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Palaeoecological Reconstructions (palaeoecological + reconstruction)
Selected AbstractsIsotopic alteration of mammalian tooth enamelINTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 1-2 2003M. J. Schoeninger Abstract Mammalian tooth enamel carbonates from a Pliocene site at Allia Bay in northern Kenya show variable carbon and oxygen isotopic alteration. Sample screening by cathodoluminescence, prior to isotopic analysis, identified areas of extensive chemical alteration and others that were minimally altered. The luminescent patterns were used to guide sampling for the isotope study. Carbon stable isotope ratios of the apatite carbonate from luminescent enamel exteriors differ from the ratios in the enamel interiors and the magnitude of difference varies widely. The interior of the enamel usually retains the carbon isotope ratios expected based on faunal identification, but in a minority of cases, all of the enamel appears to be altered isotopically. Among fauna with an apparent mixed feeding signal, it is particularly difficult to determine whether the ,13C value is due to an actual mixed feeding strategy during life or to alteration toward sediment values. Palaeoecological reconstructions based on the ,13C values of enamel carbonate in browsing fauna would be affected, in many cases, since differences of 1, are significant for such reconstructions. Even so, careful selection of unaltered enamel sections should avoid this problem. Palaeodiet reconstruction would be less affected except in those cases where the alteration approaches 5,. In such cases, a mixed feeding strategy would be the erroneous interpretation of the data. Oxygen isotope ratios in the enamel carbonates show no pattern and the retention of biogenic values is unlikely. For this reason, palaeotemperature reconstructions, based on the ,18O values of the enamel carbonate, would not be possible at this site. Copyright © 2003 John Wiley & Sons, Ltd. [source] Raptor and owl bone from Niah Caves, Sarawak: identifications and morphological variation in the humerus and tarsometatarsus of selected raptorsINTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 4 2009C. M. Stimpson Abstract This paper reports on the findings of a preliminary investigation of raptor (Accipitriformes) and owl (Strigiformes) bones recovered during the original archaeological investigations of the Niah Caves during the 1950s and 1960s. Observations of morphological characteristics that were utilised to distinguish humeri and tarsometatarsi of selected species are included. A total of 48 archaeological specimens were identified, representing five genera of Accipitridae (Order Accipitriformes) and two genera of Strigidae (Order Strigiformes). Forty-four specimens were further identified to species (Accipitriformes, four species; Strigiformes, three species) including a Late Pleistocene record of the bathawk (Machieramphus alcinus) dated to 36,470,±,250 (uncal.) bp. Modern representatives of all identified species have been recorded recently in Sarawak. The relevance of raptors and owls in the palaeoecological reconstruction of this site is discussed, and the potential role of these birds as taphonomic agents is considered. Copyright © 2009 John Wiley & Sons, Ltd. [source] Abandonment of farmland and vegetation succession following the Eurasian plague pandemic of ad 1347,52JOURNAL OF BIOGEOGRAPHY, Issue 4 2007Dan Yeloff Abstract Aim, This paper reviews the available documentary, archaeological and palaeoecological evidence for the abandonment of agricultural land and consequent regeneration of the forest in Europe after the Black Death. Location, Western and northern Europe. Methods, This review is the result of an exhaustive search of the historical, archaeological and palaeoecological literature for evidence indicating agricultural decline and forest regeneration in Eurasia during the 14th century. The available evidence for landscape change can be divided into two categories: (1) documentary and archaeological sources, and (2) palaeoecological reconstructions of past vegetation. In the past few years, several pollen diagrams from north-west Europe have been reported with precise chronologies (decadal and even annual scale) showing the abandonment of farmland and consequent ecological change in the late medieval period. Results and main conclusions, There is strong evidence of agricultural continuity at several sites in Western Europe at the time of the Black Death. The effects of the Black Death on the European rural landscape varied geographically, with major factors probably including the impact of the plague on the local population, and soil quality. At two sites in western and northern Ireland, the late medieval decline in cereal agriculture was probably a direct result of population reduction following the Black Death. In contrast, the decline in cereal production began at sites in Britain and France before the Black Death pandemic of ad 1347,52, and was probably due to the crisis in the agricultural economy, exacerbated by political instability and climate deterioration. Much of the abandoned arable land was probably exploited for grazing during the period between the decline in cereal farming and the Black Death. In the aftermath of the Black Death, grazing pressure was greatly reduced owing to reductions in the grazing animal population and a shortage of farmers. Vegetation succession on the abandoned grazing land resulted in increased cover of woody tree species, particularly Betula and Corylus, by the late 14th century. The cover of woodland was greatest at c.ad 1400, before forest clearance and agriculture increased in intensity. [source] Response of testate amoeba assemblages to environmental and climatic changes during the Lateglacial,Holocene transition at Lake Lautrey (Jura Mountains, eastern France),JOURNAL OF QUATERNARY SCIENCE, Issue 6 2010Adeline A. J. Wall Abstract We tested the response of lacustrine testate amoebae (thecamoebians) to climate and environmental changes for the Lateglacial,Holocene transition. The palaeoenvironmental history of the study site (Lake Lautrey, Jura Mountains, eastern France) was previously established based on high-resolution multi-proxy studies of the same core. The present study is characterised by a high taxonomic resolution (54 taxa), inclusion of small species (down to 25,µm) and high total counts (>500 individuals per sample on average). Changes in the composition of testate amoeba assemblages (dominant species and assemblage structure), as well as in the accumulation rate (tests cm,2 a,1), corresponded to major climatic phases (i.e. Oldest Dryas, Bølling,Allerød Interstadial, Younger Dryas, Preboreal) as well as changes in organic matter inputs. Furthermore, decreases in the accumulation rate characterised minor short-lived cooling events, such as Older Dryas event or Gerzensee oscillation. However, the Preboreal oscillation, which was well registered by other proxies at Lake Lautrey, could not be recognised in the testate amoeba record. This work demonstrates that lacustrine testate amoebae can be used for palaeoclimatic and palaeoecological reconstructions. Nevertheless, a better understanding of the relation between climate, organic matter and lacustrine testate amoebae requires further high-resolution studies based on multi-proxy approaches and the development of appropriate modern analogues. Copyright © 2010 John Wiley & Sons, Ltd. [source] | ||||||||||