and woody cover with historical black and white aerial photographs. The dot-grid and object-based image analysis (OBIA) methods were used to estimate woody cover from digital aerial photographs and the results validated with field collected woody cover data. The dot-grid method was used to estimate woody cover by expressing canopy hits as a percentage of total dots using a regular lattice of evenly spaced dots overlaid on digital aerial photograph sections. The OBIA approach selected homogeneous groups of pixels (i.e., objects) and incorporated image aspects such as shape, size, texture, and brightness into the woody cover classification. The size of the objects depended on the scale selected for identifying single woody plants and the resolution of the aerial images. The two woody cover estimators (i.e., the dot-grid and object-based image segmentation) produced contrasting results. However, more confidence was placed in the use of the dot-grid method. The linear regression models revealed weak/ non-significant relationships between woody cover and space use by sable antelope. However, woody cover was more abundant in the wet season home range (36 ± 1%) when compared with the dry season home range (30 ± 1%) (t 0.05, 163 = 3.8, P < 0.001). Woody cover in the dry season non-core areas (31 ± 1%) was significantly more than that in the core areas (28 ± 1%) (t 0.05, 182 = -1.7, P = 0.04). The avoidance of home range areas with more woody cover during the dry season suggests that sable antelope are risk sensitive foragers that maximise the intake of available low quality food resources. The results from this study also indicate that sable antelope may be selecting for woody cover at scales larger than the one used here.

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg in fulfillment of the requirements for the degree of Masters in Science. Johannesburg, August 2016.
Resource selection by herbivores is driven by processes operating across a multitude of spatial scales and is influenced by a variety of biotic and abiotic environmental conditions and resources across the landscape. Spatial scales levels are crucial in habitat selection studies because they affect the interpretation of results and what may appear important at one level may not be relevant at another. Decisions made by animals at these levels can influence animal movements and hence the spatial distribution of populations. In this way, the use of resources across different scales by individual and groups of animals can be linked to population performance as a whole. Within home ranges, habitat use is mostly influenced by variation of food resources and water availability together with competition and predation risk. The study aimed to determine sable home range extent and habitat use and to test how predation, competition and other environmental factors influenced the selection of areas within these home ranges, in the thriving sable population of the Gorongosa National Park (GNP), Mozambique. Two adult females, one per herd, were fitted with GPS collar providing 5 hours interval GPS coordinates over a year, which were used to determine the annual and seasonal home ranges extents. Home ranges were then overlaid with vegetation map to analyse habitat use. Contrary to expectation, sable home ranges in this study were larger than those found in previous studies. The herds did not limit their habitat use to woodlands, using also open grasslands, drainage lines and bottomlands that retained green grasses during the dry season. Both herds expanded their ranges during the dry season, searching for those areas that still retained green grasses and searching for remaining water sources. For the resources selection within home ranges, I used the same GPS collar coordinates to fit seasonal logistic regression models with biotic factors (predation risk and competition) and with environmental variables (distance from water, distance from roads, elevation, slope, NDVI, vegetation types and landscape). Results show that sable were less prevalent in areas with high predation risk, but herds differed in prevalence with competitors, one herd favouring areas with high reedbuck concentrations and the other favouring low concentrations. Effects of environmental variables were different between seasons and between herds, being distance from water, distance from roads, greenness and elevation the most influential environmental. Both herds, however, avoided low elevation areas during the wet season, probably in order to avoid areas flooded during this period. As conclusion, predation risk and competition influenced selection within home ranges by sable in the GNP, despite low densities of potential competitors and lions. Nevertheless, this influence seems to not be enough yet to limit the success of the population. The herds also showed evidences of being affected by dry season, as demonstrated by the home ranges expansions during this period. With increase of herbivores population other that sable, and consequently increase competition and decrease of availability of resources, this could lead to reduction of growths percentages of the sable population in the park in the future.
MT2018

Los Andes ecuatorianos albergan ecosistemas con la más alta biodiversidad sobre la tierra. Información preliminar sobre la dinámica de los ecosistemas en el pasado es necesaria para entender, conservar y manejar los ecosistemas y su biodiversidad. Tres muestras de sedimentos fueron datadas, Rabadilla de Vaca (RV) a 3244 m de altura y Valle Pequeño (VP) a 3200 m de altura, ambas en la parte central del Parque Nacional Podocarpus (PNP), y Lagunas Natosas Bosque (LNB) a 3495 m de altura, al sur del PNP al sur del Ecuador en la región llamada Depresión Andina. Estas muestras fueron estudiadas con base en análisis de polen, esporas y partículas de carbón. Los resultados revelan cambios en la vegetación en la zona de LNB durante los últimos 16,000 años, y en RVM y VP desde hace 2100 años. Durante el Plestoceno tardío (15,930 – 11,660 cal yr BP), la vegetación de páramo dominó el área y la presencia de Plantago rigida sugiere condiciones ambientales frías y húmedas en el área de LNB. La población de P. rigida disminuyó drásticamente durante el último período glacial y especialmente durante el “Younger Dryas”, que es un corto período frío (hace 12,800 a 11,500 años), y el límite superior del bosque (UFL) muy probablemente fue mas bajo que en la actualidad. Entre 11,660 – 4280 cal yr BP, ocurrió una marcada reducción de cobertura de páramo, acompañada por una expansión de la vegetación de subpáramo (arbusto enano leñoso). En la región de LNB, al sur del PNP, se evidención un cambio altitudinal hacia arriba del UFL. En este sitio se evidencia por primera vez la presencia de grandes extensiones de Polylepis en la región de la Depresión Andina. Alrededro de 4200 cal yr BP el regreso a condiciones climáticas frías y húmedas favoreció la expansión de los páramos. El Holoceno tardío hasta el presente se caracteriza por la contínua fluctuación entre vegetación de páramo y subpáramo. Sin embargo, alrededor de los 1200 cal yr BP, vegetación de subpáramo (arbustos enanos) fueron precuentes, lo que sugiere un incremento moderado en temperatura y humedad. En el área de RVM desde los 2100 hasta los 1720 cal yr BP, la dominancia de subpáramo sugiere condiciones climáticas más húmedas y cálidas. En el área de LNB después de los 500 cal yr BP, el incremento de vegetación de páramo indica condiciones más húmedas. Esto también se registró en la zona de RVM y VP desde 800 a 310 cal yr BP, donde la vegetación de páramo se expandió ampliamente y redujo la posibilidad de crecimiento de bosque. Inlfuenciada por condiciones más húmedas y fuegos (incendios) frecuentes, en el área de LNB, Polylepis estuvo casi ausente durante el Holoceno tardío. Aunque, restos de partículas de carbón indican la presencia humana desde hace más de 4000 años. La máxima concentración de partículas de carbón indican alta frecuencia de fuegos desde 1800 hasta 1600 cal yr BP y desde 600 a 400 cal yr BP. Comparando la vegetación y los regsitros de carbón entre los tres sitios, es evidente que el fuego favoreció la expansión de vegetación de páramo en detrimento de la vegetación de subpáramo y bosque montano alto (UMF). El fuego probablemente tuvo un rol importante en el control de los cambios del límite del bosque durante el Holoceno tardío. Sin embargo, es difícil establecer si cambios en las condiciones del clima también tuvieron un rol importante durante este período. Los fuegos se presentaron a distintos momentos entre los diferentes sitios, esto sugiere que existió influencia antropogénica. Es posible inferir cambios a nivel regional ocasionados por la variabilidad de clima; sin embargo, condiciones locales como temperatura, precipitación, vientos, radiación solar y geomorfología, también tienen un impacto fuerte en los patrones de la vegetación, los mismos que pueden determinar la estructura, heterogeneidad y distribución de los ecosistemas.

Understanding historical disturbance and succession is critical in park management and restoration. I examined successional patterns and disturbance dynamics in the Blakiston Valley, Waterton Lakes National Park, by analyzing changes in forest structure using field research and repeat photography. I sampled forest structural attributes in 23 stands and interpreted forest cover from oblique and aerial photographs from 1881, 1914, 1947 and 2004. I quantitatively compared the interpretation from oblique photographs to aerial photographs and geographic information system (GIS) data and related succession to environmental factors and historical disturbances. Successional patterns were dominated by transitions from open meadows and shrublands to woodlands and closed forests, and were related to a small number of environment and disturbance variables, especially elevation, potential radiation, and time since last recorded fire. Accompanying these trends is a decline in landscape diversity. These findings have implications for restoration and conservation of subalpine forests in the park and across the region. The GIS methods capture spatially approximate vegetation patterns from oblique photographs and show potential for further research, especially in combination with the photograph collection of the Mountain Legacy Project.