@misc{FischerVesteBensetal., author = {Fischer, Thomas and Veste, Maik and Bens, Oliver and H{\"u}ttl, Reinhard F.}, title = {Dew formation on the surface of biological soil crusts in central European sand ecosystems}, series = {Biogeosciences}, volume = {9}, journal = {Biogeosciences}, issn = {1726-4189}, doi = {10.5194/bg-9-4621-2012}, pages = {4621 -- 4628}, abstract = {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.}, language = {en} } @misc{SchneiderGerkeMaureretal., author = {Schneider, Anna and Gerke, Horst H. and Maurer, Thomas and Seifert, Stefan and Nenov, Rossen and H{\"u}ttl, Reinhard F.}, title = {Evaluation of remotely-sensed DEMs and modification based on plausibility rules and initial sediment budgets of an artificially-created catchment}, series = {Earth Surface Processes and Landforms}, volume = {37}, journal = {Earth Surface Processes and Landforms}, number = {7}, issn = {1096-9837}, pages = {708 -- 725}, language = {en} } @inproceedings{SproeteVesteFischeretal., author = {Spr{\"o}te, Roland and Veste, Maik and Fischer, Thomas and Raab, Thomas and Bens, Oliver and H{\"u}ttl, Reinhard F.}, title = {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)}, series = {EGU General Assembly 2012, held 22-27 April, 2012 in Vienna}, booktitle = {EGU General Assembly 2012, held 22-27 April, 2012 in Vienna}, publisher = {European Geophysical Society}, address = {Katlenburg-Lindau}, language = {en} } @misc{FischerVesteBensetal., author = {Fischer, Thomas and Veste, Maik and Bens, Oliver and H{\"u}ttl, Reinhard F.}, title = {Dew formation on the surface of biological soil crusts in central European sand ecosystems}, series = {Biogeosciences discussions}, volume = {9}, journal = {Biogeosciences discussions}, doi = {10.5194/bgd-9-8075-2012}, pages = {8075 -- 8092}, abstract = {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.}, language = {en} } @misc{BadorreckGerkeHuettl, author = {Badorreck, Annika and Gerke, Horst H. and H{\"u}ttl, Reinhard F.}, title = {Effects of Ground-Dwelling Beetle Burrows on Infiltration Patterns and Pore Structure of Initial Soil Surfaces}, series = {Vadose Zone Journal}, volume = {11}, journal = {Vadose Zone Journal}, number = {1}, issn = {1539-1663}, language = {en} } @misc{RodionovNiiAnnangBensetal., author = {Rodionov, Andrei and Nii-Annang, Seth and Bens, Oliver and Trimborn, Manfred and Schillem, Steffi and Schneider, Bernd Uwe and Raab, Thomas and H{\"u}ttl, Reinhard F.}, title = {Impacts of Soil Additives on Crop Yield and C-Sequestration in Post Mine Substrates of Lusatia, Germany}, series = {Pedosphere}, volume = {22}, journal = {Pedosphere}, number = {3}, issn = {1002-0160}, pages = {343 -- 350}, language = {en} } @misc{QuinkensteinPapeFreeseetal., author = {Quinkenstein, Ansgar and Pape, Dirk and Freese, Dirk and Schneider, Bernd Uwe and H{\"u}ttl, Reinhard F.}, title = {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)}, series = {International Journal of Forestry Research}, journal = {International Journal of Forestry Research}, pages = {10}, language = {en} } @misc{BoldtBurischSchneiderFritschetal., author = {Boldt-Burisch, Katja and Schneider, Bernd Uwe and Fritsch, Simone and H{\"u}ttl, Reinhard F.}, title = {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}, series = {Canadian journal of soil science}, volume = {92}, journal = {Canadian journal of soil science}, number = {1}, issn = {1918-1841}, pages = {67 -- 76}, language = {en} } @misc{MatosFreeseBoehmetal., author = {Matos, Eduardo da Silva and Freese, Dirk and B{\"o}hm, Christian and Quinkenstein, Ansgar and H{\"u}ttl, Reinhard F.}, title = {Organic Matter Dynamics in Reclaimed Lignite Mine Soils under Robinia pseudoacacia L. Plantations of Different Ages in Germany}, series = {Communications in Soil Science and Plant Analysis}, volume = {43}, journal = {Communications in Soil Science and Plant Analysis}, number = {5}, issn = {1532-2416}, pages = {745 -- 755}, language = {en} } @misc{FischerVesteEiseleetal., author = {Fischer, Thomas and Veste, Maik and Eisele, Andreas and Bens, Oliver and Spyra, Wolfgang and H{\"u}ttl, Reinhard F.}, title = {Small Scale Spatial Heterogeneity of Normalized Difference Vegetation Indices (NDVI) and Hot Spots of Photosynthesis in Biological Soil Crusts}, series = {Flora}, volume = {207}, journal = {Flora}, number = {3}, doi = {10.1016/j.flora.2012.01.001}, pages = {159 -- 167}, abstract = {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.}, language = {en} }