Biological soil crusts in ecosystems: Their Diversity, Ecology, and Management

August 22-25, 2010 Zellingen-Retzbach, Germany

Biological soil crusts in ecosystems: Their Diversity, Ecology, and Management

August 22-25, 2010 Zellingen-Retzbach, Germany

Program

and

Abstracts

Organized by:

Prof. Dr. Burkhard Büdel Dr. Bettina Weber

Department of Plant Ecology and Systematics University of Kaiserslautern

P.O. Box 3049 67653 Kaiserslautern

Germany

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Biological soil crusts on inland dunes in NE Germany: Can we link succession with hydrology?

Thomas Fischer1*, Maik Veste2

1Brandenburg University of Technology Cottbus, Central Analytical Laboratory 2University of Hohenheim, Institute of Botany, Experimental Botany

Biological soil crusts (BSC) were investigated on two inland dunes, one located on a former military training site near Lieberose (~15 km north of Cottbus) and the other located at the post mining site „Neuer Lugteich“ (~15 km south of Cottbus). The BSCs developed in the interspace of sparsely distributed individuals of Corynephorus canescens on silicious, carbonate free, moderately acidic (pH 4.5…7.0) sandy substrate. The mean annual rainfall amounts to 559 mm and the mean annual temperature to 9.3°C. We identified three crust types: On the surface of type 1, dominating sand grains were physically stabilized in their contact zones by accumulated organic matter and by few filamentous cyanobacteria and filamentous green algae. The pore space was dominated by the mineral matrix. On the surface of type 2, filamentous cyanobacteria and algae partially filled in the matrix pores and enmeshed sand grains. In the dry samples, the pore space was dominated by crust organisms but still micropore channels, which are known to promote water infiltration, were left. Type 3 was characterized by intense growth of filamentous and coccoid algae and cyanobacteria, by few bryophytes, which covered less than 5% of the surface and by fungi associated with bryophytes. Crust organisms completely utilized the substrate and clogged the pores between sand particles even in the dry samples. The chlorophyll contents increased from <0.10 µg cm-2 on bare substrate to 1.38, 2.45 and 2.73 µg cm-2 in crust types 1 to 3 at Lieberose and from <0.10 to 0.84, 2.83 and 2.30 µg cm-2 at Neuer Lugteich, respectively (Fischer et al. 2010, Spröte et al. 2010). The crusts were not pronounced water repellent. However, the determination of water repellency indices (Hallet and Young 1999) revealed successive increase of surface unpolarity from substrate to type 1 and to type 2, and decrease of surface unpolarity from type 2 to type 3. At the same time, the water holding capacity increased, and water infiltration rates decreased with crust succession. We conclude that crust development stabilizes the surface and suppresses infiltration of water into deeper soil. We hypothesize that BSCs may influence the settlement of mosses and higher plants and may stabilize as self-contained ecological units when being undisturbed.

Fischer T, Veste M, Wiehe W, Lange P (2010) Water repellency and pore clogging at early successional stages of microbiotic crusts on inland dunes, Brandenburg, NE Germany. Catena 80:47-52

Hallet PD, Young IM (1999) Changes to water repellence of soil aggregates caused by substrate-induced microbial activity. European Journal of Soil Science 50:35-40

Spröte R, Fischer T, Veste M, Raab T, Wiehe W, Lange P, Bens O, Hüttl RF (2010) Development of biological topsoil crusts on Quaternary substrate in artificial initial ecosystems in Brandenburg, NE Germany. Geomorphologie (submitted)

*corresponding author: thomas.fischer@tu-cottbus.de

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