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| Titel |
Impact of biocrust succession on water retention and repellency on open-cast lignite mining sites under reclamation in Lower Lusatia, NE-Germany |
| VerfasserIn |
Stella Gypser, Thomas Fischer, Philipp Lange, Maik Veste |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250127172
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| Publikation (Nr.) |
 EGU/EGU2016-7015.pdf |
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| Zusammenfassung |
| Mining activities can strongly affect ecosystem properties by destruction of naturally
developed soils and removal of vegetation. The unstructured substrates show high bulk
densities, compaction, low water infiltration rates, reduced water holding capacities and
higher susceptibility to wind and water erosion. In the initial stage of the ecosystem
development, the post-mining sites are open areas without or with a low cover of higher
vegetation. It is well-known that biocrusts are able to colonize the soil surface under such
extreme conditions without human support and affect soil hydrological processes such as
water infiltration, run-off or re-distribution. Investigations were conducted on two former
lignite open-cast mining sites, an artificial sand dune on the reclaimed watershed
Welzow “Neuer Lugteich” and a reforestation area in Schlabendorf (Brandenburg,
north-east Germany). The aim was to relate the hydrological characteristics of the
topsoil to successional stages of biological soil crusts on reclaimed soils and their
influence on repellency index and water holding capacity compared to pure mining
substrate. Our study emphasized the influence of changing successional stages and
species composition of biological soil crusts, forming a small-scale crust pattern,
on water repellency and retention on sandy soils in temperate climate. Different
successional stages of soil crusts were identified from initial scattered green algae crusts,
dominated by Zygogonium spec. and Ulothrix spec., and more developed soil crusts
containing mosses such as Ceratodon purpureus and Polytrichum piliferum. Lichens of
the Genus Cladonia were more pronouncedly contributed to biocrusts at later and
mature stages of development. The repellency index on the one hand increased due
to the cross-linking of sand particles by the filamentous green algae Zygogonium
spec. which resulted in clogging of pores, and on the other hand decreased with the
occurrence of moss plants due to absorption caused by bryophytes. The determination
of the water retention curves showed an increase of the water holding capacity,
especially in conjunction with the growth of green algae layer. The absorption capacity
of soil crust biota as well as a decreased pore diameter in the green algae layers
positively affected the water retention of crusted soil compared to pure substrate. The
occurrence of bryophytes with later succession weakened the repellent behavior of the
biocrusts, increased infiltration, and might have affected the run-off at small-scale on
biocrusts. Certainly, the biological soil crusts showed water repellent properties
but no distinctive hydrophobic characteristics. On both locations, similar trends
of water repellency and retention related to crustal formation were observed, in
spite of different relief, reclamation time and inhomogeneous distribution of crustal
organisms.
References
Gypser, S., Veste, M., Fischer, T., Lange, P. (2016): Infiltration and water retention of
biological soil crusts on reclaimed soils of former open-cast lignite mining sites in
Brandenburg, north-east Germany, Journal of Hydrology and Hydromechanics, accepted 12.
November 2015.
Gypser, S., Veste, M., Fischer, T., Lange, P. (2015): Formation of soil lichen crusts at
reclaimed post-mining sites, Lower Lusatia, North-east Germany. Graphis Scripta 27: 3-14. |
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