The ages and fecundity of some arid-zone plants in Western Australia

2013 ◽  
Vol 35 (4) ◽  
pp. 455 ◽  
Author(s):  
S. J. J. F. Davies ◽  
S. A. Kenny
Keyword(s):  
Soil Nutrients ◽  
Western Australia ◽  
Half Life ◽  
Heavy Rainfall ◽  
Arid Zone ◽  
Summer Rainfall ◽  
Individual Species ◽  
High Fecundity ◽  
High Rainfall ◽  
Arid Zone Plants

Since 1960, 22 species of individually marked, arid-zone perennial plants in the Murchison District and Gibson Desert of Western Australia have been monitored for flowering, fecundity, and survival. The age to which individual species survive was determined in terms of half-life, i.e. the time elapsed for half of the marked sample to die. The estimates ranged from 6.5 to 535 years. Phenology was recorded by observing whether the plants carried buds, flowers, fruits, or any combination of these, or were sterile. Fecundity of each species was measured by recording each year the percentage of the sample trees that carried fruit, by collecting seeds in trays placed beneath the plants and by counting the pods produced by some species. Fecundity was related to seasonal rainfall, most species responding positively to summer rainfall. The concept of mast years, as utilised in the northern hemisphere, was applied to recorded fecundities and some evidence was found that, after a year of high fecundity, the plants responded less vigorously to conditions of high rainfall than they did in the previous year of high rainfall. This suggests that, in years when fecundity is high, it diminishes the resources available within the plants to respond to heavy rainfall the following year or reduces the soil nutrients available to them.

The population dynamics of some arid zone plants during 46 years of grazing on Mileura Station, Western Australia

2015 ◽  
Vol 37 (4) ◽  
pp. 367 ◽  
Author(s):  
S. J. J. F. Davies ◽  
S. A. Kenny ◽  
T. F. M. Walsh
Keyword(s):  
Population Dynamics ◽  
Western Australia ◽  
Arid Zone ◽  
Summer Rainfall ◽  
Department Of Agriculture ◽  
Perennial Plants ◽  
Land System ◽  
Western Australian Department ◽  
Land Systems ◽  
Made In

Grazed quadrats were monitored on Mileura Station, Western Australia from 1967 to 2013 in order to study the population dynamics of the perennial plants in two of the land systems on the property. Counts of plants on four quadrats at each of 10 sites were made in 1967, 1976, 1990 and 2013, and individual plants were traced for the first three samplings. Five sites were on the Sherwood land system and five on the Belele land system. The results indicated that the populations of some species in the mulga shrubland increased steadily over the 46 years of the study whereas the populations of other species, especially the small, short-lived shrubs, fluctuated over this period. A reduction in stocking rate from 1976 to 1990 was associated with an increase in the population of perennial plants; the total numbers for the 1976 count were 1506 compared with 2102 in 1990. Mean summer rainfall increased between 1990 and 2013 and this increase may have been associated with the recruitment. Overall, the study showed that commercial stocking, although at a lower rate than that recommended by the Western Australian Department of Agriculture, was compatible with increases in the populations of the perennial components of mulga shrubland in this region.

Native microhabitats better predict tolerance to warming than latitudinal macro-climatic variables in arid-zone plants

2016 ◽  
Vol 43 (6) ◽  
pp. 1156-1165 ◽  
Author(s):  
Ellen M. Curtis ◽  
John Gollan ◽  
Brad R. Murray ◽  
Andrea Leigh
Keyword(s):  
Arid Zone ◽  
Climatic Variables ◽  
Arid Zone Plants

The germinable soil seedbank of Eucalyptus victrix grassy woodlands at Roy Hill station, Pilbara district, Western Australia

2004 ◽  
Vol 26 (1) ◽  
pp. 17 ◽  
Author(s):  
R. A. Graham ◽  
S. K. Florentine ◽  
J. E. D. Fox ◽  
T. M. Luong
Keyword(s):  
Species Composition ◽  
Western Australia ◽  
Perennial Grass ◽  
Summer Rainfall ◽  
Distribution Patterns ◽  
Grass Species ◽  
Surface Areas ◽  
Hill Station ◽  
Soil Seedbank ◽  
Germinable Seed

The paper reports soil seedbank species composition, of Eucalyptus victrix grassy woodlands, of the upper Fortescue River in the Pilbara District, Western Australia. In this study, our objectives were to investigate germinable soil seedbanks and species composition in response to three simulated seasons, using emergence. Variation in seed density from three depths was tested. Four field sites were sampled. Thirty samples were collected in late spring, after seed rain and before summer rainfall. From each sample spot, three soil depths (surface, 1–5, and 6–10 cm) were segregated from beneath surface areas of 100 cm2. Samples were later incubated in a glasshouse to simulate three different seasonal conditions (autumn, winter and spring). Germinating seedlings were recorded on emergence and grown until identified. Forty-one species germinated, comprising 11 grasses (7 annuals and 4 perennials), 25 annual herbs and 5 perennial herbs. Distribution patterns of germinable seed in both the important annual grass Eragrostis japonica and the perennial Eragrostis setifolia (a preferred cattle fodder species), suggest that seedbank accumulation differs among species and between sites. In part, this may be associated with the absence of grazing. Species with most total germinable seed were E. japonica (Poaceae; 603/m2), and the annual herbs Calotis multicaulis (Asteraceae; 346/m2), and Mimulus gracilis (Scrophulariaceae; 168/m2). Perennial grass seed was sparse. Spring simulation gave most germination (1059), followed by autumn (892) and winter (376) sets. Greatest species diversity was produced from the spring simulation (33 species), followed by autumn (26), and winter (22). Of the total germination, 92% came from 17 species that were represented in all three simulations. Of the 1227 grass seedlings counted, most were recruited from the surface soil (735), followed by the 5 (310) and 10 (182) cm depths. Marginally more grass seedlings germinated from the spring simulation (558) than the autumn set (523). Only 11.9% of grass germinants came from the winter simulation. All grass species recruited from the soil seedbanks had a C4 photosynthetic pathway. Except for Cenchrus ciliaris all grass species are native to Australia. Of the four sites sampled, one fenced to exclude cattle five years earlier had significantly more germination than the three unfenced sites. Seedbank sampling produced several new records for plants in the areas sampled.

scholarly journals A Hotspot of Arid Zone Subterranean Biodiversity: The Robe Valley in Western Australia

Diversity ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 482
Author(s):  
Huon L. Clark ◽  
Bruno A. Buzatto ◽  
Stuart A. Halse
Keyword(s):  
Western Australia ◽  
Arid Zone ◽  
Ground Level ◽  
Ore Formation ◽  
Monitoring Wells ◽  
Groundwater Aquifers ◽  
Species Lists ◽  
Below Ground ◽  
Drill Holes ◽  
Mining Exploration

Knowledge of subterranean fauna has mostly been derived from caves and streambeds, which are relatively easily accessed. In contrast, subterranean fauna inhabiting regional groundwater aquifers or the vadose zone (between surface soil layers and the watertable) is difficult to sample. Here we provide species lists for a globally significant subterranean fauna hotspot in the Robe Valley of the Pilbara region, Western Australia. This fauna was collected from up to 50 m below ground level using mining exploration drill holes and monitoring wells. Altogether, 123 subterranean species were collected over a distance of 17 km, comprising 65 troglofauna and 58 stygofauna species. Of these, 61 species were troglobionts and 48 stygobionts. The troglofauna occurs in small voids and fissures in mesas comprised mostly of an iron ore formation, while the stygofauna occurs in the alluvium of a river floodplain. The richness of the Robe Valley is not a localized aberration, but rather reflects the richness of the arid Pilbara region. While legislation in Western Australia has recognized the importance of subterranean fauna, mining is occurring in the Robe Valley hotspot with conditions of environmental approval that are designed to ensure species persistence.

Subterranean archipelago in the Australian arid zone: mitochondrial DNA phylogeography of amphipods from central Western Australia

2007 ◽  
Vol 16 (7) ◽  
pp. 1533-1544 ◽  
Author(s):  
STEVEN J. B. COOPER ◽  
JOHN H. BRADBURY ◽  
KATHLEEN M. SAINT ◽  
REMKO LEYS ◽  
ANDREW D. AUSTIN ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Western Australia ◽  
Arid Zone

Effect of month of birth and first summer's nutrition on the productivity of Merino wethers

1985 ◽  
Vol 25 (4) ◽  
pp. 777 ◽  
Author(s):  
T Marshall
Keyword(s):  
Western Australia ◽  
Mediterranean Environment ◽  
Month Of Birth ◽  
Nutritional Treatment ◽  
Wool Production ◽  
High Rainfall

Liveweight and greasy wool production of Merino wethers born in either mid-May, late June or early September in each of 2 years and subjected to three nutritional regimes (high, normal and low) over their first summer were studied over 4 years. Differences in liveweight of up to 9.0 kg between treatments due to month of birth persisted for 48 months while liveweight differences of as much as 15 3 kg due to nutritional treatment lasted only 24-30 months. Similarly, differences in greasy wool production of up to 0.8 kg between times of birth lasted for the duration of the study but differences between first summer nutritional treatment, although as much as 1.1 kg at the first adult shearing, persisted for only 2 years. The results strongly indicate that, in the high rainfall Mediterranean environment of southern Western Australia, sheep born late in the season will be of lower liveweight and will produce less wool than sheep born early in the season.

Chemical control of loose smut (Ustilago segetum var. tritici) of barley and the effects of cultivar and environment on disease incidence

1991 ◽  
Vol 31 (3) ◽  
pp. 373
Author(s):  
R Loughman ◽  
EJ Speijers ◽  
GJ Thomas ◽  
DJ Ballinger
Keyword(s):  
Western Australia ◽  
Chemical Control ◽  
Disease Incidence ◽  
Field Trials ◽  
Loose Smut ◽  
High Rainfall ◽  
Barley Cultivars ◽  
Control Disease ◽  
Moderately Resistant ◽  
Very High

The reasons for an increase in barley loose smut in high rainfall areas of Western Australia were investigated in field trials from 1986 to 1988 by examining the effects of environment, cultivar and adequacy of chemical control. Disease was 4-18 times greater in 2 seed lines produced in very high rainfall areas (>750 mm/year) compared with that produced in high (450-750 mm/year) or low (<325 mm/year) rainfall areas. The effectiveness of 5 fungicide seed treatments was assessed. No fungicide seed treatment controlled disease completely. Triadimenol at 225 mg a.i./kg and carboxin at 940 mg a.i./kg were most effective, providing 93-96% disease control. Treatments were significantly (P<0.01) less effective in high rainfall areas of Western Australia. Barley cultivars released recently in Western Australia were found to be susceptible to loose smut; we suggest that the replacement of the moderately resistant Dampier with these cultivars has contributed to an increased incidence of disease.

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