A 10,300 14C yr Record of Climate and Vegetation Change from Haiti

1999 ◽  
Vol 52 (2) ◽  
pp. 159-170 ◽  
Author(s):  
Antonia Higuera-Gundy ◽  
Mark Brenner ◽  
David A. Hodell ◽  
Jason H. Curtis ◽  
Barbara W. Leyden ◽  
...  
Keyword(s):  
Vegetation Change ◽  
Human Impacts ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Early Holocene ◽  
Pollen Record ◽  
Caribbean Islands ◽  
Moist Forest ◽  
Dry Conditions ◽  
American Tropics

Pleistocene and Holocene vegetation dynamics in the American tropics are inferred largely from pollen in continental lake sediments. Maritime influences may have moderated climate and vegetation changes on Caribbean islands. Stable isotope (δ18O) study of a 7.6-m core from Lake Miragoane, Haiti, provided a high-resolution record of changing evaporation/precipitation (E/P) since ∼10,300 14C yr B.P. The Miragoane pollen record documents climate influences and human impacts on vegetation in Hispaniola. The δ18O and pollen data near the base of the core indicate cool, dry conditions before ∼10,000 14C yr B.P. Lake Miragoane filled with water in the early Holocene as E/P declined and the freshwater aquifer rose. Despite increasing early Holocene moisture, shrubby, xeric vegetation persisted. Forest expanded ∼7000 14C yr B.P. in response to greater effective moisture and warming. The middle Holocene (∼7000–3200 14C yr B.P.) was characterized by high lake levels and greatest relative abundance of pollen from moist forest taxa. Climatic drying that began ∼3200 14C yr B.P. may have driven some mesophilic animal species to extinction. The pollen record of the last millennium reflects pre-Columbian (Taino) and European deforestation. Long-term, Holocene vegetation trends in southern Haiti are comparable to trends from continental, lowland circum-Caribbean sites, suggesting a common response to regional climate change.

scholarly journals A Holocene pollen record of savanna establishment in coastal Amapá

2008 ◽  
Vol 80 (2) ◽  
pp. 341-351 ◽  
Author(s):  
Mauro B. de Toledo ◽  
Mark B. Bush
Keyword(s):  
Vegetation Change ◽  
Human Impacts ◽  
Detrended Correspondence Analysis ◽  
Fire Frequency ◽  
Pollen Record ◽  
Human Occupation ◽  
Sample Distribution ◽  
River Flooding ◽  
History Of ◽  
Tremendous Impact

The main goal of this study was to investigate how climate and human activities may have influenced ecotonal areas of disjoint savannas within Brazilian Amazonia. The fossil pollen and charcoal records of Lake Márcio (Amapá) were used to provide a Holocene palaeoecological history of this region. Detrended correspondence analysis (DCA) was used to enhance the patterns of sample distribution along the sediment core. A marked vegetation change from closed forests with swamp elements to open flooded savanna at c. 5000 yrs BP was evident from the pollen record. Charcoal analysis revealed a pattern of increased accumulation of particles coincident with the establishment of savannas, suggesting higher fire frequency and human impacts near the lake. A 550-year sedimentary hiatus suggests that the lake depended heavily on floodwaters from the Amazon River, and that it became suddenly isolated from it. When sedimentation restarted in the lake, the environment had changed. A combination of factors, such as reduced river flooding, palaeofires and human occupation may have had a tremendous impact on the environment. As there are no other major changes in vegetation, after 4700 yrs BP, it is plausible to assume that the modern mosaic vegetation formed at that time.

Lowland forest collapse and early human impacts at the end of the African Humid Period at Lake Edward, equatorial East Africa

2017 ◽  
Vol 89 (1) ◽  
pp. 7-20 ◽  
Author(s):  
Sarah J. Ivory ◽  
James Russell
Keyword(s):  
East Africa ◽  
Iron Age ◽  
Human Activities ◽  
Human Impacts ◽  
Early Holocene ◽  
Pollen Record ◽  
Holocene Climate ◽  
Lowland Forest ◽  
Lake Edward ◽  
Early Human

AbstractIn Africa, the early Holocene was characterized by wetter, warmer conditions than today, followed by rapid aridification at ~5.2 ka. However, a lack of lowland vegetation records has prevented a detailed evaluation of forest response to Holocene climate change. Additionally, although modern vegetation communities are linked to human disturbance, few studies have addressed how prehistoric human activities helped engineer the character of modern African ecosystems. Understanding the architecture of lowland and highland forests is important to prevent further degradation from climate/land-use change. We present an 11,000 yr fossil pollen record from Lake Edward, Uganda. We show that Guineo-Congolian forests dominated the highlands and lowlands in equatorial East Africa in the early Holocene, highlighting the importance of rainfall and temperature in controlling forest communities. These forests remained until ~5.2 ka, when the climate became drier. The lacustrine ecosystem response to aridification was abrupt; however, forest decreased gradually, replaced by deciduous woodlands. Woodlands dominated until after an arid period at 2 ka; however, forest did not recover. Increased disturbance indicators and grasses suggest that the arrival of Iron Age people resulted in the modern fire-tolerant vegetation. Although late Holocene climate played a role in vegetation opening, the modern ecosystem architecture in East Africa is linked to early human activities.

scholarly journals Regional Climate Change Recorded in Moss Oxygen and Carbon Isotopes from a Late Holocene Peat Archive in the Western Antarctic Peninsula

Geosciences ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 282
Author(s):  
Jonathan M. Stelling ◽  
Zicheng Yu
Keyword(s):  
Antarctic Peninsula ◽  
Ocean Circulation ◽  
Regional Climate ◽  
Isotope Analysis ◽  
Regional Climate Change ◽  
Terrestrial Ecosystems ◽  
Southern Annular Mode ◽  
Dry Conditions ◽  
Growing Conditions ◽  
Δ13c And Δ18o

The Antarctic Peninsula (AP) climate is characterized by a high degree of variability, which poses a problem when attempting to put modern change in the context of natural variation. Therefore, novel methods are required to disentangle sometimes conflicting climate records from the region. In recent years, the development of Antarctic moss-cellulose isotopes as a proxy for summer terrestrial growing conditions has become more widespread, with the isotopes Δ13C and δ18O reflecting moss productivity and peatbank moisture conditions, respectively. Here, we used a combined Δ13C and δ18O isotope analysis of moss Chorisodontium aciphyllum cellulose from a peatbank located on Litchfield Island in the western AP to document changes in climate over the last 1700 years. High Δ13C values (>15‰) indicate warm and productive conditions on Litchfield Island from 1600 to 1350 cal yr BP (350 to 600 AD) and over the last 100 years. The δ18O record shows two distinct intervals of dry conditions at 1350–1000 cal yr BP (600–950 AD) and at 500–0 cal yr BP (1450–1950 AD). Our record indicates that terrestrial ecosystems in the AP have responded to regional climate driven by atmospheric circulation, such as the southern annular mode (SAM) and, to a lesser extent, changes in ocean circulation.

scholarly journals Multi-profile fine-resolution palynology of Late Mesolithic to Bronze Age peat at Cat Stones, Rishworth Moor, Central Pennines, UK

The Holocene ◽  
2020 ◽  
pp. 095968362097276
Author(s):  
Bruce M Albert ◽  
James B Innes ◽  
Jeff J Blackford
Keyword(s):  
Bronze Age ◽  
Vegetation Change ◽  
Human Impacts ◽  
Fire Disturbance ◽  
Pollen Record ◽  
Calluna Heath ◽  
Mesolithic Period ◽  
Fine Resolution ◽  
Late Mesolithic ◽  
Microscopic Charcoal

Palynological data from three radiocarbon dated peat profiles at Rishworth Moor in the Pennine hills of northern England provide a record of vegetation change and human impacts in the Late Mesolithic, Neolithic and Bronze Age periods. All three cultures have archaeological sites present in the vicinity, with Late Mesolithic sites by far the most abundant, comprising mainly very late assemblages dominated by ‘rod’-shaped microliths. Pollen evidence of vegetation disturbance occurs during all three archaeological periods, and is attributed to the results of human activity. Microscopic charcoal and non-pollen palynomorph analyses support the pollen evidence. Sites at Cat Stones 2 and Cat Stones 3 record evidence of Neolithic and Bronze Age date only. Cat Stones 1 extends into the Late Mesolithic period, and fine-resolution pollen analyses have been applied in this profile to the Mesolithic–Neolithic transition leading up to the mid-Holocene Elm ( Ulmus) Decline, which starts here at c. 4940 14C BP (5670 cal. BP), a typical date for it in the central Pennines. Bayesian age-depth modelling provides precise ages for the vegetation changes and their spatial correlation. The plateau was dominated by scrub and grassy Calluna heath from the Late Mesolithic onwards. Elevated microscopic charcoal levels and ruderal herb pollen record phases of fire disturbance below the Elm Decline, including a grain of Hordeum cereal-type. Whether this grain represents early cultivation requires further research. Bronze Age impacts are of greater intensity, but disturbances of all three cultural periods are low scale, agreeing with the results of previous research in the Pennines.

Terminal Pleistocene/Early Holocene Environmental Change at the Sunshine Locality, North-Central Nevada, U.S.A.

2001 ◽  
Vol 55 (3) ◽  
pp. 303-312 ◽  
Author(s):  
Gary Huckleberry ◽  
Charlotte Beck ◽  
George T. Jones ◽  
Amy Holmes ◽  
Michael Cannon ◽  
...  
Keyword(s):  
Environmental Change ◽  
Great Basin ◽  
Sand Dunes ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Early Holocene ◽  
Faunal Remains ◽  
North Central ◽  
History Of ◽  
Terminal Pleistocene

AbstractSedimentological, faunal, and archaeological investigations at the Sunshine Locality, Long Valley, Nevada reveal a history of human adaptation and environmental change at the last glacial–interglacial transition in North America's north-central Great Basin. The locality contains a suite of lacustrine, alluvial, and eolian deposits associated with fluvially reworked faunal remains and Paleoindian artifacts. Radiocarbon-dated stratigraphy indicates a history of receding pluvial lake levels followed by alluvial downcutting and subsequent valley filling with marsh-like conditions at the end of the Pleistocene. A period of alluvial deposition and shallow water tables (9,800 to 11,000 14C yr B.P.) correlates to the Younger Dryas. Subsequent drier conditions and reduced surface runoff mark the early Holocene; sand dunes replace wetlands by 8,000 14C yr B.P. The stratigraphy at Sunshine is similar to sites located 400 km south and supports regional climatic synchroneity in the central and southern Great Basin during the terminal Pleistocene/early Holocene. Given regional climate change and recurrent geomorphic settings comparable to Sunshine, we believe that there is a high potential for buried Paleoindian features in primary association with extinct fauna elsewhere in the region yet to be discovered due to limited stratigraphic exposure and consequent low visibility.

scholarly journals Vegetation and climate change during the Medieval Climate Anomaly and the Little Ice Age on the southern Cape coast of South Africa: Pollen evidence from Bo Langvlei

The Holocene ◽  
2020 ◽  
Vol 30 (12) ◽  
pp. 1716-1727
Author(s):  
Nadia du Plessis ◽  
Brian M Chase ◽  
Lynne J Quick ◽  
Torsten Haberzettl ◽  
Thomas Kasper ◽  
...  
Keyword(s):  
Little Ice Age ◽  
Vegetation Change ◽  
Storm Track ◽  
Ice Age ◽  
Pollen Record ◽  
Western Cape ◽  
Medieval Climate Anomaly ◽  
Cape Coast ◽  
Climate Anomaly ◽  
Dry Conditions

This paper presents continuous, high resolution fossil pollen and microcharcoal records from Bo Langvlei, a lake in the Wilderness Embayment on South Africa’s southern Cape coast. Spanning the past ~1300 years and encompassing the Medieval Climate Anomaly (MCA; c. AD 950–1250) and the Little Ice Age (LIA; c. AD 1300–1850), these records provide a rare southern African perspective on past temperature, moisture and vegetation change during these much debated periods of the recent geological past. Considered together with other records from the Wilderness Embayment, we conclude that conditions in the region during the MCA chronozone were – in the context of the last 1300 years – likely relatively dry (reduced levels of Afrotemperate forest pollen) and perhaps slightly cooler (increased percentages of Stoebe-type pollen) than present. The most significant phase of forest expansion, and more humid conditions, occurred during the transition between the MCA and the most prominent cooling phase of the LIA. The LIA is clearly identified at this locality as a period of cool, dry conditions between c. AD 1600 and 1850. The mechanisms driving the changes observed in the Bo Langvlei pollen record appear to be generally linked to changes in temperature, and changes in the influence of tropical circulation systems. During warmer periods, moisture availability was higher at Bo Langvlei, and rainfall was perhaps less seasonal. During colder periods, precipitation resulting from tropical disturbances was more restricted, resulting in drier conditions. While increased precipitation has been reported during the LIA from Verlorenvlei in the Western Cape as a result of an equatorward displacement of the westerly storm-track at this time, the opposing response at Bo Langvlei suggests that any increased influence of westerlies was insufficient to compensate for the concurrent reduction in tropical/local rainfall in the region.

Holocene regional climate change and formation of southern Ontario's largest swamp inferred from a kettle-lake pollen record

2021 ◽  
pp. 1-19
Author(s):  
Eunji Byun ◽  
Sharon A. Cowling ◽  
Sarah A. Finkelstein
Keyword(s):  
Vegetation History ◽  
Regional Climate ◽  
Regional Climate Change ◽  
High Water ◽  
Carbon Accumulation ◽  
Pollen Record ◽  
Thuja Occidentalis ◽  
Peat Core ◽  
Northern High Latitude ◽  
Wetland Complex

Abstract Greenock Swamp wetland complex is one of few remaining natural wetlands in the Great Lakes region and, at 89 km2 in areal extent, is currently the largest hardwood swamp in southern Ontario, Canada. We present here pollen and sediment records from a kettle hole (Schmidt Lake) and adjacent Thuja occidentalis swamp to reconstruct regional paleoclimate and vegetation history, and to assess the timing and development of the swamp ecosystem and associated carbon stocks. Pollen-inferred paleoclimate reconstructions show the expected warming in the Early Holocene, and indicate the Mid-Holocene initiation of lake-effect snow. This enhanced snowfall may have maintained high water tables in the adjacent wetland since ca. 8300 years ago, promoting the establishment of a swamp dominated by Thuja occidentalis. Carbon accumulation rates in a >2-m-long peat core collected from a Thuja occidentalis stand adjacent to Schmidt Lake are 30–40 g C/m2/yr, which is higher than the average of northern high-latitude peatlands. Using topographic and hydrological parameters, we estimated that mean swamp peat thicknesses could exceed 2 m. Thus, this study encourages future investigations on temperate swamps from the perspective of hitherto underestimated Holocene carbon sinks and shows the importance of regional hydroclimate in supporting swamp ecosystems.

scholarly journals Drought and vegetation change in the central Rocky Mountains: Potential climatic mechanisms associated with the mega drought at 4200 cal yr BP

2017 ◽  
Author(s):  
Vachel A. Carter ◽  
Jacqueline Shinker
Keyword(s):  
Great Plains ◽  
Rocky Mountains ◽  
Vegetation Change ◽  
Reanalysis Data ◽  
Pollen Record ◽  
Growing Seasons ◽  
Pressure Ridge ◽  
Dry Conditions ◽  
Central Rocky Mountains ◽  
Regional Reanalysis

Abstract. Droughts are a naturally re-occurring phenomena that result in economic and societal losses. Yet, the most historic droughts that occurred in the 1930s and 1950s in the Great Plains and western United States were both shorter in duration, and less severe than mega droughts that have plagued the region in the past. Roughly 4200 years ago, a ~ 150-year long mega drought occurred in the central Rocky Mountains, as indicated by pollen evidence from lake sediments from Long Lake, south-eastern Wyoming. However, pollen evidence does not record the climate mechanisms that caused the drought; they only provide evidence that the drought occurred. A modern climate analogue technique using North American Regional Reanalysis data was applied to the sedimentary data in order to identify possible synoptic and dynamic patterns that may have caused the mega drought at 4200  yr BP. Our results demonstrate the warm and dry conditions were a result of anomalously higher-than-normal geopotential heights that were centred over the Great Plains beginning in spring and persisting until the fall. Drought conditions during the growing seasons was the result of the anomalous high-pressure ridge, which suppressed moisture transport via the low level jet from the Gulf of Mexico, as well as brought in dry continental air from in the interior region of North America. Conditions associated with the mega drought likely led to the changes in vegetation composition as evidenced by the pollen record.

scholarly journals A 25,000 year record of climate and vegetation change from the southwestern Cape coast, South Africa

2021 ◽  
pp. 1-18
Author(s):  
Lynne J. Quick ◽  
Brian M. Chase ◽  
Andrew S. Carr ◽  
Manuel Chevalier ◽  
B. Adriaan Grobler ◽  
...  
Keyword(s):  
Climate Change ◽  
South Africa ◽  
Vegetation Change ◽  
Coastal Wetland ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Meridional Overturning Circulation ◽  
Cape Coast ◽  
Moisture Availability ◽  
Meridional Overturning

Abstract The southwestern Cape of South Africa is a particularly dynamic region in terms of long-term climate change. We analysed fossil pollen from a 25,000 year sediment core taken from a near-coastal wetland at Pearly Beach that revealed that distinct changes in vegetation composition occurred along the southwestern Cape coast. From these changes, considerable variability in temperature and moisture availability are inferred. Consistent with indications from elsewhere in southwestern Africa, variability in Atlantic Meridional Overturning Circulation (AMOC) was identified as a strong determinant of regional climate change. At Pearly Beach, this resulted in phases of relatively drier conditions (~24–22.5 cal ka BP and ~22–18 cal ka BP) demarcated by brief phases of increased humidity from ~24.5–24 cal ka BP and 22.5–22 cal ka BP. During glacial Termination I (~19–11.7 ka), a marked increase in coastal thicket pollen from ~18.5 to 15.0 cal ka BP indicates a substantial increase in moisture availability, coincident, and likely associated with, a slowing AMOC and a buildup of heat in the southern Atlantic. With clear links to glacial and deglacial Earth system dynamics and perturbations, the Pearly Beach record represents an important new contribution to a growing body of data, providing insights into the patterns and mechanisms of southwestern African climate change.

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