scholarly journals Postglacial Fire Frequency and its Relation to Long-Term Vegetational and Climatic Changes in Yellowstone Park

1993 ◽  
Vol 17 ◽  
pp. 146-152
Author(s):  
Cathy Whitlock
Keyword(s):  
Lake Sediment ◽  
Sediment Cores ◽  
Natural Disturbance ◽  
Plant Macrofossils ◽  
Fire Frequency ◽  
Environmental Perturbations ◽  
Human Perturbation ◽  
Long Term Effect ◽  
History Of

The Paleoecologic recod provides unique insights into the response of communities to environmental perturbations of different duration and intensity. Climate is a primary agent of environmental change and its long-term effect on the vegetation of the Yellowstone/Grand Teton region is revealed in a network of pollen records (Whitlock, 1993). Fire frequency is controlled by climate, and as climate changes so too does the importance of fire in shaping spatial patterns of vegetation. The prehistoric record of Yellowstone's Northern Range, for example, shows the response of vegetation to the absence of major fires in the last 150 years (Whitlock et al., 1991; Engstrom et al., 1991). In longer records spanning the last 14,000 years, periods of frequent fire are suggested by sediments containing high percentages of fire-adapted trees, including lodgepole pine and Douglas-fir, and high amounts of charcoal (Bamosky et al., 1987; Millspaugh and Whitlock, 1993; Whitlock, 1993). The primary research objective has been to study the vegetational history of Yellowstone and its sensitivity to hanges in climate and fire frequency. This information is necessary to understand better the relative effects of climate, natural disturbance, and human perturbation on the Yellowstone landscape. Fossil pollen and plant macrofossils from dated-lake sediment cores provide information on past vegetation and climate. The frequency of charcoal particles and other fire indicators in dated lake-sediment cores offer evidence of past fires.

scholarly journals Postglacial Fire Frequency and its Relation to Long-Term Vegetational and Climatic Changes in Yellowstone Park

1994 ◽  
Vol 18 ◽  
pp. 160-165
Author(s):  
Cathy Whitlock
Keyword(s):  
Carbon Dioxide ◽  
Time Scales ◽  
Lake Sediment ◽  
Sediment Cores ◽  
Fire Frequency ◽  
Response Surfaces ◽  
Potential Range ◽  
Final Report ◽  
History Of

The paleoecologic record provides unique insights into the response of communities to environmental perturbations of different duration and intensity. Climate is a primary agent of environmental change and its long-term effect on the vegetation of the Yellowstone/Grand Teton region is revealed in a network of pollen records. Fire frequency is controlled by climate, and as climate changes so too does the importance of fire in shaping spatial patterns of vegetation. The prehistoric record of Yellowstone's Northern Range, for example, shows the response of vegetation to the absence of major fires in the last 150 years (Whitlock et al., 1991; Engstrom et al., 1991, 1994). In longer records spanning the last 14,000 years, periods of frequent fire are suggested by sediments containing high percentages of fire-adapted trees, including lodgepole pine and Douglas-fir, and high amounts of charcoal (Whitlock, 1993; Whitlock and Bartlein, 1993; Whitlock et al., 1995; Millspaugh and Whitlock, 1995). The primary research objective has been to study the vegetational history of the Yellowstone region and examine the sensitivity of vegetation to changes in climate and fire frequency on different time scales. This information is necessary to understand better the relative effects of climate, natural disturbance, and human perturbation in the present and future. Fossil pollen and plant macrofossils from dated-lake sediment cores provide information on past vegetation and climate. The frequency of charcoal particles and other fire indicators in dated lake-sediment cores offer evidence of past fires. Studies of future climate and vegetation in the Yellowstone region were based on climate simulations produced by general circulation models that incorporate a doubling of carbon dioxide and an equilibrium model to project potential range displacement of selected tree taxa. Relations between present distributions of tree taxa and climate were established by the use of response surfaces. The study has been divided into three parts: (1) an investigation of the vegetation history of Yellowstone National Park (YNP), (2) an analysis of charcoal accumulation in lakes following the 1988 fires and a reconstruction of fire history in central YNP on long time scales, and (3) a study of the potential ranges of tree taxa in the future with global increases in atmospheric carbon dioxide. A final report to the UW-NPS Research Center describes the methodology and findings in detail (Whitlock et al., 1994).

scholarly journals Late-Quaternary Vegetational and Climatic History of the Yellowstone/Grand Teton Region

1988 ◽  
Vol 12 ◽  
pp. 189-192
Author(s):  
Cathy Barnosky
Keyword(s):  
Environmental History ◽  
Late Quaternary ◽  
Sediment Cores ◽  
Sediment Accumulation ◽  
Fire Frequency ◽  
Ice Age ◽  
Sediment Chemistry ◽  
History Of ◽  
Climatic History

The research underway has focused on two different aspects of the environmental history of the Yellowstone/Grand Teton region. One objective has been to examine the long-term vegetational and climatic history of Jackson Hole, the Pinyon Peak Highlands, and Yellowstone Park since the end of late Pinedale glaciation, about 14,000 years ago. Fossil pollen in sediment cores from lakes in the region is being analyzed to clarify the nature and composition of ice-age refugia, the rate and direction of plant migrations in the initial stages of reforestation, and the long-term stability of postglacial communities. Sedimentary charcoal also is being examined to reconstruct fire frequency during different climatic regions and different vegetation types in the past. This information is necessary to assess the sensitivity of plant communities to environmental change and to understand postglacial landscapes of the northern rocky Mountains. The second objective has been a multidisciplinary investigation of the relationship of climate to sedimentation rates in lakes and ponds in Yellowstone, undertaken with Drs. Wright, D.R. Engstrom and S.C. Fritz of the University of Minnesota. This facet of the research examines the relative importance of climate, fire, hillslope erosion induced by overgrazing, and nutrient enrichment in the last 150 years, as recorded in selected lakes in the northern range of Yellowstone. Populations of elk and bison are known to have fluctuated greatly during this interval, and slight climatic changes are suggested from other lines of research. In this study pollen, diatoms, charcoal, sediment chemistry, and sediment accumulation rates are analyzed in short cores from small lakes.

scholarly journals Postglacial Fire Frequency and its Relation to Long Term Vegetational and Climatic Changes in Yellowstone Park

1991 ◽  
Vol 15 ◽  
pp. 276-279
Author(s):  
Cathy Whitlock ◽  
Sarah Millspaugh
Keyword(s):  
Environmental Change ◽  
Climate Changes ◽  
Fire Frequency ◽  
Climatic Changes ◽  
Term Effect ◽  
Environmental Perturbations ◽  
Long Term Effect ◽  
Primary Agent ◽  
Pollen Records

The paleoecologic record provides unique insights into the response of coinmunities to environmental perturbations of different duration and intensity. Climate is a primary agent of environmental change and its long-term effect on the vegetation of the Yellowstone region is revealed in a network of pollen records. Fire frequency is controlled by climate, and as climate changes so too does the importance of fire in shaping and maintaining spatia\l patterns of vegetation. The prehistoric record of Yellowstone's northern range, for example, shows the response of vegetation to an absence of major fires in the last 150 years (Whitlock et al. 1991; Engstrom et al. 1991). In longer records spanning the last 14,000 year8, periods of frequent fires are suggested • by sediments containing high percentages of fire-adapted trees and high amounts of charcoal (Bamosky et al. 1987).

scholarly journals Post Glacial Fire Frequency and its Relation to Longterm Vegetational and Climatic Changes in Yellowstone Park

1990 ◽  
Vol 14 ◽  
pp. 187-190
Author(s):  
Cathy Whitlock
Keyword(s):  
Pinus Contorta ◽  
Climate Changes ◽  
Fire Frequency ◽  
Climatic Changes ◽  
Term Effect ◽  
Regional Network ◽  
Environmental Perturbations ◽  
Long Term Effect ◽  
Primary Agent

The paleoecologic record provides unique insights into the response of communities to environmental perturbations of different duration and intensity. Climate is a primary agent of environmental change and its long-term effect on the vegetation of the Yellowstone/Grand Teton region is revealed in a regional network of pollen records. Fire frequency is controlled by climate, and as climate changes, so too does the importance of fire in shaping and maintaining spatial patterns of vegetation. The prehistoric record of Yellowstone's Northern Range, for example, shows the response of vegetation to the absence of major fires in the last 150 years (Whitlock et al. 1991; Engstrom et al. in press). In longer records spanning the last 13,000 years, periods of frequent fires are suggested by sediments containing high percentages of lodgepole pine (Pinus contorta) and Douglas-fir (Pseudotsuga menziesii) and high amounts of charcoal (Barnosky et al. 1987; Whitlock in prep.).

Using a lake sediment record to infer the long-term history of cyanobacteria and the recent rise of an anatoxin producing Dolichospermum sp.

Harmful Algae ◽  
2021 ◽  
Vol 101 ◽  
pp. 101971
Author(s):  
William O. Hobbs ◽  
Theo W. Dreher ◽  
Edward W. Davis ◽  
Rolf D. Vinebrooke ◽  
Siana Wong ◽  
...  
Keyword(s):  
Lake Sediment ◽  
Sediment Record ◽  
History Of

The History of Human Impacts in the Clear Lake Watershed ( California) as Deduced from Lake Sediment Cores*

1999 ◽  
Author(s):  
Douglas Nelson ◽  
Alan Heyvaert ◽  
Laurent Meillier ◽  
Jae Kim ◽  
Xiaoping Li ◽  
...  
Keyword(s):  
Lake Sediment ◽  
Human Impacts ◽  
Sediment Cores ◽  
Clear Lake ◽  
History Of

P3-148: Long-term effect of history of coronary artery bypass grafting surgery (CABG) on cognitive diagnosis, MRI findings and episodic memory scores

2009 ◽  
Vol 5 (4S_Part_13) ◽  
pp. P387-P388
Author(s):  
Ranjan Duara ◽  
Warren W. Barker ◽  
Elizabeth Potter ◽  
Jason Appel ◽  
Nisha Bhatia ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Coronary Artery Bypass Grafting ◽  
Artery Bypass ◽  
Term Effect ◽  
Cognitive Diagnosis ◽  
Bypass Grafting ◽  
Mri Findings ◽  
Long Term Effect ◽  
History Of

scholarly journals Postglacial Fire Frequency and its Relation to Long-Term Vegetational and Climatic Changes in Yellowstone Park

1992 ◽  
Vol 16 ◽  
pp. 212-218
Author(s):  
Cathy Whitlock
Keyword(s):  
Fire Regime ◽  
Fire Frequency ◽  
Northern Rocky Mountains ◽  
Modern Pollen ◽  
Pollen Rain ◽  
History Of ◽  
Fossil Records ◽  
In Fire ◽  
The Relationship

The primary research objective has been to study the vegetational history of Yellowstone and its sensitivity to changes in climate and fire frequency. To establish a sequence of vegetational changes, a network of pollen records spanning the last 14,000 years has been studied from different types of vegetation within the Park. The relationship between modern pollen rain, modern vegetation and present­day climate in the northern Rocky Mountains has been the basis for interpreting past vegetation and climate from the fossil records. Changes in fire regime during the past 14,000 years have been inferred from sedimentary charcoal and other fire proxy in lake sediments. Calibration of the fire signal is based on a study that measures the input of charcoal into lakes following the 1988 fires in Yellowstone.

scholarly journals History of the Larsen C Ice Shelf reconstructed from sub–ice shelf and offshore sediments

Geology ◽  
2021 ◽  
Author(s):  
J.A. Smith ◽  
C.-D. Hillenbrand ◽  
C. Subt ◽  
B.E. Rosenheim ◽  
T. Frederichs ◽  
...  
Keyword(s):  
Sediment Cores ◽  
Ice Shelf ◽  
Climatic Forcing ◽  
Ice Shelves ◽  
Future Evolution ◽  
Grounding Line ◽  
History Of ◽  
Two Phases ◽  
Line Following

Because ice shelves respond to climatic forcing over a range of time scales, from years to millennia, an understanding of their long-term history is critically needed for predicting their future evolution. We present the first detailed reconstruction of the Larsen C Ice Shelf (LCIS), eastern Antarctic Peninsula (AP), based on data from sediment cores recovered from below and in front of the ice shelf. Sedimentologic and chronologic information reveals that the grounding line (GL) of an expanded AP ice sheet had started its retreat from the midshelf prior to 17.7 ± 0.53 calibrated (cal.) kyr B.P., with the calving line following ~6 k.y. later. The GL had reached the inner shelf as early as 9.83 ± 0.85 cal. kyr B.P. Since ca. 7.3 ka, the ice shelf has undergone two phases of retreat but without collapse, indicating that the climatic limit of LCIS stability was not breached during the Holocene. Future collapse of the LCIS would therefore confirm that the magnitudes of both ice loss along the eastern AP and underlying climatic forcing are unprecedented during the past 11.5 k.y.

Towards a history of Holocene P dynamics for the Northern Hemisphere using lake sediment geochemical records

2021 ◽  
Author(s):  
Madeleine Moyle ◽  
John Boyle ◽  
Richard Chiverrell
Keyword(s):  
Human Impact ◽  
Lake Sediment ◽  
Northern Hemisphere ◽  
Human Activity ◽  
Lake Water ◽  
Process Model ◽  
P Cycling ◽  
History Of ◽  
P Supply

<p>Present day phosphorus (P) enrichment and accelerated P cycling are changes superimposed on a dynamic Holocene history of landscape recovery from glaciation, changes in climate, and long-term low-intensity human activity. Knowledge of the changing role of human activity in driving long-term P dynamics is essential for understanding landscape P export and managing both terrestrial and aquatic environments.</p><p>Here we apply a simple process model to published lake sediment geochemical P records from 24 sites distributed across the Northern Hemisphere, producing Holocene records of landscape P yield and reconstructions of lake water TP concentrations. These records are a first attempt to produce values for average P export for the Northern Hemisphere over the Holocene, which can be used for constraining long-term landscape P cycling models.</p><p>Individual site trajectories of reconstructed Holocene landscape P yield and lake water TP varied systematically, with differences attributable to landscape development history, in turn driven by climate, human impact and other local factors. Three distinct traits are apparent across the records. Mountain sites with minimal direct human impact show falling Holocene P supply, and conform to conceptual models of natural soil development (Trait 1). Lowland sites  where substantial (pre-)historic agriculture was present show progressively increasing Holocene P supply (Trait 2). Lowland sites may also show a rapid acceleration in P supply over the last few centuries, where high intensity land use, including settlements and farming, are present (Trait 3).</p><p>This long-term perspective is pivotal to understanding drivers of change in coupled terrestrial and aquatic P cycling. Our reconstructions of long-term lake water TP are particularly useful for target-driven management of aquatic systems.</p>

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