Time filter

Source Type

Turangi, New Zealand

Jolly G.E.,Institute of Geological & Nuclear Sciences | Keys H.J.R.,Private Bag | Procter J.N.,Massey University | Deligne N.I.,Institute of Geological & Nuclear Sciences
Journal of Volcanology and Geothermal Research | Year: 2014

Tongariro volcano, New Zealand, lies wholly within the Tongariro National Park (TNP), one of New Zealand's major tourist destinations. Two small eruptions of the Te Maari vents on the northern flanks of Tongariro on 6 August 2012 and 21 November 2012 each produced a small ash cloud to <. 8. km height accompanied by pyroclastic density currents and ballistic projectiles. The most popular day hike in New Zealand, the Tongariro Alpine Crossing (TAC), runs within 2. km of the Te Maari vents. The larger of the two eruptions (6 August 2012) severely impacted the TAC and resulted in its closure, impacting the local economic and potentially influencing national tourism. In this paper, we document the science and risk management response to the eruption, and detail how quantitative risk assessments were applied in a rapidly evolving situation to inform robust decision-making for when the TAC would be re-opened. The volcanologist and risk manager partnership highlights the value of open communication between scientists and stakeholders during a response to, and subsequent recovery from, a volcanic eruption. © 2014 Elsevier B.V. Source

Tanentzap A.J.,Landcare Research | Walker S.,Landcare Research | Theo Stephens R.T.,Private Bag | Lee W.G.,Landcare Research | Lee W.G.,University of Auckland
Conservation Letters | Year: 2012

Conservation policy requires reliable estimates of extinction rates that consider the interactions between population size (N) and habitat area. Current approaches to estimating extinction from the endemics-area relationship (EAR) estimate only the minimum number of species that can become extinct because of habitat loss (instantaneous extinction). EARs will therefore underestimate extinction if small populations and/or habitat area (SPHA) commit species to future extinction. We demonstrate this mathematically, by assuming species require a minimum population size of two individuals, and by randomly sampling habitat loss within stem-mapped forest plots. We then develop a general framework for incorporating SPHA effects into EARs that builds upon recent advances introducing N into estimates of extinction. By accounting for effects that modify N, our framework explains extinction debt and reduces the uncertainty associated with future estimates of extinction through carefully qualifying the spatial and temporal context of predictions. © 2012 Wiley Periodicals, Inc. Source

Podgorski J.E.,ETH Zurich | Green A.G.,ETH Zurich | Kgotlhang L.,ETH Zurich | Kinzelbach W.K.H.,ETH Zurich | And 3 more authors.
Geology | Year: 2013

The near juxtaposition of the Makgadikgadi Basin (Botswana), the world's largest saltpan complex, with the Okavango Delta, one of the planet's largest inland deltas (technically an alluvial megafan), has intrigued explorers and scientists since the middle of the 19th century. It was clear from early observations that the Makgadikgadi Basin once contained a huge lake, paleo-Lake Makgadikgadi. Several authors have since speculated that this lake also covered wide regions to the north and west of the Makgadikgadi Basin. Our interpretation of unusually high-quality helicopter time-domain electromagnetic (HTEM) data indicates that paleo-Lake Makgadikgadi extended northwestward at least into the region presently occupied by the Okavango Delta. The total area of paleo-Lake Makgadikgadi exceeded 90,000 km2, larger than Earth's most extensive freshwater body today, Lake Superior (North America). Our HTEM data, constrained by ground-based geophysical and borehole information, also provide evidence for a paleo-megafan underlying paleo-Lake Makgadikgadi sediments. © 2013 Geological Society of America. Source

Masekoameng K.E.,South African Council for Scientific and Industrial Research | Leaner J.,Private Bag | Dabrowski J.,South African Council for Scientific and Industrial Research
Atmospheric Environment | Year: 2010

Recent studies suggest an increase in mercury (Hg) emissions to the global environment, particularly as a result of anthropogenic activities. This has prompted many countries to complete Hg emission inventories, based on country-specific Hg sources. In this study, information on annual coal consumption and Hg-containing commodities produced in South Africa, was used to estimate Hg emissions during 2000-2006. Based on the information, the UNEP toolkit was used to estimate the amount of Hg released to air and general waste from each activity; using South Africa specific and toolkit based emission factors. In both atmospheric and solid waste releases, coal-fired power plants were estimated to be the largest contributors of Hg emissions, viz. 27.1 to 38.9 tonnes y-1 in air, and 5.8 to 7.4 tonnes y-1 in waste. Cement production was estimated to be the second largest atmospheric Hg emission contributor (2.2-3.9 tonnes y-1), while coal gasification was estimated to be the second largest Hg contributor in terms of general waste releases (2.9-4.2 tonnes y-1). Overall, there was an increase in total atmospheric Hg emissions from all activities, estimated at ca. 34 tonnes in 2000, to 50 tonnes in 2006, with some fluctuations between the years. Similarly, the total Hg emissions released to general waste was estimated to be 9 tonnes in 2000, with an increase to 12 tonnes in 2006. © 2010 Elsevier Ltd. Source

Michaux B.,Private Bag
Biological Journal of the Linnean Society | Year: 2010

The concepts of biogeographical regions and areas of endemism are briefly reviewed prior to a discussion of what constitutes a natural biogeographical unit. It is concluded that a natural biogeographical unit comprises a group of endemic species that share a geological history. These natural biogeographical units are termed Wallacean biogeographical units in honour of the biogeographer A.R. Wallace. Models of the geological development of Indonesia and the Philippines are outlined. Areas of endemism within Wallacea are identified by distributional data, and their relationship to each other and to the adjacent continental regions are evaluated using molecular phylogenies from the literature. The boundaries of these areas of endemism are in broad agreement with earlier works, but it is argued that the Tanimbar Islands are biologically part of south Maluku, rather than the Lesser Sundas, and that Timor (plus Savu, Roti, Wetar, Damar, and Babar) and the western Lesser Sundas form areas of endemism in their own right. Wallacean biogeographical units within Wallacea are identified by congruence between areas of endemism and geological history. It is concluded that although Wallacea as a whole is not a natural biogeographical region, neither is it completely artificial as it is formed from a complex of predominantly Australasian exotic fragments linked by geological processes within a complex collision zone. The Philippines are argued to be an integral part of Wallacea, as originally intended. © 2010 The Linnean Society of London. Source

Discover hidden collaborations