Tropical Regions Of Australia Research Articles

Atmospheric sulfur and nitrogen in West Java

Wet-only rainwater composition on a weekly basis was determined at four sites in West Java, Indonesia, from June 1991 to June 1992. Three sites were near the extreme western end of Java, surrounding a coal-fired power station at Suralaya. The fourth site was ∼100 km to the east in the Indonesian capital, Jakarta. Over the 12 months study period wet deposition of sulfate at the three western sites varied between 32–46 meq m−2 while nitrate varied between 10–14 meq m−2. Wet deposition at the Jakarta site was systematically higher, at 56 meq m−2 for sulfate and 20 meq m−2 for nitrate. Since sulfate and nitrate wet deposition fluxes in the nearby and relatively unpopulated regions of tropical Australia are both only ∼5 meq m−2 anthropogenic emissions of S and N apparently cause significant atmospheric acidification in Java. It is possible that total acid deposition fluxes (of S and N) in parts of Java are comparable with those responsible for environmental degradation in acid-sensitive parts of Europe and North America.

Shell variation in Australian Notopala (Gastropoda: Prosobranchia: Viviparidae)

Abstract The viviparid snail Notopala is distributed throughout the rivers and other waterbodies of the northern tropical regions of Australia, extending south into the Lake Eyre and Murray-Darling Basins. Despitearecentexarnination of the WesternAustralian viviparids the taxonomy of a number of species, especially those from the Lake Eyre and Murray-Darling Basins, is unclear. Principal Components Analysis was used on seven shell measurements to determine which morphometric characters best delineate the species. Umbilicus width and aperture lip length explained most of the variation. The results suggest that there are four species of Notopala in Australia: N. waterhousii andN. essingtonensis in the north and northwest, N. sublineaca in the Lake Eyre and Murray-Darling Basins and N. hanleyi in the Murray-Darling Basin. With lheapparentextinction of both species ofNotopala in the natural environment of the Murray-Darling Basin, the population of N. hanleyi surviving in a Murray irrigation pipeline and the ...

A simulation model of kenaf for assisting fibre industry planning in northern Australia. I. General introduction and phenological model

The feasibility of utilizing kenaf (Hibiscus cannabinus L.) as a fibre crop and potential source of paper pulp is being investigated. This paper is the first in a series which develops and validates a simulation model of kenaf, and applies it to assessing the potential for dryland production in regions of tropical Australia. The duration from sowing to flowering is an important determinant of fibre yield in kenaf. Accordingly, the effect of temperature and photoperiod on the phenology of kenaf was examined. Data were collated from sowing-date experiments on kenaf cultivars Guatemala 4 and Everglades 71 at six locations in tropical Australia, ranging in latitude from 12� 54'S. to 19� 32'S. Data from one site, Kununurra, W.A. (15� 39'S.), was used to develop a model which described the duration from sowing to flowering in kenaf based on four stages: (1) sowing to emergence; (2) emergence to the end of the basic vegetative phase (BVP); (3) a photoperiod-induced phase (PIP) which ends at floral initiation; and (4) a flower development phase (FDP). Both kenaf cultivars responded as qualitative short-day plants where flowering did not occur above a critical photoperiod of 12.9 h. Assuming a base photoperiod of 12.0 h, the thermal time required to complete the BVP for the two cultivars was similar. However, photoperiod sensitivity during PIP, and the thermal time required for FDP, were greater for Guatemala 4 than for Everglades 71. Validation of the model against independently observed data for both cultivars at other sites resulted in close predictions in the thermal time required for flowering. This phenological model for kenaf can be used to assess the effect of sowing date on phenology at different locations in tropical environments, and is a key component of a crop growth simulation model to assess the environmental constraints to productivity in these regions.

The potential impact of exotic Lymnaea spp. on fascioliasis in Australasia

The presence of the following exotic Lymnaea spp. has been recently confirmed in Australia: L. columella (North and South America, South Africa, New Zealand,) L. viridis (China, Japan, Philippines, New Guinea, Pacific Area), L. auricularia rubiginosa (Indochina, Malaysia, Indonesia) and L. peregra (Europe). In the present studies the relative susceptibility of the exotic snails noted above to Fasciola hepatica was investigated. Two of the species, L. columella and L. viridis, were found to be highly susceptible to the Australian strain of F. hepatica and a substantial number of viable metacercariae were produced. However a strong disparity in the host— parasite relationship was evident when the parthenogenetic development of the fluke in the two exotic snails was compared with that in the native L. tomentosa. It was concluded that L. tomentosa is a more suitable intermediate host for F. hepatica than any of the introduced exotic species, but it has to be considered that the host—parasite relationships between new combinations of Fasciola and Lymnaea spp. may improve by adaptation. In view of the results of the present studies the potential danger of fascioliasis spreading to areas currently not endemic in Australasia through introduced exotic snails is discussed with particular reference to Queensland, Western Australia and the Northern Territory. There is strong circumstantial evidence that the exotic snails were introduced with aquatic plants through the relatively free overseas and Australian trade. Similarly, through the introduction of infected snails, dangerous parasites such as F. gigantica of cattle and sheep or Schistosoma ssp. which cause serious diseases of man and animals could enter the subtropical or tropical regions of Australia. Appropriate State and Federal quarantine regulations are essential to prevent further introduction and spread of the snails, and monitoring of the distribution of established exotic snails in Australasia must be continuous.

The natural land‐use regions of tropical Australia

The natural land‐use regions of tropical Australia