No abstract

The home-range size and location of reef-associated snapper Pagrus auratus: Sparidae were investigated by use of a radio acoustic-positioning telemetry (RAPT) system. Tags were surgically implanted in 5 snapper that were subsequently monitored every minute for a period of 5 mo, and then intermittently over another 7 mo. Site fidelity was high amongst these fish, with home ranges not exceeding 650 m in diameter or 139 600 m 2 in area. Eleven other snapper received tags by feeding and were tracked for periods of up to 2.5 d. Site fidelity was also high for these fish, with standardised estimates of home-range size not differing between the 2 groups. Home ranges overlapped considerably, indicating that the fish were not territorial. The location of the home ranges generally remained stable throughout the entire tracking period, although 1 fish relocated its home range bỹ 220 m. A new method of home-range estimation was developed, which matched the level of detail provided by the RAPT system, to directly estimate the time spent in an area. The relevance of this method and the residential behaviour of these fish are discussed, with reference to the general understanding of animal behaviour, previous investigations into snapper movement, and the selective capacity that may be imposed by marine reserves on fish behaviour.

The distribution of abundance amongst species with similar ways of life is a classical problem in ecology.The unified neutral theory of biodiversity, due to Hubbell, states that observed population dynamics may be explained on the assumption of per capita equivalence amongst individuals. One can thus dispense with differences between species, and differences between abundant and rare species: all individuals behave alike in respect of their probabilities of reproducing and death.It is a striking fact that such a parsimonious theory results in a non-trivial dominancediversity curve (that is, the simultaneous existence of both abundant and rare species) and even more striking that the theory predicts abundance curves that match observations across a wide range of ecologies. This paper introduces the untb package of R routines, for numerical simulation of ecological drift under the unified neutral theory. A range of visualization, analytical, and simulation tools are provided in the package and these are presented with examples in the paper.

[1] Bayesian theory of model calibration provides a coherent framework for distinguishing and encoding multiple sources of uncertainty in probabilistic predictions of flooding. This paper demonstrates the use of a Bayesian approach to computer model calibration, where the calibration data are in the form of spatial observations of flood extent. The Bayesian procedure involves generating posterior distributions of the flood model calibration parameters and observation error, as well as a Gaussian model inadequacy function, which represents the discrepancy between the best model predictions and reality. The approach is first illustrated with a simple didactic example and is then applied to a flood model of a reach of the river Thames in the UK. A predictive spatial distribution of flooding is generated for a flood of given severity.