Plant cover and composition in relation to density of Callitris glaucophylla (white cypress pine) along a rainfall gradient in eastern Australia

2005 ◽  
Vol 53 (6) ◽  
pp. 545 ◽  
Author(s):  
W. A. Thompson ◽  
D. J. Eldridge
Keyword(s):  
Plant Cover ◽  
Tree Cover ◽  
Annual Rainfall ◽  
Rainfall Gradient ◽  
Understorey Vegetation ◽  
Eastern Australia ◽  
Average Annual Rainfall ◽  
Callitris Glaucophylla ◽  
Understorey Plants ◽  
Cypress Pine

Despite the widespread distribution of Callitris glaucophylla J.Thompson & L.Johnson (white cypress pine) over large areas of eastern Australia, little is known about its impact on the diversity and cover of understorey plants. We examined C. glaucophylla woodlands to see whether stand density and land management influenced the cover and composition of the understorey vegetation. The cover and diversity of understorey plant communities were measured at 83 sites along a gradient in average annual rainfall (215–532 mm) in eastern Australia. The diversity and cover of understorey plants and the cover of trees increased, and the composition of the understorey community changed with increases in average annual rainfall. There were no clear relationships, however, between tree cover or density, and the cover or diversity of understorey plants. Sites that had not been logged contained significantly greater proportions of native and perennial vascular plants, and sites with extant eucalypts had a significantly higher proportion of shrubs than those sites without eucalypts. We attributed these differences to past forestry disturbance regimes which are correlated with the presence of mature eucalypts. Our results do not support the proposition that dense stands of C. glaucophylla suppress the understorey vegetation.

Persistence and productivity of phalaris (Phalaris aquatica) germplasm in dry marginal rainfall environments of south-eastern Australia

2017 ◽  
Vol 68 (8) ◽  
pp. 781
Author(s):  
R. A. Culvenor ◽  
M. R. Norton ◽  
J. De Faveri
Keyword(s):  
Environmental Benefits ◽  
Annual Rainfall ◽  
Summer Drought ◽  
Environment Interaction ◽  
Phalaris Aquatica ◽  
Mixed Farming ◽  
Eastern Australia ◽  
Summer Dormancy ◽  
Average Annual Rainfall ◽  
Establishment Phase

Perennial grasses have production and environmental benefits in areas of southern Australia typified by the mixed farming zone of southern New South Wales (NSW). The perennial grass phalaris (Phalaris aquatica L.) is widely used in southern Australia; however, it would find more use in the mixed farming zone if its persistence in marginal rainfall areas (450–500 mm average annual rainfall) were improved. We evaluated a range of germplasm (n = 29) including wild accessions, lines bred from these, and existing cultivars for persistence and production at three sites in a summer-dry area of southern NSW with 430–460-mm average annual rainfall. Two sites were used over 4 years and the third site over 5 years. Summer dormancy, maturity time and seedling growth were also assessed. Analysis of genotype × environment interaction employing factor analytic models and accounting for spatial and temporal correlations indicated that changes in persistence occurred mainly over time rather than between sites. Ranking changes occurred in the dry establishment phase of the experiment and during a severe final summer drought, with few changes occurring in the intervening high-rainfall years. Lines that survived the establishment phase best had vigorous seedlings and earlier maturity, whereas those surviving the final summer best were earlier maturing and higher in summer dormancy with high winter-growth activity. Some later maturing lines within the higher summer dormancy group were less persistent. Some accessions from North Africa were the most persistent; also, populations bred from these and other more persistent accessions generally persisted and produced better than cultivars used presently. However, present cultivars were capable of high yield in the higher rainfall years. We suggest that persistence of higher summer dormancy cultivars over very dry years could be improved by selecting for earlier maturity time.

Cyclic salt as a dominant factor in the genesis of soils in South-Eastern Australia.

1954 ◽  
Vol 5 (3) ◽  
pp. 448 ◽  
Author(s):  
RG Downes
Keyword(s):  
Physical Properties ◽  
Dominant Factor ◽  
Annual Rainfall ◽  
Arid Soils ◽  
South Eastern ◽  
Eastern Australia ◽  
Average Annual Rainfall ◽  
Soil Distribution ◽  
Genesis Of Soils ◽  
South Eastern Australia

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.

Landscapes of sandy areas along a rainfall gradient (90-450 mm, average annual rainfall) in the south-eastern Mediterranean area, Israel

2021 ◽  
pp. 1-12
Author(s):  
Yair Aaron
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
Environmental Variables ◽  
Eastern Mediterranean ◽  
Mediterranean Area ◽  
Annual Rainfall ◽  
Rainfall Gradient ◽  
Average Annual Rainfall ◽  
Eastern Mediterranean Area ◽  
Hydrological Effects

Dryland areas are regarded as highly sensitive to climatic changes. A positive relationship between average annual rainfall, and environmental factors (water availability, species diversity, etc.), is often assumed for areas with an average annual rainfall of 100-300 mm. However, the global climatological models fail to address an important issue. The above assumption disregards the fact that a climate change in some dry-land areas is not limited to climatic factors. It is often accompanied by a pronounced variability in surface properties, such as the deposition of loess in a wet climatic phase, and of sand during a dry climatic phase. Needless to say, the spatial variability of the new surface properties may have variable effects on water resources and related environmental variables. In addition, the climatic models, based on average annual rainfall, disregard the rainfall characteristics at the rain-shower level, which greatly influence the degree to which rainwater will percolate, or will be transformed into runoff, thereby significantly affecting the spatial redistribution of water resources. In other words, a climate change in dryland areas would be expected to have differential hydrological effects in a sandy area, a rocky area, or in a loess covered area. Differential spatial hydrological effects would be also expected within each of the areas listed above. The present manuscript deals with the complex relationships between average annual rainfall, and environmental variables in sandy areas, at three research sites, along a rainfall gradient of 90-450 mm, in the south eastern Mediterranean area, Israel. Data obtained clearly show that average annual rainfall is not a good indicator of water resources, and ecosystem structure, in each of the sites; and the controlling factors vary from one site to another.

Comparison of Wheel Point and Point Frame Methods for Plant Cover Measurement of Semiarid and Arid Rangeland Vegetation of New South Wales.

1994 ◽  
Vol 16 (1) ◽  
pp. 94
Author(s):  
H Arzani ◽  
GW King
Keyword(s):  
New South ◽  
Plant Cover ◽  
New South Wales ◽  
Annual Rainfall ◽  
Biomass Estimation ◽  
Tall Grass ◽  
South Wales ◽  
Significant Difference ◽  
Drought Conditions ◽  
Average Annual Rainfall

Ground cover is frequently estimated in rangeland monitoring and it is an important intermediate measurement between biomass estimation and satellite imagery. As a preliminary phase in a longer term program, wheel point and point frame methods were used to measure vegetation cover on four permanent Soil Conservation Service transects at each of four land systems in western New South Wales, at Nyngan (410 mm average annual rainfall), at Cobar (364 mm average annual rainfall) and two at Fowlers Gap (200 mm average annual rainfall) north of Broken Hill. The majority of this work used 400 wheel point hits per transect and 100 point quadrats sub sampled 9 - 13 times along each of four transects. There was no statistically significant difference between these techniques for total foliage cover over a combined analysis of all sites under pre-drought conditions, and for pre-drought and post-drought at Cobar. However, there was a 10% difference estimated between the techniques for total foliage cover at Nyngan when it was analysed in isolation. There were no consistent differences in technique for cover estimation for more than 40 plant species including annual grasses and herbs, perennial grasses and saltbushes. Significant differences between techniques were found for Medicago sp. and Thyridolepis mitchelliana on one occasion. We believe that these differences were due to the problems of finding small plants in tall grass and identifying heavily grazed grasses during drought conditions at Cobar and, in the latter case, this was also associated with a significantly greater estimate of mean cover for all grasses and thus total foliage cover. Although there was generally no statistical difference between techniques our observations suggest that the point frame tends to give lower estimates of cover than the wheel point in the situations measured. This may be associated with the circumference of the marker pins on the wheel point or perhaps observer error but as this effect appeared to be more noticeable with grasses we suspect that the former is most likely. The wheel point is less time consuming, more convenient and simpler to use than the point frame, and will readily accommodate most temporal and spatial variation in sampling requirements in similar land forms in western New South Wales.

Multi-decadal increases in shrub abundance in non-riverine red gum (Eucalyptus camaldulensis) woodlands occur during a period of complex land-use history

2009 ◽  
Vol 57 (3) ◽  
pp. 163 ◽  
Author(s):  
Jodi N. Price ◽  
John W. Morgan
Keyword(s):  
Land Use ◽  
National Park ◽  
Woody Plant ◽  
Plant Cover ◽  
Land Use Changes ◽  
Eucalyptus Camaldulensis ◽  
Selective Logging ◽  
Understorey Vegetation ◽  
Eastern Australia ◽  
History Of

The history of land-use was examined in Eucalyptus camaldulensis Dehnh. woodland in the Victoria Valley of the Grampians National Park, south-eastern Australia, to help interpret changes in vegetation there during the last 50 years. We used aerial photography and dendrochronological data to quantify the amount of, and the rate of change in, the woody-vegetation cover between 1948 and 1997, and historical data to document land-use changes during this time. Aerial photographs indicated that in 1948, 56% of study area had <50% cover of woody plants. By 1997, 90% of the study area had >50% woody-plant cover. The native shrub Leptospermum scoparium J.R. Forst & G. Forst (Myrtaceae) was predominantly responsible for the increases in cover. Demographic analyses indicated that recruitment has been ongoing rather than episodic; large numbers of shrubs, however, have recruited since 1994. We hypothesise that the vegetation changes observed are likely a response to changes in land-use that have occurred since European occupation. Increased woody-plant cover followed the removal of sheep grazing in the long-term absence of fire. It is very likely that the long history of stock grazing, coupled with selective logging and associated soil disturbance, initiated a change in understorey vegetation by reducing competitive native tussock grasses and fuel loads to carry fires and this reduction was initially responsible for the encroachment of shrubs into the woodland. Recruitment has been ongoing in the absence of any recent land-use changes (most utilisation ceasing after the declaration of National Park status in 1984) and hence, this transformation from species-rich herbaceous woodland to shrubby woodland is expected to continue in the future.

scholarly journals The hydrological role of biological topsoil crusts and water repellency in sandy dry-land areas

2018 ◽  
Vol 36 ◽  
pp. 33-44
Author(s):  
Aaron Yair ◽  
Ram Almog ◽  
Youval Arbel
Keyword(s):  
Water Regime ◽  
Water Repellency ◽  
Annual Rainfall ◽  
Striking Difference ◽  
Water Repellent ◽  
Runoff Generation ◽  
Rainfall Gradient ◽  
Large Trees ◽  
Average Annual Rainfall

Dryland areas are regarded as highly sensitive to climatic changes. A positive relationship between rainfall and environmental factors is often assumed for areas with an average annual rainfall of 100–300 mm. This assumption disregards the fact that a climate change in arid areas is not limited to climatic factors. It is often accompanied by a pronounced spatial variability in surface characteristics. The present work deals with the complex relationships among average annual rainfall, surface properties and the spatial redistribution of water resources in sandy areas located in the Northern Negev Desert. Two case studies are considered. The first deals with the hydrological effects of biological topsoil crusts on the water regime, along a rainfall gradient (86–170 mm). This study is based on five monitoring sites. Data obtained show a decrease in water availability with increasing annual rainfall. The findings are attributed to the decisive role played by the non-uniform properties of the topsoil crust along the rainfall gradient. The second case refers to the non-uniform development, and survival, of planted trees. Trees planted on steep dunes are well developed, with a high survival rate, whereas trees planted on low angle dunes are small. This study focused on the role of a water repellent layer on the water regime. Data obtained show a striking difference between steep and low dunes in all aspects studied, namely the degree of water repellency, frequency and magnitude of runoff events, infiltration depth and soil moisture. All variables monitored were found higher on steep than on low dunes. The large trees shed a substantial amount of leaves, whose decay developed a water repellent layer. Runoff generation over the repellent layer enhanced deep water penetration, through the process of subsurface flow. The lack of a water repellent layer over the low dunes prevented runoff generation, with its positive effects.

White cypress pine (Callitris glaucophylla): a review of its roles in landscape and ecological processes in eastern Australia

2005 ◽  
Vol 53 (6) ◽  
pp. 555 ◽  
Author(s):  
W. A. Thompson ◽  
D. J. Eldridge
Keyword(s):  
Selective Logging ◽  
Past Century ◽  
Ecological Role ◽  
Vegetation Community ◽  
Ecological Processes ◽  
The Past ◽  
Eastern Australia ◽  
Callitris Glaucophylla ◽  
Cypress Pine

Callitris glaucophylla (J.Thompson & L.Johnson, white cypress pine) woodlands are an important vegetation community over relatively large areas of continental eastern Australia. C. glaucophylla communities were originally reserved because of their value to the timber industry, but renewed attention is being placed on these woodlands because of their putative role in the conservation of native plants and animals. The pre-European distribution of C. glaucophylla was altered dramatically in the past century because of a combination of grazing by domestic livestock and feral animals, altered fire regimes and weed invasion. Today, the majority of C. glaucophylla woodlands are highly fragmented remnants, with many managed as formal forestry reserves. Selective logging during the past 30 years has led to a community that is dominated by single-aged stands, often at high densities, leading to the perception that C. glaucophylla communities are severely degraded and floristically depauperate. Increased interest in the structure and function of grassy woodlands in eastern Australia over the past decade has led to a re-evaluation of the importance of this vegetation community for habitat and for maintaining essential ecosystem processes. The timing of this review is appropriate because (1) much has been published on the ecological role of C. glaucophylla over the past decade in Australia, although mostly in unpublished reports, and (2) there is a need to resolve some of the conflicting issues relating to the value of C. glaucophylla woodlands for healthy soils and vegetation. Here, we review the ecological role of C. glaucophylla, with an emphasis on eastern Australia, drawing on a range of published and unpublished literature. We describe the characteristics and distribution of C. glaucophylla in eastern Australia, its role in soil and ecological processes, and the impacts of fire and grazing. Finally, we discuss the management of C. glaucophylla for a range of landuses.

Modelling the dynamics of white cypress pine Callitris glaucophylla woodlands in inland south-eastern Australia

2008 ◽  
Vol 211 (1-2) ◽  
pp. 11-24 ◽  
Author(s):  
Karen A. Ross ◽  
Michael Bedward ◽  
Murray V. Ellis ◽  
Andrew Deane ◽  
Christopher C. Simpson ◽  
...  
Keyword(s):  
South Eastern ◽  
Eastern Australia ◽  
Callitris Glaucophylla ◽  
Cypress Pine ◽  
South Eastern Australia

THE ROLE OF GRASSLAND IN MANAGEMENT

1968 ◽  
pp. 44-49
Author(s):  
B.K. Cameron
Keyword(s):  
Soil Temperature ◽  
Annual Rainfall ◽  
Silt Loam ◽  
Average Annual Rainfall ◽  
Very High ◽  
Wilting Point

THE PROPERTY to be discussed is a mixed sheep and cropping unit, situated ei ht a miles east of Ashburton and midway between the Ra aia and the Ashburton rivers. Average annual rainfall is 27 in., evenly spread, but there is very high summer evaporation and therefore frequent droughts. On average, the soil is below wilting point for 40 to 50 days each summer. Winters are cold with the soil temperature being below 48°F for about four months each year. The soil is a Lismore stony silt loam averaging 9 in. in depth over gravel.

scholarly journals The role of climatic and terrain attributes in estimating baseflow recession in tropical catchments

2010 ◽  
Vol 14 (11) ◽  
pp. 2193-2205 ◽  
Author(s):  
J. L. Peña-Arancibia ◽  
A. I. J. M. van Dijk ◽  
M. Mulligan ◽  
L. A. Bruijnzeel
Keyword(s):  
Potential Evapotranspiration ◽  
Aridity Index ◽  
Global Scale ◽  
Tree Cover ◽  
Annual Rainfall ◽  
Ungauged Catchments ◽  
Ongoing Research ◽  
Daily Streamflow ◽  
Terrain Attributes ◽  
Streamflow Data

Abstract. The understanding of low flows in rivers is paramount more than ever as demand for water increases on a global scale. At the same time, limited streamflow data to investigate this phenomenon, particularly in the tropics, makes the provision of accurate estimations in ungauged areas an ongoing research need. This paper analysed the potential of climatic and terrain attributes of 167 tropical and sub-tropical unregulated catchments to predict baseflow recession rates. Daily streamflow data (m3 s–1) from the Global River Discharge Center (GRDC) and a linear reservoir model were used to obtain baseflow recession coefficients (kbf) for these catchments. Climatic attributes included annual and seasonal indicators of rainfall and potential evapotranspiration. Terrain attributes included indicators of catchment shape, morphology, land cover, soils and geology. Stepwise regression was used to identify the best predictors for baseflow recession coefficients. Mean annual rainfall (MAR) and aridity index (AI) were found to explain 49% of the spatial variation of kbf. The rest of climatic indices and the terrain indices average catchment slope (SLO) and tree cover were also good predictors, but co-correlated with MAR. Catchment elongation (CE), a measure of catchment shape, was also found to be statistically significant, although weakly correlated. An analysis of clusters of catchments of smaller size, showed that in these areas, presumably with some similarity of soils and geology due to proximity, residuals of the regression could be explained by SLO and CE. The approach used provides a potential alternative for kbf parameterisation in ungauged catchments.

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