Pollen Analysis of Digger's Creek Bog, Kosciuszko National Park: Vegetation History and Tree-line Change

1999 ◽  
Vol 47 (5) ◽  
pp. 725 ◽  
Author(s):  
A. R. H. Martin
Keyword(s):  
National Park ◽  
Vegetation History ◽  
Early 20Th Century ◽  
Peat Bog ◽  
Tree Line ◽  
Before Present ◽  
Near Surface ◽  
Lake Zone ◽  
Arboreal Pollen ◽  
Eastern Australia

Digger's Creek Bog, an Empodisma minus–Callistemon pityoides–Sphagnum cristatum shrubby subalpine peat bog, alt. c. 1690 m, not far below local altitudinal tree-line, began development > 10 000 years before present as an Astelia sp.–Carex alpine soak. Surrounding vegetation was a grassy alpine herbfield with many Asteraceae, Apiaceae and Gentianella diemensis, corresponding to the regional Club Lake Zone C, dated to the same period. Astelia died out c. 6500 years before present approximately at the Club Lake C/D 1 boundary, marked by spread of Pomaderris in subjacent montane forests. Thereafter, shrubs, mainly Myrtaceae and Epacridaceae, and Restionaceae (Empodisma and Restio australis) dominated the bog. Epacris cf. paludosa and C. pityoides seem to have been the earliest shrubs to invade, Baeckea, probably B. gunniana, and Richea continentis reaching maximum prominence 5000–3000 years before present. Sphagnum was uncommon until recently. Regional arboreal pollen enable comparisons with other sites in south-eastern Australia but immigration of the tree-line species Eucalyptus pauciflora subsp. niphophila (snowgum) is not well expressed in the pollen spectra. Surface and near-surface counts of this species are higher than at any preceding time, and correspond most closely to surface counts in adjacent young snowgum woodland. The co-occurrence of weed pollens, probably associated with the late 19th and early 20th century practice of summer pasturing stock on the alpine–subalpine tract, suggests that pasturing and burning, responsible for widespread severe fires on this range, led both to the formation of dense even-aged snowgum woodland that had been open and patchy at this altitude, and a spread of Sphagnum on the bog surface.

scholarly journals New ground ice maps for Canada using a paleogeographic modelling approach

2019 ◽  
Vol 13 (3) ◽  
pp. 753-773 ◽  
Author(s):  
H. Brendan O'Neill ◽  
Stephen A. Wolfe ◽  
Caroline Duchesne
Keyword(s):  
Glacial Lake ◽  
Significant Advance ◽  
Small Scale ◽  
Permafrost Degradation ◽  
Field Observations ◽  
Tree Line ◽  
Ground Ice ◽  
Near Surface ◽  
Western Arctic ◽  
Modelling Approach

Abstract. Ground ice melt caused by climate-induced permafrost degradation may trigger significant ecological change, damage infrastructure, and alter biogeochemical cycles. The fundamental ground ice mapping for Canada is now >20 years old and does not include significant new insights gained from recent field- and remote-sensing-based studies. New modelling incorporating paleogeography is presented in this paper to depict the distribution of three ground ice types (relict ice, segregated ice, and wedge ice) in northern Canada. The modelling uses an expert-system approach in a geographic information system (GIS), founded in conceptual principles gained from empirically based research, to predict ground ice abundance in near-surface permafrost. Datasets of surficial geology, deglaciation, paleovegetation, glacial lake and marine limits, and modern permafrost distribution allow representations in the models of paleoclimatic shifts, tree line migration, marine and glacial lake inundation, and terrestrial emergence, and their effect on ground ice abundance. The model outputs are generally consistent with field observations, indicating abundant relict ice in the western Arctic, where it has remained preserved since deglaciation in thick glacigenic sediments in continuous permafrost. Segregated ice is widely distributed in fine-grained deposits, occurring in the highest abundance in glacial lake and marine sediments. The modelled abundance of wedge ice largely reflects the exposure time of terrain to low air temperatures in tundra environments following deglaciation or marine/glacial lake inundation and is thus highest in the western Arctic. Holocene environmental changes result in reduced ice abundance where the tree line advanced during warmer periods. Published observations of thaw slumps and massive ice exposures, segregated ice and associated landforms, and ice wedges allow a favourable preliminary assessment of the models, and the results are generally comparable with the previous ground ice mapping for Canada. However, the model outputs are more spatially explicit and better reflect observed ground ice conditions in many regions. Synthetic modelling products that incorporated the previous ground ice information may therefore include inaccuracies. The presented modelling approach is a significant advance in permafrost mapping, but additional field observations and volumetric ice estimates from more areas in Canada are required to improve calibration and validation of small-scale ground ice modelling. The ground ice maps from this paper are available in the supplement in GeoTIFF format.

The Rabbit in Subalpine South-eastern Australia. I. Population Structure and Productivity

1974 ◽  
Vol 1 (1) ◽  
pp. 1 ◽  
Author(s):  
DJ Dunsmore
Keyword(s):  
Population Structure ◽  
National Park ◽  
Initial Level ◽  
Adult Survival ◽  
South Eastern ◽  
Breeding Group ◽  
Eastern Australia ◽  
Domestic Livestock ◽  
A Site ◽  
Better Than

An unconfined, almost completely tagged rabbit population on a site of about 100 ha was studied by observation and trapping for 5 years. The commencement of the study coincided approximately with the incorporation of the area into the Kosciusko National Park, the elimination of grazing by domestic livestock, and the cessation of the previously almost annual burning of the area. During the 5-yr study the fecundity of the rabbits declined to little more than half the initial level. This was not a result of the concurrently increasing age of the population, which was shown to be quite unrelated. It was also shown that the 1yr old rabbits were less fecund than the older rabbits, whose fecundity remained constant. Although it appeared subjectively to be so, the area was not uniformly suitable for the survival of rabbits. In one of its four subdivisions adult survival was much better than in the others; and in one of the others it was much the worst. During the study there was considerable immigration to the area, presumably balanced by migration. Females tended to remain where they were born and in no case changed from one breeding group to another. Males were considerably less sedentary than the females.

scholarly journals Transformation of Lake Ecosystem into Peat Bog and Vegetation History Based on Durne Bagno Mire (Lublin Polesie, E Poland)

2007 ◽  
Vol 29 (-1) ◽  
pp. 23-43 ◽  
Author(s):  
Krystyna Bałaga
Keyword(s):  
Vegetation History ◽  
Chemical Elements ◽  
Late Glacial ◽  
Unique Element ◽  
Peat Bogs ◽  
Lake Ecosystem ◽  
Peat Bog ◽  
Mineral Material ◽  
Late Glacial And Holocene ◽  
Almost All

Transformation of Lake Ecosystem into Peat Bog and Vegetation History Based on Durne Bagno Mire (Lublin Polesie, E Poland)In this paper, the history of Durne Bagno, i.e. the largest peat bog in the Lublin Polesie, is shown. Peat bogs are a unique element of the Polesie landscape. They occur mostly in the subregion of the Łęczna-Włodawa Lake District occupying 1.07% of its area. They fill basin-shaped depressions without outflow, often in the immediate vicinity of dystrophic lakes. Based on interdisciplinary research, the changes of vegetation cover and the Durne Bagno lake-mire ecosystem in the Late Glacial and Holocene are presented. The environmental conditions are reconstructed from pollen analysis, detailed identification of algae ofPediastrumgenus and chemical composition of deposits, together with the results of Cladocera analysis. The distribution of archaeological artefacts in the surroundings of Durne Bagno peat bog gives the view on the intensity of settlement in this area. The duration of the limnic and mire stages during the development of the ecosystem was different in different parts of the examined depression. In its central part the limnic stage lasted about 8000 years and included the period from the Late Glacial to the middle Holocene (to about 6000 BP). It is represented by 7 pollen zones and 6 chemical zones. The mire stage contained a part the Atlantic period and on the Subboreal and Subatlantic periods. It is represented by 4 pollen zones and 5 chemical zones. Limnic and mire deposits differ widely in the concentrations of chemical elements. The contents of mineral material and almost all analyzed elements in limnic deposits are high. These deposits are characterized by positive correlation between the contents of Zn and Cr and the frequency of Cladocera fauna. Peat contains very low amount of mineral material. The contents of Ca, Sr and Ba are rather high in sedgemoss peat. The concentrations of these elements decrease upwards due to oligotrophic processes and sedentation of sedge-Eriophorum-Sphagnumpeat. Peat succession was modified by pastoral economy of prehistoric man.

scholarly journals Southeastern Australian Heat Waves from a Trajectory Viewpoint

2017 ◽  
Vol 145 (10) ◽  
pp. 4109-4125 ◽  
Author(s):  
Julian F. Quinting ◽  
Michael J. Reeder
Keyword(s):  
Indian Ocean ◽  
Heat Wave ◽  
Heat Waves ◽  
The South ◽  
South Indian Ocean ◽  
Near Surface ◽  
South Indian ◽  
Eastern Australia ◽  
Upper Level

Although heat waves account for more premature deaths in the Australian region than any other natural disaster, an understanding of their dynamics is still incomplete. The present study identifies the dynamical mechanisms responsible for heat waves in southeastern Australia using 10-day backward trajectories computed from the ERA-Interim reanalyses. Prior to the formation of a heat wave, trajectories located over the south Indian Ocean and over Australia in the lower and midtroposphere ascend diabatically ahead of an upper-level trough and over a baroclinic zone to the south of the continent. These trajectories account for 44% of all trajectories forming the anticyclonic upper-level potential vorticity anomalies that characterize heat waves in the region. At the same time, trajectories located over the south Indian Ocean in the lower part of the troposphere descend and aggregate over the Tasman Sea. This descent is accompanied by a strong adiabatic warming. A key finding is that the temperatures are raised further through diabatic heating in the boundary layer over eastern Australia but not over the inner Australian continent. From eastern Australia, the air parcels are advected southward as they become incorporated into the near-surface anticyclone that defines the heat wave. In contrast to past studies, the importance of cloud-diabatic processes in the evolution of the midlatitude large-scale flow and the role of adiabatic compression in elevating the near-surface temperatures is emphasized. Likewise, the role of the local surface sensible heat fluxes is deemphasized.

Classics and archives

2016 ◽  
Vol 40 (5) ◽  
pp. 732-737 ◽  
Author(s):  
David R. Butler
Keyword(s):  
20Th Century ◽  
Landscape Change ◽  
National Park ◽  
Aerial Photographs ◽  
Glacier National Park ◽  
Early 20Th Century ◽  
Us Army ◽  
Geological Survey Professional Paper ◽  
National Archives ◽  
The Us

In 1925, then-Captain AW Stevens of the US Army Air Corps took low-angle, oblique aerial photographs of the spectacular landscape of Glacier National Park, Montana (USA). Two of those photographs, of astonishing clarity, were used in a US Geological Survey Professional Paper published in 1959, but were subsequently assigned to the US National Archives and never utilized again. This paper advocates the usefulness of Stevens’ photographs for documenting landscape change from the early 20th century to the present. Stevens’ photographs illustrate the “state” of numerous Park glaciers in 1925, and are the first known aerial photographs of the Park glaciers. These photographs can be used in comparison to modern photographs to illustrate the extent of glacial recession that has occurred in the Park since 1925.

scholarly journals Multidecadally resolved polarity oscillations during a geomagnetic excursion

2018 ◽  
Vol 115 (36) ◽  
pp. 8913-8918 ◽  
Author(s):  
Yu-Min Chou ◽  
Xiuyang Jiang ◽  
Qingsong Liu ◽  
Hsun-Ming Hu ◽  
Chung-Che Wu ◽  
...  
Keyword(s):  
20Th Century ◽  
Geomagnetic Field ◽  
Early 20Th Century ◽  
Human Society ◽  
Before Present ◽  
Earth History ◽  
Geomagnetic Excursion ◽  
Deep Interior ◽  
Polarity Reversals ◽  
Chinese Stalagmite

Polarity reversals of the geomagnetic field have occurred through billions of years of Earth history and were first revealed in the early 20th century. Almost a century later, details of transitional field behavior during geomagnetic reversals and excursions remain poorly known. Here, we present a multidecadally resolved geomagnetic excursion record from a radioisotopically dated Chinese stalagmite at 107–91 thousand years before present with age precision of several decades. The duration of geomagnetic directional oscillations ranged from several centuries at 106–103 thousand years before present to millennia at 98–92 thousand years before present, with one abrupt reversal transition occurring in one to two centuries when the field was weakest. These features indicate prolonged geodynamo instability. Repeated asymmetrical interhemispheric polarity drifts associated with weak dipole fields likely originated in Earth’s deep interior. If such rapid polarity changes occurred in future, they could severely affect satellites and human society.

An assessment of the relationship between tree-ring counts and basal girth of high-altitude populations of Eucalyptus pauciflora (Myrtaceae)

2009 ◽  
Vol 57 (7) ◽  
pp. 583 ◽  
Author(s):  
Libby Rumpff ◽  
Seraphina C. Cutler ◽  
Ian Thomas ◽  
John W. Morgan
Keyword(s):  
High Altitude ◽  
National Park ◽  
Linear Growth ◽  
Growth Ring ◽  
Tree Line ◽  
Growth Rings ◽  
Regression Methods ◽  
Ski Resorts ◽  
Non Linear ◽  
The Relationship

We investigated the relationship between the number of growth rings (a surrogate for approximate age of stems) and basal girth for Eucalyptus pauciflora (Maiden & Blakely) L.A.S.Johnson & Blaxell. Using basal-girth measurements and growth-ring counts obtained from trees felled on ski slopes at three Victorian alpine ski resorts, as well as seedlings destructively sampled from near the tree line on four summits, we modelled the relationship between growth rings and basal girth by using simple linear and non-linear regression methods. We compared our data to growth-ring–basal-girth data collected from low- and high-altitude E. pauciflora woodland stands in Kosciuszko National Park. The relationship between the number of tree rings and basal girth at Victorian sites was non-linear (growth rings = 3.62 × girth0.63, R2 = 0.96). In general, the Victorian and Kosciuszko datasets were in broad agreement, although caution is required when attempting to estimate the age of trees with >115-cm girth. We suggest that the model we have developed can be combined with dendrological techniques to estimate the age of older trees accurately.

Scattered native trees and soil patterns in grazing land on the Northern Tablelands of New South Wales, Australia

Soil Research ◽  
2007 ◽  
Vol 45 (3) ◽  
pp. 199 ◽  
Author(s):  
Brian R. Wilson ◽  
Ivor Growns ◽  
John Lemon
Keyword(s):  
New South ◽  
New South Wales ◽  
Tree Canopy ◽  
Deep Drainage ◽  
Grazing Land ◽  
Near Surface ◽  
Soil Layers ◽  
South Wales ◽  
Eastern Australia ◽  
Canopy Effect

Over large areas of south-eastern Australia, the original cover of native woodland has been extensively cleared or modified, and what remains is often characterised by scattered trees beneath which the ground-storey vegetation is largely grazed or otherwise managed. This study investigated the influence of scattered Blakely’s red gum (Eucalyptus blakelyi) trees on both near-surface and deeper soil layers in temperate grazed pastures on the Northern Tablelands of New South Wales, Australia. A significant canopy effect was observed with elevated soil pH, carbon, and nutrient status inside the tree canopy indicating soil enrichment in a zone around the tree. This effect, however, was largely restricted to the surface (0–0.20 m) soil layers. Chloride concentrations were elevated near to trees but only in the deeper soil layers, suggesting that a modified water use and deep drainage mechanism occurred near the trees. Close to the tree, however, a significant acidification was observed between 0.40–0.60 m depth in the soil, without any obvious depletion in other soil element concentrations. It is concluded that this acidification provides strong evidence in support of a ‘biological pumping’ mechanism that has been proposed elsewhere. Key questions remain as to the management implications of these results, whether the subsurface acidification that was observed is common among native Australian trees, if it might be persistent through time, and if this might be a soil issue that requires management.

The influence of aeolian dust deposits on alpine soils in south-eastern Australia

Soil Research ◽  
2001 ◽  
Vol 39 (1) ◽  
pp. 81 ◽  
Author(s):  
Stuart William Johnston
Keyword(s):  
Particle Size ◽  
National Park ◽  
Clay Mineralogy ◽  
Exchangeable Cations ◽  
Soil Profiles ◽  
Alpine Soils ◽  
Aeolian Dust ◽  
Eastern Australia ◽  
Aeolian Sediment ◽  
Dust Deposits

Aeolian sediment collected from 2 locations across the ‘Main Range’ of Kosciuszko National Park, along with a series of soil profiles that were analysed for particle size, were used as a baseline from which to estimate the effects of aeolian sedimentation in this region. Laboratory analysis of the soil profiles indicated that the properties of the surface horizons of the alpine humus soils were heavily influenced by aeolian dust accumulation; however, the sub-surface horizons were mainly derived from the natural bedrock. The surface and subsurface horizons differed in texture bulk density, pH, electrical conductivity, exchangeable cations, and clay mineralogy. This study confirmed that the snow patch meadow soils exhibited particle size and mineralogy consistent with dust enrichment, with distinct bands being found in some profiles.

scholarly journals Studies on Metatherian Sex Chromosomes. IX. Sex Chromosomes of the Greater Glider (Marsupialia : Petauridae)

1979 ◽  
Vol 32 (3) ◽  
pp. 375 ◽  
Author(s):  
JD Murray ◽  
GM McKay ◽  
GB Sharman
Keyword(s):  
X Chromosome ◽  
Sex Chromosomes ◽  
National Park ◽  
Secondary Constriction ◽  
X Chromosomes ◽  
Cultured Fibroblasts ◽  
Multiple Sex Chromosomes ◽  
Eastern Australia ◽  
Xy Bivalent ◽  
Secondary Constrictions

The greater glider, currently but incorrectly known as Schoinobates vo/ans, is widely distributed in forested regions in eastern Australia. All animals studied from six different localities had 20 autosomes but there were four chromosomally distinct populations. At Royal National Park, N.S.W., all female greater gliders studied had 22 chromosomes including two large submetacentric X chromosomes with subterminal secondary constrictions in their longer arms. This form of X chromosome occurred also at Bondo State Forest, Myall Lakes and Coff's Harbour, N.S.W., and at Eidsvold, Qld. At Coomooboolaroo, Qld, the X chromosome was also a large submetacentric but a secondary constriction occurred in the shorter arm. Two chromosomally distinct types apparently occur in Royal National Park, one with XY m,ales as in all other populations, and one with XY1Y2 males. Y or Yb but not Y 2, chromosomes were eliminated from the bone marrow in all populations but were present in spermatogonia, primary sperrnatocytes and cultured fibroblasts. Animals from Bondo State Forest had three or more acrocentric or metacentric supernumerary chromosomes. [Other keywords: C-banding, eytotaxonomy, multiple sex chromosomes, XY bivalent.]

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