Phytogeography of Acacia in Australia in Relation to Climate and Species-Richness

1988 ◽  
Vol 36 (4) ◽  
pp. 361
Author(s):  
RJ Hnatiuk ◽  
BR Maslin

This paper reports on the kinds of geographic patterns encountered in the distribution of Australian species of Acacia and on some climatic correlates of these patterns. The analyses were based on distribution data of 837 species mapped on a 1° x 1.5° grid. The area of highest density of species was the south-west corner of the continent, especially adjacent to the major boundary separating the Arid Zone from the more humid South West Botanical Province. The second major centre of richness occurred in eastern Australia south of the Tropic of Capricorn along the topographically heterogeneous Great Dividing Range. Secondary centres of species-richness occurred in northern and north-eastern Australia, a number of rocky tablelands of the Arid Zone and in western Victoria. The principal species-poor areas were located in sandy and some riverine areas of the Arid Zone, in temperate forests of Tasmania and in coastal areas of the north of the continent. The geographic patterns of each section of Acacia, when combined with those of species density, highlighted the tropical (section Juliflorae) v. temperate areas (sections Phyllodineae, Pulchellae, Botrycephalae and Alatae). The numerical classification of grids resulted in the recognition of eight major Acacia areas, arranged under four Acacia regions: (1) South-west; (2) Eastern, comprising a southern and a northern area; (3) Northern, comprising an eastern and a western area; (4) Central, comprising a south-east, a central and a north-west area. A discriminant function analysis indicated that precipitation was more important than temperature in distinguishing between areas. Discussion of the potential evolutionary significance of these findings and brief comparison with other biogeographic studies are given.

1988 ◽  
Vol 36 (4) ◽  
pp. 385 ◽  
Author(s):  
BR Maslin ◽  
L Pedley

Patterns of distribution are described for the three subgenera and nine sections that make up the Australian Acacia flora. Subgenus Phyllodineae (833 species) is widespread and contains 99% of the species; subgenus Acacia (six species) and subgenus Aculeiferum (one species) are poorly represented and virtually confined to the north of the continent. The geographic patterns of species-richness are strongly influenced by sections Phyllodineae (352 species), Juliflorae (219 species) and Plurinerves (178 species). Section Phyllodineae has centres of richness south of the Tropic of Capricorn in temperate and adjacent semiarid areas of eastern, south-eastern and south-western Australia. The section is poorly represented in the tropics. The closely related sections Juliflorae and Plurinerves predominate in the north of the continent, semiarid areas of the south-west, many rocky tablelands of the Arid Zone and along the Great Dividing Range and adjacent inland riverine lowland areas in eastern Australia. The remaining four sections contribute little to the overall patterns of species-richness. The principal speciespoor areas are sandy and fluvial lowland regions of the Arid Zone. In eastern Australia, sections Botrycephalae, Juliflorae, Phyllodineae and Plurinerves show discontinuous patterns of species-richness along the Great Dividing Range. All sections have species whose ranges terminate in the area of the McPherson-Macleay Overlap region.


Author(s):  
Aleksander Kołos

Betula humilis Schrank (shrubby birch) is among the most endangered shrub species in Poland. All localities are in the eastern and northern parts of the country, where the species reaches the western border of its geographical range in Europe. Betula humilis is disappearing in Poland due to wetland melioration and shrub succession. Over 80% of the localities described in Poland have not been confirmed in the last 20 years. Five new localities of B. humilis in the North Podlasie Lowland were recorded from 2008 to 2019 in the Upper Nurzec Valley (Fig. 1): 1–1.5 km south-west of Pawlinowo village (in the ATPOL GC7146 plot) and 1.5–2 km north-west of Żuki village (ATPOL GC7155, GC156 and GC166). The population near Pawlinowo (locality 1) is currently composed of ~80 individuals (101 individuals were noted in 2010) and is one of the largest populations in north-eastern Poland. Betula humilis grows there within patches dominated by Salix rosmarinifolia and megaforbs. The population at locality 5 is composed of 18 individuals. At the remaining localities, only 1–4 individuals were found, scattered along drainage ditches surrounded by hay meadows. At some of these localities the species is threatened with extinction. It is suggested to remove competitive trees and shrubs (mainly Populus tremula, Betula pubescens and Salix cinerea) in order to maintain the local populations.


2004 ◽  
Vol 48 (1) ◽  
pp. 49-68 ◽  
Author(s):  
Ian Mortimer

The licensing of provincial surgeons and physicians in the post-Restoration period has proved an awkward subject for medical historians. It has divided writers between those who regard the possession of a local licence as a mark of professionalism or proficiency, those who see the existence of diocesan licences as a mark of an essentially unregulated and decentralized trade, and those who discount the distinction of licensing in assessing medical expertise availability in a given region. Such a diversity of interpretations has meant that the very descriptors by which practitioners were known to their contemporaries (and are referred to by historians) have become fragmented and difficult to use without a specific context. As David Harley has pointed out in his study of licensed physicians in the north-west of England, “historians often define eighteenth-century physicians as men with medical degrees, thus ignoring … the many licensed physicians throughout the country”. One could similarly draw attention to the inadequacy of the word “surgeon” to cover licensed and unlicensed practitioners, barber-surgeons, Company members in towns, self-taught practitioners using surgical manuals, and procedural specialists whose work came under the umbrella of surgery, such as bonesetters, midwives and phlebotomists. Although such fragmentation of meaning reflects a diversity of practices carried on under the same occupational descriptors in early modern England, the result is an imprecise historical literature in which the importance of licensing, and especially local licensing, is either ignored as a delimiter or viewed as an inaccurate gauge of medical proficiency.


1954 ◽  
Vol 49 ◽  
pp. 267-291
Author(s):  
Elizabeth B. Wace

The Cyclopean Terrace Building lies to the north-west of the Lion Gate on the northern end of the Panagia Ridge and faces almost due west across the valley of the Kephissos and modern main road from Corinth to Argos. It lies just below the 200 m. contour line, and one terrace below the houses excavated in 1950–51 by Dr. Papadimitriou and Mr. Petsas to the east at the same end of the ridge. The area contains a complex of buildings, both successive and contemporary, and in view of the discovery of structures both to the south-west and, by the Greek Archaeological Service, to the north-east it is likely that this whole slope was covered by a portion of the outer town of Mycenae. This report will deal only with the structure to which the name Cyclopean Terrace Building was originally given, the so-called ‘North Megaron’, supported by the heavy main terrace wall.The excavation of this structure was begun in 1923. The main terrace wall was cleared and two L.H. IIIC burials discovered in the top of the fill in the south room. In 1950 it was decided to attempt to clear this building entirely in an endeavour to find out its date and purpose. The clearing was not, however, substantially completed until the close of the 1953 excavation season, and this report presents the available evidence for the date as determined by the pottery found beneath the building; the purpose is still a matter for study, though various tentative conclusions can be put forward.


1894 ◽  
Vol 1 (9) ◽  
pp. 394-399 ◽  
Author(s):  
J. Burr Tyrrell

In the extreme northernmost part of Canada, lying between North Latitudes 56° and 68° and West Longitudes 88° and 112°, is an area of about 400,000 square miles, which had up to the past two years remained geologically unexplored.In 1892 the Director of the Geological Survey of Canada sent the writer to explore the country north of Churchill River, and south-west of Lake Athabasca;in1893 the exploration was continued northward, along the north shore of Athabasca Lake


1947 ◽  
Vol 84 (3) ◽  
pp. 178-180
Author(s):  
D. D. C. Pochin Mould

The Broadlaw “Granite” is one of the small granitic intrusions of Caledonian age found in the eastern part of the Southern Uplands of Scotland. It is situated on the north-west flank of Broadlaw in the Moorfoot Hills, three miles south-west of Middleton House.


1904 ◽  
Vol 1 (6) ◽  
pp. 265-272
Author(s):  
P. W. Stuart-Menteath

On the rail to Biarritz the roots of the Pyrenees first appear at Dax, and are accompanied by those ophites and thermal springs which are special features of the entire chain. Vast deposits of salt, to whose first development I contributed, have added an important industry to the resources of this ancient capital of Aquœ Tarbelliœ, where the exact harness depicted on Roman medals is still characteristic of every cart. Beneath the existing ditch of the Roman fortifications rock-salt was accidentally discovered by a boring for mineral water, and the salt is now worked at three miles to the south-east, and is indicated by springs for a distance of seven miles. The deposit is known to be about 100 feet in thickness, but is of unknown depth beneath the existing borings.Along the entire outskirts of both sides of the Pyrenees similar salt deposits abound, and they are often similarly accompanied by igneous rocks.The salt formation of Dax is distinctly limited by the valley of the Adour, which here ceases to wander among the sands of the plain, and is suddenly and sharply diverted along a tectonic depression, running towards the Pyrenees in a south-west direction. Precisely parallel to this course, in the Cretaceous and Tertiary rocks of the Pyrenees, there runs, at a dozen miles to the north-west, the most remarkable example known of a tectonic valley sunk beneath the ocean. The Gouf de Capbreton, sinking with steep sides to over 3,000 feet beneath the even bottom of the Atlantic skirt, and affording evidence of igneous rocks in its surroundings and in the irregularities of its floor, is a perfect analogue of the neighbouring tectonic portion of the Adour.


1757 ◽  
Vol 50 ◽  
pp. 645-648

I went to make my observation upon the natural history of the sea; and when I arrived at a place called the Cauldrons of Lance Caraibe, near Lancebertrand, a part of the island of Grande Terre Guadaloupe, in which place the coast runs north-east and south-west, the sea being much agitated that day flowed from the north-west.


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