Cette thèse présente les données des pollens et micro-charbons fossiles couvrant la période des 50 000 dernières années à partir de sites sélectionnés transversalement nord-sud du désert de Namib. Dans le cadre de cette thèse, on utilise le rock hyrax middens, l’accumulation des boulettes et des urines fossilisés du Procavia capensis, représentant une excellente archive pour archives pour la préservation des pollens et micro-charbons à long-terme. Trois sites des hyrax middens ont été sélectionnés pour l'analyse: au sud du désert de Namib (Pella), la marge est des dunes de sable de Namib (Zizou) et le centre de la Namib (Spitzkoppe). En plus, le régime pluvial de ces sites se caractérise par une forte variabilité annuelle et interannuelle. En conséquence, tous ces sites se situent au long de l’écotone du Désert et du biome Nama-Karoo, ainsi qu'à l’est (biome de Savane). Alors que ces sites sont répertoriés dans des écosystèmes similaires, l’écotone, lui, est considéré comme une zone potentiellement très sensible au changement du système climatique régional. Un intérêt spécifique de ces enregistrements terrestres est pour évaluer s’ils corroborent ou s’opposent avec les résultats provenant ceux des sédiments marins de la côte namibienne, en particulier la conclusion : l’abondance des taxa dominants du Fynbos Biome du Cape peut indiquer significativement une expansion vers le nord de la flore du Cape pendant les périodes plus froides glaciaires. Selon les sites d’études sélectionnées, les conclusions principales de ce travail sont les suivantes:Les hyrax middens de Pella fournissent le premier enregistrement pollinique continué au sud du désert de Namib durant la période des 50 000 dernières années. Ces données polliniques ont permis de reconstruire le changement de la végétation et d'estimer la température et l'aridité. Les résultats indiquent que la période glaciaire se caractérise par une augmentation de la disponibilité de l'eau sur le site par rapport à l'Holocène. Les changements de la température et de l'évapotranspiration potentielle semblent avoir joué un rôle important dans la détermination de l'équilibre hydrologique.L'enregistrement de Zizou hyrax midden met en évidence des changements de la végétation à la marge l'est des dunes de sable depuis 38 000 ans cal BP. La végétation de la période glaciaire se caractérise par les pourcentages relativement élevés des Astéracées pollen, et plus particulièrement par des taxa du climat plus froid: Stoebe et Artemisia¬-type. En accord avec les données de Pella, le réchauffement au début de l'Holocène indiqué par la dominance de pollen des graminées dans l'assemblage pollinique suggère une expansion du biome de Désert.Les hyrax middens de Spitzkoppe enregistrent les changements de la végétation dans le centre du désert de Namib au cours des 32 000 dernières années. Les résultats sont globalement cohérents en comparant aux autres enregistrements terrestres dans la région. L'analyse de ces données n'est cependant pas encore terminée.Dans tous ces sites, une variabilité significative a été observée à la fois dans la dernière période glaciaire et l'Holocène. Les conditions plus froides de l'ère glaciaire semblent être caractérisées par une augmentation de la disponibilité de l'eau le long de la totalité de notre zone d'étude. Au contraire des résultats provenant des carottes marines, nos enregistrements indiquent aucune expansion de la végétation de Fynbos biome, et seulement des traces de Restionaceae pollen dans le site extrêmement au sud à Pella (pas plus de 1%), mais aucun trace de ce pollen n'ayant été observé à Zizou ainsi qu’à Spitzkoppe. / This thesis presents fossil pollen and microcharcoal data during the last 50,000 years from a north-south transect of the Namib Desert. The arid environment of the Namib precludes the development of permanent wetlands, and as a result few palaeoenvironmental records exist from the region. In this study, we employ rock hyrax middens – fossilised accumulations of the faecal pellets and urine of the Procavia capensis. Hyrax middens from three sites were selected for analysis: the southern Namib (Pella), the eastern margin of Namib Sand Sea (Zizou), and the central Namib (Spitzkoppe). The results from these terrestrial sites are the extent to which they may corroborate or conflict with findings from pollen records obtained from marine sediments of the Namibian coast.The Pella hyrax middens provide the first continuous pollen record from the southern Namib Desert since the last 50,000 years, and are used to reconstruct vegetation change and quantitative estimates of temperature and aridity. Results indicate that the last glacial period was characterised by increased water availability relative to the Holocene. Changes in temperature and potential evapotranspiration appear to have played a significant role in determining the hydrologic balance. The record can be considered in two sections: 1) the last glacial period, when low temperatures favoured the development of more mesic Nama-Karoo vegetation at the site, with periods of increased humidity concurrent with increased coastal upwelling, both responding to lower global/regional temperatures; and 2) the Holocene, high temperatures and potential evapotranspiration resulted in increased aridity and an expansion of the Desert Biome.Considered in the context of discussions of forcing mechanisms of regional climate change and environmental dynamics, the results from Pella stand in clear contrast with many inferences of terrestrial environmental change derived from regional marine records. Observations of a strong precessional signal and interpretations of increased humidity during phases of high local summer insolation in the marine records are not consistent with the data from Pella. Similarly, while high percentages of Restionaceae pollen has been observed in marine sediments during the last glacial period, they do not exceed 1% of the assemblage from Pella, indicating that no significant expansion of the Fynbos Biome has occurred during the last 50,000 years.The Zizou hyrax midden highlights vegetation changes on the eastern margin of the Namib Sand Sea since 38,000 cal BP. Results show the different vegetation compositions between the last glacial period and the Holocene. Glacial vegetation characterised with relatively high percentages of Asteraceae pollen, particularly cool climate taxa such as Stoebe and Artemisia types. Similar to the data from Pella, with the onset of Holocene warming grass pollen comes to dominate the assemblage, suggesting an expansion of the Desert Biome. We suggest that the climate during the last glacial period was more humid, and supported the development of shrubs/small trees. Arid conditions during the Holocene saw the depletion of this resource, and the development of grasslands that could exploit the rare rains that the region experiences today. In common with the Pella record, no elements of the Cape flora are found in the Zizou middens.The Spitzkoppe hyrax middens record vegetation changes in the central Namib during the last 32,000 years. The last glacial vegetation compositions composed of Olea, Artemisia¬-type, Stoebe¬-type and grasses. In the Holocene, the arboreal taxa such as Olea was replaced by others like Eculea, Dombeya, Commiphora, and Croton¬-type with relative higher percentage of grasses at early Holocene.

Thesis (doctoral)--Universität St. Gallen, 1996.

Weedon Island, a peninsula located on the western inner shoreline of Tampa Bay, Florida, is the location of a collaborative geological and archaeological project that aims to relate the present day geomorphology to natural processes and human occupational activity during the middle to late Holocene. The area is known for extensive archaeological sites, which were originally investigated in the 1920s, although they have received relatively little scientific attention during most of the last century. We hypothesize that activities associated with pre-historic human occupation of Weedon Island at various times during the last ca. 5,000 years influenced the geomorphic evolution of the peninsula. An interdisciplinary approach, including geomorphic mapping, sediment-coring, and archaeological survey and excavation, is being used to test our hypothesis and is expected to reveal the extent to which natural processes and human activities interacted to shape the present-day configuration of the peninsula. More recent human impacts on the peninsula have impeded our efforts in some areas. During the twentieth century, dredging, mosquito ditching, and road construction, have disturbed the surface and portions of the upper sediment record in many locations. Sediments below obvious disturbances or in unimpacted areas of the peninsula, along with radiocarbon dating, have helped reconstruct the mid to late Holocene paleoenvironments and paleolandscape of Weedon Island.

ABSTRACT Recent archaeological investigations indicate that coastal Fort Walton cultures in the St. Joseph Bay region of northwest Florida emphasized marine and estuarine foraging. These late prehistoric (A.D. 1000-1500) peoples collected fish, shellfish, and other aquatic resources. At the Richardson's Hammock site (8Gu10), radiocarbon-dated to about A.D. 1300, as at dozens of other shell middens around this salty bay, large gastropods were a major subsistence component. This adaptation is in sharp contrast with that of contemporaneous inland Fort Walton societies, who relied on maize agriculture. It is unknown whether coastal groups represent separate hunter-gatherer-fisher populations or seasonal migrations by inland farming villagers. This thesis research uses stable oxygen and carbon isotope analysis on lightning whelks (Busycon sinistrum) to determine the seasonality of Fort Walton foraging, and compares the environment of prehistoric St. Joseph Bay with that of the modern bay. Oxygen isotope profiles suggest that shellfish collecting was relegated primarily to the summer months, producing a scheduling conflict with the primary growing season for maize in northwest Florida. Thus, it is argued that coastal and inland Fort Walton probably represent separate culture groups. The relationship between d18Oshell and d13Cshell indicates similar environmental and climatic conditions between prehistoric St. Joseph Bay and today. However, modern whelks are depleted in d13C compared to Fort Walton whelks, which reflects both twentieth century CO2 emissions and years of dredging and wastewater pollution entering the bay.

Thesis (doctoral) - Universität, Mannheim, 2005. / Includes bibliographical references.

The dawn of the eighteenth century in the Apalachicola delta region of the Florida panhandle was a time of major social upheaval that has been underexplored by current research. There are no historic records that describe the events and peoples in the region during establishment of the Spanish missions in the Tallahassee area to the east. Archaeological evidence shows the disappearance of the late prehistoric Mississippian Fort Walton people and the brief emergence of the protohistoric Lamar archaeological culture during the time of the destruction of the Spanish mission system around 1704. The Lighthouse Bayou site, 8Gu114, in Gulf County, has both a Fort Walton and a Lamar component, and therefore offers an opportunity to understand this tumultuous time period better. Comparison of the ceramics shows a transition from incised rectilinear scrolling motifs during Fort Walton to a series of incised and stamped designs, along with the emergence of check-stamping as common surface decorations during Lamar. Temper choices are further indicative: pottery of both components has extensive sand and grit tempering, with only limited shell- or grog-tempered vessels, suggesting that indigenous peoples here did not identify with the missionized Apalachee Indians. The lithic data, while limited, show that both the Fort Walton and Lamar inhabitants were more likely retouching existing tools rather than creating new ones; however, the proportion of flake types suggest that the Lamar inhabitants may have exploited chert to a greater extent than did their Fort Walton counterparts. The faunal data show considerable difference in food source exploitation strategies. The Fort Walton inhabitants used the Lighthouse Bayou site specifically to procure shellfish and fish, while the Lamar inhabitants made use of a wider variety of protein sources throughout the area. These differences suggest a contrast between the two time periods: Fort Walton existed under the relatively stable aegis of the late prehistoric Mississippian era. The Lamar people, while not Apalachee Indians, must have been another group fleeing the conflict amid the destruction of the Spanish missions and the general social collapse in Florida’s early eighteenth century.

Humans have transformed much of the earth’s surface through a wide range of activities of varying intensities and scales, shaping the landscape we see today. The combination of time and complex human-environment interactions within the Hakai Lúxvbálís Conservancy on the Central Coast of British Columbia has resulted in a landscape with many anthropogenically-generated modifications, such as shell middens which can be found at sites with histories of long-term habitation. Globally, shell middens (and in general, habitation sites) have been found to be factors in shaping site ecology. This thesis seeks to investigate this relationship between human activity and occupation and the landscape. The goal of this project is to examine the legacies from past land use, and subsidies from shell middens, within the present-day plant communities. I conducted an observational study to determine if species richness and overall plant communities on these habitation sites differed from sites without a history of intense occupation. To do this I selected ten habitation sites with known extensive shell middens and paired them with ten control sites with similar site conditions (but without the same site history or shell middens). I measured species abundances within 540 1 m x 1 m quadrats. I also surveyed a select group of culturally significant plant species and culturally modified trees within belt transects at each site. Data regarding the water table level and soil and foliar samples were also collected. A variety of environmental factors, along with the site history were evaluated as explanatory variables. Principal component analyses were used to describe how the gradients within the vegetation communities at three vegetation layers (ground, herb, shrub) to see if they respond differently to long-term site use. The habitation sites were found to be characterized by N-rich plant communities, which were significantly different from the plant communities on the control sites at the ground layer, herb layer, and with all layers combined, at both transect distances analysed, but the shrub layer was only significantly different when the entire transect was considered. The results show plant community composition is most strongly influenced by a combination of factors including site type, canopy cover, slope, topography, and distance from shore, with the weight of their importance depending on what vegetation layer is considered. The habitation sites had a lower average species richness at all layers, compared to the control sites, and their plant communities were shown to change differently with distance from the marine shoreline. Habitation sites also differed by having higher soil nutrient content, lower water table levels, and contained culturally important plant species that were absent on the control sites. This research highlights the influence that humans have had on landscapes in this region. This study shows how the patterns within the plant communities at the habitation sites differ from what is expected within the Coastal Western Hemlock zone. The research improves our understanding of the factors influencing vegetation patterns on the Central Coast of British Columbia with this examination of the complex intersection of historical practices and environmental changes. / Graduate

Thesis (doctoral)--Universität St. Gallen, 1997.

The impact of human activity on ecosystems is an issue at the forefront of global concern. Marine ecosystems are a particular concern, given their importance for human sustenance. Through the removal of species that are highly susceptible to the effects of overfishing, global fisheries have been driven to near collapse in recent decades. The long-term effects of such practices has resulted in declines in mean trophic level of aggregate fish catches over time, as well as decreasing diversity of species available for regular harvest (Jackson et al. 2001; Pauly et al. 1998). These supposedly “modern” problems have been recently identified in archaeological contexts, and attest to the extent of anthropogenic ecosystem alteration that has occurred since humans first began intensively exploiting marine ecosystems (Erlandson and Rick 2010; Quitmyer and Reitz 2006; Reitz 2004; Wing and Wing 2001). Here, I evaluate the degree of change in mean trophic level, diversity, and equitability of midden deposits at Crystal River and Roberts Island, two roughly contemporaneous Middle-to-Late Woodland Period (AD 1to 1000) mound complexes located on the west-central Florida Gulf Coast. This research identifies the extent to which humans altered the characteristics of the estuarine ecosystem surrounding the two sites, promotes alternative theoretical perspectives on past human-environment interactions, and provides modern ecosystems management agencies with a temporally-expansive data set to aid in future ecosystem conservation efforts.

Site 38CH1693 is a coastal site located in Charleston County, South Carolina. Thom’s Creek ceramics place the site in the Late Archaic/Early Woodland Period and radiocarbon dating corroborates this, placing the features present between 3650 and 3950 BP. Faunal analysis was undertaken to assess seasonality in order to understand the occupations that occurred at the site. Faunal seasonality, botanical seasonality, and sedentariness indicators are used to determine the sedentariness of the site. The presence of certain marine fish species is one of the most important seasonality indicators used. It is determined from the available evidence that at least one short-duration, year-round occupation is represented by the materials recovered at 38CH1693. Site 38CH1693 does not fit into the current Late Archaic settlement pattern models for the coast, calling for a reevaluation of these settlement pattern models and the sedentary sites within them.