Morphological and genetic variation within the widespread species Acacia victoriae (Mimosaceae)

2007 ◽  
Vol 20 (1) ◽  
pp. 54 ◽  
Author(s):  
Siti R. Ariati ◽  
Daniel J. Murphy ◽  
Stuart Gardner ◽  
Pauline Y. Ladiges
Keyword(s):  
Genetic Variation ◽  
Morphological Variation ◽  
Genetic Divergence ◽  
Arid Regions ◽  
Nuclear Dna ◽  
Northern Australia ◽  
Parsimony Analysis ◽  
Widespread Species ◽  
Central Australia ◽  
Semi Arid

Morphological variation in Acacia victoriae, a species widespread in arid and semi-arid regions of Australia, was analysed by phenetic methods of classification and ordination. Three morphological groups were identified on the basis of phyllode characters and are treated as subspecies. Populations with short, elliptic and tomentose phyllodes are confirmed as A. victoriae subsp. arida Pedley; this form occurs mainly in central Australia. Populations with linear to oblong, non-tomentose phyllodes are referred to subsp. victoriae; this subspecies is the most variable and widely distributed across Australia. Populations with very long, narrow phyllodes, distributed in northern Australia from the Kimberley to Queensland, are described as fasciaria subsp. nov. A small number of non-tomentose specimens with broad elliptic phyllodes from central Australia require further assessment. Thirteen accessions previously sequenced for internal spacer regions and external spacer regions of ribosomal nuclear DNA showed genetic divergence. Six accessions of subsp. fasciaria formed a clade in a parsimony analysis, confirming that the long phyllode form is genetically distinct.

scholarly journals Fire-induced rock spalling as a mechanism of weathering responsible for flared slope and inselberg development

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Solomon Buckman ◽  
Rowena H. Morris ◽  
Robert P. Bourman
Keyword(s):  
Arid Regions ◽  
Chemical Weathering ◽  
Ground Level ◽  
Physical Weathering ◽  
Weathering Processes ◽  
Central Australia ◽  
In Fire ◽  
New Hypothesis ◽  
Primary Agent ◽  
Semi Arid

AbstractInselbergs, such as Uluru in central Australia, are iconic landscape features of semi-arid and deeply denuded continental interiors. These islands of rock are commonly skirted by steep, overhanging cliffs (flared slopes) at ground level. The weathering processes responsible for formation of flared slopes and steep-sided inselbergs in flat, planated landscapes are enigmatic. One model emphasizes sub-surface weathering followed by denudation and excavation of saprolite to expose the unweathered bedrock while other models advocate slope development under subaerial conditions at ground level. We present a new hypothesis that identifies wildfire as a primary agent of flared slope development via fire-induced rock spalling around the periphery of inselbergs. Widespread fire-spalling following the 2019–2020 Australian fires illustrates that this is a common form of physical weathering in fire-prone environments but its effects are particularly evident in semi-arid regions where lateral fire-spalling dominates over fluvial and chemical weathering to create flared slopes and steep-sided inselbergs.

Thirsty work: Testing the risk reduction model of mid- to late-Holocene stone points with distance decay from freshwater in northern Australia

The Holocene ◽  
2021 ◽  
pp. 095968362110331
Author(s):  
Tim Ryan Maloney
Keyword(s):  
Risk Reduction ◽  
Late Holocene ◽  
Arid Regions ◽  
Water Sources ◽  
Stone Tool ◽  
Northern Australia ◽  
Risk Minimisation ◽  
The World ◽  
Primary Water ◽  
Semi Arid

A key tenant of risk reduction models in archaeology the world over is that changes in resource availability drove mobility increases and created a need for an extension of stone tool use life. This manuscript directly addresses the question, is retouch intensity of tools related to distance from freshwater, by using extant localities of major Gorges, Rivers and water holes in the southern Kimberley region of northern Australia. Previous research has argued that retouched stone points during the mid to late-Holocene were part of a risk minimisation strategy, within broader technological organisation models. Modelling the distance from primary water sources, in arid to semi-arid regions of the southern Kimberley, reduction intensity of points is found to increase with distance from water sources consistently. This research provides an appropriate test of existing risk minimisation models and highlights global significance for similar studies where retouch tool reduction and forager mobility are linked to environmental change.

BIODIVERSITY OF HALOPHYTES IN SEMI-ARID REGIONS CASE OF ZAHREZ GHARBI AND ZAHREZ CHERGUI (ZAAFRANE-DJELFA) IN ALGERIA

2020 ◽  
Vol 76 (11) ◽  
Author(s):  
Senni Rachida ◽  
De Belair Gerard ◽  
Abdelkrim Hacene
Keyword(s):  
Arid Regions ◽  
Semi Arid

Water Resources Management in the Semi-Arid Central Valley of California

1987 ◽  
Vol 19 (9) ◽  
pp. 97-106
Author(s):  
J. J. Vasconcelos
Keyword(s):  
Resource Management ◽  
Ground Water ◽  
Water Resource ◽  
Water Resource Management ◽  
Arid Regions ◽  
Central Valley ◽  
The United States ◽  
Policy Makers ◽  
Ground Water Resource ◽  
Semi Arid

Hater resource managers in semi-arid regions are faced with some unique problems. The wide variations in precipitation and stream flows in semi-arid regions increase man's dependence on the ground water resource for an ample and reliable supply of water. Proper management of the ground water resource is absolutely essential to the economic well being of semi-arid regions. Historians have discovered the remains of vanished advanced civilizations based on irrigated agriculture which were ignorant of the importance of proper ground water resource management. In the United States a great deal of effort is presently being expended in the study and control of toxic discharges to the ground water resource. What many public policy makers fail to understand is that the potential loss to society resulting from the mineralization of the ground water resource is potentially much greater than the loss caused by toxic wastes discharges, particularly in developing countries. Appropriations for ground water resource management studies in developed countries such as the United States are presently much less than those for toxic wastes management and should be increased. It is the reponsibility of the water resource professional to emphasize to public policy makers the importance of ground water resource management. Applications of ground water resource management models in the semi-arid Central Valley of California are presented. The results demonstrate the need for proper ground water resource management practices in semi-arid regions and the use of ground water management models as a valuable tool for the water resource manager.

scholarly journals Mulching as water-saving technique in dryland agriculture: review article

2019 ◽  
Vol 43 (1) ◽  
Author(s):  
Mohammad Abdul Kader ◽  
Ashutus Singha ◽  
Mili Amena Begum ◽  
Arif Jewel ◽  
Ferdous Hossain Khan ◽  
...  
Keyword(s):  
Arid Regions ◽  
Review Article ◽  
Water Saving ◽  
Future Research ◽  
Agricultural Water ◽  
Plastic Mulch ◽  
Dryland Agriculture ◽  
Crop Cultivation ◽  
Agricultural Water Resources ◽  
Semi Arid

Abstract Agricultural water resources have been limited over the years due to global warming and irregular rainfall in the arid and semi-arid regions. To mitigate the water stress in agriculture, mulching has a crucial impact as a water-saving technique in rain-fed crop cultivation. It is important mainly for preserving soil moisture, relegating soil temperature, and limiting soil evaporation, which affects the crop yield. Mulching has many strategic effects on soil ecosystem, crop growth, and climate. Mulch insulates the soil, helping to provide a buffer from cold and hot temperatures that have a crucial activity in creating beautiful and protected landscapes. This study has accumulated a series of information about both organic and plastic mulch materials and its applicability on crop cultivation. Moreover, future research potentials of mulching with modeling were discussed to quantify water loss in agriculture.

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