Camaenid Land Sanil Reproductive Cycle and Growth Patterns in Semiarid Areas of North Western Australia

1984 ◽  
Vol 32 (4) ◽  
pp. 471 ◽  
Author(s):  
A Solem ◽  
CC Christensen
Keyword(s):  
Western Australia ◽  
General Pattern ◽  
Growth Patterns ◽  
Land Snails ◽  
Food Storage ◽  
Growth Time ◽  
Wet Season ◽  
Shell Size ◽  
Moisture Conditions ◽  
North Western

Dissections of camaenid land snails collected in the Kimberley Region of north-western Australia between 1975 and 1980 reveal a general pattern of sexual maturation. Snails reach half adult shell size in the wet season of their birth, reach adult shell size and become mature males at the end of their second wet season, and function as males at the beginning of their third wet season; the female genitalia mature near the end of this season; and snails function as both males and females in their fourth and subsequent wet seasons. A life span of >8 years is demonstrated. Seasonal genital variation in adults involves: (1) gross size reduction of the apical genitalia during the mid-wet season, which provides maximum space for food storage, thereby allowing survival during aestivation over the long dry season; (2) becoming male active at or shortly before the normal start ofthe wet season at that particular locality; (3) activation of the female system after the first rains of the wet season. Adult shell size is hypothesized to depend upon moisture conditions near the end ofthe snail's second wet season: any early interruption of moisture supply causes growth to stop at a lower whorl count and produces smaller adults; favourable moisture conditions allow extended growth time, with cessation occurring at a higher whorl count, and producing a larger sized adult.

Predicting the ecological impact of cane toads (Bufo marinus) on threatened camaenid land snails in north-western Australia

2009 ◽  
Vol 36 (6) ◽  
pp. 533 ◽  
Author(s):  
David Pearson ◽  
Matthew Greenlees ◽  
Georgia Ward-Fear ◽  
Richard Shine
Keyword(s):  
Western Australia ◽  
Life Histories ◽  
Activity Patterns ◽  
Ecological Impact ◽  
Bufo Marinus ◽  
Land Snails ◽  
Field Surveys ◽  
Habitat Overlap ◽  
Litoria Caerulea ◽  
North Western

The spread of cane toads (Bufo marinus) through north-western Australia may threaten populations of endemic camaenid land snails because these snails exhibit restricted geographic distributions, low vagility and ‘slow’ life-histories. We conducted laboratory trials to determine whether toads would consume camaenids if they encountered them, and conducted field surveys to evaluate the likelihood of such encounters (on the basis of habitat overlap). In laboratory trials with 13 camaenid species, cane toads were more likely to consume camaenids than were two species of native frogs that we tested (Cyclorana australis, Litoria caerulea). However, field surveys suggested that many camaenids are active on vertical surfaces in limestone outcrops, and cane toads rarely venture into these habitats. Although the preferred habitats and activity patterns of camaenids thus reduce their vulnerability to cane toads, we recommend regular surveys of toad and snail numbers to monitor toad impacts. Given the restricted distributions of threatened saxicoline camaenid species in the Kimberley, localised management of grazing stock and fire is feasible to maintain vine-thicket vegetation cover and snail populations, as well as reducing open habitats favoured by toads.

The effect of drought feeding with whole cottonseed, and vitamin therapy, on the serum lipids and liveweight changes of beef cattle in North-western Australia

1968 ◽  
Vol 19 (4) ◽  
pp. 657 ◽  
Author(s):  
JC O'Kelly ◽  
DW Robinson
Keyword(s):  
Western Australia ◽  
Serum Lipids ◽  
Blood Lipids ◽  
Blood Lipid ◽  
Serum Levels ◽  
Wet Season ◽  
Supplementation Period ◽  
Vitamin Therapy ◽  
Whole Cottonseed ◽  
North Western

An experiment with 79 Shorthorn cattle was carried out in the Kimberley region of north-western Australia, to study the influence of drought feeding with whole cottonseed, and of vitamin therapy, on blood lipid components and liveweight changes in cattle during the dry season. The blood serum levels of total, free, and esterified cholesterol, triglycerides, and phospholipids were elevated as a result of cottonseed supplementation, as compared with levels at the end of the following wet season. In general the levels of these blood lipids were higher in the animals fed on cottonseed for longer periods. Neither the level of free fatty acids nor the ratio of free to esterified cholesterol was affected significantly by cottonseed supplementation. Liveweight responses were proportional to the duration of the supplementation period. There were no differences in liveweight changes or the blood components measured which could be attributed to vitamin therapy.

Seasonal changes in the nutritive value of some native pasture species in North-western Australia.

1980 ◽  
Vol 2 (2) ◽  
pp. 175 ◽  
Author(s):  
AM Holm ◽  
GJ Eliot
Keyword(s):  
Western Australia ◽  
Crude Protein ◽  
Nutritive Value ◽  
Dry Season ◽  
In Vitro Digestibility ◽  
Research Station ◽  
Wet Season ◽  
Crude Fibre ◽  
Pasture Land ◽  
North Western

The nutritive value of Astrebla elymoides, A. pectinata, Chrysopogon fallax, Iseilema vaginiflorum, Neptunia monosperma from black soil plains (BSP) pasture land; and Plectrachne pungens, Chrysopogon fallax, Sorghum plumosum, and Eriachne obtusa of curly spinifex-ribbon grass (CSRC;) pasture land, was assessed over the period October 1975 to October 1977 at the Fitzroy Pastoral Research Station, north Western Australia. Seasonal trends in crude protein, crude fibre. phosphorus. calcium and in vitro digestibility, together with some physiological parameters are described for each species. BSP pastures were found to be higher in crude protein, lower in crude fibre and more digestible than CSRG pasture species. Crude protein contents of most BSP pasture species were sufficient for maintenance of cattle during the dry season while CSRG species were below maintenance All species were deficient in phosphorus over the dry season and some species were marginal to deficient over the wet season.

The response of weaner cattle grazing natural pastures in north western Australia to phosphoric acid, non protein nitrogen and sulphur in their drinking water.

1981 ◽  
Vol 3 (2) ◽  
pp. 133
Author(s):  
A.McR. Holm ◽  
AL Payne ◽  
PD Morgan ◽  
EJ Speijers
Keyword(s):  
Drinking Water ◽  
Phosphoric Acid ◽  
Western Australia ◽  
Cattle Grazing ◽  
Dry Season ◽  
Research Station ◽  
Wet Season ◽  
Protein Nitrogen ◽  
Nitrogenous Compounds ◽  
North Western

The study was designed to evaluate the effects of phosphorus and non protein nitrogen supplementation on weaner cattle grazing natural pastures on the Fitzroy Pastoral Research Station, north Western Australia. The study was repeated over the period July 1971 to April 1976, with four drafts of weaners which grazed Mitchell grass pastures during the dry season and curly spinifex-ribbon grass pastures during the wet season. In each year, one of four groups received either no supplement (control), urea plus sulphuric acid, phosphoric acid, or urea plus ammonium sulphate plus phosphoric acid. The supplements were measured into and mixed with the drinking water. Weaners given phosphoric acid gained between 10.5 and 21.7 kg a head more than those not given phosphorus. The response was significant in two of the four dry seasons, three of the four wet seasons and for every ye= when both seasons were considered together. Urea supplements increased liveweight gain over the dry season and depressed liveweight gain over the wet season. There was no advantage to urea when the two seasons were combined. Cattle given supplements through the drinking water drank less water and more of those given nitrogenous compounds died than those not receiving supplements.

Effects of mineral supplementation on the performance of steers grazing birdwood grass (Cenchrus setiger) pastures in north Western Australia

1980 ◽  
Vol 20 (105) ◽  
pp. 398 ◽  
Author(s):  
AM Holm ◽  
AL Payne
Keyword(s):  
Drinking Water ◽  
Phosphoric Acid ◽  
Cobalt Oxide ◽  
Ammonium Sulphate ◽  
Western Australia ◽  
Positive Response ◽  
Wet Season ◽  
Mineral Supplementation ◽  
Grazing Period ◽  
North Western

The liveweight of Shorthorn steers on fertilized birdwood grass (Cenchrus setiger) pastures, growing on sandy 'Pindan' soils, at Derby, north Western Australia, was recorded over 3 years from September 1973 to July 1976. A separate draft of steers was used in each of the 3 years. Half of the steers in each draft were given a supplement of urea, phosphoric acid and ammonium sulphate in the drinking water. These supplemented steers gained an average of 147 kg, 128 kg and 93 kg per head, or 31 kg, 70 kg and 44 kg per head more, than unsupplemented steers in the 3 years. There was a consistent positive response in liveweight gains in all post-wet and pre-wet season periods, and a positive response in two of the three wet seasons. Two levels of pasture use were also imposed but did not have any consistent effect on pasture composition or liveweight gain. Copper injections, and cobalt as cobalt oxide bullets, were given to approximately half the stock in years 1 and 2 respectively. There was a small response (P < 0.05) to copper during the post-wet season, but over the whole grazing period the response was negligible. The cobalt bullets had no effect.

scholarly journals Large‐scale eDNA metabarcoding survey reveals marine biogeographic break and transitions over tropical north‐western Australia

2021 ◽  
Author(s):  
Katrina West ◽  
Michael J. Travers ◽  
Michael Stat ◽  
Euan S. Harvey ◽  
Zoe T. Richards ◽  
...  
Keyword(s):  
Western Australia ◽  
Large Scale ◽  
North Western

Effects of moisture supply in the dry season and subsequent defoliation on persistence of the savanna grasses Themeda triandra, Heteropogon contortus and Panicum maximum

1992 ◽  
Vol 43 (2) ◽  
pp. 241 ◽  
Author(s):  
JJ Mott ◽  
MM Ludlow ◽  
JH Richards ◽  
AD Parsons
Keyword(s):  
Growing Season ◽  
Close Correlation ◽  
Dry Season ◽  
Carbon Gain ◽  
Panicum Maximum ◽  
Wet Season ◽  
Themeda Triandra ◽  
Heteropogon Contortus ◽  
Moisture Conditions ◽  
Sheath Material

The close correlation between grazing-induced mortality and major climatic patterns in Australian savannas, led us to the hypothesis that moisture conditions during the dry, non-growing season could affect sensitivity to grazing in the subsequent growing season. Using three widespread savanna species (Themeda triandra, Heteropogon contortus and Panicum maximum), this hypothesis was tested experimentally and the mechanisms controlling this response examined and quantified. In T. triandra drought during the dry season led to major mortality in defoliated plants in the next growing season. This mortality was caused by a synchrony of tillering at the commencement of the wet season, leaving few buds for replacement once parent tillers were killed by defoliation. T. triandra was also the most sensitive species to defoliation. This sensitivity was due to the poor ability of the plant to maintain positive carbon gain after defoliation. Several factors contributed to this poor ability, including: low total photosynthetic rate, low specific leaf area, and a large proportion of sheath material with poor photosynthetic capacity remaining after cutting. Both H. contortus and P. maximum growing under irrigated and fertilized conditions did not display any effects of previous moisture treatments when defoliated during the next wet season and were much less sensitive to defoliation than T. triandra.

Drivers of species richness and abundance of marine macrophytes on shallow tropical reefs of north‐western Australia

2018 ◽  
Author(s):  
Ylva S. Olsen ◽  
Lydiane Mattio ◽  
Andrea Zavala Perez ◽  
Russ C. Babcock ◽  
Damian Thompson ◽  
...  
Keyword(s):  
Species Richness ◽  
Western Australia ◽  
Tropical Reefs ◽  
Marine Macrophytes ◽  
Species Richness And Abundance ◽  
North Western

Bysmatrum teres sp. nov., a new sand-dwelling dinoflagellate from north-western Australia

Phycologia ◽  
2006 ◽  
Vol 45 (2) ◽  
pp. 161-167 ◽  
Author(s):  
Shauna Murray ◽  
Mona Hoppenrath ◽  
Jacob Larsen ◽  
David J. Patterson
Keyword(s):  
Western Australia ◽  
North Western
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