Ecological studies on reproduction and establishment of the woody weed, groundsel bush (Baccharis halimifolia L.: Asteraceae)

1975 ◽  
Vol 26 (5) ◽  
pp. 855 ◽  
Author(s):  
WE Westman ◽  
FD Panetta ◽  
TD Stanely
Keyword(s):  
Integrated Control ◽  
High Light Intensity ◽  
Annual Rainfall ◽  
Cool Temperature ◽  
Vegetative Cover ◽  
Baccharis Halimifolia ◽  
Tall Plant ◽  
Coastal Species ◽  
Eastern Australia ◽  
Total Seed

Groundsel bush (Baccharis halimifolia) is spreading southward along the coastal range of eastern Australia where the annual rainfall exceeds 90 cm. This advance conforms with its cool temperature optimum for germination (15-20�C) and its superior germination when given a cold pretreatment (5�C for 1 week). The species has a facultative light requirement for germination, which suggests that the maintenance of a very dense vegetative cover in the herb layer could discourage establishment of the weed. Once established, however, B. halimifolia can produce viable seed in very dense shade (3 % of open light conditions), even though total seed production per plant is reduced. Prolific seeding occurs with high light intensity. Thus a tall plant (2 m) may release c. 1.5 million seeds. Seedlings possess an unusual ability to maintain growth under low nitrogen conditions during their first 13 weeks, and to survive even when the supply of all nutrients is poor. Seedlings showed no growth response when the strength of a standard nutrient solution was doubled. The fact that growth is not inhibited under enriched nutrient conditions, however, may account for the superior competitive performance of B, halimifolia on fertilized sites containing native coastal species adapted to low soil fertility. Implications with respect to integrated control of the weed are briefly discussed.

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.

A revision of the textricellin spider genus Raveniella (Araneae:Araneoidea:Micropholcommatidae): exploring patterns of phylogeny and biogeography in an Australian biodiversity hotspot

2010 ◽  
Vol 24 (3) ◽  
pp. 209 ◽  
Author(s):  
Michael G. Rix ◽  
Mark S. Harvey ◽  
J. Dale Roberts
Keyword(s):  
New Species ◽  
Western Australia ◽  
Coastal Plain ◽  
Mitochondrial Protein ◽  
Biodiversity Hotspot ◽  
Rrna Genes ◽  
Protein Coding ◽  
Swan Coastal Plain ◽  
Coastal Species ◽  
Eastern Australia

South-western Western Australia is a biodiversity hotspot, with high levels of local endemism and a rich but largely undescribed terrestrial invertebrate fauna. Very few phylogeographic studies have been undertaken on south-western Australian invertebrate taxa, and almost nothing is known about historical biogeographic or cladogenic processes, particularly on the relatively young, speciose Quaternary sand dune habitats of the Swan Coastal Plain. Phylogeographic and taxonomic patterns were studied in textricellin micropholcommatid spiders belonging to the genus Raveniella Rix & Harvey. The Micropholcommatidae is a family of small spiders with a widespread distribution in southern Western Australia, and most species are spatially restricted to refugial microhabitats. In total, 340 specimens of Raveniella were collected from 36 surveyed localities on the Swan Coastal Plain and 17 non-Swan Coastal Plain reference localities in south-western Western Australia. Fragments from three nuclear rRNA genes (5.8S, 18S and ITS2), and one mitochondrial protein-coding gene (COI) were used to infer the phylogeny of the genus Raveniella, and to examine phylogeographic patterns on the Swan Coastal Plain. Five new species of Raveniella are described from Western Australia (R. arenacea, sp. nov., R. cirrata, sp. nov., R. janineae, sp. nov., R. mucronata, sp. nov. and R. subcirrata, sp. nov.), along with a single new species from south-eastern Australia (R. apopsis, sp. nov.). Four species of Raveniella were found on the Swan Coastal Plain: two with broader distributions in the High Rainfall and Transitional Rainfall Zones (R. peckorum Rix & Harvey, R. cirrata); and two endemic to the Swan Coastal Plain, found only on the western-most Quindalup dunes (R. arenacea, R. subcirrata). Two coastally restricted species (R. subcirrata, R. janineae) were found to be morphologically cryptic but genetically highly distinct, with female specimens morphologically indistinguishable from their respective sister-taxa (R. cirrata and R. peckorum). The greater Perth region is an important biogeographic overlap zone for all four Swan Coastal Plain species, where the ranges of two endemic coastal species join the northern and south-western limits of the ranges of R. peckorum and R. cirrata, respectively. Most species of Raveniella were found to occupy long, highly autapomorphic molecular branches exhibiting little intraspecific variation, and an analysis of ITS2 rRNA secondary structures among different species of Raveniella revealed the presence of an extraordinary hypervariable helix, ranging from 31 to over 400 nucleotides in length.

Accumulation of soil carbon under zero tillage cropping and perennial vegetation on the Liverpool Plains, eastern Australia

Soil Research ◽  
2009 ◽  
Vol 47 (3) ◽  
pp. 273 ◽  
Author(s):  
R. R. Young ◽  
B. Wilson ◽  
S. Harden ◽  
A. Bernardi
Keyword(s):  
Field Experiment ◽  
Soil Carbon ◽  
Cropping Systems ◽  
Annual Rainfall ◽  
Continuous Cropping ◽  
Zero Tillage ◽  
Accumulation Rates ◽  
Eastern Australia ◽  
Perennial Vegetation ◽  
Semi Arid

Australian agriculture contributes an estimated 16% of all national greenhouse gas emissions, and considerable attention is now focused on management approaches that reduce net emissions. One area of potential is the modification of cropping practices to increase soil carbon storage. Here, we report short–medium term changes in soil carbon under zero tillage cropping systems and perennial vegetation, both in a replicated field experiment and on nearby farmers’ paddocks, on carbon-depleted Black Vertosols in the upper Liverpool Plains catchment. Soil organic carbon stocks (CS) remained unchanged under both zero tillage long fallow wheat–sorghum rotations and zero tillage continuous winter cereal in a replicated field experiment from 1994 to 2000. There was some evidence of accumulation of CS under intensive (>1 crop/year) zero tillage response cropping. There was significant accumulation of CS (~0.35 Mg/ha.year) under 3 types of perennial pasture, despite removal of aerial biomass with each harvest. Significant accumulation was detected in the 0–0.1, 0.1–0.2, and 0.2–0.4 m depth increments under lucerne and the top 2 increments under mixed pastures of lucerne and phalaris and of C3 and C4 perennial grasses. Average annual rainfall for the period of observations was 772 mm, greater than the 40-year average of 680 mm. A comparison of major attributes of cropping systems and perennial pastures showed no association between aerial biomass production and accumulation rates of CS but a positive correlation between the residence times of established plants and accumulation rates of CS. CS also remained unchanged (1998/2000–07) under zero tillage cropping on nearby farms, irrespective of paddock history before 1998/2000 (zero tillage cropping, traditional cropping, or ~10 years of sown perennial pasture). These results are consistent with previous work in Queensland and central western New South Wales suggesting that the climate (warm, semi-arid temperate, semi-arid subtropical) of much of the inland cropping country in eastern Australia is not conducive to accumulation of soil carbon under continuous cropping, although they do suggest that CS may accumulate under several years of healthy perennial pastures in rotation with zero tillage cropping.

The Brigalow Catchment Study: III. Productivity changes on brigalow land cleared for long-term cropping and for grazing

Soil Research ◽  
2007 ◽  
Vol 45 (7) ◽  
pp. 512 ◽  
Author(s):  
B. J. Radford ◽  
C. M. Thornton ◽  
B. A. Cowie ◽  
M. L. Stephens
Keyword(s):  
Crop Production ◽  
Clay Soil ◽  
Soil Nutrient ◽  
Grain Protein Content ◽  
Annual Rainfall ◽  
Soil N ◽  
Stocking Rate ◽  
Beef Production ◽  
Eastern Australia ◽  
Productivity Decline

Productivity of grain crops and grazed pastures inevitably declines without soil nutrient replacement and may eventually make these enterprises unprofitable. We monitored these declines in north-eastern Australia during 23 years after clearing 2 of 3 adjacent brigalow catchments, in order to define the productivity levels of developed brigalow land over time. One catchment (11.7 ha) was used for grain production and another (12.7 ha) for beef production from a sown buffel grass pasture. There was no upward or downward trend in annual rainfall amounts throughout the study period. In the cropped catchment, grain yield from 14 winter crops without added nutrients declined significantly in 20 years from 2.9 to 1.1 t/ha.year on the upper-slope clay soil (92 kg/ha.year) and from 2.4 to 0.6 t/ha.year on the Sodosol (88 kg/ha.year). Crop production per year declined by 20% between 2 successive 10-year periods. Wheat grain protein content also declined with time, falling below the critical value for adequate soil N supply (11.5%) 12 years after clearing on the Sodosol and 16 years after clearing on the clay soil. Such declines in grain quantity and quality without applied fertiliser reduce profitability. The initial pasture dry matter on offer of 8 t/ha had halved 3 years after clearing, and a decline in cattle liveweight gain of 4 kg/ha.year was observed over an 8-year period with constant stocking of 0.59 head/ha. Due to fluctuating stocking rate levels of 0.3–0.7 head/ha over the trial period, liveweight productivity trends are attributed to the multiple effects of stocking rate changes and fertility decline. The amount of nitrogen exported from the cleared catchments was 36.1 kg/ha.year in grain but only 1.6 kg/ha.year in cattle (as liveweight gain). Total soil N at 0–0.3 m declined by 84 kg/ha.year under cropping but there was no significant decline under grazing. The soil nutrients removed during grain and beef production need to be replaced in order to avert productivity decline post-clearing.

Soil organic matter in rainfed cropping systems of the Australian cereal belt

Soil Research ◽  
2001 ◽  
Vol 39 (3) ◽  
pp. 435 ◽  
Author(s):  
R. C. Dalal ◽  
K. Y. Chan
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Management Practices ◽  
Performance Indicator ◽  
Annual Rainfall ◽  
Soil Productivity ◽  
Organic C ◽  
Soil C ◽  
Eastern Australia

The Australian cereal belt stretches as an arc from north-eastern Australia to south-western Australia (24˚S–40˚S and 125˚E–147˚E), with mean annual temperatures from 14˚C (temperate) to 26˚C (subtropical), and with annual rainfall ranging from 250 mm to 1500 mm. The predominant soil types of the cereal belt include Chromosols, Kandosols, Sodosols, and Vertosols, with significant areas of Ferrosols, Kurosols, Podosols, and Dermosols, covering approximately 20 Mha of arable cropping and 21 Mha of ley pastures. Cultivation and cropping has led to a substantial loss of soil organic matter (SOM) from the Australian cereal belt; the long-term SOM loss often exceeds 60% from the top 0–0.1 m depth after 50 years of cereal cropping. Loss of labile components of SOM such as sand-size or particulate SOM, microbial biomass, and mineralisable nitrogen has been even higher, thus resulting in greater loss in soil productivity than that assessed from the loss of total SOM alone. Since SOM is heterogeneous in nature, the significance and functions of its various components are ambiguous. It is essential that the relationship between levels of total SOM or its identif iable components and the most affected soil properties be established and then quantif ied before the concentrations or amounts of SOM and/or its components can be used as a performance indicator. There is also a need for experimentally verifiable soil organic C pools in modelling the dynamics and management of SOM. Furthermore, the interaction of environmental pollutants added to soil, soil microbial biodiversity, and SOM is poorly understood and therefore requires further study. Biophysically appropriate and cost-effective management practices for cereal cropping lands are required for restoring and maintaining organic matter for sustainable agriculture and restoration of degraded lands. The additional benefit of SOM restoration will be an increase in the long-term greenhouse C sink, which has the potentialto reduce greenhouse emissions by about 50 Mt CO2 equivalents/year over a 20-year period, although current improved agricultural practices can only sequester an estimated 23% of the potential soil C sink.

Crop stubbles are as important for sheep production as annual pastures in the Victorian Mallee

2006 ◽  
Vol 46 (8) ◽  
pp. 993 ◽  
Author(s):  
S. M. Robertson
Keyword(s):  
Plant Density ◽  
Cropping Systems ◽  
Management Strategies ◽  
Simulation Modelling ◽  
Annual Rainfall ◽  
Pasture Management ◽  
Pasture Production ◽  
Eastern Australia ◽  
Sheep Production ◽  
The Impact

The impact of different management strategies on production and profit can be evaluated with knowledge of how sheep production responds to changes in the available feed base and sheep or pasture management. This study aimed to quantify on-farm pasture and sheep production in mixed sheep and cropping systems in the Victorian Mallee of south-eastern Australia (325 ± 50 mm annual rainfall) as a prelude to computer simulation modelling. During 2001 (average rainfall) and 2002 (extreme drought) pasture production, the feed base and sheep production were monitored in 15 paddocks on 5 properties located across the region. Crop stubbles were the major source of feed for 6 months of the year, enabling ewes to maintain liveweight. There was more variation in pasture parameters between paddocks at the 1 location than between locations. The botanical composition, plant density, soil fertility and management were key variables associated with between-paddock variation in pasture production. Variation in pasture production between years was larger than within-year differences. In contrast, stocking rates were not much lower in the drought year of 2002 than in 2001. This study suggests there is potential for management to improve pasture production, and demonstrates the importance of feed sources other than annual pasture for sheep production in environments where the annual pasture growing season is short.

Clinal Variation in Electrophoretic and Morphological Characters between Two Nominal Species of the Genus Pseudomugil (Pisces : Atheriniformes : Pseudomugilidae)

1979 ◽  
Vol 30 (3) ◽  
pp. 375 ◽  
Author(s):  
AJ Hadfield ◽  
V Ivantsoff ◽  
PG Johnson
Keyword(s):  
Principal Components ◽  
Major Part ◽  
Single Species ◽  
Morphological Characters ◽  
Morphological Data ◽  
Nominal Species ◽  
Clinal Variation ◽  
Brackish Waters ◽  
Coastal Species ◽  
Eastern Australia

Electrophoretic and morphological comparisons were made between 14 populations representing the major part of the known range of the nominal fish species, Pseudomugil signifer Kner and Pseudomugil signatus (Gunther), described from the fresh and brackish waters of eastern Australia. Analysis by principal components was used to assess the morphological data. .Clinal variation revealed in 10 morphological characters and at two enzyme loci was found to bridge most of the previously described differences between species. The type material of P. signatus afinis from the Low Isles, Queensland, was re-examined and did not appear to differ morphologically from the coastal species. It is therefore suggested that the populations studied represent a single species Pseudomugil signifer Kner.

scholarly journals BARRON RIVER DELTA INVESTIGATION

1980 ◽  
Vol 1 (17) ◽  
pp. 54 ◽  
Author(s):  
D.A. Robinson ◽  
D.J. Cook ◽  
J.G. Barff
Keyword(s):  
Beach Sand ◽  
Annual Rainfall ◽  
Electric Power Station ◽  
River Flows ◽  
Farm Land ◽  
Main River ◽  
Eastern Australia ◽  
Sand And Gravel ◽  
The Tropics ◽  
Resort Towns

The Barron River flows to sea through a 50 km2 alluvial Delta on the narrow coastal plain near Cairns, Queensland in north eastern Australia. The Delta is in the tropics at 17 degrees south latitude. Most of the 2175 km2 catchment lies above 450 m above sea level. The coastal portion of the catchment has an average annual rainfall in excess of 2000 mm. River flows are highly variable with peak flood flows of over 4000 m3s"', and dry season flows of less than 15 m3s"'. The Delta is tidal with ocean tides having a range of 1.8 m at Spring Tides. There are three water storages on the catchment, one on the upper catchment having an ungated spillway and a capacity of 407 x 106 m3 for irrigation purposes and the other two just upstream of the Delta, are a small weir of 1.7 x 106 m3 capacity to regulate water supply to the Barron Gorge Hydro-electric Power Station, and Copperlode Falls Dam on Freshwater Creek, a 45 x 106 m3 ungated storage to provide water to Cairns City and the nearby Mulgrave Shire. The Delta consists of alluvial soils which support 3600 hectares of sugar cane farm land. The beaches in the Delta are being developed as resort towns and dormitory suburbs. Sand and gravel is reularly dredged from the lower reaches of the main river in the Delta at the rate of 50,000-80,000 m3 per year. Increasing scarcity of sand sources, and the concern that dredging and dam construction is threatening beach sand sources have raised conflicting pressures on the Authority which licences the extraction of sand and gravel from the river. This, coupled with regular flooding of the Delta and the cutting of major highways, and the continuing erosion of cane farm land has initiated a major data collection programme as a prerequisite to formulating solutions for the flooding and erosion problems.

Leaf injury to bean plants grown in carbon dioxide enriched atmospheres

1985 ◽  
Vol 63 (11) ◽  
pp. 2015-2020 ◽  
Author(s):  
David L. Ehret ◽  
Peter A. Jolliffe
Keyword(s):  
Water Status ◽  
Photosynthetic Photon Flux Density ◽  
High Light Intensity ◽  
Starch Accumulation ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Cool Temperature ◽  
Leaf Water Status ◽  
Leaf Injury ◽  
Diffusive Resistance

Bush bean (Phaseolus vulgaris L.) plants grown in atmospheres enriched with CO2 (1400 μL L−1) showed marked reductions in photosynthetic capacity and accelerated chlorosis of primary leaves. Leaf injury was observed only in CO2-enriched plants, but the degree of injury was regulated by secondary factors, light and temperature. Conditions of relatively high light intensity (340–370 μmol m−2 s−1 photosynthetic photon flux density) or cool temperature (20 °C) promoted leaf injury of CO2-enriched plants. Leaf starch accumulation was highest under conditions that caused injury. The enhanced chlorosis and corresponding decline in photosynthetic activity, however, were not related to changes in stomatal diffusive resistance or leaf water status. Contaminant gases, such as ethylene, were not detectable in the CO2-enrichment chambers.

Puccinia striiformis in Australia: a review of the incursion, evolution, and adaptation of stripe rust in the period 1979 - 2006

2007 ◽  
Vol 58 (6) ◽  
pp. 567 ◽  
Author(s):  
C. R. Wellings
Keyword(s):  
Stripe Rust ◽  
Chemical Control ◽  
Puccinia Striiformis ◽  
Cool Temperature ◽  
Pathogen Population ◽  
European Origin ◽  
Yield And Quality ◽  
Eastern Australia ◽  
Major Shift ◽  
Pathogen Populations

The wheat stripe rust pathogen (Puccinia striiformis f. sp. tritici; Pst) was first detected in Australia in 1979. The features of the initial pathotype suggested that it was of European origin, and later work provided evidence that it was most likely transmitted as adherent spores on travellers’ clothing. Despite long-held views that this cool temperature pathogen would not adapt to Australian conditions, Pst became endemic and progressively adapted to commercial wheat production through step-wise mutation. Several of these mutant pathotypes became frequent in the Pst population, causing widespread infection and significant costs to production (yield and quality losses; chemical control expenditure) in certain cultivars and seasons. Pathotype evolution, including adaptation to native barley grass (Hordeum spp.) populations, is described. The occurrence of an exotic pathotype of Pst in Western Australia in 2002, and its subsequent spread to eastern Australia, represented a major shift in the pathogen population. This pathotype dominated pathogen populations throughout Australia from 2003, with chemical control expenditure estimated at AU$40–90 million annually. Another exotic introduction was detected in 1998. Initial data indicated that certain isolates collected from barley grass were highly avirulent to wheat differentials, with the exception of partial virulence to Chinese 166. Further seedling tests revealed that these isolates, tentatively designated barley grass stripe rust (BGYR), were virulent on several Australian barleys, notably those of Skiff parentage. Data, including molecular studies, suggest that BGYR is a new forma specialis of P. striiformis. Field nurseries indicate that BGYR is likely to have little impact on commercial barley, although this may change with further pathotype evolution or the release of susceptible cultivars.

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