Geniculo-Cortical Projection Diversity Revealed within the Mouse Visual Thalamus

This is the final version of the article. It was first available from PLOS via http://dx.doi.org/10.1371/journal.pone.0144846All dLGN cell co-ordinates, V1 injection sites, dLGN boundary coordinates, experimental protocols and analysis scripts are available for download from figshare at https://figshare.com/s/36c6d937b1844eec80a1.The mouse dorsal lateral geniculate nucleus (dLGN) is an intermediary between retina and primary visual cortex (V1). Recent investigations are beginning to reveal regional complexity in mouse dLGN. Using local injections of retrograde tracers into V1 of adult and neonatal mice, we examined the developing organisation of geniculate projection columns: the population of dLGN-V1 projection neurons that converge in cortex. Serial sectioning of the dLGN enabled the distribution of labelled projection neurons to be reconstructed and collated within a common standardised space. This enabled us to determine: the organisation of cells within the dLGN-V1 projection columns; their internal organisation (topology); and their order relative to V1 (topography). Here, we report parameters of projection columns that are highly variable in young animals and refined in the adult, exhibiting profiles consistent with shell and core zones of the dLGN. Additionally, such profiles are disrupted in adult animals with reduced correlated spontaneous activity during development. Assessing the variability between groups with partial least squares regression suggests that 4?6 cryptic lamina may exist along the length of the projection column. Our findings further spotlight the diversity of the mouse dLGN?an increasingly important model system for understanding the pre-cortical organisation and processing of visual information. Furthermore, our approach of using standardised spaces and pooling information across many animals will enhance future functional studies of the dLGN.Funding was provided by a Wellcome Trust grant jointly awarded to IDT and SJE (083205, www.wellcome.ac.uk), and by MRC PhD Studentships awarded to MNL and ACH (http://www.mrc.ac.uk/)

Microvariation in the fauna of a sublittoral sand bank, Moreton Bay, Queensland

Benthic macrofauna was sampled from Naval Reserve Bank, Moreton Bay, Queensland, using an 0.05 m2 van Veen grab, and data were used to investigate spatial micropatterning. Samples were taken within a 5 × 6 square sampling grid (total area 730 in2) with an intersampling distance of 6 m. Samples were taken in duplicate on each occasion at 2‐inonth intervals. Particle size of sediments and depth data were also collected. Data on other abiotic factors such as temperature, salinity and currents were inferred. Sampling gave data for 131 species. Hierarchical numerical classificatory techniques were employed to obtain (a) spatial patterns (site‐groups) based on biotic data, and (b) species‐groups which characterize the above site groups. Species diversity (SH) species richness (S), species evenness (J’) and individual species diversity (I) indices were computed for the total data set for each site with the species summated over the sampling times. A selected number of species were used in the classification. The spatial patterns were well defined but the species‐groups categorizing them were somewhat confused. Species diversity indices were found to be of little aid in the interpretation of the site patterns or in generating alternative hypotheses. Copyrigh

Sustainable development of tropical Australia: R&D for Management of Land, Water and Marine Resources

The scoping study aims to synthesise social, economic, natural resource and institutional data to develop a systems understanding of natural resource planning and management. It therefore examines biophysical, socioeconomic and institutional issues, all of which affect the selection of a study area in which the aims can be achieved. Rather than examining the different resource management systems (eg. fisheries, irrigation), this study focuses on whether an integrated approach would be appropriate and effective

Maintain or modify — alternative views of managing critical fisheries habitat — how much can we lose?

Recently fisheries management in Australia has shifted to emphasise management of resources within the principles of ecologically sustainable development. This has resulted in management to sustain fish stocks, maximise economic efficiency when harvesting those stocks, and a trend towards granting property rights to the fishers. To achieve the goal of management to sustain fish stocks, a major focus of fisheries agencies has been to preserve the critical habitats upon which the long-term productivity of the fisheries depends. For penaeid prawns this has meant that seagrass (tiger prawns), and mangroves (banana prawns) have achieved special status to fishers, fisheries biologists, managers and legislators. Is this justified? Is this the appropriate management strategy to preserve critical fisheries habitat? We examine these questions using two case studies: cyclones, seagrasses and tiger prawns in the Gulf of Carpentaria and king prawns in the Peel-Harvey estuarine system in Western Australia. It is clear that a greater understanding of the key processes operating in the coastal zone is a critical requirement for fisheries management. It is not enough to just map, monitor and maintain subsets of these systems based on coarse distribution and abundance studies of prawn populations. With increasing pressure on the coastal zone from competing interest groups, fisheries managers need a greater understanding of the factors which determine the carrying capacity of nursery habitats for juvenile penaeid prawns, and the factors which limit the distribution of key fisheries habitats within coastal ecosystems. Fisheries scientists and managers need to develop the knowledge base and management procedures for the implementation of ecosystem management

Effects of cyclones on seagrass communities and penaeid prawn stocks of the Gulf of Carpentaria

Seagrass beds are important habitats for juvenile commercial prawns. Since the start of the CSIRO seagrass and cyclone program in 1984, there have been four cyclones in the western Gulf of Carpentaria. Of these, only two have affected seagrass beds, and only one of these, cyclone 'Sandy', had a severe effect. The extent of damage to the seagrass beds is probably the result of a combination of factors, including the path of the cyclone, the strength of the winds and the currents associated with the cyclone, the height of the tide at the time of the cyclone and whether the storm surge associated with the cyclone is positive or negative. Cyclone 'Sandy' removed about 183 km2 of seagrass from the Gulf of Carpentaria, which has resulted in the juvenile prawn populations in the area changing from commercially important tiger and endeavour prawns to non-commercial species. The catch of tiger prawns in this area has been consistently lower than in unaffected areas. Seagrasses have begun to grow in the area again. However, it is a very slow process and small species that do not provide a suitable habitat for juvenile prawns are the first to colonise. In addition, the sediment in some areas may now be unsuitable for seagrass. Seagrass revegetation and recolonisation by juveniles of commercially important prawns is likely to take at least 10 to 15 years

Detecting an environmental impact of dredging on seagrass beds with a BACIR sampling design

The impact of maintenance dredging an access channel to a canal estate in Deception Bay, Australia, on the nearby seagrasses was monitored over 18 months with a Before/After, Control/Impact, Repeated measures (BACIR) sampling design. Three seagrasses were collected in the study area; Zostera capricorni Aschers., Halophila ovalis (R.Br.) Hook. f. and Halophila spinulosa (R.Br.) Aschers. All seagrasses were found less than 700 m offshore. The biomass of Z. capricorni, the numerically dominant seagrass, was significantly lower in the access channel border compared with the control area before dredging, which was attributed to direct or indirect effects associated with the channel. There was no significant effect of maintenance dredging statistically detected for Z. capricorni biomass in the access channel border even though seagrass was absent in the access channel 14 months after dredging. This was due to the high background variability of seagrass biomass in the control area. In contrast the biomass of H. ovalis declined at a significantly higher rate in the control area than in the access channel border but had also disappeared from the access channel border 14 months after dredging. Without a control we may have concluded that the disappearance of seagrass from the access channel border was due to the effects of dredging, whereas with a BACIR sampling program there remained a possibility that the decline in seagrass was due to larger scale changes in the bay