Factors Affecting the Distribution of Nutrients in the Tree Organs of Eucalyptus camaldulensis in the Arid Lands of Western Australia

Seed production and persistence of the Carnamah, Northam A, Dwalganup, and Geraldton strains of subterranean clover (Trifolium subterraneum L.) were examined in undefoliated swards in the wheatbelt of Western Australia. The early flowering characteristic of Carnamah was not always associated with higher seed yields. Only when there was a well-defined, early finish to the growing season, or when flowering was very much earlier in Carnamah (viz., following an early 'break' to the season), did this strain clearly outyield both Northam A and Geraldton. The seed yield of Dwalganup was generally inferior to that of the other strains. Factors affecting regeneration are discussed. Under low rainfall conditions, poorer germination-regulation of Carnamah, compared with Geraldton and Northam A, would be expected to result in poorer persistence unless offset by higher seed yields in the Carnamah strain.

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The ecology of Sminthurus viridis (L.) (Collembola). I. Processes influencing numbers in pastures in Western Australia

Australian Journal of Zoology ◽

10.1071/zo9671173 ◽

1967 ◽

Vol 15 (6) ◽

pp. 1173 ◽

Cited By ~ 26

Author(s):

MMH Wallace

Keyword(s):

Western Australia ◽

Dominant Role ◽

Clay Content ◽

Early Death ◽

Factors Affecting ◽

Dead Bodies ◽

Fat Bodies ◽

Set Up ◽

Content Support ◽

Type 3

The changes in numbers of Sminthurus viridis (Collembola: Sminthuridae) in pastures in Western Australia were studied for 9 years on one site and for shorter periods on other sites. Five factors affecting numbers are described: (1) weather, (2) soil type (3) botanical composition of the pasture, (4) predation by Bdellodes lapidaria (Acarina: Bdellidae), and (5) eating of dead bodies by newly hatched nymphs. Weather is generally favourable for the active stages during autumn, winter, and spring. In the summer, the species is maintained by aestivating eggs. Dry periods during the winter months sometimes cause high mortalities. Soils containing a high silt-plus-clay content support higher numbers due mainly to increased oviposition. Flea densities increase more rapidly where there is a high proportion of broad-leaved plants, such as clover and capeweed in the pasture. Grassy areas are not favoured. Predation by B. lapidaria effectively reduces numbers. The presence of more than 20 B. lapidaria per square metre early in the winter prevents any outbreak of fleas later in the season. Bdellodes lapidaria numbers increase in response to an increase in flea numbers. An irregular predator-prey cycle is set up in this way. Density-induced mortality, resulting from the newly hatched nymphs eating the bodies of recently dead fleas, plays a dominant role at high densities. This process operates continuously though at decreased intensity at lower densities. When newly hatched nymphs feed upon dead nymphs and adults they ingest materials which cause early death. Sometimes this may lead to a dramatic collapse of the population. Fleas from high-density populations usually contain large quantities of uric acid in their "fat-bodies". It is suggested that death of the mature fleas at high densities is hastened through the storage of excessive amounts of waste material. Death of the young nymphs feeding upon the dead bodies may be brought about by the ingestion of these waste materials, although this has yet to be proven.

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Factors affecting nestling condition and timing of egg-laying in the endangered Carnaby’s cockatoo, Calyptorhynchus latirostris

Pacific Conservation Biology ◽

10.1071/pc19010 ◽

2020 ◽

Vol 26 (1) ◽

pp. 22

Author(s):

Denis A. Saunders ◽

Rick Dawson ◽

Peter R. Mawson ◽

A. O. Nicholls

Keyword(s):

Body Mass ◽

Western Australia ◽

Egg Laying ◽

Breeding Habitat ◽

Left Wing ◽

Factors Affecting ◽

Failure Data ◽

Breeding Populations ◽

Nestling Condition ◽

Breeding Failure

Carnaby’s cockatoo, Calyptorhynchus latirostris, is endemic to south-western Australia. It has undergone a major decline in range and abundance as a result of extensive removal of breeding and foraging habitat. It is now classified as endangered by the State of Western Australia, the Australian government, and internationally. In order to plan effective conservation management for the species it is important to assess the success of breeding populations throughout its range. In this paper we examine the efficacy of using the relationship between growth in the length of a nestling’s folded left wing and body mass to assess nestling condition, and examine known breeding failure in relation to nestling condition in two breeding populations: one at Coomallo Creek (studied from 1970–2017), and the other at Manmanning (1969–76). Results demonstrated that the lighter the nestlings, the higher the rate of breeding failure. Data from the Coomallo Creek population were used to prepare a table of nestling folded left wing length and body mass as a benchmark for assessing nestling condition in 10 other breeding populations, based on data collected from 1970 to the present. Following extensive clearing that removed foraging and breeding habitat, two of the 10 populations produced nestlings that were significantly lighter than the benchmark, and both populations subsequently declined to extinction. The commencement of egg-laying each season at Coomallo Creek was strongly influenced by total rainfall in the first half of autumn. The length of the egg-laying period between 1970–76 and 2009–17 increased by 5.2 weeks (40%). This increase was related to changes in rainfall and temperature over more than four decades. Despite the lengthening of the egg-laying period, nestling condition was unaffected, suggesting that, at least in the short term, the Carnaby’s cockatoo population at Coomallo Creek is coping with the effects of climate change.

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A Review of Ecological Factors Affecting Seed Germination of Species Used in the Reclamation of Western Australia Bauxite Mining

Journal American Society of Mining and Reclamation ◽

10.21000/jasmr95010125 ◽

1995 ◽

Vol 1995 (1) ◽

pp. 125-135

Author(s):

D. T. Bell

Keyword(s):

Seed Germination ◽

Western Australia ◽

Ecological Factors ◽

Bauxite Mining ◽

Factors Affecting

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Factors affecting the abundance of hollows in logs in jarrah forest of south-western Australia

Forest Ecology and Management ◽

10.1016/s0378-1127(97)00015-7 ◽

1997 ◽

Vol 95 (2) ◽

pp. 153-160 ◽

Cited By ~ 23

Author(s):

Matthew R. Williams ◽

K. Faunt

Keyword(s):

Western Australia ◽

Jarrah Forest ◽

Factors Affecting

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Ecological factors affecting distribution and abundance of Medicago minima

Crop and Pasture Science ◽

10.1071/cp03123 ◽

2011 ◽

Vol 62 (7) ◽

pp. 581 ◽

Cited By ~ 1

Author(s):

Diana E. Fresnillo-Fedorenko ◽

Philip S. Cocks ◽

John W. Bowden

Keyword(s):

Western Australia ◽

Ecological Factors ◽

Annual Rainfall ◽

Available Phosphorus ◽

Soil Factors ◽

Factors Affecting ◽

Pasture Legumes ◽

Ecological Success ◽

Physical And Chemical ◽

Pasture Legume

A survey was conducted to study the distribution and abundance of Medicago minima in relation to soil factors and rainfall. The collection targeted two regions of Western Australia where this species is known to occur. The frequency and pod density of M. minima and other naturalised annual pasture legumes (Medicago spp. and Trifolium spp.) was recorded per site. In addition, soil samples were taken and analysed for physical and chemical characteristics. Soils where M. minima was present were finer textured, higher in pH, nitrate and potassium, and lower in available phosphorus than soils where it was absent. These soils were commonly found in low rainfall areas. The highest frequency (55%) and density (4000 pods/m2) of M. minima were recorded in areas with 275 mm average annual rainfall. In a third of the collection sites M. minima was the only pasture legume present in the plant community. In the driest areas (260 mm annual rainfall) with the lowest content of available phosphorus (7.5 mg/kg) M. laciniata was associated with M. minima. In areas with 300–325 mm rainfall, M. minima was associated with M. truncatula, M. polymorpha and M. littoralis. The absence of M. minima in areas of Western Australia with >325 mm annual rainfall was related to its low tolerance to soil acidity. This paper examines the ecological success of M. minima with regard to its ability to use phosphorus in soils of high pH and lime content, and to set seed under water stress. It also discusses the distribution of M. minima in Western Australia in relation to its distribution in the Mediterranean Basin and other areas that the species is known to have colonised.

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