Quaternary paleoecology

Stabilized sand sheets and dunes hold a remarkable amount of information on paleoenvironmental conditions under which late Quaternary landscapes evolved in northern subarctic regions. We provide the results of a project focused on understanding the development of lowland environments and ecosystems, including dunes and sand sheets, which were critical habitat for early human occupations in subarctic regions. Our study area is the Rosa-Keystone Dunes Field in the Shaw Creek Flats of the middle Tanana River basin, interior Alaska, one of the oldest continuously occupied areas in North America (14,000 cal. BP to present). The disturbance regimes of reactivated dunes and associated forest fire cycles between 12,500 and 8800 cal. BP fostered a unique early to mid-successional mixed vegetation community including herbaceous tundra, shrubs, and deciduous trees. This environment provided key habitats for large grazers and browsers, significant resources for early hunter-gatherer populations in central Alaska. After 8000 cal. BP, the expansion of black spruce and peatlands heightened landscape stability but decreased the range of local habitat for large grazers. Hunter-gatherer economic change during these periods is consistent with human responses to local and regional landscape disturbance and restructuring.

En México existen más de 800 localidades Pleistocénicas con presencia de mamíferos, ubicadas principalmente en el Cinturón Volcánico Trans-Mexicano, las cuales representan sitios que han contribuido al conocimiento de la evolución de la megafauna del Pleistoceno en México. Particularmente, en Michoacán, la mayoría de los yacimientos fosilíferos de vertebrados se localizan en la Cuenca de Cuitzeo y los estudios paleontológicos hechos en esta área son primordialmente de tipo taxonómico y sólo muy pocos tienen un enfoque paleoecológico. De tal modo, el presente trabajo tiene como objetivo estudiar la fauna fósil del nuevo yacimiento de Ciudad Universitaria (UMSNH), ubicado en Morelia, dentro de la subcuenca Charo, que forma parte de la Cuenca de Cuitzeo, con la finalidad de aportar datos que corroboren la preferencia alimenticia y de hábitat de las especies encontradas, además de recabar información acerca del paleoambiente del sitio; utilizando para ello el método de isótopos estables de (δ 13 C y δ 18 O). Los resultados muestran cinco facies estratigráficas que sugieren diferentes ambientes sedimentarios. La fauna fósil se encontró en una biofacies fluviolacustre, y pertenece a tres diferentes ordenes, familias y géneros (Mammuthus columbi, Equus sp., Bison sp.). Además, la presencia de Bison sp. indica una edad Rancholabreano para este yacimiento fosilífero. Los análisis de isótopos estables δ 13 C y δ 18 O sugieren una dieta mixta (C 3/4 ) para el M. columbi y una dieta pacedora (C 4 ) para el Equus sp., por lo que se podría deducir para la zona un ambiente heterogéneo, es decir con vegetación de zonas cerradas (bosques) y abiertas (pastizales y/o praderas) conteniendo una proporción más o menos similar de pastos, herbáceas, arbustos y árboles.

Fire is a natural disturbance component and driver of forest composition in the western United States. Cooler/wetter climates are typically associated with less frequent fires and succession of montane forests to more shade-tolerant, fire-sensitive taxa. Native Americans have lived in California since the terminal Pleistocene and used fire to alter the landscape and maximize natural resources. Determining the extent and impact of anthropogenic burning on California's landscape is difficult; however, because the archaeological record is mostly silent on the subject. The region's ethnographies also mention the practice from a prehistoric context only in passing. Here, we show that comparing the prevalence of fire-sensitive to fire-adapted taxa in the pollen record can help distinguish periods when vegetation does not respond as expected to climate change. We argue that the prevalence of shade-intolerant/fire-adapted taxa during climatically cool, wet periods such as the Little Ice Age provide evidence for anthropogenic burning. At Holey Meadow, in Sequoia National Forest, we find strong evidence for a Native American influenced landscape from 750 to 100 cal yr BP. We also see a strong anthropogenic effect on modern vegetation following European settlement in A.D. 1854, a period marked by a precipitous decline in traditional tribal use of the area and the inception of modern fire exclusion policies. These results indicate that anthropogenic impacts on forest composition can be distinguished from climatic drivers through the use of paleoenvironmental proxies. They further indicate that anthropogenic burning helped structure Late Holocene southern Sierra Nevada biomes.

Celem niniejszego artykułu jest poznanie cech litologicznych i geochemicznych osadów postglacjalnych występujących w dnie misy Zalewu Szczecińskiego, a także utworów akumulowanych współcześnie w tym akwenie. Uzyskane informacje stanowią podstawę dla rekonstrukcji środowisk sedymentacyjnych i warunków akumulacji osadów panujących na obszarze dzisiejszego Zalewu Szczecińskiego
od schyłku ostatniego zlodowacenia do czasów współczesnych.

Dead and live molluscan assemblages from the coastal area of Phetchaburi (NW Gulf of Thailand) were compared by means of multivariate analysis. Seven thanatofacies were recognized, thriving in the area after the 1960s. Five of them, scattered along the tidal flat, represent oligotypic intertidal biotopes linked to a variety of environmental factors; the remaining two mirror high-diversity infralittoral associations. Conversely, only two poor, ill-defined biofacies thrive at present between the intertidal and the shallow infralittoral zones, somewhat resembling two of the thanatofacies. Diversity indexes reveal a dramatic biodiversity decline occurred from the 1960s onwards, far beyond the effects of time-averaging and accumulation. The responsibility for this reduction is largely attributable to the high impact of human activities, such as the intensive sea bottom trawling, the wastewaters from aquaculture (shrimp and fish ponds) and dense coastal villages, and, at a minor extent, the digging of edible molluscs from the tidal flat.

Новые исследования пещеры Отвале-Клде и Бонди, расположенных на расстоянии около 2 км друг от друга в Чиатурском районе Имеретии в Западной Грузии привели к важным выводам, обособляющим данный палеолитический регион от Северного и Южного Кавказа. Система жизнеобеспечения, стратегия охоты среднепалеолитических неандертальцев, как и разделка, транспортировка и употребление в пищу животных оказались довольно сходны с теми, которые практиковали люди современного облика в верхнем палеолите. В данной работе экспериментально-трасологическими методами были определены следы антропогенного воздействия на костных остатках из пещер Ортвале Клде и Бонди. Был детально воссоздан процесс первичного расщепления кости, получения первичной заготовки в сравнительном плане по слоям и памятникам с учётом результатов изучения орудийного состава. Сделан вывод о том, что какая-то часть заготовок из длинных трубчатых костей копытных животных могла быть результатом дополнительных преднамеренных ударов по идущим трещинам и ударов по торцу эпифиза кости продольно оси предмета. Поставлен вопрос о дополнительных пищевых источниках, отличных от поедания костного мозга, и их роли в возникновении техники продольного раскалывания в костяных индустриях. На примере материалов среднепалеолитических и верхнепалеолитических слоёв пещеры Отвале Клде наблюдается непрерывность единой стратегии утилизации костного сырья, связанная напрямую с особенностями жизнеобеспечения и экономики древнего хозяйства. Авторы получили ещё одно подтверждение единой системы жизнеобеспечения среднепалеолитических неандертальцев и современных людей в раннем верхнем палеолите Западной Грузии

A new study of the Otvalė-Klde and Bondi caves, located about 2 km apart in the Chiatura region of Imereti in Western Georgia, led to important conclusions highlighting this Paleolithic region from the Northern and Southern Caucasus. The life support system, the hunting strategy of the Middle Paleolithic Neanderthals, as well as the cutting, transportation and consumption of animals proved to be quite similar to those practiced
by modern people in the Upper Paleolithic. In this work, traces of anthropogenic impact on bone remains from Orvale Klede and Bondi caves were determined by experimental traceological methods. The process of primary splitting of the bone was reconstructed in detail, obtaining the primary billet in a comparative plan by layers and sites, taking into account the results of studying the gun composition. It is concluded that some part of the billets from the long tubular bones of ungulate animals could be the result of additional deliberate strokes on the cracks and impacts along the butt end of the epiphysis of the bone along the axis of the object. The question is raised about additional food sources, other than eating bone marrow, and their role in the emergence of the technique of longitudinal cleavage in bone industries.

On the example of materials of the Middle Paleolithic and Upper Paleolithic layers of the Otvalė Klde cave, the unified strategy of utilization of bone raw materials is closely connected with the peculiarities of the life and economy of the ancient economy. Accordingly, we have received another confirmation of a single life support system for the Middle Paleolithic Neanderthals and modern people in the early Upper Paleolithic of Western Georgia.