HOLOCENE FIRE HISTORY OF A COASTAL TEMPERATE RAIN FOREST BASED ON SOIL CHARCOAL RADIOCARBON DATES

Previous paleoclimate studies have suggested a warm/dry event during the mid-Holocene in páramo vegetation of the tropical Andes of South America. However, the timing of the mid-Holocene warm/dry event in Tres Lagunas, Ecuador, remains uncertain, since a previously reported bog core record characterized the warm/dry event during a hiatus in sediment deposition. In order to understand the timing of the warm/dry event in Tres Lagunas in relation to regional records, a lake sediment core was collected. Subsamples from the core were analyzed for radiocarbon dates, pollen, magnetic susceptibility, and charcoal to reconstruct the depositional, vegetational, and fire history of the area. A near-constant sedimentation rate in the lake core indicated that the lake did not dry, in contrast to the adjacent previously reported bog core. Increases in lower elevation pollen types suggest a warm period between 2700 and 2200 cal. yr BP, with the peak of warming at 2200 cal. yr BP co-occurring with the end of hiatus in the bog core record. Statistically significant increases in charcoal influx and magnetic susceptibility from 3900 to 800 cal. yr BP also suggest a dry climate during this period. While the lake record corroborates the presence of a warm/dry period in Tres Lagunas during the mid-Holocene, this record suggests a shorter period of warm/dry climate where the intensity was not sufficient to cause the lake to dry. However, anthropogenic alteration of the landscape, either vegetation or burning, must also be considered when interpreting Holocene records from this region.

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Direct dating reveals the early history of opium poppy in western Europe

Scientific Reports ◽

10.1038/s41598-020-76924-3 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Aurélie Salavert ◽

Antoine Zazzo ◽

Lucie Martin ◽

Ferran Antolín ◽

Caroline Gauthier ◽

...

Keyword(s):

Western Europe ◽

Western Alps ◽

Western Mediterranean ◽

Opium Poppy ◽

Radiocarbon Dates ◽

Macrobotanical Remains ◽

History Of ◽

Temperate Europe ◽

Radiocarbon Chronology ◽

Botanical Remains

AbstractThis paper aims to define the first chrono-cultural framework on the domestication and early diffusion of the opium poppy using small-sized botanical remains from archaeological sites, opening the way to directly date minute short-lived botanical samples. We produced the initial set of radiocarbon dates directly from the opium poppy remains of eleven Neolithic sites (5900–3500 cal BCE) in the central and western Mediterranean, northwestern temperate Europe, and the western Alps. When possible, we also dated the macrobotanical remains originating from the same sediment sample. In total, 22 samples were taken into account, including 12 dates directly obtained from opium poppy remains. The radiocarbon chronology ranges from 5622 to 4050 cal BCE. The results show that opium poppy is present from at least the middle of the sixth millennium in the Mediterranean, where it possibly grew naturally and was cultivated by pioneer Neolithic communities. Its dispersal outside of its native area was early, being found west of the Rhine in 5300–5200 cal BCE. It was introduced to the western Alps around 5000–4800 cal BCE, becoming widespread from the second half of the fifth millennium. This research evidences different rhythms in the introduction of opium poppy in western Europe.

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RADIOCARBON DATES FROM THE MONASTERY ON KOM H IN OLD DONGOLA (SUDAN) AND THE CHRONOLOGY OF MEDIEVAL NUBIAN POTTERY

Radiocarbon ◽

10.1017/rdc.2021.4 ◽

2021 ◽

pp. 1-21

Author(s):

Dorota Dzierzbicka ◽

Katarzyna Danys

Keyword(s):

Historical Research ◽

Crucial Importance ◽

Radiocarbon Dates ◽

14Th Century ◽

15Th Century ◽

History Of

ABSTRACT The paper presents and discusses a series of radiocarbon (14C) dates from a medieval Nubian monastery found on Kom H of Old Dongola, the capital of the kingdom of Makuria located in modern-day Sudan. The monastery was founded in the 6th–7th century AD and although it probably ceased to function in the 14th century, the site remained occupied until the beginning of the 15th century. The investigated courtyard of the monastery was in use from the 11th to the 14th century, as indicated by the ceramics and 14C analysis results presented here. The dates under consideration are the first published series of 14C dates from this site, which is of crucial importance for historical research on medieval Nubian Christianity and monasticism. They permit to begin building an absolute chronological framework for research on the archaeological finds from the site and region. A group of finds in particular need of such a framework are ceramics, and the implications of the 14C dates for pottery assemblages found in the dated contexts are discussed. The conclusions summarize the significance of the datings for the history of the site.

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Morphometrics of the aerial roots of Kingia australis (Liliales)

Australian Journal of Botany ◽

10.1071/bt9810081 ◽

1981 ◽

Vol 29 (1) ◽

pp. 81 ◽

Cited By ~ 11

Author(s):

B Lamont

Keyword(s):

Fire History ◽

Dead Zone ◽

Dry Weight ◽

Root Primordia ◽

Stem Apex ◽

Primary Roots ◽

Aerial Roots ◽

History Of ◽

Lateral Branches ◽

Potential Height

Kingia australis, common in the heaths and forests of south-western Australia, is distinguished from all other grass trees in Australia by the presence of a mantle of concealed aerial roots. A ring of up to 50 root primordia is initiated in winter from the stem apex. In plants more than 1 m high, initiation and commencement of elongation of the primary roots are no longer annual but dependent on the fire history of the plant. These roots descend between the stem and persistent leaf bases at about 2 cm per growing month, sending many lateral branches among the leaf bases. Aerial roots gradually replace the space occupied by the leaf bases until they may account for 45% of the dry weight of the aerial caudex. The caudex of one 6-m-high specimen bore up to 27 roots per cm2 transection of the root mantle, with about 3000 primary roots entering the soil. All underground primary roots (except the initial contractile roots) have an aerial origin and are concentrated vertically under the canopy. After 300-400 years the stem starts to die back from the base, and the aerial roots attached to that portion disintegrate. By propping up the stem and bridging the dead zone of the stem, the living aerial roots greatly extend the potential height and longevity of the plant. In addition, the hairy laterals are ideally located to absorb water and nutrients directly from the leaf bases. Protective and aerating functions are also indicated.

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Holocene stand-scale vegetation dynamics and fire history of an old-growth spruce forest in southern Finland

Vegetation History and Archaeobotany ◽

10.1007/s00334-015-0533-z ◽

2015 ◽

Vol 24 (6) ◽

pp. 731-741 ◽

Cited By ~ 9

Author(s):

Jennifer L. Clear ◽

Heikki Seppä ◽

Niina Kuosmanen ◽

Richard H. W. Bradshaw

Keyword(s):

Vegetation Dynamics ◽

Fire History ◽

Spruce Forest ◽

Old Growth ◽

History Of

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Vegetation and fire history of the Euganean Hills (Colli Euganei) as recorded by Lateglacial and Holocene sedimentary series from Lago della Costa (northeastern Italy)

The Holocene ◽

10.1177/0959683609358911 ◽

2010 ◽

Vol 20 (5) ◽

pp. 679-695 ◽

Cited By ~ 56

Author(s):

Petra Kaltenrieder ◽

Giovanni Procacci ◽

Boris Vannière ◽

Willy Tinner

Keyword(s):

Fire History ◽

Northeastern Italy ◽

History Of

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Genetic variation in allozymes of western larch

Canadian Journal of Forest Research ◽

10.1139/x86-177 ◽

1986 ◽

Vol 16 (5) ◽

pp. 1013-1018 ◽

Cited By ~ 25

Author(s):

Lauren Fins ◽

Lisa W. Seeb

Keyword(s):

Genetic Variation ◽

Genetic Drift ◽

Fire History ◽

Glacial History ◽

Geographic Proximity ◽

Electrophoretic Variation ◽

Inland Empire ◽

Genetic History ◽

Expected Heterozygosity ◽

History Of

Seed samples from 19 stands of Larixoccidentalis Nutt. were analyzed for electrophoretic variation at 23 loci. Because sample sizes consisted of only 9 or 10 trees per stand (18–20 alleles per locus per stand), samples were grouped by geographic proximity into four larger samples. For all measures of variation, this species scored lower than most, but within the range observed for other western conifers. Most of the variation was found within rather than between the population groups. The single southern sample appeared to be genetically distinct from the others. Although some variation was observed between individual stand samples in expected heterozygosity, the consistently low values for all samples suggest that genetic drift has played a major role in the genetic history of the species in the Inland Empire, both through its glacial history in postulated refugia and through fire history in recent times.

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Past and recent biodiversity profiling in ancient Lake Chalco Mexico by a metagenomics analysis

10.5194/egusphere-egu21-6277 ◽

2021 ◽

Author(s):

Bárbara Moguel ◽

Liseth Pérez ◽

Luis David Alcaraz ◽

Socorro Lozano-García ◽

Luis Herrera-Estrella ◽

...

Keyword(s):

Volcanic Belt ◽

Environmental Dna ◽

Radiocarbon Dates ◽

The Past ◽

Mexican Volcanic Belt ◽

History Of ◽

High Throughput Dna Sequencing ◽

High Altitude Lake ◽

Taxonomic Groups ◽

The Relationship

<p>For decades, paleoecological studies in lake sediments have focused on reconstructing the environments of the past and explaining phenomena linked to climatic variations. Recent advances in high-throughput DNA sequencing have allowed access to environmental DNA (eDNA) and ancient sedimentary DNA (sedaDNA) as a new and efficient proxy for past and present biodiversity. The basin of Mexico (BM) is located in the central part of the Trans-Mexican Volcanic Belt at 2,200 m a.s.l.; with the southern portion harboring the Chalco sub-basin. Lake Chalco is one of the last remaining natural aquatic ecosystems within the ever-expanding urban area surrounding Mexico City. The paleoenvironmental history of this lake has been previously characterized using sedimentological and geochemical proxies, as well as preserved microfossils (diatoms, pollen) with a temporal framework based on multiple radiocarbon dates. However, information for the remaining taxonomic groups and metabolic pathways remained unexplored. Here, we present the first metagenomics-based study for the Holocene in a high-altitude lake in Central Mexico &#8211;Lake Chalco. We explored the relationship between the lake&#8217;s paleoenvironmental condition and estimations of taxonomic and metabolic profiles across the sedimentary sequence (2.5 meters long). Multiple biological and abiotic variables revealed three main environmental phases: 1) a cool freshwater lake (FW1: 11,500-11,000 cal years BP), 2) a warm hyposaline lake (HS2: 11,000-6,000 cal years BP), and 3) a temperate, subsaline lake (SS3, <6,000 cal years BP). We describe the structure of the microbiota community and taxonomy richness turnover in the three Holocene paleoenvironmental phases. During the past 12 000 years BP the most abundant domains in Lake Chalco sediments were Bacteria, followed by Archaea, and Eukarya (36,722 genera). The analysis of functional proteins showed high biodiversity with a total of 27,636,243 proteins identified, but it was only possible to annotate 3,227,398 of them. Also, we identified several genes associated with some relevant pathways, such as methanogenesis. Altogether, this study allowed us to reconstruct the natural history of lake Chalco and its surroundings.</p>

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