Ecosystem development in post-mining sites

  • Patterns and processes of initial terrestrial-ecosystem development

Ecosystems are characterized as complex systems with abiotic and biotic processes interacting between the various components that have evolved over long-term periods. Most ecosystem studies so far have been carried out in mature systems. Only limited knowledge exists on the very initial phase of ecosystem development. Concepts on the development of ecosystems are often based on assumptions and extrapolations with respect to structure–process interactions in the initial stage. To characterize the effect of this initial phase on structure and functioning of ecosystems in later stages, it is necessary to disentangle the close interaction of spatial and temporal patterns of ecosystem structural assemblages with processes of ecosystem development. The study of initial, less complex systems could help to better identify and characterize coupled patterns and processes.

This paper gives an overview of concepts for the initial development of different ecosystem compartments and identifies open questions and research gaps. The artificial catchment site “Chicken Creek” is introduced as a new research approach to investigate these patterns and processes of initial ecosystem development under defined boundary conditions. This approach allows to integrate the relevant processes with related pattern and structure development over temporal and spatial scales and to derive thresholds and stages in state and functioning of ecosystems at the catchment level.

Schaaf, W., Bens, B., Fischer, A., Gerke, H.H., Gerwin, W., Grünewald, U., Holländer, H.M., Kögel-Knabner, I., Mutz, M., Schloter, M., Schulin, R., Veste, M., Winter, S., Hüttl, R.F., Journal of Plant Nutrition and Soil Sciences 174 (2), 229-239, 2011. (more…)

  • Formation of soil lichen crusts at reclaimed post-mining sites, Lower Lusatia, 
    North-east Germany

Biological soil crusts were investigated at reclaimed post-mining sites near Welzow and Schlabendorf in Lower Lusatia (Brandenburg, Germany). Various development stages from initial biological soil crusts built up by green algae, to more developed soil crusts with mosses, as well as moss-soil lichen crusts, were classified. The spatial-temporal dynamics during the development resulted in a moss-lichens cover with discrete patches of pioneer organisms like green algae in between. At the study sites, 13 species of terricolous lichens were identified. The formation of the biological soil crust is important for the accumulation of soil organic matter in the first millimeters of the topsoil of these pioneer ecosystems. A correlation between cryptogamic biomass and soil carbon content were found.

More informations about biological soil crusts. 

  • Initial pedogenesis in a topsoil crust 3 years after construction of an artificial catchment in Brandenburg, NE Germany

Cyanobacteria and green algae present in biological soil crusts are able to colonize mineral substrates even under extreme environmental conditions. As pioneer organisms, they play a key role during the first phases of habitat colonization. A characteristic crust was sampled 3 years after installation of the artificial water catchment “Chicken creek”, thus representing an early successional stage of ecosystem development. Mean annual rainfall and temperature were 559 mm and 9.3°C, respectively. We combined scanning electron microscopy (SEM/EDX) and infrared (FTIR) microscopy to study the contact zone of algal and cyanobacterial mucilage with soil minerals in an undisturbed biological soil crust and in the subjacent sandy substrate. The crust was characterized by an approximately 50 μm thick surface layer, where microorganisms resided and where mineral deposition was trapped, and by an approximately 2.5 mm thick lower crust where mineral particles were stabilized by organo-mineral structures. SEM/EDX microscopy was used to determine the spatial distribution of elements, organic compounds and minerals were identified using FTIR microscopy and X-ray diffraction (XRD). The concentration of organic carbon in the crust was about twice as much as in the parent material. Depletion of Fe, Al and Mn in the lower crust and in the subjacent 5 mm compared to the geological substrate was observed. This could be interpreted as the initial phase of podzolization. Existence of bridging structures between mineral particles of the lower crust, containing phyllosilicates, Fe compounds and organic matter (OM), may indicate the formation of organo-mineral associations. pH decreased from 8.1 in the original substrate to 5.1 on the crust surface 3 years after construction, pointing to rapid weathering of carbonates. Weathering of silicates could not be detected.

Fischer, T., Veste, M., Schaaf, W., Bens, O., Dümig, A., Kögel-Knabner, I, Wiehe, W.,  Hüttl, R.F., Biogeochemistry 101, 165-176, 2010. (more…)

  • Biological topsoil crusts at early successional stages on Quaternary substrates dumped by mining in Brandenburg, NE Germany

The influence of biological soil crusts in natural ecosystems on structures and processes is well investigated. However, in South-Brandenburg (Germany), it is possible to study the development of biological soil crusts (BSC) during initial ecosystem genesis on two artificial water catchments with well-known ages and under differing starting conditions. The two experimental sites are located in the recultivation area of the lignite open-cast mining district of southern Brandenburg with a distance of approximately 1 km between them. Two different topographies were constructed at the experimental sites: the experimental plot at the catchment Neuer Lugteich was shaped like a dune, whereas the artificial water catchment Hühnerwasser was modelled as an inclined slope. The catchment Neuer Lugteich is four years older than Hühnerwasser. The original substrate at Neuer Lugteich is more sandy and carbonate-free compared to the original substrate dumped at Hühnerwasser. At both sites geomorphological differentiation and crust development were compared and the importance of substrate-dependent water availability and crust type clarified. Once settled, the crusts influenced the water regime of the soils by delaying infiltration through enhanced water repellency, and by limiting water infiltration. Chlorophyll analysis revealed that all crusts were at early stages of development. At Neuer Lugteich, the establishment of the biological soil crusts was closely associated with the vegetation succession, whereas no clear succession of the crusts could be observed at Hühnerwasser. The mosaic-like pattern of the biological soils crusts is associated with the distribution of fine-grained material here.

Spröte, R.,Fischer, T., Veste, M., Raab, T., Wiehe, W., Lange, P., Bens, O., Hüttl, R.F.,Géomorphologie: relief, processus, environnement 4/2010: 359-370. 

  • Overview and first results of ecological monitoring at the artificial watershed Chicken Creek (Germany)

An artificial catchment of 6 ha was established in the Lusatian lignite mining district (Germany). A comprehensive monitoring program was launched immediately after the construction was finished in autumn 2005. The setup of the monitoring and first results of the period 2005–2008 are presented in this paper. From the monitoring measurements it is obvious that the establishing ecosystem is highly dynamic. In addition, important components of the artificially created system are governed by characteristic, often seasonal trends. These observations make clear that the performance of the artificial catchment is generally in agreement with naturally formed watersheds but the system is still in a very initial phase of establishment. Especially, soil properties, hydrological behaviour and vegetation succession illustrate that the development of the system started very close to “point zero”. Even if the construction of the site itself left different initial structures the starting conditions of the catchment can be characterized in general as relatively homogenous in comparison with other close to “point zero” systems. However, new structures emerging at the surface of the site but also in the sub-surface differentiated the system significantly soon after “point zero”.

Gerwin, W., Schaaf, W., Biemelt, D., Winter, S., Fischer, A., Veste, M., Hüttl R.F.,  Physics and Chemistry of the Earth 36: 61-73, 2011. (more…)

  • Soil moisture in an artificial water catchment

The main part of the Chicken Creek catchment is formed by a large water storage body composed of Quaternary sediments. The water storage capacity and water transport characteristics are important regulators of the catchment water balance. Since direct measurements of soil water fluxes are not possible, fluxes have to be calculated from matrix potential and soil moisture measurements in combination with substrate properties using soil water flux models. High temporal resolutions of the measurements allow detection of soil water changes and are important calibration and validation data for these models. Water transport occurs in the pore system of the soil. The relations between the pore size distribution, the resulting matrix forces and the soil water content are characterized by the retention function. Measurements of matrix potential and water contents are therefore necessary to derive this function.

Biemelt, D., Veste, M. In: Schaaf, W., Biemelt, D., Hüttl, R.F. (eds) Initial development of the artificial catchment ‘Chicken Creek’ – monitoring program and survey 2005 - 2008. Ecosystem Development 2, pp. 57-70, 2010. (more…)

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