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In response to the increasing global demand for energy, on exploration and development are expanding into frontier areas of the Arctic, where slow-growing tundra vegetation and the underlying permafrost Soils are Very sensitive to disturbance. The creation of vehicle trails on the tundra from seismic exploration for on has accelerated in the past decade, and the cumulative impact represents a geographic footprint that covers a greater extent of Alaska's North Slope tundra than all other direct human impacts combined. Seismic exploration for on and gas was conducted on the coastal plain of the Arctic National Wildlife Refuge, Alaska, USA, in the winters of 1984 and 1985. This study documents recovery Of vegetation...
Mining and civil engineering industries sometimes use drilling muds for stabilizing a borehole during drilling wells for methane drainage, geothermal energy and radioactive waste disposal. Standard theories predicting borehole breakdown pressure assume breakdown occurs when a small fracture initiates at a location where the largest tangential stress at the borehole reaches the tensile strength of formation. Fracturing tests conducted in this study, how- ever, showed that when drilling fluid was used as an injection fluid, borehole breakdown did not occur even if a fracture initiated at a borehole wall. Bore- hole breakdown occurred when the initiated fracture became unstable after significant growth with O. 76cm...
Protected areas vary enormously in their contribution to conserving biodiversity, and the inefficiency of protected area systems is widely acknowledged. However, conservation plans focus overwhelmingly on adding new sites to current protected area estates. Here we show that the conservation performance of a protected area system can be radically improved, without extra expenditure, by replacing a small number of protected areas with new ones that achieve more for conservation. Replacing the least cost-effective 1% of Australia's 6,990 strictly protected areas could increase the number of vegetation types that have 15% or more of their original extent protected from 18 to 54, of a maximum possible of 58. Moreover,...
The acquisition or designation of new protected areas is usually based on criteria for representation of different ecosystems or land-cover classes, and it is unclear how well-threatened species are conserved within protected-area networks. Here, we assessed how Australia's terrestrial protected-area system (89 million ha, 11.6% of the continent) overlaps with the geographic distributions of threatened species and compared this overlap against a model that randomly placed protected areas across the continent and a spatially efficient model that placed protected areas across the continent to maximize threatened species' representation within the protected-area estate. We defined the minimum area needed to conserve...
Mangroves are species of halophytic intertidal trees and shrubs derived from tropical genera and are likely delimited in latitudinal range by varying sensitivity to cold. There is now sufficient evidence that mangrove species have proliferated at or near their poleward limits on at least five continents over the past half century, at the expense of salt marsh. Avicennia is the most cold-tolerant genus worldwide, and is the subject of most of the observed changes. Avicennia germinans has extended in range along the USA Atlantic coast and expanded into salt marsh as a consequence of lower frost frequency and intensity in the southern USA. The genus has also expanded into salt marsh at its southern limit in Peru,...
Long-term natural gas contracts and their specific features are at the forefront of legal and policy discussions around the world. Issues like oil price indexation and price reviews, flexibility and take-or-pay clauses or a move to shorter term trading are being debated. This is particularly true for Europe where major changes are taking place, but also in places like Australia and Asia. This study will focus on the antitrust treatment of long-term take-or-pay natural gas contracts and their specific provisions in the European Union and the United States. It will also examine the regulatory treatment of these contracts and the regulatory environment in which these contracts operate. Issues that are covered include...
Mining and civil engineering industries sometimes use drilling muds for stabilizing a borehole during drilling wells for methane drainage, geothermal energy and radioactive waste disposal. Standard theories predicting borehole breakdown pressure assume breakdown occurs when a small fracture initiates at a location where the largest tangential stress at the borehole reaches the tensile strength of formation. Fracturing tests conducted in this study, how- ever, showed that when drilling fluid was used as an injection fluid, borehole breakdown did not occur even if a fracture initiated at a borehole wall. Bore- hole breakdown occurred when the initiated fracture became unstable after significant growth with O. 76cm...