Soil Surface Lichens in Arid and Subarid South-Eastern Australia. III. The Relationship Between Distribution and Environment

1972 ◽  
Vol 20 (3) ◽  
pp. 301 ◽  
Author(s):  
RW Rogers

From a consideration of the distribution of species and species groups in relation to soil and climatic factors, it is shown that mean annual rainfall and mean maximum January temperature largely explain the distribution pattern of arid zone soil surface lichens. A past distribution of lichen crusts in southern Australia is postulated on the basis of factors controlling lichen crust development, and known variations from this pattern explained in terms of stocking history.

Soil Research ◽  
2017 ◽  
Vol 55 (8) ◽  
pp. 799 ◽  
Author(s):  
Susan E. Orgill ◽  
Jason R. Condon ◽  
Mark K. Conyers ◽  
Stephen G. Morris ◽  
Brian W. Murphy ◽  
...  

In the present field survey, 72 sites were sampled to assess the effect of climate (Monaro, Boorowa and Coleambally regions) and parent material (Monaro region only; basalt and granite) on soil organic carbon (OC) under perennial pastures. In the higher-rainfall zone (Monaro and Boorowa; >500mm mean annual rainfall), OC stocks under introduced and native perennial pastures were compared, whereas in the lower-rainfall zone (Coleambally; <500mm mean annual rainfall) OC stocks under crops and pastures were compared. Carbon fractions included total OC (TOC), particulate OC (POC), resistant OC (ROC) and humic OC (HUM). Higher OC stocks were associated with higher spring and summer rainfall and lower annual temperatures. Within a climatic zone, parent material affected the stock of OC fractions in the 0–30cm soil layer. Within a climatic zone, when grouped by parent material, there was no difference in OC stock with vegetation type. There were significant correlations between soil factors associated with parent material and OC concentration, including negative correlations between SiO2 and HUM (P<0.05) and positive correlations between cation exchange capacity and TOC, POC and ROC (P<0.01). TOC was also positively correlated with total nitrogen (N) and available sulfur (S; P<0.05), indicating organic matter in soil is important for N and S supply for plant production in the studied regions, and vice versa. Although ensuring adequate available S may increase OC stocks in south-eastern Australia, the large stock of OC in the soil under perennial pastures, and the dominating effect of climate and parent material on this stock, may mean that modest increases in soil OC due to management factors go undetected.


1972 ◽  
Vol 20 (2) ◽  
pp. 215 ◽  
Author(s):  
RW Rogers

Five lichen species groups were delimited, principal components analysis and influence analysis being used as aids to group identification. With these same techniques it was demonstrated that two of the species groups formed "background" floras in adjacent geographic areas, the other three species groups, being superimposed upon the "background" floras to produce five separate geographic zones of lichen distribution.


1998 ◽  
Vol 46 (1) ◽  
pp. 27 ◽  
Author(s):  
J. Sumner ◽  
C. R. Dickman

This study describes genetical differences between three morphologically similar species of Antechinus in south-eastern Australia, and uses the climatic model BIOCLIM to clarify their expected geographical distributions. Allozyme electrophoresis revealed Nei’s distances of >0.2 between A. flavipes and A. stuartii and A. flavipes and A. agilis, the latter a newly recognised species in south-eastern Australia. Fixed allele differences were determined in five proteins between A. stuartii and A. flavipes from an area of sympatry in northern New South Wales, confirming their genetic distinctness. A smaller distance (0.08) separated A. stuartii from A. agilis, but fixed allele differences in albumin and mannose phosphate isomerase distinguished these species clearly. Locality records for the three species were compiled from the electrophoretic results, museum specimen records and published data, and used to generate expected distributions for each species. A. flavipes is predicted to occur primarily in warm, inland areas of south- eastern Australia with a mean annual rainfall of 785 mm, but to occur along the coast in South Australia and southern Queensland. In contrast, the distributions of A. stuartii and A. agilis are predicted to be broadly coastal, with the former occurring in northern New South Wales and southern Queensland in areas with high mean annual rainfall (1430 mm) and temperature (16.0°C), the latter in southern New South Wales and Victoria in cooler areas (11.8°C annual mean) with intermediate rainfall (1071 mm). Sympatry appears to be limited between A. flavipes and its two congeners; A. stuartii and A. agilis are predicted to be parapatric with only two small areas of overlap being evident.


1955 ◽  
Vol 6 (4) ◽  
pp. 466 ◽  
Author(s):  
RH Hayman

Previous work on this subject has indicated the importance of climatic factors, particularly rainfall, in the development of fleece-rot. Over an 8-year period 19 outbreaks were recorded on the F. D. McMaster Field Station, C.S.I.R.O. Of these, 16 occurred during calendar months which had eight or more wet days and 4 or more in. of rain. Using these data as criteria, rainfall records for the period 1911-1940 were examined in order to give broad definition to zones in which fleece-rot might be expected as a rare, or frequent, occurrence. Records were taken from 18 selected towns in south-eastern Australia. In the zone in which occurrence of the condition was expected to be high, there were differences between localities as to the season of the year at which expectation was highest, in the frequency of wet days per month, and in the intensity of daily rainfall. In some localities shearing during certain months of the year would assist sheep to escape fleece-rot, as they would be in short wool when it was most likely to occur.


Author(s):  
Mohamed Meddi

Soil erosion by rain and surface runoff is an important problem in the Mediterranean countries. The study of the relationship between erosion and sediment transport with hydrological and climatic factors have been conducted in many countries around the world. The aim of this work is to show rainfall impact on the variability of spatial and temporal concentration in twelve drainage basins in the west of Algeria. We will also seek to find a representative parameter of rainfall erosive potential on a Time and spatial scale. When studying sediment transport in twelve drainage basins of the Centre and the west of Algeria, we have found that the modified Fournier index Which explains much of the specific degradation compared to the Fournier index. The study of the temporal variability of the annual rainfall series, modified Fournier index and concentration of the precipitation in the year for a series from 1930 to 2007 showed a negative trend of the two variables. The annual rainfall and modified Fournier index have declined by more than 20%. This decline is more significant in inland areas.


Author(s):  
Julie A Tall ◽  
Michelle L Gatton

AbstractFlood frequency is expected to increase across the globe with climate change. Understanding the relationship between flooding and arboviral disease can reduce disease risk and associated costs. South-eastern Australia is dominated by the flood-prone Murray-Darling River system where the incidence of Australia’s most common arboviral disease, Ross River virus (RRV), is high. This study aimed to determine the relationship between riverine flooding and RRV disease outbreaks in inland south-eastern Australia, specifically New South Wales (NSW). Each study month from 1991 to 2013, for each of 37 local government areas (LGAs) was assigned ‘outbreak/non-outbreak’ status based on long-term trimmed-average age-standardized RRV notification rates and ‘flood/non-flood’ status based on riverine overflow. LGAs were grouped into eight climate zones with the relationship between flood and RRV outbreak modeled using generalized estimating equations. Modeling adjusted for rainfall in the previous 1–3 mo. Spring–summer flooding increased the odds of summer RRV outbreaks in three climate zones before and after adjusting for rainfall 1, 2, and 3 mo prior to the outbreak. Flooding at any time of the year was not predictive of RRV outbreaks in the remaining five climate zones. Predicting RRV disease outbreaks with flood events can assist with more targeted mosquito spraying programs, thereby reducing disease transmission and mosquito resistance.


1954 ◽  
Vol 5 (3) ◽  
pp. 448 ◽  
Author(s):  
RG Downes

A theory is presented suggesting that during the Recent Arid Period the rainfall was approximately half that of the present day and enabled cyclic salt to be accumulated in areas in south-eastern Australia, where it does not 'accumulate at present. The salinization and subsequent desalinization during the wetter conditions since the Arid Period have operated with varying degrees of intensity to produce solods, solodic and solonized soils over large areas. However, irrespective of the degree of intensity, some of the pre-Arid soils because of their chemical or physical properties have been able to resist these processes and remain unaffected. Five "pedogenetic zones" have been defined according to the degrees of intensity with which the salinization and desalinization processes are thought to have operated, and it is found that soil distribution and morphology is correlated with these defined zones. The zone in which the effect has been most intense has an average annual rainfall at present of between 20 and 30 in., and the most widespread soils, those formerly called red and yellow podzolics, are solodic soils and solods. The theory provides a reasonable explanation for the anoxalous distribution of soils within the "podzol" zone where those showing the greatest degree of horizon differentiation (solods and solodic soils) occur in the driest parts. In addition, the postulated processes for the formation of the soils provide a reason why molybdenum deficiency is so common on these soils in zone 3.


2003 ◽  
Vol 43 (10) ◽  
pp. 1231 ◽  
Author(s):  
S. J. Marcroft ◽  
S. J. Sprague ◽  
S. J. Pymer ◽  
P. A. Salisbury ◽  
B. J. Howlett

The production of windborne ascospore inoculum of the blackleg fungus (Leptosphaeria maculans) was determined during 2000 and 2001 in 3 environments (Birchip, low rainfall; Wonwondah, medium rainfall; Lake Bolac, high rainfall) in Victoria. The weight of canola stubble (kg/ha) remaining on the soil surface in paddocks was estimated 6, 18, 30 and 42 months after harvest of the original canola crop. In all 3 environments only small amounts of stubble were present 18 months after harvest. Eighty percent of the 6-month-old stubble comprised stems and branches, with the remaining 20% being root material, while 42-month-old stubble consisted only of root material. Paddocks subjected to raking and burning contained only half the weight of stubble compared with paddocks that were harrowed. Where canola was harvested in January, even when no management strategy was used, 80% of subsequent stubble was no longer on the soil surface by July of that year. Pseudothecia from 6-month-old stubble from the high rainfall environment discharged significantly more ascospores than stubble of the same age from the medium rainfall environment, which in turn discharged more than stubble from the low rainfall environment. In all environments, paddocks containing 6-month-old canola stubble discharged 30-fold as many ascospores per hectare as older stubble paddocks.


Soil Research ◽  
2016 ◽  
Vol 54 (5) ◽  
pp. 512 ◽  
Author(s):  
Guangdi D. Li ◽  
Mark K. Conyers ◽  
Graeme D. Schwenke ◽  
Richard C. Hayes ◽  
De Li Liu ◽  
...  

Dryland cereal production systems of south-eastern Australia require viable options for reducing nitrous oxide (N2O) emissions without compromising productivity and profitability. A 4-year rotational experiment with wheat (Triticum aestivum L.)–canola (Brassica napus L.)–grain legumes–wheat in sequence was established at Wagga Wagga, NSW, Australia, in a semiarid Mediterranean-type environment where long-term average annual rainfall is 541mm and the incidence of summer rainfall is episodic and unreliable. The objectives of the experiment were to investigate whether (i) tillage increases N2O emissions and (ii) nitrogen (N) application can improve productivity without increasing N2O emissions. The base experimental design for each crop phase was a split-plot design with tillage treatment (tilled versus no-till) as the whole plot, and N fertiliser rate (0, 25, 50 and 100kgN/ha) as the subplot, replicated three times. This paper reports high resolution N2O emission data under a canola crop. The daily N2O emission rate averaged 0.55g N2O-N/ha.day, ranging between –0.81 and 6.71g N2O-N/ha.day. The annual cumulative N2O-N emitted was 175.6 and 224.3g N2O-N/ha under 0 and 100kgN/ha treatments respectively. There was no evidence to support the first hypothesis that tillage increases N2O emissions, a result which may give farmers more confidence to use tillage strategically to manage weeds and diseases where necessary. However, increasing N fertiliser rate tended to increase N2O emissions, but did not increase crop production at this site.


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