@misc{KleefeldGypserHerppichetal., author = {Kleefeld, Andreas and Gypser, Stella and Herppich, Werner B. and Bader, Georg and Veste, Maik}, title = {Identification of spatial pattern of photosynthesis hotspots in moss- and lichen-dominated biological soil crusts by combining chlorophyll fluorescence imaging and multispectral BNDVI images}, series = {Pedobiologia}, volume = {68}, journal = {Pedobiologia}, issn = {1873-1511}, doi = {10.1016/j.pedobi.2018.04.001}, pages = {1 -- 11}, abstract = {Although biological soil crusts can be found in open landscapes worldwide, their species composition depends on soil properties such as texture and pH, on microclimate, and their respective developmental stage. In addition, local variations in water holding capacity and/or chemical properties of soils influence the formation of spatial patterns and different types of biocrusts on the landscape level. For the evaluation of biocrusts functions and their impact on soil carbon pools, the analysis of the interrelationship between photosynthetic activity and the variations of spatial distribution pattern and types of biocrust is indispensable. For this purpose, an image processing approach was applied that combined chlorophyll fluorescence analyses and multispectral BNDVI to comprehensively characterize the spatial patterns of photosynthetic hotspots in biological soil crusts. For image analysis, five biological soil crust samples with different ratios of substrate, mosses and lichens were collected on an inland dune system in Lieberose, dominated by the moss Polytrichum piliferum, and the lichens Cladonia fimbriata and C. coccifera. RGB-images of the biocrusts were taken with a standard consumer camera Nikon 5200, BNDVI images with a modified Canon S110 NIR camera and chlorophyll fluorescence images with a modular open FluorCAM FC 800-O/1010, respectively. BNDVI and Fv/Fm were nearly in the same range for all biocrust samples related to the total surface area. Although mosses showed higher BNDVI than lichens within the separate biocrust samples. F0 and Fm increased with species coverage and with advancing biocrust development. Overlapping of BNDVI with F0 and Fm images showed that not all crustal organisms contribute to BNDVI and chlorophyll fluorescence. The overlapping areas of BNDVI and F0 ranged between 13\% and 29\%, that of BNDVI and Fm between 17\% and 47\%. Matching of RGB, BNDVI and CFI allows visualizing spatial pattern with high or low photosynthesis in biocrusts.}, language = {en} } @misc{CarlBiberVesteetal., author = {Carl, Christin and Biber, Peter and Veste, Maik and Landgraf, Dirk and Pretzsch, Hans}, title = {Key drivers of competition and growth partitioning among Robinia pseudoacacia L. trees}, series = {Forest Ecology and Management}, volume = {430}, journal = {Forest Ecology and Management}, issn = {0378-1127}, doi = {10.1016/j.foreco.2018.08.002}, pages = {86 -- 93}, abstract = {Competition for above- and below-ground resources depends on their availability and results in varied growth partitioning. This becomes clear as the supply and limitation of the main resources influence the slope of the size-growth relationship in stands. Nevertheless, growth partitioning among trees, especially among black locust (R. pseudoacacia) trees is not understood in sufficient detail. To scrutinize and estimate the mode of competition of R. pseudoacacia, this research analyzed 1333 trees in Germany in 10 study sites, consisting in total 27 sample plots, with similar climate but varying soil conditions. The stand age ranged from 2 to 32 years, with a diameter at breast height ranging from 0.6 to 29.1 cm. The main focus of the study was to evaluate the impact of nitrogen, phosphorus, and water supply on the competition mode of R. pseudoacacia by varying growth partitioning. We applied the size-growth relationship in a mixed-effects model with a random intercept and slope. Fixed effects were the basal area, phosphorus, water, the sunlight competition index, and the interactions between below- and above-ground resources. Site specific effects of the analyzed stands were quantified with the aid of the random effects. Depending on the supply and limitation of phosphorus and water, this study determined how the competition mode as well as the growth partitioning among R. pseudoacacia trees were influenced. Hence, if phosphorus and water availability increased, then the competition for above-ground resources (primarily sunlight) and the slope of the size-growth relationship increased. Large trees grew disproportionately more than smaller trees. If the available phosphorus and water decreased, then the competition for the below-ground resources increased and the slope of the size-growth relationship decreased - to be more flattened. Moreover, it was found that available nitrogen as a below-ground resource had no influence on the mode of competition. In summary, phosphorus was the most important nutrient and, together with water, was the main driver of growth partitioning among R. pseudoacacia trees.}, language = {en} } @misc{FischerVeste, author = {Fischer, Thomas and Veste, Maik}, title = {Carbon cycling of biological soil crusts mirrors ecological maturity along a Central European inland dune catena}, series = {Catena}, volume = {160}, journal = {Catena}, issn = {0341-8162}, doi = {10.1016/j.catena.2017.09.004}, pages = {68 -- 75}, abstract = {Photosynthesis and respiration of biological soil crusts (BSCs) sampled along a mobile inland dune catena were determined to evaluate the applicability of Odum's P/R ratio, determined under controlled conditions, for estimation of ecosystem maturity. The theory is that in the early stages of ecological succession, the total photosynthesis (P) exceeds the rate of community respiration (R), so that the P/R ratio is greater than 1, and that P/R approaches 1 as succession occurs. In the special case of organic pollution, the P/R ratio is typically less than 1. Samples were collected in the deflation zone of the dune near the crest (BSC1, thickness 2-3 mm), at the lee side of grass tussocks at the slope (BSC2, thickness 2-4 mm) and near the base (BSC3, thickness 4-6 mm). Non crusted sand was used as control (BSC0). Photosynthesis, respiration, crust biomass, as well as fossil and allochthonous pedogenic carbon entering the system with mineral substrate were determined. The respiration of the BSC1 was dominated by the degradation of allochthonous organic matter, leading to a diminished P/R ratio. The better developed BSC2 and BSC3 were less influenced by allochthonous organic matter, where BSC maturity increased downslope with biomass increase. No significant relation between the P/R ratio and soil water tension was found. Crust carbon pools increased and flows intensified, but mineralization constants decreased with system maturation. It was concluded that Odum's P/R ratio and accumulation of recalcitrant to biodegradation organic matter are indicative for biocrust maturity.}, language = {en} } @misc{SesermanPohleVesteetal., author = {Seserman, Diana-Maria and Pohle, Ina and Veste, Maik and Freese, Dirk}, title = {Simulating Climate Change Impacts on Hybrid-Poplar and Black Locust Short Rotation Coppices}, series = {Forestry}, volume = {9}, journal = {Forestry}, number = {7}, issn = {1464-3626}, doi = {10.3390/f9070419}, pages = {25}, abstract = {In Brandenburg, north-eastern Germany, climate change is associated with increasing annual temperatures and decreasing summer precipitation. Appraising short rotation coppices (SRCs), given their long-time planning horizon demands for systematic assessments of woody biomass production under a considerable spectrum of climate change prospects. This paper investigates the prospective growth sensitivity of poplar and black locust SRCs, established in Brandenburg to a variety of weather conditions and long-term climate change, from 2015 to 2054, by a combined experimental and simulation study. The analysis employed (i) a biophysical, process-based model to simulate the daily tree growth and (ii) 100 realisations of the statistical regional climate model STAR 2K. In the last growing period, the simulations showed that the assumed climate change could lead to a decrease in the woody biomass of about 5 Mg ha -1 (18\%) for poplar and a decrease of about 1.7 Mg ha -1 (11\%) for black locust trees with respect to the median observed in the reference period. The findings corroborate the potential tree growth vulnerability to prospective climatic changes, particularly to changes in water availability and underline the importance of coping management strategies in SRCs for forthcoming risk assessments and adaptation scenarios.}, language = {en} } @misc{MatosFreeseSlazaketal., author = {Matos, Eduardo da Silva and Freese, Dirk and Slazak, Anna and Bachmann, Ute and Veste, Maik and H{\"u}ttl, Reinhard F.}, title = {Organic-carbon and nitrogen stocks and organic-carbon fractions in soils under mixed pine and oak forest stands of different ages in NE Germany}, series = {Journal of plant nutrition and soil science}, volume = {173}, journal = {Journal of plant nutrition and soil science}, number = {5}, issn = {1522-2624}, pages = {654 -- 661}, 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} } @misc{FischerVesteSchaafetal., author = {Fischer, Thomas and Veste, Maik and Schaaf, Wolfgang and D{\"u}mig, Alexander and K{\"o}gel-Knabner, Ingrid and Wiehe, Wolfgang and Bens, Oliver and H{\"u}ttl, Reinhard F.}, title = {Initial pedogenesis in a topsoil crust 3 years after construction of an artificial water catchment in Brandenburg, NE Germany}, series = {Biogeochemistry}, volume = {101}, journal = {Biogeochemistry}, number = {1-3}, issn = {1573-515X}, doi = {10.1007/s10533-010-9464-z}, pages = {165 -- 176}, abstract = {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.}, language = {en} } @misc{VesteHalkeGarbeetal., author = {Veste, Maik and Halke, Christian and Garbe, Daniel and Freese, Dirk}, title = {Einfluss von Stickstoffd{\"u}ngung und Kompost auf Photosynthese und Wachstum der Virginiamalve (Sida hermaphrodita Rusby)}, series = {Journal f{\"u}r Kulturpflanzen}, volume = {68}, journal = {Journal f{\"u}r Kulturpflanzen}, number = {12}, issn = {1867-0911}, doi = {10.1399/JFK.2016.12.13}, pages = {423 -- 428}, abstract = {Als mehrj{\"a}hrige Bioenergiepflanze kann Sida hermaphrodita eine wichtige Rolle f{\"u}r den Anbau auf marginalen Standorten in der nahen Zukunft spielen. In einem kontrollierten Topfexperiment wurde der Einfluss von verschiedenen Kompostgehalten (10, 20, 30, 50\%) und mineralischem Stickstoffd{\"u}nger (100 kg N ha-1) auf Biomasse, Wuchsh{\"o}he und Kohlenstoffallokation w{\"a}hrend der Etablierungsphase untersucht. Weiterhin wurden {\"o}kophysiologische Parameter (Gaswechsel, Chlorophyllfluoreszenz, Chlorophyllgehalte) mit nicht-destruktiven Methoden bestimmt. Die Ergebnisse des Experimentes zeigen, dass sowohl die Stickstoffd{\"u}ngung als auch die Kompostgabe positive Effekte f{\"u}r das Wachstumsverhalten hat. W{\"a}hrend der Etablierungsphase erreichten die ged{\"u}ngten Pflanzen eine mittlere Pflanzenh{\"o}he von bis zu 127 cm (maximale Wuchsh{\"o}he 168 cm). Die Photosynthese wurde nicht durch die unterschiedlichen Behandlungen beeinflusst. Die mittlere CO2-Austauschrate variiert zwischen 5,8 und 9,9 μmol m-2 s-1 und die Elektronentransportrate zwischen 34,5 und 53,9 μmol m-2 s-1. Die Verwendung von Kompost und Stickstoff ist f{\"u}r eine bessere Biomasseproduktion von Sida in marginalen B{\"o}den m{\"o}glich, auch wenn das Wachstum im ersten Jahr limitiert ist und es negative R{\"u}ckwirkungen auf die Bestandesetablierung gibt.}, language = {de} } @misc{VesteKriebitzsch, author = {Veste, Maik and Kriebitzsch, Wolf-Ulrich}, title = {Photosyntheseverhalten der Stechpalme (Ilex aquifolium L.) in milden Winter in Mitteleuropa: Ein {\"o}kophysiologischer Vorteil durch den Klimawandel?}, series = {Allgemeine Forst- und Jagd-Zeitung}, volume = {189}, journal = {Allgemeine Forst- und Jagd-Zeitung}, number = {7/8}, issn = {0002-5852}, pages = {143 -- 153}, abstract = {Die Wintertemperaturen und insbesondere Frost sind wichtige Umweltfaktoren, die das Verbreitungsgebiet der Stechpalme (Ilex aquifolium L.) Mitteleuropa beschr{\"a}nken. Bereits heute profitiert diese Art von dem Klimawandel durch eine erweiterte Verbreitung in Mitteleuropa und an seiner n{\"o}rdlichen Verbreitungsgrenze in Skandinavien. In dieser Arbeit wird die Bedeutung der milder werdenden Wintertemperaturen f{\"u}r den Stoffwechsel von I. aquifolium untersucht, insbesondere die Akklimatisation der Photosynthese w{\"a}hrend des Winters. Daf{\"u}r wurde die Photosynthese mit der Chlorophyllfluoreszenz-Methode gemessen. W{\"a}hrend milder Wintertage bei Temperaturen wenig unter 0°C erholte sich die Photosynthese innerhalb von zwei Stunden, sobald die Pflanzen Raumtemperatur ausgesetzt wurden. Dagegen war die Photosynthese nach langanhaltenden Frostperioden und die gemessenen Elektronentransportraten der im Freiland wachsenden Ilex-B{\"a}ume um bis zu 50\% niedriger als bei den Vergleichspflanzen im Gew{\"a}chshaus. Somit wird die Photosynthese im Winter von der minimalen Temperatur und der Frostdauer beeinflusst. In der Regel war die immergr{\"u}ne Stechpalme in der Lage ihre Photosynthese im Winter aufrecht zu erhalten und flexibel auf frostfreie Tage zu reagieren. Damit profitiert die Stechpalme w{\"a}hrend milder Tage im Winter und Fr{\"u}hjahr von dem im Vergleich zu den Sommermonaten hohem Lichtgenuss im Unterwuchs, wenn die sommergr{\"u}nen B{\"a}ume in der Baumschicht unbelaubt sind.}, language = {de} } @misc{Veste, author = {Veste, Maik}, title = {Bioenergie aus W{\"u}stenpflanzen}, series = {Naturwissenschaftliche Rundschau}, volume = {67}, journal = {Naturwissenschaftliche Rundschau}, number = {2}, issn = {0028-1050}, pages = {80 -- 81}, language = {de} }