scholarly journals Characterization and frequency analysis of flooding solid flow in semi-arid zone: case of Mekerra catchment in the north-west of Algeria

2020 ◽  
Vol 10 (2) ◽  
Author(s):  
M. Diaf ◽  
A. Hazzab ◽  
A. Yahiaoui ◽  
A. Belkendil
Keyword(s):  
Frequency Analysis ◽  
Arid Zone ◽  
Solid Flow ◽  
North West ◽  
The North ◽  
Semi Arid

Agriculture expansion and deforestation in seasonally dry forests of north-west Argentina

2005 ◽  
Vol 32 (2) ◽  
pp. 140-148 ◽  
Author(s):  
H. RICARDO GRAU ◽  
N. IGNACIO GASPARRI ◽  
T. MITCHELL AIDE
Keyword(s):  
Global Trends ◽  
North West ◽  
Conservation Policies ◽  
Seasonally Dry ◽  
The North ◽  
Agriculture Expansion ◽  
Soybean Price ◽  
Different Levels ◽  
Semi Arid ◽  
Arid Chaco

In Argentina, deforestation due to agriculture expansion is threatening the Semi-arid Chaco, one of the largest forested biomes of South America. This study focuses on the north-west boundary of the Argentine Semi-arid Chaco, where soybean is the most important crop. Deforestation was estimated for areas with different levels of soil and rainfall limitation for agriculture between 1972 and 2001, with a finer analysis in three periods starting in 1984, which are characterized by differences in rainfall, soybean price, production cost, technology-driven yield and national gross domestic product. Between 1972 and 2001, 588 900 ha (c. 20% of the forests) were deforested. Deforestation has been accelerating, reaching >28 000 ha yr−1 after 1997. The initial deforestation was associated with black bean cultivation following an increase in rainfall during the 1970s. In the 1980s, high soybean prices stimulated further deforestation. Finally, the introduction of soybean transgenic cultivars in 1997 reduced plantation costs and stimulated a further increase in deforestation. The domestic economy had little association with deforestation. Although deforestation was more intense in the moister (rainfall >600 mm yr−1) areas, more than 300 000 ha have already been deforested in the drier areas, suggesting that climatic limitations are being overcome by technological and genetic improvement. Furthermore, more than 300 000 ha of forest occur in sectors without major soil and rainfall limitations. If global trends of technology, soybean markets and climate continue, and no active conservation policies are applied, vast areas of the Chaco will be deforested in the coming decades.

scholarly journals Myxomatosis: the occurrence of antibody to a soluble antigen of myxoma virus in wild rabbits, Oryctolagus cuniculus (L.), in Victoria, Australia

1978 ◽  
Vol 81 (2) ◽  
pp. 245-249 ◽  
Author(s):  
J. W. Edmonds ◽  
Rosamond C. H. Shepherd ◽  
I. F. Nolan
Keyword(s):  
Breeding Season ◽  
Infection Rate ◽  
Oryctolagus Cuniculus ◽  
Myxoma Virus ◽  
European Rabbit ◽  
Soluble Antigen ◽  
Relative Timing ◽  
North West ◽  
The North ◽  
Semi Arid

SummaryThe occurrence of antibody to myxoma virus in wild rabbits following epizootics is highest in the semi-arid north-west of Victoria and lowest in temperate southern Victoria. Occurrence ranges up to about 90% in the north-west and to about 70% in the south except on the Western Plains where epizootics are rare and antibody occurrence seldom exceeds 30%.The establishment of the European rabbit flea may be changing the pattern of occurrence of antibody in the north-west by causing spring outbreaks of myxomatosis. It is suggested that the effects of the replacement of a simple recurring system of epizootic and breeding season several months apart by the occurrence of myxomatosis twice in the same year, once coincident with the breeding season, will be complex. The occurrence of detectable antibody may be less dependent on the infection rate and may be dependent to some extent on the relative timing of spring myxomatosis and the breeding season.

Sedimentary provinces of the fishing grounds of the North West Shelf of Australia: Grain-size frequency analysis of surficial sediments

1985 ◽  
Vol 36 (5) ◽  
pp. 671 ◽  
Author(s):  
RJ McLoughlin ◽  
PC Young
Keyword(s):  
Grain Size ◽  
Frequency Analysis ◽  
Fine Sand ◽  
Carbonate Content ◽  
North West ◽  
North East ◽  
The North ◽  
Size Frequency ◽  
Sediment Types ◽  
Shelf Slope

As part of a multidisciplinary study of the continental shelf of north-west Australia, 354 sediment samples were taken to describe the distribution of sedimentary provinces contained within the region. A grain-size frequency analysis and subsequent classification have revealed six principal sediment types roughly corresponding to an east-west and inshore-offshore distribution. The study area is characterized by coarse skeletal detritus in the south-west, with a transition to a significant accretionary carbonate component in the form of oolites, pellets and infilled biogenic particles in the north-east. Superimposed on this pattern is a decrease in grain size from shallow to deeper waters, culminating in carbonate muds on the shelf slope. Carbonate content of sediments is uniformly high, ranging from 60 to 100% of the total weight of all samples. Non-carbonate material is principally clay; however, small quantities (less than 1%) of fine sand-size angular quartz are present.

Australian Aborigines: geographical variability of craniological features.

2019 ◽  
Vol 48 (4) ◽  
pp. 243-251
Author(s):  
Aleksey V. Ivanov ◽  
Sergey V. Vasilyev
Keyword(s):  
Arid Zone ◽  
South Australia ◽  
Northern Territory ◽  
Australian Aborigines ◽  
North West ◽  
The North ◽  
South Wales ◽  
High Form ◽  
Australian Continent ◽  
Mixed Origin

This work is devoted to the study of craniological traits of Australian aborigines (male and female samples) and their geographical differentiation applying a special program of cranial traits. According to the craniological classification (Pestryakov, Grigorieva, 2004), native population of Australia belongs to the Tropid craniotype, i.e. is characterized by a relatively small size and long, narrow and relatively high form of the skull. The primary settlement of the Australian continent could only origin in the North. There are two contrasting craniotypes in Australia, which probably reflect the two main waves of the aboriginal migration across the continent. The skulls of the first migratory wave were larger and relatively low-vaulted. They are mostly characteristic of the aborigines of South Australia, who later also migrated to the north, to the arid zone of Central Australia. The second major wave is characterized by smaller high-vaulted skulls, which are now characteristic of the population of the north of the continent (Queensland and, especially, the Northern Territory and North-West Australia). The territory of the southeast of Australia (Victoria and New South Wales states) is the most favorable area for human living. The two main migratory waves mixed there, which led to the observed craniological heterosis. The craniological samples of western and northwestern Australia are also of mixed origin, but are more comparable to the Northern Territory groups. The Tasmanians are significantly different from the General Australian population in terms of craniology. This is especially true for the female sample. Perhaps the ancestors of the Tasmanians represented the very first settlement wave of the ancient Sahul continent, before the separation of the island from the mainland.

Preliminary spatial behaviour of warru (Petrogale lateralis MacDonnell Ranges race) in the Anangu Pitjantjatjara Yankunytjatjara Lands, South Australia

2011 ◽  
Vol 33 (2) ◽  
pp. 181 ◽  
Author(s):  
Laura Ruykys ◽  
Matthew J. Ward ◽  
David A. Taggart ◽  
William G. Breed
Keyword(s):  
Global Positioning System ◽  
Arid Zone ◽  
Management Strategies ◽  
South Australia ◽  
High Mobility ◽  
Future Research ◽  
North West ◽  
The North ◽  
Similar Work ◽  
Global Positioning

This study aimed to determine the home range and movement patterns of Petrogale lateralis in the arid-zone Anangu Pitjantjatjara Yankunytjatjara Lands in the north-west of South Australia. Ten Global Positioning System radio-collars were attached to animals, with collars programmed to function in 2008–09. Catastrophic collar failure resulted in only 28 days of data, from July 2008, being retrieved from one adult female. During this time, the female occupied a 90% kernel range of 57.9 ha and core (50%) range of 9.3 ha. The animal moved a total of 50.8 km and undertook three journeys of over 1 km. The longest of these was 1.2 km, undertaken in 89 min. The high mobility of the study animal has implications for management, particularly predator baiting and fire management strategies. Future research should assess the validity of these results by increasing sample size and conducting similar work for other arid-zone P. lateralis. The lessons learnt from the current GPS collar deployment may also be of interest to other researchers.

scholarly journals Conspicuously concealed: revision of the arid clade of theGehyra variegata(Gekkonidae) group in Western Australia using an integrative molecular and morphological approach, with the description of five cryptic species

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5334 ◽  
Author(s):  
Luke Kealley ◽  
Paul Doughty ◽  
Mitzy Pepper ◽  
J. Scott Keogh ◽  
Mia Hillyer ◽  
...  
Keyword(s):  
New Species ◽  
Cryptic Species ◽  
Western Australia ◽  
Arid Zone ◽  
Morphological Characters ◽  
Sea Levels ◽  
North West ◽  
The North ◽  
Large Numbers ◽  
Extreme North

The methods used to detect and describe morphologically cryptic species have advanced in recent years, owing to the integrative nature of molecular and morphological techniques required to elucidate them. Here we integrate recent phylogenomic work that sequenced many genes but few individuals, with new data from mtDNA and morphology from hundreds of gecko specimens of theGehyra variegatagroup from the Australian arid zone. To better understand morphological and geographical boundaries among cryptic forms, we generated new sequences from 656Gehyraindividuals, largely assigned toG. variegatagroup members over a wide area in Western Australia, with especially dense sampling in the Pilbara region, and combined them with 566Gehyrasequences from GenBank, resulting in a dataset of 1,222 specimens. Results indicated the existence of several cryptic species, from new species with diagnostic morphological characters, to cases when there were no useful characters to discriminate among genetically distinctive species. In addition, the cryptic species often showed counter-intuitive distributions, including broad sympatry among some forms and short range endemism in other cases. Two new species were on long branches in the phylogram and restricted to the northern Pilbara region: most records of the moderately sizedG. incognitasp. nov. are near the coast with isolated inland records, whereas the small-bodied saxicolineG. unguiculatasp. nov. is only known from a small area in the extreme north of the Pilbara. Three new species were on shorter branches in the phylogram and allied toG. montium. The moderately sizedG. cryptasp. nov. occurs in the western and southern Pilbara and extends south through the Murchison region; this species was distinctive genetically, but with wide overlap of characters with its sister species,G. montium. Accordingly, we provide a table of diagnostic nucleotides for this species as well as for all other species treated here. Two small-bodied species occur in isolated coastal regions:G. capensissp. nov. is restricted to the North West Cape andG. ocellatasp. nov. occurs on Barrow Island and other neighbouring islands. The latter species showed evidence of introgression with the mtDNA ofG. cryptasp. nov., possibly due to recent connectivity with the mainland owing to fluctuating sea levels. However,G. ocellatasp. nov. was more closely related toG. capensissp. nov. in the phylogenomic data and in morphology. Our study illustrates the benefits of combining phylogenomic data with extensive screens of mtDNA to identify large numbers of individuals to the correct cryptic species. This approach was able to provide sufficient samples with which to assess morphological variation. Furthermore, determination of geographic distributions of the new cryptic species should greatly assist with identification in the field, demonstrating the utility of sampling large numbers of specimens across wide areas.

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