TY - GEN A1 - Fischer, Thomas A1 - Veste, Maik A1 - Bens, Oliver A1 - Hüttl, Reinhard F. T1 - Dew formation on the surface of biological soil crusts in central European sand ecosystems T2 - Biogeosciences N2 - Dew formation was investigated in three developmental stages of biological soil crusts (BSC), which were collected along a catena of an inland dune and in the initial substrate. The Penman equation, which was developed for saturated surfaces, was modified for unsaturated surfaces and used for prediction of dewfall rates. The levels of surface saturation required for this approach were predicted using the water retention functions and the thicknesses of the BSCs. During a first field campaign (2–3 August 2011), dewfall increased from 0.042 kg m−2 for the initial sandy substrate to 0.058, 0.143 and 0.178 kg m−2 for crusts 1 to 3, respectively. During a second field campaign (17–18 August 2011), where dew formation was recorded in 1.5 to 2.75-h intervals after installation at 21:30 CEST, dewfall increased from 0.011 kg m−2 for the initial sandy substrate to 0.013, 0.028 and 0.055 kg m−2 for crusts 1 to 3, respectively. Dewfall rates remained on low levels for the substrate and for crust 1, and decreased overnight for crusts 2 and 3 (with crust 3 > crust 2 > crust 1 throughout the campaign). Dew formation was well reflected by the model response. The suggested mechanism of dew formation involves a delay in water saturation in near-surface soil pores and extracellular polymeric substances (EPS) where the crusts were thicker and where the water capacity was high, resulting in elevated vapor flux towards the surface. The results also indicate that the amount of dewfall was too low to saturate the BSCs and to observe water flow into deeper soil. Analysis of the soil water retention curves revealed that, despite the sandy mineral matrix, moist crusts clogged by swollen EPS pores exhibited a clay-like behavior. It is hypothesized that BSCs gain double benefit from suppressing their competitors by runoff generation and from improving their water supply by dew collection. Despite higher amounts of dew, the water availability to the crust community decreases with crust development, which may be compensated by ecophysiological adaptation of crust organisms, and which may further suppress higher vegetation or mosses. Y1 - 2012 U6 - https://doi.org/10.5194/bg-9-4621-2012 SN - 1726-4189 VL - 9 SP - 4621 EP - 4628 ER - TY - GEN A1 - Schneider, Anna A1 - Gerke, Horst H. A1 - Maurer, Thomas A1 - Seifert, Stefan A1 - Nenov, Rossen A1 - Hüttl, Reinhard F. T1 - Evaluation of remotely-sensed DEMs and modification based on plausibility rules and initial sediment budgets of an artificially-created catchment T2 - Earth Surface Processes and Landforms Y1 - 2012 SN - 1096-9837 VL - 37 IS - 7 SP - 708 EP - 725 ER - TY - CHAP A1 - Spröte, Roland A1 - Veste, Maik A1 - Fischer, Thomas A1 - Raab, Thomas A1 - Bens, Oliver A1 - Hüttl, Reinhard F. T1 - Development of biological soil crusts and their influence on soil hydrology in the recultivation area of lignite open-cast mining district in Lower Lusatia (Germany) T2 - EGU General Assembly 2012, held 22-27 April, 2012 in Vienna Y1 - 2012 N1 - EGU2012-6372 PB - European Geophysical Society CY - Katlenburg-Lindau ER - TY - GEN A1 - Fischer, Thomas A1 - Veste, Maik A1 - Bens, Oliver A1 - Hüttl, Reinhard F. T1 - Dew formation on the surface of biological soil crusts in central European sand ecosystems T2 - Biogeosciences discussions N2 - Dew formation was investigated in three developmental stages of biological soil crusts (BSC), which were collected along a catena of an inland dune and in the initial substrate. The Penman equation, which was developed for saturated surfaces, was modified for unsaturated surfaces and used for prediction of dewfall rates. The levels of surface saturation required for this approach were predicted using the water retention functions and the thicknesses of the BSCs. During a single event, dewfall increased with crust development from 0.08 kg m−2 for the initial substrate to 0.10, 0.20 and 0.25 kg m−2 for crusts stages 1 to 3, respectively, which was well reflected by the model response. The suggested mechanism of dew formation involves a delay in water saturation in near-surface soil pores and EPS where the crusts were thicker and where the water capacity was high, resulting in elevated vapor flux towards the surface. The results also indicate that the amount of dewfall was too low to observe water flow into deeper soil. Analysis of the soil water retention curves revealed that, despite the sandy mineral matrix, moist crusts with clogged by swollen EPS pores exhibited a clay-like behavior. It is hypothesized that BSCs gain double benefit from suppressing their competitors by runoff generation and from improving their water supply by dew collection. Despite higher amounts of dew, the water availability to the crust community decreases with crust development, which may be compensated by ecophysiological adaptation of crust organisms, and which may further suppress higher vegetation or mosses. Y1 - 2012 U6 - https://doi.org/10.5194/bgd-9-8075-2012 VL - 9 SP - 8075 EP - 8092 ER - TY - GEN A1 - Badorreck, Annika A1 - Gerke, Horst H. A1 - Hüttl, Reinhard F. T1 - Effects of Ground-Dwelling Beetle Burrows on Infiltration Patterns and Pore Structure of Initial Soil Surfaces T2 - Vadose Zone Journal Y1 - 2012 SN - 1539-1663 VL - 11 IS - 1 ER - TY - GEN A1 - Rodionov, Andrei A1 - Nii-Annang, Seth A1 - Bens, Oliver A1 - Trimborn, Manfred A1 - Schillem, Steffi A1 - Schneider, Bernd Uwe A1 - Raab, Thomas A1 - Hüttl, Reinhard F. T1 - Impacts of Soil Additives on Crop Yield and C-Sequestration in Post Mine Substrates of Lusatia, Germany T2 - Pedosphere Y1 - 2012 SN - 1002-0160 VL - 22 IS - 3 SP - 343 EP - 350 ER - TY - GEN A1 - Quinkenstein, Ansgar A1 - Pape, Dirk A1 - Freese, Dirk A1 - Schneider, Bernd Uwe A1 - Hüttl, Reinhard F. T1 - Biomass, Carbon and Nitrogen Distribution in Living Woody Plant Parts of Robinia pseudoacacia L. Growing on Reclamation Sites in the Mining Region of Lower Lusatia (Northeast Germany) T2 - International Journal of Forestry Research Y1 - 2012 N1 - Article ID 891798 ER - TY - GEN A1 - Boldt-Burisch, Katja A1 - Schneider, Bernd Uwe A1 - Fritsch, Simone A1 - Hüttl, Reinhard F. T1 - Influence of root growth of two pioneering plant species on soil development during the initial stage of ecosystem genesis in the Lusatian post mining landscape T2 - Canadian journal of soil science Y1 - 2012 SN - 1918-1841 VL - 92 IS - 1 SP - 67 EP - 76 ER - TY - GEN A1 - Matos, Eduardo da Silva A1 - Freese, Dirk A1 - Böhm, Christian A1 - Quinkenstein, Ansgar A1 - Hüttl, Reinhard F. T1 - Organic Matter Dynamics in Reclaimed Lignite Mine Soils under Robinia pseudoacacia L. Plantations of Different Ages in Germany T2 - Communications in Soil Science and Plant Analysis Y1 - 2012 SN - 1532-2416 VL - 43 IS - 5 SP - 745 EP - 755 ER - TY - GEN A1 - Fischer, Thomas A1 - Veste, Maik A1 - Eisele, Andreas A1 - Bens, Oliver A1 - Spyra, Wolfgang A1 - Hüttl, Reinhard F. T1 - Small Scale Spatial Heterogeneity of Normalized Difference Vegetation Indices (NDVI) and Hot Spots of Photosynthesis in Biological Soil Crusts T2 - Flora N2 - Normalized Difference Vegetation Indices (NDVIs) are typically determined using satellite or airborne remote sensing, or field portable spectrometers, which give an averaged signal on centimetre to metre scale plots. Biological soil crust (BSC) patches may have smaller sizes, and ecophysiological, hydrological as well as pedological processes may be heterogeneously distributed within this level of resolution. A ground-based NDVI imaging procedure using low-cost equipment (Olympus Camedia 5000z digital camera equipped with a Hoya R72 infrared filter) was developed in this study to fill this gap at the level of field research, where carrying costly and bulky equipment to remote locations is often the limiting factor for data collection. Method principle and field data are presented, and the field experiment was deepened comparing NDVI measurements and CO2 turnover of soil crust samples in the laboratory, backing the reliability of the approach. A commercially available colour rendition chart with known red (600–700 nm) and NIR (800–900 nm) reflectances was placed into each scene and used for calibration purposes on a per-image basis. Generation of NDVI images involved (i) determination of red and NIR reflectances from the pixel values of the red and NIR channels, respectively, and (ii) calculation and imaging of the NDVI, where NDVI values of −1 to +1 were mapped to grey values of 0 to 255. The correlation between NDVI values retrieved from these images and NDVI values determined using field spectrometry was close (r2 = 0.91), the 95% confidence interval amounted to 0.10 NDVI units. The pixel resolution was 0.8 mm in the field and 0.2 mm in the laboratory, but can still be improved significantly with closer distance to the crust or with higher camera resolution. NDVI values obtained using the new method were related to the net CO2 uptake of BSCs, where both slope and correlation coefficient of the respective regression function conformed with literature data. Geostatistical analysis revealed that both spatial variability of net CO2 uptake as well as size of individual hot spots of this parameter increased with crust development. The latter never exceeded 4 mm in the investigated crusts, which points to the necessity of high resolution imaging for linking remote sensing with ecophysiology. Perspectively, the new method could be used for field monitoring of both biological soil crusts and vascular vegetation. Y1 - 2012 U6 - https://doi.org/10.1016/j.flora.2012.01.001 VL - 207 IS - 3 SP - 159 EP - 167 ER -