POLLEN EVIDENCE FOR CLIMATIC VARIABILITY AND CULTURAL DISTURBANCE IN THE MAYA LOWLANDS

2002 ◽  
Vol 13 (1) ◽  
pp. 85-101 ◽  
Author(s):  
Barbara W. Leyden
Keyword(s):  
Environmental Change ◽  
Late Holocene ◽  
Climatic Variability ◽  
Late Glacial ◽  
Early Holocene ◽  
Maya Lowlands ◽  
Late Glacial Period ◽  
Plant Associations ◽  
Multidisciplinary Studies ◽  
Isotopic Records

Palynology provides a record of past environmental change in the Maya Lowlands. The underlying principles are simple, but, as with all proxies, there are limitations. During the late glacial period, environmental change was governed by climate, which was cooler and much drier and supported sparse temperate vegetation. The early Holocene epoch was warmer and very wet in the southern Lowlands when mesic tropical forests predominated, while the northern Yucatan Peninsula was edaphically dry until eustatic sea level rose. The modern distributions of plant associations and climatic gradients were established at the end of the early Holocene. Climatic variability continued throughout the Holocene. However, the ability of palynology to identify climatic events is hindered after the Maya became numerous in the Lowlands. Then, multidisciplinary studies provide a better interpretation of events, especially during the late Holocene. Pollen records poorly reflect cyclical droughts seen in isotopic records, as natural vegetation has adapted to these fluctuations.

Local and regional vegetation change on the northeastern Olympic Peninsula during the Holocene

1995 ◽  
Vol 73 (10) ◽  
pp. 1618-1627 ◽  
Author(s):  
J. S. McLachlan ◽  
L. B. Brubaker
Keyword(s):  
Late Holocene ◽  
Vegetation History ◽  
Late Glacial ◽  
Early Holocene ◽  
Thuja Plicata ◽  
Alnus Rubra ◽  
Glacial Period ◽  
Olympic Peninsula ◽  
The Holocene ◽  
Late Glacial Period

The postglacial vegetation history of the northeastern Olympic Peninsula was investigated at different spatial scales by comparing the pollen, macrofossil, and charcoal records from a low elevation lake (Crocker Lake) and a nearby forested swamp (Cedar Swamp). The regional pollen record from Crocker Lake revealed a parkland of coniferous species with divergent modern ecological tolerances, including Pinus contorta, Picea sitchensis, and Abies lasiocarpa during the late glacial period (~ 13 000 – 10 000 BP). Disturbance-adapted species such as Alnus rubra and Pseudotsuga menziesii dominated forests during the early Holocene (10 000 – 7000 BP). Modern forests containing mesic late-successional species such as Tsuga heterophylla and Thuja plicata were established during the late Holocene (7000 BP to present). During the late glacial period, the local vegetation at Cedar Swamp was dominated by Alnus sinuata. Hydrologic changes resulted in the establishment of a deep marsh during the early Holocene. Hydrosere succession from an open aquatic environment to a forested wetland and disturbance-mediated alternations between Thuja plicata and Alnus rubra characterized the local vegetation during the late Holocene. Throughout the Holocene, the vegetation of the northeastern Olympic Peninsula was governed by broad climatic and physiographic parameters at the regional scale and the effects of local geomorphologic constraints and disturbance history at the finer landscape scale. Key words: fossil pollen, vegetation history, Olympic Peninsula, Quaternary.

scholarly journals Paleoclimate reconstruction in the Levant region from the geochemistry of a Holocene stalagmite from the Jeita cave, Lebanon

2008 ◽  
Vol 70 (3) ◽  
pp. 368-381 ◽  
Author(s):  
Sophie Verheyden ◽  
Fadi H. Nader ◽  
Hai J. Cheng ◽  
Lawrence R. Edwards ◽  
Rudy Swennen
Keyword(s):  
Growth Rate ◽  
Late Glacial ◽  
Early Holocene ◽  
Glacial Period ◽  
Progressive Change ◽  
Paleoclimate Reconstruction ◽  
Late Glacial Period ◽  
Carbon Isotopic ◽  
Isotopic Records ◽  
Crystallographic Aspect

AbstractDated oxygen and carbon isotopic profiles from a Holocene stalagmite (11.9–1.1 ka) from the Jeita cave, Lebanon, are compared to variations in crystallographic habit, stalagmite diameter and growth rate. The profiles show generally high δ18O and δ13C values during the late-glacial period, low values during the early Holocene, and again high values after 5.8 ka. On the basis of the good correlation between the morphological and crystallographic aspect of the stalagmite and its isotopic records, as well as the isotopic response of speleothems from central and northern Israel, we relate high δ18O and δ13C values to drier conditions. Between 6.5 and 5.8 ka an increase in isotopic values, a decrease in growth rate and stalagmite diameter suggest a transition from wet conditions in the early Holocene towards drier conditions in the mid-Holocene. The transition occurred in two steps, first a progressive change to drier conditions started at 6.5 ka but was interrupted by a short (∼ 100 years) return to wetter conditions, followed by an equally rapid (< 200 years) change to drier conditions.

Holocene dune activity and environmental change in the prairie parki and and boreal forest, central Saskatchewan, Canada

The Holocene ◽  
2006 ◽  
Vol 16 (1) ◽  
pp. 17-29 ◽  
Author(s):  
Stephen A. Wolfe ◽  
Jeff Ollerhead ◽  
David J. Huntley ◽  
Olav B. Lian
Keyword(s):  
Environmental Change ◽  
Boreal Forest ◽  
Great Plains ◽  
Late Holocene ◽  
Early Holocene ◽  
Aeolian Activity ◽  
Landscape Response ◽  
Response To Environmental Change ◽  
Holocene Activity ◽  
Dune Activity

Past aeolian activity was reconstructed at four dunefields in the prairie parkland and boreal forest of central Saskatchewan to elucidate landscape response to environmental change. Optical ages from stabilized dunes in the boreal transition ecoregion indicate two episodes of activity. The first, at about 11 ka, corresponds to a period of early-Holocene parkland and grassland cover following deglaciation and drainage after about 13.0 ka, and brief establishment of boreal forest. The second, between about 7.5 and 5 ka, corresponds to a period of mid-Holocene parkland-grassland cover. Optical ages from dunefields in the prairie parkland primarily record mid-Holocene activity, between about 7.5 and 4.7 ka, corresponding to a period of grassland cover, with some reworking continuing into the late Holocene. Although this area was deglaciated by about 13.5 ka, there is no evidence of early-Holocene dune activity, suggesting that mid-Holocene activity may have reworked earlier deposits here. Consequently, much of the morphology and stratigraphy observed in these dunefields are associated with mid-Holocene activity, likely associated with increased aridity and reduced vegetation cover at that time. This study provides the most northerly evidence of mid-Holocene dune reactivation on the Great Plains, lending support to the assertion that aeolian activity was widespread at that time.

Postglacial vegetation and fire history of the southern Cascade Range, Oregon

2015 ◽  
Vol 84 (3) ◽  
pp. 348-357 ◽  
Author(s):  
Alicia White ◽  
Christy Briles ◽  
Cathy Whitlock
Keyword(s):  
Late Holocene ◽  
Large Scale ◽  
Fire History ◽  
Late Glacial ◽  
Fire Frequency ◽  
Cascade Range ◽  
Early Holocene ◽  
Glacial Period ◽  
Holocene Thermal Maximum ◽  
History Of

The Cascade Range of southwestern Oregon contains some of North America's most diverse forests, but the ecological history of this area is poorly understood. A 7900-yr-long pollen and charcoal record was examined to better understand past changes in vegetation and fire activity in relation to large-scale climate variability. From 7900 to 3500 cal yr BP, the dominance of xerophytic species and the frequent fires are consistent with a climate that was warmer and drier than at present. The period from 3500 cal yr BP to present experienced an abundance of mesophytic taxa and reduced fire frequency, suggesting cooler and wetter conditions. The regional history of Abies indicates that it was most widespread during the late-glacial period; its range contracted during the early Holocene thermal maximum, and it steadily expanded during the middle and late Holocene. In contrast, Pseudotsuga was restricted in range during the glacial period, became abundant at low-elevation sites in the Coast and northern Cascade ranges during the early Holocene, and was more prevalent in southern mid-elevation sites as the climate became cooler and wetter in the late Holocene. The sensitivity of these species to past climate change suggests that biogeographic responses to future conditions will be highly variable in this region.

Lake-Level Chronology on the Southern Bolivian Altiplano (18°–23°S) During Late-Glacial Time and the Early Holocene

1999 ◽  
Vol 51 (1) ◽  
pp. 54-66 ◽  
Author(s):  
Florence Sylvestre ◽  
Michel Servant ◽  
Simone Servant-Vildary ◽  
Christiane Causse ◽  
Marc Fournier ◽  
...  
Keyword(s):  
Lake Level ◽  
Large Scale ◽  
Late Glacial ◽  
Climatic Changes ◽  
Early Holocene ◽  
Late Glacial Period ◽  
High Lake Level ◽  
Tropical Areas ◽  
Bolivian Altiplano ◽  
Glacial Time

AbstractStratigraphic analyses of outcrops, shorelines, and diatoms from the southern Bolivian Altiplano (Uyuni-Coipasa basin) reveal two major lacustrine phases during the late-glacial period and the early Holocene, based on a chronology established by radiocarbon and U/Th control. A comparison of14C and230Th/234U ages shows that during times of high lake level, radiocarbon ages are valid. However, during low-water periods,14C ages must be corrected for a reservoir effect. The lacustrine Tauca phase started a little before 16,00014C yr B.P., and the lake level reached its maximum between 13,000 and 12,00014C yr B.P. A dry event (Ticaña) occurred after ca. 12,000 and before 950014C yr B.P. A moderate lacustrine oscillation (Coipasa event) occurred between ca. 9500 and 850014C yr B.P., using a reservoir-corrected conventional14C chronology. Comparisons between the lake-level chronology in the Uyuni-Coipasa basin and data from other southern tropical areas of South America suggest that the lacustrine evolution may reflect large-scale climatic changes.

The postglacial history of three Picea species in New England, USA

2003 ◽  
Vol 59 (1) ◽  
pp. 61-69 ◽  
Author(s):  
Matts Lindbladh ◽  
George L. Jacobson ◽  
Molly Schauffler
Keyword(s):  
New England ◽  
Late Holocene ◽  
Classification Tree ◽  
Population Expansion ◽  
Pollen Grains ◽  
Late Glacial ◽  
Early Holocene ◽  
Pollen Record ◽  
Recent Population Expansion ◽  
Picea Species

AbstractGiven the difficulty of separating the three Picea species—P. glauca, P. mariana, and P. rubens (white, black, and red spruce)—in the pollen record, little is known about their unique histories in eastern North America following deglaciation. Here we report the first use of a classification tree analysis (CART) to distinguish pollen grains of these species. It was successfully applied to fossil pollen from eight sites in Maine and one in Massachusetts. We focused on the late glacial/early Holocene (14,000 to 8000 cal yr B.P.) and the late Holocene (1400 cal yr B.P. to present)—the two key periods since deglaciation when Picea has been abundant in the region. The result shows a shift from a Picea forest of P. glauca and P. mariana in the late glacial to a forest of P. rubens and P. mariana in the late Holocene. The small number of P. rubens grains identified from the late glacial/early Holocene samples (<5%) suggests that that species was either absent or rare at most of the sites. The occurrence and distribution of the three species do not reveal any geographic or temporal trend during late glacial time, but the data suggest that they were distributed in local patches on the landscape. The results of this study indicate that the recent population expansion of Picea (1000 to 500 cal yr B.P.) was likely the first time since deglaciation that P. rubens was abundant in the region.

High vegetation and environmental diversity during the Late Glacial and Early Holocene on the example of lowlands in the Czech Republic

Biologia ◽  
2014 ◽  
Vol 69 (7) ◽  
Author(s):  
Libor Petr ◽  
Jan Novák
Keyword(s):  
Woody Species ◽  
Late Glacial ◽  
Pine Forest ◽  
Early Holocene ◽  
Glacial Period ◽  
Elbe River ◽  
Environmental Diversity ◽  
The Czech Republic ◽  
Late Glacial Period ◽  
The Elbe River

AbstractThe diversity of vegetation and the environment in the Late Glacial period in the Elbe region is illustrated by a comparison of three palynological localities. The localities differ in their history, profile lithology and position relative to the Elbe river. The Hrabanovská černava profile holds a record of the development of a shallow lake, which was surrounded by a cold continental steppe in the Early Dryas. Evidence of a pine forest in the Late Glacial period is captured in the surroundings of the profile Chrást. The Mělnický úval — Přívory locality is an interdune infill, where marl sediments redeposited in shallow water. The surrounding vegetation was diffuse and influenced by erosion. In the Early Holocene, the landscape was covered by an open birch-pine forest. Broad-leaved woody species appeared later. Localities in the Elbe region share a high proportion of Pinus throughout the Holocene as a result of the spread of drift and terrace sands. The human impact in the mid Holocene manifests as evidence of intensive charring of localities.

A 14,300-year-long record of fire–vegetation–climate linkages at Battle Ground Lake, southwestern Washington

2008 ◽  
Vol 70 (2) ◽  
pp. 251-264 ◽  
Author(s):  
Megan K. Walsh ◽  
Cathy Whitlock ◽  
Patrick J. Bartlein
Keyword(s):  
Late Holocene ◽  
Fire History ◽  
Late Glacial ◽  
Tsuga Heterophylla ◽  
Fire Season ◽  
Charcoal Analysis ◽  
Vegetation Shifts ◽  
Late Glacial Period ◽  
High Severity ◽  
History Record

AbstractHigh-resolution macroscopic charcoal analysis was used to reconstruct a 14,300-year-long fire history record from the lower Columbia River Valley in southwestern Washington, which was compared to a previous vegetation reconstruction for the site. In the late-glacial period (ca. 14,300-13,100 cal yr BP), Pinus/Picea-dominated parkland supported little to no fire activity. From the late-glacial to the early Holocene (ca. 13,100-10,800 cal yr BP), Pseudotsuga/Abies-dominated forest featured more frequent fire episodes that burned mostly woody vegetation. In the early to middle Holocene (ca. 10,800-5200 cal yr BP), Quercus-dominated savanna was associated with frequent fire episodes of low-to-moderate severity, with an increased herbaceous (i.e., grass) charcoal content. From the middle to late Holocene (ca. 5200 cal yr BP to present), forest dominated by Pseudotsuga, Thuja-type, and Tsuga heterophylla supported less frequent, but mostly large or high-severity fire episodes. Fire episodes were least frequent, but were largest or most severe, after ca. 2500 cal yr BP. The fire history at Battle Ground Lake was apparently driven by climate, directly through the length and severity of the fire season, and indirectly through climate-driven vegetation shifts, which affected available fuel biomass.

A comparison of postglacial arcellacean (“Thecamoebian”) and pollen succession in Atlantic Canada, illustrating the potential of arcellaceans for paleoclimatic reconstruction

1995 ◽  
Vol 69 (5) ◽  
pp. 980-993 ◽  
Author(s):  
Francine M. G. Mccarthy ◽  
Eric S. Collins ◽  
John H. Mcandrews ◽  
Helen A. Kerr ◽  
David B. Scott ◽  
...  
Keyword(s):  
Late Holocene ◽  
Transfer Functions ◽  
Ice Sheets ◽  
Younger Dryas ◽  
Late Glacial ◽  
Early Holocene ◽  
Atlantic Canada ◽  
Pollen Record ◽  
Pollen Data ◽  
Pollen Species

Cores dating back to deglaciation were taken from three lakes in Atlantic Canada and analyzed for arcellaceans and pollen. Paleotemperatures and paleo-precipitation were calculated from the pollen data using transfer functions. A sudden warming is recorded by the pollen around 10,000 years B.P., followed by a general warming to the mid Holocene Hypsithermal, then by a decrease in temperature and increase in effective precipitation to the present. The three lakes, two in western Newfoundland and one in eastern Nova Scotia, contain similar late glacial (13-10 ka), early Holocene (10-8 ka), mid Holocene (8-4 ka), and late Holocene (4-0 ka) arcellacean assemblages. Immediately following retreat of the ice sheets, Centropyxis aculeata, Centropyxis constricta, Difflugia oblonga, Difflugia urceolata, and Difflugia corona were common. The latter part of the late glacial is characterized by sparse assemblages dominated by C. aculeata. The arcellacean record thus suggests a climatic reversal in Atlantic Canada between 11,500 and 10,000 years B.P., analogous to the Younger Dryas, although this is not recorded by the pollen. Species diversity increased sharply at the beginning of the Holocene, and D. oblonga is the dominant taxon in early Holocene sediments. Difflugia oblonga remained common through the mid Holocene, but percentages of C. aculeata were very low, and Pontigulasia compressa and Difflugia bacillifera peaked in abundance during the Hypsithermal. The late Holocene is characterized by a resurgence in C. aculeata at the expense of other taxa. The increase in Heleopera sphagni and Nebella collaris since 5,000 years B.P. at the two sites in southwestern Newfoundland reflects paludification in response to increased precipitation since the Hypsithermal. Because the changes in arcellacean assemblages are regionally synchronous in all three lakes and coincide with climatically driven vegetational successions indicated by the pollen record, arcellaceans appear to respond to climatic change, and thus may be useful paleoecological and paleolimnological indicators. With their quicker generation time, these protists may be better suited than pollen to recording short-lived phenomena, like the mid-Holocene Hypsithermal and the Younger Dryas reversal.

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