An assessment of pedoturbation by two species of mound-building ants, Camponotus intrepidus (Kirby) and Iridomyrmex purpureus (F. Smith)

Soil Research ◽  
1985 ◽  
Vol 23 (1) ◽  
pp. 95 ◽  
Author(s):  
JA Cowan ◽  
GS Humphreys ◽  
PB Mitchell ◽  
CL Murphy
Keyword(s):  
Impact Energy ◽  
Organic Material ◽  
Size Structure ◽  
New South ◽  
New South Wales ◽  
Size Composition ◽  
Soil Mixing ◽  
South Wales ◽  
Erosion Protection ◽  
Raindrop Impact

Details of the size, structure and occurrence of Carnponotus intrepidus nests and the size, composition and source of the mound cover on Iridomyrmex purpureus nests are reported from several areas of eastern New South Wales. Both species are common, and construct large mounds of mixed topsoil and subsoil with surface covers, which appear to protect the mound from rainsplash erosion. Camponotus thatches the mound with charcoal, leaves and twigs; Iridomyrmex covers the mound in granules of inorganic or organic material that are sufficiently large to absorb most raindrop impact energy. This material is collected from the surface and carried 10-15 m to the nest. Rainsplash erosion protection is probably a factor contributing to nest longevity, which may be as much as 100 years for Iridomyrmex. It is concluded that, despite the impressive size of the nests and the selective use of materials, neither species is very significant in terms of soil mixing when compared with the smaller, more common ant Aphaenogaster longiceps.

Small-scale patterns of distribution and size-structure of the intertidal littorinid Littorina unifasciata (Gastropoda: Littorinidae) in New South Wales

1994 ◽  
Vol 45 (4) ◽  
pp. 635 ◽  
Author(s):  
MG Chapman
Keyword(s):  
Size Structure ◽  
New South ◽  
Spatial Scales ◽  
New South Wales ◽  
Small Scale ◽  
Rock Surface ◽  
Strongly Correlated ◽  
Patterns Of Distribution ◽  
South Wales ◽  
Potential Factors

Within-shore and among-shore patterns of distribution, abundance and size structure of Littorina unifasciata Gray were identified on a number of shores in New South Wales. There was significant patchiness in distribution, abundance and size of L. unifasciata among patches of shore only a few metres apart, at different heights on the shore and from shore to shore. On a particular shore, the sizes of snails were strongly correlated with densities. In contrast, differences in densities at different heights from one shore to another were not correlated with mean size of snails. Density and size were each strongly correlated with the height on the shore at which snails were found. At any one height, differences in densities and size were also correlated with the distribution of particular microhabitat variables, such as the slope of the rock surface, the presence of pits and shallow pools and the presence of barnacles. Densities were also negatively correlated with densities of the large microalgae-grazing limpet Cellana tramoserica but were independent of other littorinids. A number of alternative models have been proposed to account for these patterns of distribution, abundance and size. Although processes that might account for these patterns were not investigated here, quantification of such patterns at a number of spatial scales is necessary before potential factors that might affect small-scale spatial variation in densities and sizes of L. unifasciata can be identified and investigated.

Large-scale patterns in habitat structure on subtidal rocky reefs in New South Wales

2000 ◽  
Vol 51 (3) ◽  
pp. 255 ◽  
Author(s):  
N. L. Andrew ◽  
A. L. O'Neill
Keyword(s):  
Sea Urchin ◽  
Geographical Information Systems ◽  
Large Scale ◽  
Size Structure ◽  
New South ◽  
New South Wales ◽  
Geographical Information ◽  
South Wales ◽  
Subtidal Rocky Reefs ◽  
A Site

Aerial photography was used to estimate the representation of shallow subtidal habitats in New South Wales. Sixty sites, each between 4 and 5 hectares, were mapped with Geographical Information Systems software using ortho-rectified images digitized from 1:8000-scale photographs and ‘ground truthed’ in the field by divers. Barrens habitat covered an estimated 50% (s.e. = 3.9) of nearshore reefs between Port Stephens and Disaster Bay. Coverage of barrens habitat was greatest in Disaster Bay (68%, s.e. = 6.7) and least south of Disaster Bay (1%, s.e. = 0.3). There were clear differences among localities in the area of reef within the mapped sites; those at Cape Howe, Nadgee, and Turingal were significantly smaller in area than all others. There was no clear latitudinal trend in these differences but there was evidence of sand inundation at a site at Nadgee, where the reef was small. Differences in the densities and size-structure of the sea urchin Centrostephanus rodgersiiat 27 of the mapped sites provide a basis for testing relationships between the demography of this species and the persistence of the barrens habitat. The extensive coverage of the barrens habitat in New South Wales is likely to limit the productivity of the abalone industry. The development of a sea urchin fishery may have large impacts on habitat representation on nearshore reefs.

Effects of predation on the size structure of the gastropod Salinator solida (Martens) populations at Towra Point, NSW, Australia

1998 ◽  
Vol 49 (8) ◽  
pp. 779 ◽  
Author(s):  
A. C. Roach
Keyword(s):  
Population Size ◽  
Mangrove Forest ◽  
Size Structure ◽  
New South ◽  
New South Wales ◽  
Age Classes ◽  
South Wales ◽  
Mean Size ◽  
The Mean ◽  
Pulmonate Gastropod

The pulmonate gastropod Salinator solida inhabits intertidal mangrove and saltmarsh communities throughout New South Wales. Studies at Towra Point and elsewhere have consistently found that the mean size and range of size/age classes increases with height on shore. Afield experiment was undertaken to test the hypothesis that predation was responsible for reductions in the mean size of individuals inS. solida populations in the upper mangrove forest. Twelve months after the establishment of fenced plots, there were significantly more individuals in the fenced plots than in unfenced or partially fenced control plots; the number of snails in the 4.1–8.0 mm and > 8.1 mm size classes had increased in the fenced plots but not in the control plots. The results suggest that predation is a major factor determining variation in population size structure by acting to significantly reduce the abundance of adults in the upper mangrove forest.

Issues of size and viability of pastoral holdings in the Western Division of New South Wales.

1990 ◽  
Vol 12 (2) ◽  
pp. 67 ◽  
Author(s):  
ND Macleod
Keyword(s):  
Public Involvement ◽  
Management Practices ◽  
Size Structure ◽  
New South ◽  
New South Wales ◽  
Economic Welfare ◽  
Future Scenario ◽  
South Wales ◽  
Western Division ◽  
Enterprise Size

Uany pastoral leases in western New South Wales are too small to ensure that viable pastoral enterprisu will persist in the medium to longer term. Apart from attendant welfare problems for leaseholders and their dependants, there is some evidence that this has exacerbated overgrazing problems which creates undesirable and potentially irreversible degradation of vegetation and soil resources. Arguably, the small size problem has sufficiently weakened the economic welfare of many lessees to make private acquisition of additional areas andl or adoption of conservation oriented management practices non-economic. The future scenario is then one of greater public involvement in property adjustment measures; or a growing population of non-viable pastoral enterprises with its attendant efficiency, welfare and resource conservation problems. The paper examines trends in property enterprise size, structure and concentration and the existence and extent of size economies for wool and livestock production in western New South Wales. Several issues are addressed concerning the economic viability of pastoral properties and several public policy prescriptions are presented for addressing the sizehiability problem.

scholarly journals Comparative Angler Catches of Australian Bass (Macquaria novemaculeata) in Three Major River Systems in New South Wales, Australia

2005 ◽  
Vol 18 (2) ◽  
Author(s):  
B. VAN DER WALT ◽  
R. A. FARAGHER ◽  
J. HARRIS
Keyword(s):  
Time Series Data ◽  
New South ◽  
New South Wales ◽  
River System ◽  
Size Composition ◽  
Series Data ◽  
Severe Drought ◽  
Catch Per Unit Effort ◽  
South Wales ◽  
Catch Rates

A joint program between New South Wales Fisheries and three fishing clubs was initiated in 1988 with the aim of collecting standardised catch and effort data during biannual fishing competitions on three major rivers in New South Wales. This paper examines the data to determine trends in the catch of the target species, Australian bass (Macquaria novemaculeata) and to evaluate whether the data can be used to assess Australian bass populations over time. Distinct trends in Australian bass mean length in each river system were evident but catch rates were more variable. Median catch per unit effort was similar (mostly between 0.5 and 1.5 Australian bass·h-1 ) in the Nepean and Williams Rivers although catch rates in the Manning River were nearly always zero. There was an increasing trend in the mean length of Australian bass in all three rivers, possibly representing a recovery in fish populations following severe drought from 1979 to 1983. Low or zero catch rates were continually recorded in the Manning River and size composition data indicated a lack of recruitment through most of the study period. The standardised format of the data collection program provided qualitative and reliable time series data allowing the determination of long-term trends in the population structure of Australian bass which can be used for monitoring and management purposes.

The New South Wales Trawlfishery: Review of Past Course and Examination of Present Condition

1955 ◽  
Vol 6 (2) ◽  
pp. 165 ◽  
Author(s):  
TW Houston
Keyword(s):  
New South ◽  
New South Wales ◽  
Size Composition ◽  
Fishing Effort ◽  
Present Condition ◽  
Catch Per Unit Effort ◽  
Nineteen Thirties ◽  
Unit Effort ◽  
South Wales ◽  
Post War

The past course of the New South Wales mixed trawlfishery is reviewed mainly on the basis of the available catch and fishing effort statistics. The size composition of tiger flathead landings from 1946-47 to 1953-54, and the age composition for certain post-war years, are analysed in conjunction with catch per unit effort data. The results suggest that 1943-44, 1944-45, 1947-48, and 1948-49 were relatively poor brood years, and 1945-46 and 1946-47 relatively good. The fluctuations in availability of tiger flathead (Neoplatycephalus macrodon (Ogilby) ) are accounted for after making certain valid assumptions. It is considered probable that the unexpectedly low catches of tiger flathead in the immediate post-war years were due to inefficiency of the few steam trawlers then working, and that Danish seiners were unable to exploit fully the available V+ and higher age-group fish. An examination of the present situation indicates that the New South Wales stock of tiger flathead is at a low level and is likely to reach even lower levels in the future if fishing intensity remains as high as in 1953-54. An improvement of the existing catch per unit effort would be expected if fishing intensity was reduced to the level of the middle nineteen-thirties (i.e. approx. 3500 trawler-tons) . Other regulative measures would need to be introduced to bring about an improvement in the annual catch of tiger flathead. These measures should aim at ensuring a more favourable weight-length relation.

Distribution, population structure and biological aspects of Squalus spp. (Chondrichthyes:Squaliformes) from New South Wales and adjacent Australian waters

2005 ◽  
Vol 56 (4) ◽  
pp. 405 ◽  
Author(s):  
Ken J. Graham
Keyword(s):  
New South ◽  
New South Wales ◽  
Size Composition ◽  
Adult Size ◽  
Mixed Species ◽  
Trawl Fishery ◽  
South Wales ◽  
Female Data ◽  
Biological Aspects ◽  
Upper Slope

Four species of Squalus dogsharks, S. megalops, S. cf. mitsukurii, Squalus sp. B and Squalus sp. F inhabit shelf and upper-slope depths off New South Wales and adjacent Australian states. During fishery surveys between 1976 and 2001, distributional, size composition and reproductive data were collected for these species. Adult size classes dominated catches and, for S. megalops, heavily biased sex ratios were observed. Although no female data were available for the rarely caught Squalus sp. B, reproduction in the other three species was found to be continuous with no evidence of seasonality. Fecundity was 1–3 embryos for S. megalops, 1–5 for Squalus sp. F and 4–10 for S. cf. mitsukurii. All species are commercially exploited, contributing to the mixed species demersal trawl fishery off New South Wales. Stocks of some species are greatly depleted on the main trawling grounds, but the overall distributions of all species include large areas of lightly exploited habitat.

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