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91.
The need for conservation planning across the landscape, regardless of tenure, is widely recognised. In Australia, attempts to coordinate the management of conservation lands are characterised by models such as Biosphere Reserves and Conservation Management Networks. This paper outlines the history behind the formation and development of three networks in Australia—the Bookmark Biosphere Reserve, the Gippsland Plains Conservation Management Network, and the Grassy Box Woodlands Conservation Management Network—with particular emphasis on the tenure and protection attributes of the various components within these networks. Despite?having a similar number of components, the total area represented in the networks varied markedly. There were few similarities in the proportion of components of various tenures and protection mechanisms among networks. Composition of networks is likely to be strongly influenced by both historical factors (degree of subdivision, land ownership and remaining vegetation) and contemporary factors (aims of the network and willingness of landowners to participate). Continued research into both the evolution and the physical and social dynamics of multi-tenure reserve networks enables a better understanding of their operation, and will ultimately assist in improved conservation planning across the landscape. 相似文献
92.
93.
Negri A Vollhardt C Humphrey C Heyward A Jones R Eaglesham G Fabricius K 《Marine pollution bulletin》2005,51(1-4):370-383
The effects of the herbicide diuron on the early life history stages of broadcast spawning and brooding corals were examined in laboratory experiments. Fertilisation of Acropora millepora and Montipora aequituberculata oocytes were not inhibited at diuron concentrations of up to 1000 microg l(-1). Metamorphosis of symbiont-free A. millepora larvae was only significantly inhibited at 300 microg l(-1) diuron. Pocillopora damicornis larvae, which contain symbiotic dinoflagellates, were able to undergo metamorphosis after 24 h exposure to diuron at 1000 microg l(-1). Two-week old P. damicornis recruits on the other hand were as susceptible to diuron as adult colonies, with expulsion of symbiotic dinoflagellates (bleaching) evident at 10 microg l(-1) diuron after 96 h exposure. Reversible metamorphosis was observed at high diuron concentrations, with fully bleached polyps escaping from their skeletons. Pulse amplitude modulation (PAM) chlorophyll fluorescence techniques demonstrated a reduction in photosynthetic efficiency (Delta F/F(m)') in illuminated P. damicornis recruits after a 2 h exposure to 1 microg l(-1) diuron. The dark-adapted quantum yields (F(v)/F(m)) also declined, indicating chronic photoinhibition and damage to photosystem II. 相似文献
94.
95.
Geoff Bertram 《GeoJournal》2004,59(2):93-106
Four interrelated patterns of structural change in the New Zealand economy since 1980 are identified and analysed, against
the backdrop of a growth rate which fell substantially behind the rest of the OECD in the late 1980s and early 1990s before
recovering, but without catchup, from 1993.
The changes discussed are: a shift in sharemarket capitalization from formerly-dominant productive activities in agriculture,
manufacturing and construction to the current predominance of utilities, transport and finance; a sharp increase in overseas
investors' share of the economic surplus, from around 20% to over half of post-tax corporate profits; a steady rise in international
indebtedness at the same time as sovereign foreign-currency debt was eliminated; hence overseas debt was successfully privatized;
a weakening of regulatory control over monopoly profits, opening the way for a surge of rent-seeking activity during the 1990s.
The neoliberal reform programme has achieved fiscal and monetary sustainability, increased market flexibility, and insulated
the economy against external shocks. At the same time it has led to denationalisation of economic surplus, ongoing current
account deficits, and a significant diversion of resources from productive use into rent-seeking.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
96.
The morphology and processes of formation and maintenance of waterfalls are more varied and complex than is suggested by the simple caprock‐undercutting model that is closely identified with Niagara Falls. The dominant process of retreat of two buttressed waterfalls near Cowra, NSW, seems to be failure along joint planes at the lips of the waterfalls. In the case of the larger of the two waterfalls, this process is significantly enhanced by the formation and subsequent destruction of potholes at the waterfall lip. 相似文献
97.
Gürol Seyito
lu Duncan Anderson Geoff Nowell Barry Scott 《Journal of Volcanology and Geothermal Research》1997,76(1-2)
New K-Ar dating and major- and trace-element analyses from the U
ak-Selendi-Emet (USE) area constrain the timing of changes in the nature of volcanism in the Miocene in western Turkey. The data reveal a change from dominantly calc-alkaline and silicic in the Early Miocene to largely alkaline and more mafic volcanism in the Middle Miocene. This probably reflects a decreasing amount of crustal contamination with time, a result of extensional tectonics. High levels of various incompatible elements (including K) in the more mafic members, suggest an enriched subcontinental lithospheric source region for the Middle Miocene USE lavas. Highly variable Nb/Y, Ti/Y and Th/Nb ratios suggest a lithospheric mantle heterogeneously enriched by two processes: (1) enrichment by subduction-related processes producing high Th/Nb but low Nb/Y and Ti/Y; and (2) enrichment by small degree melts of depleted upper mantle producing low Th/Nb but high Nb/Y and Ti/Y. Both of these enrichment processes have variably contributed to Middle Miocene K-rich lavas in the USE area. The mechanism which initiated the melting of the enriched lithosphere is considered to be extension which produced decompression melting. Comparisons with the nearby Kula lavas reveals that by the Pliocene to Quaternary, volcanism, although still enriched in incompatible elements, had become sodic. It seems likely that continued extension up to this time thinned the lithosphere to such an extent that asthenospheric melts were produced which ascended and mixed with previously enriched lithosphere. 相似文献
98.
Helen M. Roberts Daniel R. Muhs Ann G. Wintle Geoff A. T. Duller E. Arthur Bettis III 《Quaternary Research》2003,59(3):411-419
A high-resolution chronology for Peoria (last glacial period) Loess from three sites in Nebraska, midcontinental North America, is determined by applying optically stimulated luminescence (OSL) dating to 35–50 μm quartz. At Bignell Hill, Nebraska, an OSL age of 25,000 yr near the contact of Peoria Loess with the underlying Gilman Canyon Formation shows that dust accumulation occurred early during the last glacial maximum (LGM), whereas at Devil’s Den and Eustis, Nebraska, basal OSL ages are significantly younger (18,000 and 21,000 yr, respectively). At all three localities, dust accumulation ended at some time after 14,000 yr ago. Mass accumulation rates (MARs) for western Nebraska, calculated using the OSL ages, are extremely high from 18,000 to 14,000 yr—much higher than those calculated for any other pre-Holocene location worldwide. These unprecedented MARs coincide with the timing of a mismatch between paleoenvironmental evidence from central North America, and the paleoclimate simulations from atmospheric global circulation models (AGCMs). We infer that the high atmospheric dust loading implied by these MARs may have played an important role, through radiative forcing, in maintaining a colder-than-present climate over central North America for several thousand years after summer insolation exceeded present-day values. 相似文献
99.
Cleary Paul W. Prakash Mahesh Mead Stuart Lemiale Vincent Robinson Geoff K. Ye Fanghong Ouyang Sida Tang Xinming 《Natural Hazards》2015,75(2):1489-1530
Natural Hazards - Failure modes for earth dams are extensively reviewed and analysed using a three-pronged approach including a literature review, physical observations of a representative earth... 相似文献
100.
Charlotte G. Kenchington Simon J. Harris Philip B. Vixseboxse Chris Pickup Philip R. Wilby 《Proceedings of the Geologists' Association. Geologists' Association》2018,129(3):264-277
Charnwood Forest (UK) hosts some of the oldest and best-preserved macrofossils known from the Ediacaran. It is the counterpoint to the more widely studied fossil sites of south-eastern Newfoundland (Canada), which include the recently-designated UNESCO World Heritage Site of Mistaken Point. Discoveries made in Charnwood Forest since 2008 have the potential to revolutionise our understanding of the evolution of complex macroscopic life and the subsequent development of ‘modern’ (i.e. Phanerozoic) ecosystems. The sites in Charnwood include the holotypes for several iconic Ediacaran taxa, and potentially both the oldest and youngest representatives of the deep-water Avalon Assemblage. These communities provide a unique opportunity to test models of community ecology, biological endemism and environmental sensitivity and adaptability in the Ediacaran. Here, we review the geology of Charnwood Forest and the palaeobiology of its biotas, and we summarise recent scientific advances in the context of our developing understanding of early macroscopic life. We review the application of Reflectance Transformation Imaging to these ancient communities, and signpost exciting new directions for research in Charnwood Forest, almost 170 years after the fossils were first brought to light. 相似文献