ACTIVITY BUDGETS OF SPURWINGED AND EGYPTIAN GEESE AT BARBERSPAN DURING WINTER

Halse, S. A. 1985. Activity budgets of Spurwinged and Egyptian Geese at Barberspan during winter. Ostrich 56:104-110.

Daily behaviour of Spurwinged and Egyptian Geese was studied during winter at Barbers an, a large lake in the Transvaal. Non-moulting Spurwinged and Egyptian Geese spend about 2 h and 1,5h, respectively, feeding in farmland surrounding the lake in the early morning and about 20 min and 30 min, respectively, feeding there in the evening. They return to Barberspan during the day.

Activity budgets were calculated for all Spurwinged and all Egyptian Geese, including both moulting and non-moulting birds, at the lake during the day. Both species spend most of the day sleeping on the shore and relatively little time feeding. Both species spend a large proportion of this limited feeding time on open water picking at floating Potamogeton pectinatus. Closer to the shore the feeding habits of the species differ, Egyptian Geese feeding mostly along the shoreline in water a few centimetres deep, immersing only the bill, while Spurwinged Geese upend or submerge their heads and necks in deeper water.

An energy budget was calculated for Spurwinged Geese using the activity budget data. An averag-sized non-moulting goose (5,2 kg) requires about 2000 kJ/day for maintenance. During moult energy requirements increase 30 per cent to 2500 kJ/day because of the extra energy required for feather growth.     

Genetic diversity in Australian ancient asexual <Emphasis Type="Italic">Vestalenula</Emphasis> (Ostracoda,Darwinulidae): little variability down under

Darwinulid ostracods are putative ancient asexuals, and are thus assumed to be unable to purge deleterious mutations from their genomes. Some darwinulids species can be found both above (epigeic) and below ground (hypogeic). We hypothesize that surface populations carry more mutations than their below-ground counterparts, which are buffered from mutagens such as UV-B. Given the age of the investigated area, the Pilbara in Western Australia, we also expect geographic patterning of observed haplotypes. We have used DNA sequence data from the nuclear ITS and the mitochondrial COI region to investigate a (limited) data set on two Australian species, the endemic Vestalenula matildae and V. marmonieri from the Pilbara region. We do not find differences in genetic variability between specimens from subterranean habitats as compared to those from habitats above ground. There was also no congruence between hydrological basins and distribution patterns of the haplotypes identified. Although our data indicate that the two species may have split from each other ca. 70 myr ago, this has not resulted in any clear phylogeographic patterns among the analysed specimens across the regions of the Pilbara.     

Conditionally immortalized cell lines as model systems for high-throughput biology in drug discovery

There is an increasing emphasis on the need for high-quality biological data much earlier in the drug-discovery process. This has led to the development of high-throughput approaches to biology, many of which rely on the use of cell-culture models. Unfortunately, available cell-culture models often reflect poorly the characteristics of the tissue they are supposed to represent. However, the conditional-immortalization approach as applied by Xcellsyz offers the possibility of producing human cell lines on demand, which are truly representative of the tissue from which they derive.     

Temporal Changes between Ecological Regimes in a Range of Primary and Secondary Salinised Wetlands

Many rivers and wetlands in south-western Australia are threatened by salinisation due to rising saline watertables, which have resulted from land clearing and the replacement of deep-rooted perennial species with shallow-rooted annual species. A four to six weekly sampling program of water quality, submerged macrophytes and macroinvertebrates was undertaken at six wetlands, from September 2002 to February 2004, to investigate seasonal variation in a range of primary and secondary saline systems. The wetlands dried and filled at different times in response to local rainfall patterns, and salinities varied accordingly with evapoconcentration and dilution. Two types of clear-water wetlands were recognised; those dominated by submerged aquatic macrophytes (Ruppia, Lepilaena and Lamprothamnium) and those dominated by benthic microbial communities. Two types of turbid wetlands were also recognised; those with high concentrations of phytoplankton and those with high concentrations of suspended sediments. A primary saline lake and two lakes that have only recently been affected by secondary salinisation persisted in a clear, macrophyte-dominated regime throughout most of the study period, except during drying and filling. Two lakes with a long history of secondary salinisation (70 years) moved between regimes over the study period. A clear, benthic microbial community – dominated regime only persisted at the wetland which contained permanent water throughout the study period. The turbid regimes were only present during drying and refilling phases. A richer and more abundant macroinvertebrate fauna was associated with the clear, macrophyte- dominated wetlands. Our results suggest that the development of management guidelines that recognise the presence of different ecological regimes and that consider the interactions between water regime, salinity, and primary and secondary production will be more useful in protecting biodiversity and ecological function in these systems than managing salinity as a single factor.     

Patterns of distribution of macroinvertebrate families in rivers of north-western Australia

1. The northern half of Western Australia is a large, sparsely populated area with a climate that ranges from monsoonal in the Kimberley to arid in the Gascoyne and Pilbara regions. The aquatic invertebrate fauna is poorly known. 2. Fifty-one sites located on 14 river systems were sampled three times between August 1994 and October 1995. A total of 90 taxa, most identified to family level, were collected. The fauna was dominated by insects, which constituted 74% of the total number of taxa collected. 3. Major habitats at each site were sampled separately and sites with more habitats tended to have a richer fauna. All habitats showed significant differences in taxonomic richness between regions. Family richness decreased with increasing latitude, being highest in the Kimberley region and lowest in the Gascoyne. 4. Despite the differences in taxon richness between regions, community composition of the aquatic invertebrate fauna at the family level did not differ greatly. Four major groups of sites were identified by cluster analysis, based on the invertebrate families present at each site, but differences between groups were small. 5. Significant temporal variation in taxon richness was found in channel habitat but not the three other habitats sampled (riffle, macrophyte, pool-rocks). Community composition in channel habitat varied temporally among groups of sites identified by cluster analysis but the pattern was not consistent.     

Ketosis Treatment and Milk Yield in Dairy Cows Related to Milk Acetoacetate Levels

Milk yield and milk acetoacetate (M-acac) were measured weekly for the first 6 weeks of lactation in 5 herds with a ketosis problem. Ketosis treatments and the corresponding ketotest score, were also recorded. The treatment rate was highest 7–16 days after calving. Most of these early cases were associated with low ketone levels in milk, whereas the treatment ratefor cows with high ketone levels was highest 17–31 days after calving. Nearly half of the treated cows were low-ketone animals. They were classified as ketosis cases in the cow health card records, although probably suffering from other post partum disturbances in many instances. About 40 % of the cows with high ketone levels recovered spontaneously. Reduction in milk yield associated with peak M-acac levels was transient and moderate. It was concluded that health card statistics overestimates the severity of the ketosis problem in Norway.     

Planning for the recovery of Lake Toolibin,Western Australia

Lake Toolibin, an intermittently flooded freshwater wetland in the southwest of Western Australia, is threatened by salinization due to extensive clearing within its catchment. The lake is a Wetland of International Importance under the Ramsar Convention because of the extensive stands of trees on the lake bed and its significance as a waterbird breeding site. Past research and monitoring have identified the causes of wetland vegetation and water quality decline and this information has been used to design a Recovery Plan for the lake. The plan is currently in the early stages of implementation and includes both short-term engineering measures to reduce salinity within the lake and long-term rehabilitation measures within the catchment. Community involvement in the recovery process is an integral part of the plan and ensures that recovery of the lake remains as the focus for ongoing catchment rehabilitation.     

Monitoring change in aquatic invertebrate biodiversity: sample size, faunal elements and analytical methods

Replication is usually regarded as an integral part of biological sampling, yet the cost of extensive within-wetland replication prohibits its use in broad-scale monitoring of trends in aquatic invertebrate biodiversity. In this paper, we report results of testing an alternative protocol, whereby only two samples are collected from a wetland per monitoring event and then analysed using ordination to detect any changes in invertebrate biodiversity over time. Simulated data suggested ordination of combined data from the two samples would detect 20% species turnover and be a cost-effective method of monitoring changes in biodiversity, whereas power analyses showed about 10 samples were required to detect 20% change in species richness using ANOVA. Errors will be higher if years with extreme climatic events (e.g. drought), which often have dramatic short-term effects on invertebrate communities, are included in analyses. We also suggest that protocols for monitoring aquatic invertebrate biodiversity should include microinvertebrates. Almost half the species collected from the wetlands in this study were microinvertebrates and their biodiversity was poorly predicted by macroinvertebrate data.     

Aluminium accumulation and immunosuppressive effect in recipients of kidney transplants.

Aluminium that has accumulated in the body is thought to have a generalised cytotoxic effect. A prospective study of aluminium accumulation in bone-that is, subclinical aluminium toxicity--was carried out in 94 recipients of kidney allografts, who were followed up for three years. Subclinical aluminium toxicity was found in 66 patients. A significantly smaller proportion of patients with aluminium accumulation experienced a rejection episode: 30 (58%) nu 12 (86%) who received grafts from cadavers and 4 (29%) nu 10 (71%) who received grafts from living donors. On multivariate analysis only the source of the kidney and aluminium accumulation were found to influence the rejection rate. These findings suggest that aluminium accumulation has an immunosuppressive effect.