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Conflicts between human development of the landscape and conservation of biodiversiry will continue to grow. Given this reality, there have been a number of attempts to model the optimal selection of conservation reserve sites such that maximum biodiversity protection can be attained within a limited budget for land acquisition. Here we adapt the Location-Allocation module of ARC/INFO to solve the problem of representing, or covering, as many species as possible in a fixed number of selected reserve sites. Resident ARC/INFO solution routines are applied to an innovative 'logical' network that converts the problem of optimal reserve selection into a problem of optimal facility placement, which the Location-Allocation module can recognize and solve. Use of this unique logical network structure as input to ARC/INFO's internal solvers makes possible, compared to previous methods, a much tighter integration of spatial optimization tools with mapping and database tools, all of which are internal to the GIS and accessed via a menu-driven interface. The main advantage is that users of public domain data (such as the US Gap Analysis data) can conduct their own explorations of possible reserve systems without having to acquire and master optimization packages and reformat model output data for GIS display and post-analysis of solutions. Our sample application uses species data from south-western California. We also present a second major form of species-covering model grounded in the same logical network. This enhanced modcl accommodates weighting of species by their conservation importance, thus allowing reserve systems to be designed around the protection of the most threatened or vulnerable biota. 相似文献
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A unique instance of Holocene estuarine phosphogenesis has been investigated in Raglan Harbour, on the west coast of North Island, New Zealand. Nodular calcareous concretions, which formed within surficial estuarine muds between 6500 and 3600 years BP, were superficially impregnated by carbonate fluorapatite between 3600 and 1600 years BP. The phosphatized nodules lie beneath a late Quaternary shore platform, which is reinforced by a mass of intertwined bioturbation structures and tubular rootlet casts impregnated by limonite and goethite. Large polygonal cracks, indicative of a desiccatory regime, are locally conspicuous on the platform surface and in the immediately subjacent muds. The phosphogenesis in Raglan Harbour is here related to an episode of lowered sea-level, during which a paludal environment succeeded the estuarine, to be followed, in turn, by a positively and interlude. The subsequent rise of sea-level to its present position over the last 1600 years or so has reinstated the shore platform in its present intertidal situation. 相似文献
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DAVID J. CULLEN 《Sedimentology》1988,35(3):421-428
By far the commonest consituents of insular phosphate deposits are calcium phosphates of the apatite series of minerals, especially varieties that contain structural carbonate in their crystal lattices, e.g. francolite and dahllite. This reflects the fact that the vast majority of described insular phosphate deposits occur in low latitudes, where they have formed, in a tropical environment, by metasomatic replacement of carbonate in coral substrates by phosphate derived either from avian excrement or from phosphorus-enriched lagoonal/lacustrine waters. Thin, recently-formed guano accumulations on islands of the subantarctic Bounty group differ radically in that they consist principally of struvite, a hydrated ammonium magnesium phosphate that is better known as a component of human/mammalian urinary stones and enteroliths, and of bat guano in sheltered speleothems. Apatite occurs only in an accessory role in the Bounty Islands guano. This contrast in mineralogy, and the somewhat anomalous survival of soft, unstable struvite in a totally exposed environment on the Bounty Islands, are attributed to climatic factors and to the nature of the granodioritic rock substrate. 相似文献
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A Lateglacial archaeological site in the far north‐west of Europe at Rubha Port an t‐Seilich,Isle of Islay,western Scotland: Ahrensburgian‐style artefacts,absolute dating and geoarchaeology 
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下载免费PDF全文 STEVEN MITHEN KAREN WICKS ANNE PIRIE FELIX RIEDE CHRISTINE LANE ROWENA BANERJEA VICTORIA CULLEN MATTHEW GITTINS NICHOLAS PANKHURST 《第四纪科学杂志》2015,30(5):396-416
The exact pattern, process and timing of the human re‐colonization of northern Europe after the end of the last Ice Age remain controversial. Recent research has provided increasingly early dates for at least pioneer explorations of latitudes above 54°N in many regions, yet the far north‐west of the European landmass, Scotland, has remained an unexplained exception to this pattern. Although the recently described Hamburgian artefacts from Howburn and an assemblage belonging to the arch‐backed point complex from Kilmelfort Cave have established at least a sporadic human presence during earlier stages of the Lateglacial Interstadial, we currently lack evidence for Younger Dryas/Greenland Stadial 1 (GS‐1) activity other than rare stray finds that have been claimed to be of Ahrensburgian affiliation but are difficult to interpret in isolation. We here report the discovery of chipped stone artefacts with technological and typological characteristics similar to those of the continental Ahrensburgian at a locality in western Scotland. A preliminary analysis of associated tephra, pollen and phytoliths, along with microstratigraphic analysis, suggest the artefacts represent one or more episodes of human activity that fall within the second half of GS‐1 and the Preboreal period. © 2015 The Authors. Journal of Quaternary Science published by John Wiley & Sons, Ltd. 相似文献
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Smoking in New Zealand is more common in deprived areas and in areas with a significant Maori population. Despite its status as a major health problem there has been little work investigating this apparent geography of smoking Data from the 1996 Census is used to construct a multilevel ‘proportions‐as‐responses’ model of smoking prevalence. This enables an exploration of the geography of smoking at different spatial scales. Levels within the model distinguish contextual variation between local authorities, census area units and meshblocks. Particular account is taken of the influence of deprivation and ethnicity on smoking. Results confirm the importance of ethnicity and deprivation and indicate that cross‐level interaction between meshblock and census area unit measures is significant. They also challenge crude stereotypes about the apparent geography of smoking and suggest that, while levels of smoking may be high in parts of North Island, they are less high than might be expected given the socio‐demographic composition of the areas concerned. Conversely, smoking is more prevalent than expected in parts of South Island. The paper notes the health policy implications of these emergent geographies. 相似文献
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Two recent databases show that the fossil record of insects is better than commonly supposed, comprising over 1000 families and 5000 genera. Insects (hexapods) first appeared in the Devonian, but by the Permian the number of orders present was similar to that of the present day. However, family data suggest an unsteady increase in diversity during the Phanerozoic, with four main peaks and troughs but no sudden change (supported by genera) at the Cretaceous/Tertiary transition. 相似文献
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