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Preece N.,Charles Darwin University | Harvey K.,Coonawarra Base | Hempel C.,Level 10 Capital | Woinarski J.C.Z.,Charles Darwin University
Ecological Management and Restoration | Year: 2010

Summary: The Top End region of the Northern Territory, Australia, is noted for its relatively unmodified natural state. To gain some insight into the potential for maintaining ecosystem health in this region we undertook a study that assessed the distribution of weeds across very extensive transects. This weed survey was distinct from other studies in that many of the sample sites were distant from tracks or other infrastructure. Twenty-one weed species were recorded along 2000 km of transects. Weeds were reported from 18.7% of the 718 sample points. The incidence of weeds was found to be significantly associated with land tenure, being highest on pastoral lands and peri-urban areas, and very low on Aboriginal lands. The incidence of weeds increased significantly with increasing levels of infrastructure and with increasing proximity to watercourses. There are three main conclusions from this study. First, much of the Top End, particularly remote Aboriginal lands, has exceptionally low levels of weed infestation. Secondly, in such areas, given the relatively small extent of vegetation change through weed invasion, maintenance or re-imposition of traditional fire regimes should be achievable. Thirdly, there is substantial potential for spread of weeds to remote areas, with such spread most likely to occur through increased penetration by infrastructure. Importantly this study indicates that there is still opportunity to prevent widespread weed invasion across the Top End, which is timely given the current Government consideration of the potential for the region to support future agricultural expansion and the fast-paced development of mining, oil and gas resources. © 2010 Ecological Society of Australia. Source

Williams J.,Level 10 Capital
International Journal of Water | Year: 2010

The paper outlines the four fundamental principles of Natural Sequence Farming (NSF). It explains historical changes in the Australian landscape affecting vegetation, drainage, and morphology, including the typical perched water flows. NSF management techniques are analysed as structural and non-structural and, in the opinion of the CSIRO Expert Panel, both produce manifold benefits in terms of erosive water velocities, aquifer recharge, soil structure, erosion, compaction, and pasture productivity, to name a few. © 2010 Inderscience Enterprises Ltd. Source

Shima J.S.,Victoria University of Wellington | McNaughtan D.,Victoria University of Wellington | Strong A.T.,Victoria University of Wellington | Strong A.T.,Level 10 Capital
Marine Biology | Year: 2015

Intraspecific variation in coral colony growth forms is common and often attributed to phenotypic plasticity. The ability of other organisms to induce variation in coral colony growth forms has received less attention, but has implications for both taxonomy and the fates of corals and associated species (e.g. fishes and invertebrates). Variation in growth forms and photochemical efficiency of massive Porites spp. in lagoons of Moorea, French Polynesia (17.48°S, 149.85°W), were quantified in 2012. The presence of a vermetid gastropod (Ceraesignum maximum) was correlated with (1) reduced rugosity of coral colonies and (2) reduced photochemical efficiency (Fv/Fm) on terminal “hummocks” (coral tissue in contact with vermetid mucus nets) relative to adjacent “interstitial” locations (tissue not in contact vermetid mucus nets). A manipulative field experiment confirmed that the relative growth rate of coral tissue was greater in interstices than hummocks when vermetids were present and similar (but with a trend for faster growth on hummocks) when vermetids were absent. Collectively, these results indicate that vermetid gastropods interact (presumably via their mucus nets) with coral colony architecture to impair photochemical efficiency, reduce growth rates of specific portions of a coral tissue, and induce a smoothed colony morphology. Given that structural complexity of coral colonies is an important determinant of “habitat quality” for many other species (fishes and invertebrates), these results suggest that the vermetid gastropod, C. maximum (with a widespread distribution and reported increases in density in some portions of its range), may have important indirect effects on many coral-associated organisms. © 2015, Springer-Verlag Berlin Heidelberg. Source

Cardoso D.N.,University of Aveiro | Santos M.J.G.,University of Aveiro | Santos M.J.G.,Level 10 Capital | Soares A.M.V.M.,University of Aveiro | Loureiro S.,University of Aveiro
Chemosphere | Year: 2015

The application of molluscicides baits on the soil surface is the most common practice to control terrestrial gastropods. There seems to be a gap in the accurate evaluation of molluscicidal baits effects to soil arthropods, since their hazard to non-target organisms has been considered low after mixing baits into soil. In this work the ecotoxicological effects of two molluscicide baits (metaldehyde and methiocarb) to the collembolan Folsomia candida were evaluated using two different approaches: (1) molluscicidal baits were applied to the top soil once and only at the beginning of the exposure and avoidance behaviour and reproduction were evaluated; and (2) baits were replaced by new ones after 14-d of exposure, simulating the recommended application rate recommended by the manufacturer and reproduction was assessed (repeated/pulse exposure). A preference for the side contaminated for methiocarb was observed but the distribution of collembolans in the avoidance test with metaldehyde was random. Exposure to metaldehyde resulted in a significant increase in mortality. For methiocarb, a reduction in the juveniles produced but no acute effects were observed. In the bait pulse test, the toxic effects of each chemical was significantly increased compared with the single exposure test, for all treatments used (both reproduction and mortality). In summary, molluscicides have an adverse effect on F. candida, with severe effects on their behaviour (only for methiocarb), reproduction and survival (for both), which can lead to population collapse with time. © 2015 . Source

Coventry J.,Australian National University | Andraka C.,Sandia National Laboratories | Pye J.,Australian National University | Blanco M.,CSIRO | Fisher J.,Level 10 Capital
Solar Energy | Year: 2015

This paper examines the potential of sodium receivers to increase the overall solar-to-electricity efficiency of central receiver solar power plants, also known as solar tower systems. It re-visits some of the key outcomes and conclusions from past sodium receiver experiments, in particular those at Sandia National Laboratories and Plataforma Solar de Almeria in the 1980s, and discusses some current development activities in the area. It also discusses research in sodium receivers with a liquid-vapour phase change (heat pipes and pool boilers), to explore whether technologies developed for dish-Stirling systems have applicability for solar tower systems. Lessons learnt from experience in the nuclear industry with liquid sodium systems are discussed in the context of safety risks. © 2015 Elsevier Ltd. Source

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