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.

Variation in algal assemblages on wave-exposed rocky shores in New South Wales

1998 ◽  
Vol 49 (3) ◽  
pp. 241 ◽  
Author(s):  
A. J. Underwood ◽  
M. G. Chapman
Keyword(s):  
Large Scale ◽  
New South ◽  
New South Wales ◽  
Temporal Patterns ◽  
Explanatory Models ◽  
Small Scale ◽  
Rocky Shores ◽  
Spatial And Temporal Patterns ◽  
South Wales ◽  
Algal Assemblages

Data were collected in New South Wales from replicate sites on five wave-exposed shores separated by hundreds of kilometres at three-monthly intervals for four years, to examine large and small spatial and temporal patterns in low-shore algal assemblages. These data were used to test hypotheses from the models that algal assemblages show large-scale, predictable changes in structure or, alternatively, that variation from time to time is small-scale and differs from shore to shore or site to site on a shore. There was considerable variation at all scales examined — among replicate quadrats within sites, between sites on a shore and among shores. Similarly, assemblages differed from one sampling period to the next and changes in the assemblages over time periods of three months were as great as from year to year. These changes were interactive, with no two sites or shores showing similar temporal patterns. Thus, understanding diversity along a coast-line requires detailed understanding of local processes. Without adequate spatial and temporal replication in sampling designs and without explanatory models, the large and complex variability in intertidal assemblages at different scales cannot be documented and understood.

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.

Reproduction of the turban shell Turbo torquatus Gmelin 1791 (Mollusca : Gastropoda), in New South Wales, Australia

2002 ◽  
Vol 53 (1) ◽  
pp. 85 ◽  
Author(s):  
D. W. Ward ◽  
A. R. Davis
Keyword(s):  
Reproductive Cycle ◽  
Developmental Stages ◽  
New South ◽  
Gonadosomatic Index ◽  
New South Wales ◽  
Gonad Development ◽  
Gonadal Development ◽  
Small Scale ◽  
Frequency Distributions ◽  
South Wales

The Sydney turban shell Turbo torquatus is the focus of a small-scale commercial fishery in New South Wales. Effective management requires knowledge of the reproductive biology, yet this is lacking for NSW waters. The reproductive cycle was investigated at three localities on the southern New South Wales coast. Samples of T. torquatus were collected monthly at Wollongong, Ulladulla and Eden from February 1996 until August or December 1997. The reproductive cycle was investigated by three methods: monthly determination of a gonadosomatic index, estimation of oocyte size-frequency distributions and classification of female gonads into developmental stages following histological sectioning. Males and females within a population underwent synchronous gonad development and spawning. Spawning events were often protracted over a period of several months with females in various stages of gonadal development. Two spawning events occurred each year, with a spawning event in autumn–winter and another in spring–summer. These events were asynchronous among the three localities, and partial spawning appeared to be a common occurrence. Owing to variation in the timing of spawning between populations separated by a distance as small as 15 km, seasonal closures to protect spawning stocks are unlikely to be effective.

Changes in Numbers of Rabbits and their Burrows in a Subalpine Environment in South-eastern New South Wales.

1975 ◽  
Vol 2 (2) ◽  
pp. 121 ◽  
Author(s):  
K Myers ◽  
BS Parker ◽  
JD Dunsmore
Keyword(s):  
New South ◽  
New South Wales ◽  
Alpine Grasslands ◽  
South Eastern ◽  
Patterns Of Distribution ◽  
South Wales ◽  
Careful Measurement ◽  
Burrow Use

Patterns of distribution and use of rabbit warrens in 540 acres (219 ha) of subalpine habitat during 1963 and 1966-71 are described. The numbers of rabbits and of burrows in which they live can fluctuate independently of each other. It is demonstrated in a marked population that careful measurement of changes in burrow use can be used to estimate changes in the numbers of rabbits using the burrows. The most favourable habitat for rabbits in subalpine regions is raised areas on the floor and sides of valleys in open alpine grasslands, where there are projecting granite tors and moraine-like materials.

Classifying landform at broad spatial scales: the distribution and conservation of wetlands in New South Wales, Australia

2004 ◽  
Vol 55 (1) ◽  
pp. 17 ◽  
Author(s):  
R. T. Kingsford ◽  
K. Brandis ◽  
R. F. Thomas ◽  
P. Crighton ◽  
E. Knowles ◽  
...  
Keyword(s):  
Large Scale ◽  
New South ◽  
Coastal Lagoons ◽  
Spatial Scales ◽  
Conservation Status ◽  
Satellite Image ◽  
New South Wales ◽  
North West ◽  
Inland River ◽  
South Wales

Relatively few large-scale inventories of the world's wetlands exist because of the difficulties of spatial scale, associated cost and multiple objectives, often temporally confounded, that drive classification. The extent of wetlands across a large part of Australia (New South Wales, 80.6 million ha) was determined using satellite image analyses. These data allowed analyses of the distribution of wetlands, their conservation status and potential threats at different spatial scales; that is, State, coastal and inland, and catchment. Approximately 5.6% of New South Wales is wetland (4.5 million ha), mostly (96%) in inland river catchments. Broad classification allowed identification of the extent of wetland types: (i) floodplains (89%); (ii) freshwater lakes (6.6%); (iii) saline lakes (< 1%); (iv) estuarine wetlands (2.5%); and (v) coastal lagoons and lakes (1.5%). Conservation reserves protect only 3% of wetland area. The analyses identified the north-west as the key area for wetland conservation as most other catchments have lower wetland extent and more potential threatening processes. The first stage of a large-scale inventory is to determine the extent and location of wetlands, with immediate benefits for strategic conservation and management. Other objectives (e.g. classification, biotic composition, hydrology and threats) seldom have sufficient data available for large-scale inventories but can be completed later with resources.

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