The population dynamics of five remnant rock-wallaby populations (Petrogale lateralis) persisting on granite outcrops in the central wheatbelt region of Western Australia were monitored over a six year period. From 1979 to 1982 all populations remained relatively static or declined for unknown reasons, but circumstantial evidence implicated fox predation. A fox control program was implemented in 1982 on two outcrops and was maintained for four years with the result that the two resident rock-wallaby populations increased by 138 and 223%. Two rock-wallaby populations occupying sites not subjected to fox control declined by 14 and 85%, and the third population increased by 29%. It was concluded that the fox has probably been a significant factor in the demise and decline of native mammals in the past, and that surviving populations are still at risk. Control of predation pressure on nature reserves was shown to be feasible from a management perspective.

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The population dynamics of five remnant rock-wallaby populations (Petrogale lateralis) persisting on granite outcrops in the central wheatbelt region of Western Australia were monitored over a six year period. From 1979 to 1982 all populations remained relatively static or declined for unknown reasons, but circumstantial evidence implicated fox predation. A fox control program was implemented in 1982 on two outcrops and was maintained for four years with the result that the two resident rock-wallaby populations increased by 138 and 223%. Two rock-wallaby populations occupying sites not subjected to fox control declined by 14 and 85%, and the third population increased by 29%. It was concluded that the fox has probably been a significant factor in the demise and decline of native mammals in the past, and that surviving populations are still at risk. Control of predation pressure on nature reserves was shown to be feasible from a management perspective.

The ability to confidently identify or exclude a population as the source of an individual has numerous powerful applications in molecular ecology. Several alternative assignment methods have recently been developed and are yet to be fully evaluated with empirical data. In this study we tested the efficacy of different assignment methods by using a translocated rock-wallaby (Petrogale lateralis) population, of known provenance. Specimens from the translocated population (n = 43), its known source population (n = 30) and four other nearby populations (n = 19-32) were genotyped for 11 polymorphic microsatellite loci. The results identified Bayesian clustering, frequency and Bayesian methods as the most consistent and accurate, correctly assigning 93-100% of individuals up to a significance threshold of P = 0.01. Performance was variable among the distance-based methods, with the Cavalli-Sforza and Edwards chord distance performing best, whereas Goldstein et al.'s (deltamu)2 consistently performed poorly. Using Bayesian clustering, frequency and Bayesian methods we then attempted to determine the source of rock-wallabies which have recently recolonized an outcrop (Gardners) 8 km from the nearest rock-wallaby population. Results indicate that the population at Gardners originated via a recent dispersal event from the eastern end of Mt. Caroline. This is only the second published record of dispersal by rock-wallabies between habitat patches and is the longest movement recorded to date. Molecular techniques and methods of analysis are now available to allow detailed studies of dispersal in rock-wallabies and should also be possible for many other taxa.

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Abstract. Predation is widely believed to be the main threatening process for many native vertebrates in Australia. For 25 years, predator-baiting experiments have been used in the Western Australian Central Wheatbelt to control red fox predation on rock-wallabies and other endangered marsupial prey elsewhere. We review here the history of a series of baiting experiments designed to protect rock-wallaby colonies by controlling red foxes with 1080 poison baits. We continue to support the conclusion that red foxes can reduce or exterminate rock-wallaby populations in Western Australia. Research trials from 1990 to 2008 have uniformly shown a dramatic recovery of rock-wallaby populations once red foxes are baited. Baiting experiments are often black boxes and their success should not blind us to their weaknesses. Ideally, what we would like to measure are the functional responses of predators to prey abundance directly. As a contribution towards this goal, we describe new technology that enables one to determine which predator killed which prey, at exactly what time, with improved research and management outcomes.

R factors were detected in 3.3% of 233 hospital isolates of Pseudomonas aeruginosa using P. aeruginosa recipients in conjugations. Transferred markers included streptomycin, tetracycline, and sulfonamide resistance. Gentamicin resistance was transferred from two strains previously shown to acetylate gentamicin. A group of R factors exemplified by R931 were characterized by failure to transfer to Escherichia coli recipients. Such R factors formed a single compatibility group when examined in a P. aeruginosa recipient. Other P. aeruginosa R factors, including RP4, showed stable coexistence with the R931 group. It is proposed that RP4 and similar R factors be members of the P-1 compatibility group and that R931, R3108, R209, and R130 be members of a group termed P-2. The buoyant densities of all R factors examined were similar, about 1.716 to 1.719 g/cm3. The content of R-factor deoxyribonucleic acid (DNA) relative to the total DNA varied among the different R factors, ranging from about 18 ± 2% in logphase cells of 931 (R931) to undetectable for 679 (R679). However, R679, which transferred from strain 679 at extremely low and irregular frequencies to an E. coli host, was shown to represent about 4% R-factor DNA in that host. The relative DNA content of R931 appeared to decline in the stationary growth phase of 931 (R931) or 280 (R931). R931 covalently closed circular DNA was isolated by ethidium bromide-CsCl gradient centrifugation and examined by electron microscopy. Two major molecular distributions existed, having contour lengths of 0.5 and 12.4 ,um. The molecular weights were estimated to be 106 and 25 x 106. Both molecules were under relaxed replication control. R factor R931 exists as a naturally occurring high-frequency transfer system in P. aeruginosa strains 931 and 1310. However, in strain 280 it acts as if subject to fertility repression. Other members of the P-2 compatibility group also are high-frequency transfer systems in the natural host and in strain 1310. RP4 is restricted from recipient strain 1310. Some additional recipient effects were noted in that strains 1310 or 280 sometimes differed in recipient effectiveness with a given donor. Agglutination reactions with absorbed antiserum were able to distinguish between two members of the same R-factor compatibility group, R931 and R3108.Previous evidence (5) strongly suggested that at least some Pseudomonas R factors, including R931, are host-restricted. Such R factors contrast with other Pseudomonas R factors, described by several workers (11,14,17,27,31), which seem to be freely transferable between P. aeruginosa and members of the Enterobacteriaceae. Grinsted et al. (17) and Datta et al. (11) examined some of the properties of the latter R factors, but the former have not been described in detail. The work in this paper describes some of the characteristics of partially or completely host-restricted Pseudomonas R factors. MATERIALS AND METHODSOrganisms. All P. aeruginosa strains were originally obtained from clinical specimens and identified a...