Eradication of Feral Cats (Felis catus) from Gabo Island, south-east Victoria

Summary Concerns about the effects of predation by Feral Cats ( Felis catus ) on native fauna, particularly breeding seabirds, precipitated a decision in 1987 to control and eventually eradicate cats from Gabo Island. The size of the population prior to control was at least 30 animals. A control programme, undertaken between 1987 and 1991, centred on shooting, trapping and an extensive 1080 poison-baiting programme. Trapping and shooting were ineffectual. Poisoning was the most successful and effective technique for the rapid and widespread reduction in the Feral Cat population on Gabo Island. The effectiveness of dead 1-day-old chickens as a poison carrier was demonstrated. Effective poison baiting was attributed to bait selection and strategic timing of baiting to periods when prey was at low levels. Outcomes from the trapping programme and post-control monitoring strongly suggested that the cat population had been reduced to only two or three animals, possibly of the same sex. Monitoring between 1992 and 1998 failed to record any evidence of cats, indicating that the cats remaining after poison baiting had been unable to sustain a viable population. On the basis of the available evidence, Feral Cats appear to have been successfully eradicated from Gabo Island.     

Survival of Escherichia coli O157 in a soil protozoan: implications for disease

Intra-protozoal growth of bacterial pathogens has been associated with increased environmental survival, virulence and resistance to biocides and antibiotics. Using laboratory microcosms we have shown that Escherichia coli O157 survives and replicates in a common environmental protozoan, Acanthamoeba polyphaga. As protozoa are widely distributed in soils and effluents, they may constitute an important environmental reservoir for transmission of E. coli O157 and other pathogens.     

The BTO Heronries Census of England and Wales 1928–2000: new indices and a comparison of analytical methods

A census of Grey Heron Ardea cinerea colonies has been made annually by volunteer observers in England and Wales since a first national survey in 1928. This data set has recently been thoroughly upgraded and here we apply a new method of indexing Heron population changes to produce a new 73-year time-series, the longest time-series describing the abundance of any breeding bird in the world. The indexing methodology is based on the use of weighted ratio estimators, as developed by G.E. Thomas, but with modifications that use reasonable assumptions regarding the likely rates of colony extinction and formation. There is little reliable information about such rates of site turnover, but the results were not sensitive to the assumptions made. The new analytical method, based on counts since 1964, suggests a population estimate of just over 9000 breeding pairs (95% CI 8529–9776) in England and Wales in the year 2000, some 2000 more than suggested in earlier publications. Only minor differences in trend are apparent over the course of the time-series between the new results and those previously published. Regional analysis suggests that the population in southern England and South Wales has remained relatively constant since the 1970s, but those in the North have tended to increase in the 1990s.     

Re-evaluation of the cytokinin receptor role of the Arabidopsis gene GCR1

GCR1 has been tentatively identified inArabidopsis thaliana as the first plant G-protein coupled receptor (GPCR) (Josefsson and Rask 1997) implicated in the cytokinin sensory pathway (Plakidou-Dymock et al. 1998). A protein fusion of GCR1 and green fluorescent protein has been expressed inArabidopsis and shown GCR1 to be located on the plasma membrane. Studies of plants with altered GCR1 expression have led us to question GCR1's involvement in cytokinin signaling. TransgenicArabidopsis plants containing sense and antisense constructs for GCR1 have been produced and over- and under-expression confirmed. The analysis of 12 antisense and 17 sense lines has failed to reveal the previously reported »Dainty« phenotype or altered cytokinin sensitivity. We have used the »Gauntlet« approach to test the plants' response to various plant hormones although this has not yet identified a mutant phenotype. The yeast-two hybrid system has been used and so far there is no evidence to suggest GCR1 interacts with heterotrimeric G proteins. Before GCR1 can be identified as genuine G-protein coupled receptor, the identification of a ligand and a proof of association with heterotrimeric G-proteins should be obtained.