Cooperative Research Centre

About: Cooperative Research Centre is a based out in . It is known for research contribution in the topics: Population & Sea ice. The organization has 7633 authors who have published 8607 publications receiving 429721 citations.

Response of eucalyptus‐dominated savanna to frequent fires: lessons from munmarlary, 1973–1996

Abstract: We assess a replicated fire plot experiment undertaken between 1973 and 1996 in two Eucalyptus-dominated savanna vegetation formations (open forest, woodland), at Munmarlary, in monsoonal northern Australia. Four treatments, each with three replicates, were imposed on each vegetation type: annual early dry-season burning; annual late dry- season burning; biennial early dry-season burning; and unburned controls. Treatments were imposed faithfully, with noted exceptions, on 1-ha plots. Fire intensities were typically low (,1000 kW/m) to moderate (1000-2500 kW/m), varied significantly between treatments, and generally were greater in woodland. In both woodland and open forest, pH was sig- nificantly lower and NO 3-N was significantly higher in unburned plots. Organic C was not significantly greater in unburned treatments. Effects of fire regime on other soil chemical properties differed between open forest and woodland sites. Among the grasses, invariant frequent burning led to the dominance of a small number of annual species, notably re- gionally dominant Sorghum. In the absence of burning, annuals declined generally, whereas some perennials increased while most decreased. These responses usually were apparent within the first five years of the experiment. At the relatively small spatial scale of the grass sampling regime, there was high turnover of both annual and perennial grasses. Under low- to moderate-intensity, frequent burning regimes, woody vegetation dominated by ma- ture eucalypts is structurally stable. In the absence of burning for at least five years, there was release of the non-eucalypt, woody component into the midstory; this occurred more rapidly in open forest. Accession of rain forest species occurred on some woodland plots, especially the unburned treatment. In contrast, eucalypts were not released significantly from the understory. Rather, as suggested by other studies, recruitment of eucalypts into the canopy appears to involve significantly reduced root competition through death of dominant eucalypts. Although the Munmarlary experiment provides invaluable quantitative data for exploring relationships between fire regimes and the responses of north Australian savanna systems, it has been less successful in meeting the complex information require- ments of regional fire managers. Replicated experimental fire plot designs, no matter how elegant and rigorously implemented, may substantially fail the test of management rele- vance, given the fundamental requirement for savanna biodiversity managers to experience the integrated effects of fire regimes that vary idiosyncratically over multiple time and spatial scales. We suggest that such information requirements are better met through modest, targeted ''adaptive management'' studies, involving collaborative partnerships between managers and researchers.

Silicone hydrogel contact lenses and the ocular surface.

Abstract: For 30 years, contact lens research focused on the need for highly oxygen-permeable (Dk) soft lens materials. High Dk silicone hydrogel contact lenses, made available in 1999, met this need. The purpose of this review is to examine how silicone hydrogel lens wear affects the ocular surfaces and to highlight areas in which further research is needed to improve biocompatibility. Silicone hydrogel lenses have eliminated lens-induced hypoxia for the majority of wearers and have a less pronounced effect on corneal homeostasis compared to other lens types; however, mechanical interaction with ocular tissue and the effects on tear film structure and physiology are similar to that found with soft lens wear in general. Although the ocular health benefits of silicone hydrogel lenses have increased the length of time lenses can be worn overnight, the risk of infection is similar to that found with other soft lens types, and overnight wear remains a higher risk factor for infection than daily wear, regardless of lens material. Future contact lens research will focus on gaining a better understanding of the way in which contact lenses interact with the corneal surface, upper eyelid, and the tear film, and the lens-related factors contributing to infection and inflammatory responses.

Constraints on recovery: using molecular methods to study connectivity of aquatic biota in rivers and streams

Abstract: Summary 1. The ‘Field of Dreams Hypothesis’ states ‘if we build it, they will come’, referring to the assumption that if habitats are restored, species will recolonise them. However, the ability of a species to recolonise a restored site will depend not only on the appropriate habitat being present, but also on the ability to get there. This is likely to depend on both the species’ dispersal behaviour and the position of a site in the landscape. 2. Animals with good potential for dispersal are more likely to be able to disperse to newly restored sites. Similarly, sites in lowland streams with limited altitudinal differences between sites may be easier to reach than upstream sites. This is because upstream sites are connected to one another via lowland streams that have different characteristics and therefore may be difficult for animals to traverse. 3. In this paper, genetic data from a range of freshwater species that have been analysed in my laboratory are used to assess the importance of life cycle and position in the landscape (i.e. upland versus lowland streams) on connectivity patterns (and thus recolonisation potential) among populations. 4. In general, contemporary dispersal across catchment boundaries is negligible, except for aquatic insects with an adult flight stage. Dispersal among streams within catchments appears to be more limited than was predicted from knowledge on life histories, except for fish in lowland rivers and streams. 5. As predicted, dispersal of fish, crustaceans and molluscs among streams within catchments is significantly greater in lowland rivers than in upland streams. 6. Overall, these analyses suggest that, with the exception of most insects, and fishes in lowland rivers, natural recolonisation of restored sites is only likely from sites within the same stream. If a species has disappeared from the whole stream, then restoration of habitat alone may not be sufficient for its re-establishment.