Settlement in different-sized patches by the gregarious intertidal barnacle Chamaesipho tasmanica Foster and Anderson in New South Wales

Most models on settlement of open marine invertebrate populations are based on space-limitation. These models, however, do not recognise that free space may not drive the demography of populations when larval numbers are small or when larval supply varies along a gradient in the habitat. They also do not incorporate the effects of larval choice when settling. It has been hypothesised that, in gregarious barnacles, the effects of adult conspecifics, rather than available free space, may play a primary role in settlement. That is, cues from adults along perimeters of patches, rather than space available, may enhance colonisation. This study therefore aimed to distinguish between these separate influences on populations of Chamaesipho tasmanica, a gregarious barnacle characterised by relatively few larvae arriving to settle each year. Patches of 6, 3 and 1.5 cm diameter were cleared within aggregations of barnacles at three heights (Low, Mid, Upper) of Chamaesipho's distribution at two sites and during 2 years of settlement. Total numbers of settlers in each year were manipulated to determine the separate influences on settlement due to availability of substratum or the effects of conspecific adults. To test for the effects of available free space, numbers of settlers per unit area were analysed. To test for gregarious effects due to the presence of adults, numbers of settlers per unit perimeter were analysed. While available substratum was found not to affect settlement of this barnacle, gregarious settlement in response to adults at perimeters of patches was thought to be confounded by differential larval supply and differential conspecific cues among heights on the shore. Results from this study therefore have important implications for survival of gregarious populations following disturbances, especially in species where larval supply is poor.     

Larval development of the chthamaloid barnacles Catomerus polymerus Darwin, Chamaesipho tasmanica Foster & Anderson and Chthamulus antennatus Darwin (Crustacea: Girripedia)

The presence of embryos in the mantle cavity of Catomerus polymerus, Chamaesipho tasmanica and Chthamalus antennatus was monitored over a two year period. C. polymerus and C. tasmanica show a clearly defined breeding season spanning late autumn, winter and early spring. C. antennatus breeds more continuously throughout the year, with a decline in breeding during the winter. The larval stages of C. polymerus, C. tasmanica and C. antennatus are described from larvae reared in the laboratory. Morphological differences allow each larval stage of the three species to be distinguished without difficulty. Unique larval features permit identification to superfamily, family and genus. The similarities of chthamaloid nauplii to those of lepadomorphs and verrucomorphs and their differences from the nauplii of other balanomorphs are discussed. Larval evidence supports the view that the chthamaloids are related more closely than other balanomorphs to the lepadomorphs, and that the coronuloids and balanoids share a comon derivation from the chthamaloids.     

Influence of isolation from the sea on spatial patterns of macroinfauna in intermittently closed/open coastal lakes in New South Wales

Abstract Intermittently open/closed coastal lakes and lagoons are susceptible to contamination and nutrient‐enrichment. Although many of them are considered to be degraded, our understanding of their ecology and the effects of anthropogenic activity is limited. This study of coastal lakes in New South Wales compared the density and distribution of macrobenthos in localities that differed in their degree of isolation from the sea, that is, open versus closed lakes and mouths versus inner reaches. Lakes kept open artificially (to improve water quality and reduce flooding), were also compared with naturally open or closed lakes. Densities of macrobenthos were usually greater in the mouths of open than of closed lakes, but the opposite was true in inner reaches. While isolated localities differed more between lakes than did mouths, small‐scale variability was greater in the latter. Spatial patterns were less temporally consistent in inner reaches than in mouths. Differences in densities and spatial variability between mouths and inner reaches were influenced primarily by whether a lake was open or closed and secondarily by manipulation of the mouth. While, for example, densities in open manipulated systems were usually greater in the mouths, but smaller in the inner reaches, the effect of manipulation was less obvious in closed lakes. Differences in density between types of lakes were not clearly related to physical factors although, within lakes, benthos generally correlated negatively with salinity and positively with median particle‐size, silt and organic content. The effects of factors that modify the degree of isolation of coastal lakes are discussed and it is concluded that current levels of isolation do not appear to affect macrobenthos adversely. Nevertheless, increased isolation, which is likely as a result of climatic change, may well do so, particularly in lakes already stressed by human impacts.     

Small- and broad-scale patterns of distribution of the upper-shore littorinid Nodilittorina pyramidalis in New South Wales

Abstract mall-scale (within-shore) and broad-scale (among-shore) patterns of distribution, abundance and size structure of Nodilittorina pyramidalis were measured on a number of shores in New South Wales. This species showed significant patchiness in distribution and size structure. The mean density and mean shell length of snails differed among patches of shore only a few metres apart, among different heights on the shore and from shore to shore. Differences in densities appeared to be strongly correlated to the distribution of particular microhabitats, especially cracks, crevices and pits within the rock surface. This relationship and the presence or absence of these microhabitats appeared to determine the patterns of distribution of this species within and among different shores. The sizes of snails were not correlated with densities of Nodilittorina nor with the coexisting species, Littorina unifasciata, in the populations examined. Processes influencing the distribution and abundance of Nodilittorina were not investigated, but the patterns of distribution found on these shores suggest that recruitment was limited to areas of topographic complexity, ft also seems likely that limited dispersal by the adult snails retain them within restricted patches on the shore.     

Scutelluid trilobites from the Silurian of New South Wales

Abstract: Twenty‐six species (nineteen of them formally named) of scutelluid trilobites belonging to eight genera are described from limestones of the lower Wenlock to Ludlow Mirrabooka Formation and its stratigraphical equivalents in the Orange district of New South Wales. Two genera, Borenoria and Mirrabooka, are new. Japonoscutellum, previously employed mainly for several species from Japan, is a globally widely distributed genus in rocks of middle Llandovery to Ludlow age and includes a number of species previously assigned to Kosovopeltis. Japonoscutellum is remarkably diverse in the faunas from Orange where it is represented by eleven species, one of them known also from Kazakhstan. Flexiscutellum and Tosacephalus are regarded as junior synonyms of Decoroscutellum and Kosovopeltis, respectively. The homology of various scutelluid cephalic structures is discussed, in particular the cephalic borders and border furrows that have routinely been misidentified; the term ‘bolus’ is introduced for the variably developed swelling that is enclosed by S1 on the glabella of most scutelluids. New species are Australoscutellum iota, A. microps, A. pulex, A. trica, Borenoria cirrita, Decoroscutellum planes, Eoscutellum annosum, Illaenoscutellum tryo, Japonoscutellum borenorense, J. crassum, J. diascetum, J. gephyricum, J. guttulatum, J. serangicum, J. strabo, Kosovopeltis trepida, K. xynon and Mirrabooka harryi. Some of these trilobites show strong affinity with species from the Kurosegawa Terrane of south‐western Japan and the Chu‐Ili Terrane of Kazakhstan, as previously reported also for the effaced Illaenina from the same limestones. Australoscutellum and Mirrabooka are presently known only from eastern Australia. The new genus Securifrons is proposed for several species previously assigned to Kosovopeltis or Eokosovopeltis from the Sandbian or Katian to Llandovery of North Greenland, Canada, Scotland, South China and New South Wales.     

Studies in the ecology of coastal heath in New South Wales

Effects of heating dry seed were investigated in Banksia serratifolia and B. ericifolia. Seeds were inviable after 7 min exposure at 150°C or higher temperatures but remained viable after exposure at 100°C and lower temperatures. Imbibed seeds show no dormancy, and seeds survive fire insulated from heat in the thick woody follicles which may persist unopened for several years on the parent plant but open following fire. Effects of nutritional supplements were observed in the seed germination and seedling survival and growth of Banksia serratifolia, B. aspleniifolia and B. ericifolia. Germination with radicle and hypocotyls extension was not significantly affected by a wide range of mineral nutrient regimes. In pot experiments using a heath soil seedling survival and growth were adversely affected by moderate additions of phosphate with surviving seedlings showing toxicity symptoms and poor development of proteoid roots. Moderate supplements of potassium had no adverse effect, and in B. serratifolia and B. ericifolia lessened the adverse effects of phosphate addition. The slow growth of the seedlings accords with the normal low nutrient availability in heath soils but seedlings show little capacity for rapid exploitation of any temporary increase of available nutrients after fire.     

Land management in semi-arid environments of New South Wales

Land of the semi-arid zone of Australia is generally managed to produce wool or beef. Past management has caused many changes in the land. These changes may be difficult to detect and assess. Much of the available information is at too coarse a scale to be really useful in assessing change. Graziers' perceptions of change are unknown but survey results from the agricultural zone suggest that their perceptions are probably incorrect. Apportioning the causes of change is very difficult as the main agents (climate, stocking rates, bushfires, legislation and economics) are not independent. Three different approaches to separating cause are described: use of historical information, integrating all information and using unpalatable plants as proxies for key economic species. Some difficulties with the historical approach are outlined. The major issues in semi-arid land management are social rather than technical. However, key aspects such as perceptions, motivation, and sources of information used by graziers are neglected research subjects. Recent research into an objective basis for assessing stocking rates from forage biomass production will replace traditional estimates based on extrapolating from similar country. This will significantly assist graziers in determining appropriate stocking rates to maximise their incomes. Other research by graziers has demonstrated the benefits of low stocking rates leading to increased incomes on both an animal and area basis. Such advances by graziers provide keys for future extension programs to achieve the desired goals of a stable grazing industry with good financial rewards, and improved land management.Abbreviations dse dry sheep equivalent. A standard animal unit equivalent to a medium sized wether or non-lactating ewe used to assess total grazing pressure on an area. All other vertebrates can be converted to dse using laboratory data. For this paper, I adopt the conversions factors of 1 beast (cattle, horse) =10 dse, 1.6 kangaroos =1 dse, 16 rabbits =1 dse.     

Occurrence of the mayfly family Teloganodidae in northern New South Wales

Teloganodid mayfly nymphs, previously known in Australia only from south-eastern Queensland, have now been recorded from numerous localities in the coastal drainages of northern New South Wales (NSW) from the Barrington Tops district to the Richmond River system. The nymphs seem to be restricted to riffles in forest streams and occur over a wide altitudinal range with records up to 940 m. They appear identical to those of Austremerella picta Riek, but rearing to the adult is needed to be certain that they represent the same species. The apparent restriction of Australian Teloganodidae to southern Queensland and northern NSW poses a biogeographical puzzle.     

Composition,spatial and temporal variability of the soil seed pool in a Eucalyptus populnea shrub woodland in central New South Wales

Three sites in a Eucalyptus populnea woodland in central New South Wales were sampled for the number and composition of seed in the surface cm of soil. There was a total of 3200 seeds/m² beneath eucalypt canopy, 13800 seeds/m² in grassy inter-tree areas and 4000 seeds/m² in bare inter-tree areas in April, 1975. These numbers were reduced by 23, 73 and 66% respectively during the subsequent 10 months, when there was no addition of seed. This decline was thought to be mainly due to predation, with germination as a secondary factor. Species composition of the seed pool differed between the three sites with seed of some species being only found beneath the eucalypt canopy or in the inter-tree areas. There were no seeds that were not present as plants in the community. Any attempts to restore this woodland to its former grassy nature should take into account the low seed population of many of the formerly common grass species and the high number of shrub seeds (>200/m²). Species distribution of seed was highly heterogeneous making adequate sampling very difficult. Extracting and identifying the seed took 8 to 12 man-h per 100 g sample.     

A fossil Selaginella from the Permian of New South Wales

Selaginella harrisiana ap. nov. is described from the Permian (Kungurian) Upper Coal Measures at Victoria Pass, N.S.W. It resembles Selaginella selaginoides in its leafy parts but has a long leafless rhizome recalling Asteroxylon. The present evidence suggests that the herbaceous and arborescent ly copsids are taxonomically remote.     

Threat and stress in the Clarence River estuary of Northern New South Wales

The estuarine system of the Clarence River in northern New South Wales, Australia is examined. Although many such systems in Australia have been placed at risk as a result of human-induced environmental pressure, it is contended that this is not the case with the Clarence River system. Rather it is suggested that perceived environmental threats in this case are the result of particular local environmental cognitions and that actual stress exerted on the system is largely independent of human use.     

Extended statistical approaches to modelling spatial pattern in biodiversity in northeast New South Wales. I. Species-level modelling

Statistical modelling of biological survey data in relation to remotely mapped environmental variables is a powerful technique for making more effective use of sparse data in regional conservation planning. Application of such modelling to planning in the northeast New South Wales (NSW) region of Australia represents one of the most extensive and longest running case studies of this approach anywhere in the world. Since the early 1980s, statistical modelling has been used to extrapolate distributions of over 2300 species of plants and animals, and a wide variety of higher-level communities and assemblages. These modelled distributions have played a pivotal role in a series of major land-use planning processes, culminating in extensive additions to the region's protected area system. This paper provides an overview of the analytical methodology used to model distributions of individual species in northeast NSW, including approaches to: (1) developing a basic integrated statistical and geographical information system (GIS) framework to facilitate automated fitting and extrapolation of species models; (2) extending this basic approach to incorporate consideration of spatial autocorrelation, land-cover mapping and expert knowledge; and (3) evaluating the performance of species modelling, both in terms of predictive accuracy and in terms of the effectiveness with which such models function as general surrogates for biodiversity.     

Extended statistical approaches to modelling spatial pattern in biodiversity in northeast New South Wales. II. Community-level modelling

Regional conservation planning can often make more effective use of sparse biological data by linking these data to remotely mapped environmental variables through statistical modelling. While modelling distributions of individual species is the best known and most widely used approach to such modelling, there are many situations in which more information can be extracted from available data by supplementing, or replacing, species-level modelling with modelling of communities or assemblages. This paper provides an overview of approaches to community-level modelling employed in a series of major land-use planning processes in the northeast New South Wales region of Australia, and evaluates how well communities and assemblages derived using these techniques function as surrogates in regional conservation planning. We also outline three new directions that may enhance the effectiveness of community-level modelling by: (1) more closely integrating modelling with traditional ecological mapping (e.g. vegetation mapping); (2) more tightly linking numerical classification and spatial modelling through application of canonical classification techniques; and (3) enhancing the applicability of modelling to data-poor regions through employment of a new technique for modelling spatial pattern in compositional dissimilarity.     

Temporal and spatial distribution patterns of echinoderm larvae in La Parguera, Puerto Rico

This study describes temporal and spatial abundance patterns of echinoderm larvae in La Parguera, Puerto Rico. For the temporal study, larvae were sampled by a series of monthly tows taken with a 64 microm mesh net between the new and full moon from April 2005 to July 2006, September 2006 and August 2007. In order to measure spatial variation of echinoderm larval abundances, oblique tows were taken with 64 and 202 microm mesh nets at seven different sites within the shelf, at the shelf-edge, and at a nearby oceanic stations during August 2007. Overall, Echinoidea (sea urchin) exhibited the highest abundance with a total of 11 921 larvae, representing 52.5% of the total collection. Ophiuroidea (brittle star) ranked second in abundance with 45.6% of the total larvae. Holothuroidea (sea cucumber) and Asteroidea larvae (sea star) accounted for less than 2% of the total echinoderm larval collection. Early larval stages (2-8 day old) of Diadema antillarum represented 20% of the total Echinoidea larvae. There was no marked seasonal trend of echinoderm larval abundance; Echinoidea and Ophiuroidea larvae were present in all monthly samples indicating that reproduction occurs year-round. Peak abundances of later-stage Echinoidea larvae were observed during January, July and October and of later-stage Ophiuroidea larvae during June, August and October. The observed peaks of later-stage larval abundances may be indicative of higher recruitment activity during these months. There was a significant difference of echinoderm larval abundance between spatial stations, with higher abundances collected at the shelf-edge. Later-stage (approximately 24 day old) D. antillarum larvae were mostly collected at shelf-edge and oceanic locations. In addition, the 64 microm mesh net was more efficient for collection of echinoderm larvae than the 202 microm mesh net.     

Variations in the microclimate in rabbit warrens in semi-arid New South Wales

Rabbit burrows in three different habitats in an arid area showed characteristic variations and differences. Burrows in stony soil were generally cooler and more humid than burrows in sand and gravel soil. The temperature of the burrows in sand and gravel showed similar characteristics but the humidity in the gravel burrows was almost always significantly less than that of the sand burrows. Air and ground temperatures were significantly correlated but air and ground humidities showed a less significant correlation. Seasonal differences in microclimate within and between the three types of burrows were pronounced and are thought to cause differences in the survival of rabbits in arid areas.     

Myrmecochory in sclerophyll vegetation of the West Head,New South Wales

The incidence of myrmecochory (plants providing inducements for ants to disperse their seeds) was studied in thirty-eight plots on the West Head, New South Wales. The vegetation is made up of species from the temperate Australian flora which includes the largest known concentration of myrmecochores. Four plots with few myrmecochores either were frequently or permanently flooded, or were on fertile volcanic soil. Most plots were in well-drained sites on infertile sandstone. An average of 30% of the species on each of these were certainly myrmecochores, accounting for an average of 15% of the total cover. Within this majority of plots, the incidence of myrmecochory was not related to slope, aspect or vegetation structure. Although many myrmecochores were widespread in distribution, the majority did not contribute heavily to cover of the stands where they occurred.