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The restoration of surface mining landscapes requires the (re)creation of ecosystems. In Lusatia (eastern Germany), large-scale open-cast lignite mining operations generated spoil dumps widely consisting of acidified, phytotoxic substrates. Amelioration and rehabilitation measures have been developed and applied to these substrates since the 1950s. However, it is still not clear whether these approaches are sustainable. This paper reports on collaborative research work into the ecological potential of forest ecosystem development on typical minesites in the Lusatian lignite district. At first sight, pine stands on minesites along a chronosequence comprising about 35 years did not show differences when compared with stands on non-mined sites of the general region. Furthermore, with some modification, conceptual models for flora and fauna succession in forest stands on non-mined sites seem to be applicable, at least for the early stages of forest ecosystem development. For example, soil organism abundance and activity at minesites had already reached levels typical of non-mined sites after about 20-30 years. In contrast, mine soils are very different from non-mined soils of the test region. Chemically, mine soil development is dominated by processes originating from pyrite oxidation. Geogenic, i.e. lignitic, soil organic carbon was shown to substitute for some functions of pedogenic soil organic matter. Rooting was hampered but not completely impeded in strongly acidified soil compartments. Roots and mycorrhizae are apparently able to make use of the characteristic heterogeneity of young mine soils. Considering these recent results and the knowledge accumulated during more than 30 years of research on minesite rehabilitation internationally, it can be stated that minesite restoration might be used as an ideal case study for forest ecosystem development starting at "point zero" on "terra nova". 相似文献
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Torvanger Asbjørn Rypdal Kristin Kallbekken Steffen 《Mitigation and Adaptation Strategies for Global Change》2005,10(4):693-715
Carbon dioxide (CO2) capture and storage is increasingly being considered as an important climate change mitigation option. This paper explores
provisions for including geological CO2 storage in climate policy. The storage capacity of Norway's Continental Shelf is alone sufficient to store a large share
of European CO2 emissions for many decades. If CO2 is injected into oil reservoirs there is an additional benefit in terms of enhanced oil recovery. However, there are significant
technical and economic challenges, including the large investment in infrastructure required, with related economies of scale
properties. Thus CO2 capture, transportation and storage projects are likely to be more economically attractive if developed on a large scale,
which could mean involving two or more nations. An additional challenge is the risk of future leakages from storage sites,
where the government must take on a major responsibility. In institutional and policy terms, important challenges are the
unsettled status of geological CO2 storage as a policy measure in the Kyoto Protocol, lack of relevant reporting and verification procedures, and lack of decisions
on how the option should be linked to the flexibility mechanisms under the Kyoto Protocol. In terms of competitiveness with
expected prices for CO2 permits under Kyoto Protocol trading, the relatively high costs per tonne of CO2 stored means that geological CO2 storage is primarily of interest where enhanced oil recovery is possible. These shortcomings and uncertainties mean that
companies and governments today only have weak incentives to venture into geological CO2 storage. 相似文献
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Foraging desert ants, Cataglyphis fortis, encounter different sequences of visual landmarks while navigating by path integration. This paper explores the question whether the storage of landmark information depends on the context in which the landmarks are learned during an ant's foraging journey. Two experimental set-ups were designed in which the ants experienced an artificial landmark panorama that was placed either around the nest entrance (nest marks) or along the vector route leading straight towards the feeder (route marks). The two training paradigms resulted in pronounced differences in the storage characteristics of the acquired landmark information: memory traces of nest marks were much more robust against extinction and/or suppression than those of route marks. In functional terms, this result is in accord with the observation that desert ants encounter new route marks during every foraging run but always pass the same landmarks when approaching the nest entrance. 相似文献
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