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[1] The accuracy of synoptic-based weather forecasting deteriorates rapidly after five days and is not routinely available beyond 10 days. Conversely, climate forecasts are generally not feasible for periods of less than 3 months, resulting in a weather-climate gap. The tropical atmospheric phenomenon known as the Madden-Julian Oscillation (MJO) has a return interval of 30 to 80 days that might partly fill this gap. Our near-global analysis demonstrates that the MJO is a significant phenomenon that can influence daily rainfall patterns, even at higher latitudes, via teleconnections with broadscale mean sea level pressure (MSLP) patterns. These weather states provide a mechanistic basis for an MJO-based forecasting capacity that bridges the weather-climate divide. Knowledge of these tropical and extra-tropical MJOassociated weather states can significantly improve the tactical management of climate-sensitive systems such as agriculture. Citation: Donald, A

The bank vole (Clethrionomys glareolus) is the natural reservoir of Puumala virus (PUUV), a species in the genus Hantavirus. PUUV is the etiologic agent of nephropathia epidemica, a mild form of hemorrhagic fever with renal syndrome. Factors that influence hantavirus transmission within host populations are not well understood. We evaluated a number of factors influencing on the association of increased PUUV infection in bank voles captured in a region in northern Sweden endemic for the virus. Logistic regression showed four factors that together correctly predicted 80% of the model outcome: age, body mass index, population phase during sampling (increase, peak, or decline/low), and gender. This analysis highlights the importance of population demography in the successful circulation of hantavirus. The chance of infection was greatest during the peak of the population cycle, implying that the likelihood of exposure to hantavirus increases with increasing population density.

Puumala virus (PUUV), genus hantavirus, causes nephropathia epidemica, a mild form of hemorrhagic fever with renal syndrome in humans. In this study, bank voles, the natural reservoir of PUUV, were captured at locations of previous human PUUV exposure and paired controls within a region of high incidence in northern Sweden. The aim of the study was to evaluate the influence of environmental factors on the abundance of bank voles and the occurrence of PUUV. The total number of voles and the number of PUUV-infected voles did not differ between locations of previous human PUUV exposure and paired controls. The number of bank voles expressing antibodies to PUUV infection increased linearly with total bank vole abundance implying density independent transmission. Using principal component and partial correlation analysis, we found that particular environmental characteristics associated with old-growth moist forests (i.e., those dominated by Alectoria spp., Picea abies, fallen wood, and Vaccinium myrtillus) were also associated with increased abundance of bank vole and hence the number of PUUV-infected bank voles, whereas there were no correlations with factors associated with dry environments (i.e., Pinus sylvestris and V. vitis-idea). This suggests that circulation and persistence of PUUV within bank vole populations was influenced by habitat factors. Future modeling of risk of exposure to hantavirus and transmission of PUUV within vole populations should include the influence of these factors.

Background: Plotless density estimators are those that are based on distance measures rather than counts per unit area (quadrats or plots) to estimate the density of some usually stationary event, e.g. burrow openings, damage to plant stems, etc. These estimators typically use distance measures between events and from random points to events to derive an estimate of density. The error and bias of these estimators for the various spatial patterns found in nature have been examined using simulated populations only. In this study we investigated eight plotless density estimators to determine which were robust across a wide range of data sets from fully mapped field sites. They covered a wide range of situations including animal damage to rice and corn, nest locations, active rodent burrows and distribution of plants. Monte Carlo simulations were applied to sample the data sets, and in all cases the error of the estimate (measured as relative root mean square error) was reduced with increasing sample size. The method of calculation and ease of use in the field were also used to judge the usefulness of the estimator. Estimators were evaluated in their original published forms, although the variable area transect (VAT) and ordered distance methods have been the subjects of optimization studies.

Colonization may favor self-compatibility (SC) in invasive plants, a process consistent with Baker's law. We investigated this hypothesis in invasive eastern North American populations of tristylous Lythrum salicaria L. (purple loosestrife) by controlled self-and cross-pollinations of 124 plants sampled from 12 populations grown under uniform glasshouse conditions. We evaluated whether populations at the northern front of the invasion exhibited higher levels of SC than southern populations, which are closer to source populations for the North American invasion. We also sought evidence for morph-specific differences in the strength of trimorphic incompatibility. We used the ASTER statistical program to jointly model three measures of SC: (1) the probability of producing at least one seed following self-pollination, (2) the number of fruits produced by selfpollination, and (3) the average number of seeds per fruit resulting from self-pollination. Just over one-quarter of plants set at least one fruit after self-pollination, and there was a significant effect of style morph on variation in SC, with the mid-styled morph most compatible. Although variation for SC was detected in 11 of the 12 populations, there was no evidence that SC increased toward the northern range limit as a result of the invasion process.

This study investigated home-range size, utilisation of tree species and patches, and the influence of spacing behaviour by females on social organisation. It was undertaken in south-east Queensland in an area dominated by agricultural activity (beef and dairy cattle and cropping). Extensive clearing in the study area resulted in patches of vegetation that varied in size from less that 1 ha to blocks of 50–100 ha. Eucalyptus tereticornis and E. crebra were the dominant species in these patches and koalas used both species. The average home-range size (delineated by the 95% probability polygon from a kernel estimator) was 34.4 ha and 15.0 ha for males and females respectively; that delineated by the 70% probability polygon was 12.5 ha and 5.0 ha for males and females respectively. Koalas were not reliant on corridor systems and sometimes moved further than 5 km in a season. Koalas have few non-food-related requirements, i.e. they do not need den sites, nest sites, display areas, etc. Furthermore, they do not utilise the understorey and their mobility between patches does not appear to be compromised by the absence of corridors of trees. It is suggested that, in comparison with other arboreal marsupials, it should be relatively easy to provide habitat for koalas within rural areas.

Puumala virus, genus Hantavirus, is the etiologic agent of nephropathia epidemica, a mild form of hemorrhagic fever with renal syndrome. The bank vole (Clethrionomys glareolus) is the natural reservoir species of this hantavirus. We initiated sampling of bank voles at sites of recently identified human nephropathia epidemica cases and paired control sites in the fall of 1995 in coastal areas of northern Sweden. Sites were trapped annually in spring and fall until 1999. Prevalence of antibody to Puumala virus was similar among local bank vole populations in the two types of sites over time. During peak years, however, the absolute number of bank voles was higher in case sites than control sites. Consequently, the likelihood of Puumala virus exposure was increased at case sites during population highs. This would imply that the risk of Puumala virus exposure to conspecifics and humans is habitat and site dependent with a temporal component.