Forest ecosystem development in post-mining landscapes: a case study of the Lusatian lignite district

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".     

Radio-telemetric evidence of migration in the gregarious but not the solitary morph of the Mormon cricket (Anabrus simplex: Orthoptera: Tettigoniidae)

 The Mormon cricket, Anabrus simplex, is one of just a few species of katydids (or bushcrickets, Orthoptera: Tettigoniidae) that, like migratory locusts, appear to have solitary and migratory morphs. Using radio telemetry we studied movements of individuals of two morphs of this flightless species. Individuals within each migratory band had similar rates of movements along similar directional headings whereas solitary individuals moved little and showed little evidence of directionality in movement. Our results also add to other recent radio-telemetry studies showing that flightless insects of 1–2 g in mass can be tracked successfully using these methods. Received: 28 February 2000 / Accepted in revised form: 19 June 2000     

莫桑比克的海洋生物学研究:过去、现在及未来

本文概述了莫桑比克包括渔业在内的海洋生物学研究的发展情况.莫桑比克的海岸线约为3000km,海洋的生物资源在莫桑比克的社会中起着重要的作用,主要是作为人们的蛋白质来源以及收入和出口创汇的来源.     

Landmark memories are more robust when acquired at the nest site than en route: experiments in desert ants

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.