TY - INPR A1 - Wellstein, Camilla A1 - Schröder-Esselbach, Boris A1 - Reineking, Bjoern A1 - Zimmermann, Niklaus E. T1 - Understanding species and community response to environmental change - A functional trait perspective T2 - Agriculture, ecosystems & environment : an international journal for scientific research on the relationship of agriculture and food production to the biosphere KW - Functional traits KW - Functional diversity KW - Database KW - Land use KW - Management KW - Climate change KW - Landscape KW - Ecosystem function KW - Clonal plants KW - Dispersal KW - Plant growth KW - Orthoptera Y1 - 2011 U6 - https://doi.org/10.1016/j.agee.2011.06.024 SN - 0167-8809 VL - 145 IS - 1 SP - 1 EP - 4 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Veh, Georg A1 - Korup, Oliver A1 - von Specht, Sebastian A1 - Rößner, Sigrid A1 - Walz, Ariane T1 - Unchanged frequency of moraine-dammed glacial lake outburst floods in the Himalaya JF - Nature climate change N2 - Shrinking glaciers in the Hindu Kush-Karakoram-Himalaya-Nyainqentanglha (HKKHN) region have formed several thousand moraine-dammed glacial lakes(1-3), some of these having grown rapidly in past decades(3,4). This growth may promote more frequent and potentially destructive glacial lake outburst floods (GLOFs)(5-7). Testing this hypothesis, however, is confounded by incomplete databases of the few reliable, though selective, case studies. Here we present a consistent Himalayan GLOF inventory derived automatically from all available Landsat imagery since the late 1980s. We more than double the known GLOF count and identify the southern Himalayas as a hotspot region, compared to the more rarely affected Hindu Kush-Karakoram ranges. Nevertheless, the average annual frequency of 1.3 GLOFs has no credible posterior trend despite reported increases in glacial lake areas in most of the HKKHN3,8, so that GLOF activity per unit lake area has decreased since the late 1980s. We conclude that learning more about the frequency and magnitude of outburst triggers, rather than focusing solely on rapidly growing glacial lakes, might improve the appraisal of GLOF hazards. KW - Climate change KW - Cryospheric science KW - Environmental impact KW - Geomorphology Y1 - 2019 U6 - https://doi.org/10.1038/s41558-019-0437-5 SN - 1758-678X SN - 1758-6798 VL - 9 IS - 5 SP - 379 EP - 383 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Norris, Jesse A1 - Carvalho, Leila M. V. A1 - Jones, Charles A1 - Cannon, Forest A1 - Bookhagen, Bodo A1 - Palazzi, Elisa A1 - Tahir, Adnan Ahmad T1 - The spatiotemporal variability of precipitation over the Himalaya: evaluation of one-year WRF model simulation JF - Climate dynamics : observational, theoretical and computational research on the climate system N2 - The Weather Research and Forecasting (WRF) model is used to simulate the spatiotemporal distribution of precipitation over central Asia over the year April 2005 through March 2006. Experiments are performed at 6.7 km horizontal grid spacing, with an emphasis on winter and summer precipitation over the Himalaya. The model and the Tropical Rainfall Measuring Mission show a similar inter-seasonal cycle of precipitation, from extratropical cyclones to monsoon precipitation, with agreement also in the diurnal cycle of monsoon precipitation. In winter months, WRF compares better in timeseries of daily precipitation to stations below than above 3-km elevation, likely due to inferior measurement of snow than rain by the stations, highlighting the need for reliable snowfall measurements at high elevations in winter. In summer months, the nocturnal precipitation cycle in the foothills and valleys of the Himalaya is captured by this 6.7-km WRF simulation, while coarser simulations with convective parameterization show near zero nocturnal precipitation. In winter months, higher resolution is less important, serving only to slightly increase precipitation magnitudes due to steeper slopes. However, even in the 6.7-km simulation, afternoon precipitation is overestimated at high elevations, which can be reduced by even higher-resolution (2.2-km) simulations. These results indicate that WRF provides skillful simulations of precipitation relevant for studies of water resources over the complex terrain in the Himalaya. KW - WRF KW - Himalayas KW - Mesoscale KW - Precipitation KW - Climate change KW - Orographicprecipitation KW - Water resources Y1 - 2017 U6 - https://doi.org/10.1007/s00382-016-3414-y SN - 0930-7575 SN - 1432-0894 VL - 49 SP - 2179 EP - 2204 PB - Springer CY - New York ER - TY - JOUR A1 - Yair, Aaron A1 - Bryan, Rorke B. A1 - Lavee, Hanoch A1 - Schwanghart, Wolfgang A1 - Kuhn, Nikolaus J. T1 - The resilience of a badland area to climate change in an arid environment JF - Catena : an interdisciplinary journal of soil science, hydrology, geomorphology focusing on geoecology and landscape evolution N2 - Badlands have long been considered as model landscapes due to their perceived close relationship between form and process. The often intense features of erosion have also attracted many geomorphologists because the associated high rates of erosion appeared to offer the opportunity for studying surface processes and the resulting forms. Recently, the perceived simplicity of badlands has been questioned because the expected relationships between driving forces for erosion and the resulting sediment yield could not be observed. Further, a high variability in erosion and sediment yield has been observed across scales. Finally, denudation based on currently observed erosion rates would have lead to the destruction of most badlands a long time ago. While the perceived simplicity of badlands has sparked a disproportional (compared to the land surface they cover) amount of research, our increasing amount of information has not necessarily increased our understanding of badlands in equal terms. Overall, badlands appear to be more complex than initially assumed. In this paper, we review 40 years of research in the Zin Valley Badlands in Israel to reconcile some of the conflicting results observed there and develop a perspective on the function of badlands as model landscapes. While the data collected in the Zin Valley clearly confirm that spatial and temporal patterns of geomorphic processes and their interaction with topography and surface properties have to be understood, we still conclude that the process of realizing complexity in the "simple" badlands has a model function both for our understanding as well as perspective on all landscape systems. KW - Badlands KW - Model landscape KW - Climate change KW - Resilience Y1 - 2013 U6 - https://doi.org/10.1016/j.catena.2012.04.006 SN - 0341-8162 VL - 106 IS - 4 SP - 12 EP - 21 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Wiesmeier, Martin A1 - Prietzel, Jörg A1 - Barthold, Frauke Katrin A1 - Spörlein, Peter A1 - Geuss, Uwe A1 - Hangen, Edzard A1 - Reischl, Arthur A1 - Schilling, Bernd A1 - von Lützow, Margit A1 - Kögel-Knabner, Ingrid T1 - Storage and drivers of organic carbon in forest soils of southeast Germany (Bavaria) - Implications for carbon sequestration JF - Forest ecology and management N2 - Temperate forest soils of central Europe are regarded as important pools for soil organic carbon (SOC) and thought to have a high potential for carbon (C) sequestration. However, comprehensive data on total SOC storage, particularly under different forest types, and its drivers is limited. In this study, we analyzed a forest data set of 596 completely sampled soil profiles down to the parent material or to a depth of 1 m within Bavaria in southeast Germany in order to determine representative SOC stocks under different forest types in central Europe and the impact of different environmental parameters. We calculated a total median SOC stock of 9.8 kg m(-2) which is considerably lower compared with many other inventories within central Europe that used modelled instead of measured soil properties. Statistical analyses revealed climate as controlling parameter for the storage of SOC with increasing stocks in cool, humid mountainous regions and a strong decrease in areas with higher temperatures. No significant differences of total SOC storage were found between broadleaf, coniferous and mixed forests. However, coniferous forests stored around 35% of total SOC in the labile organic layer that is prone to human disturbance, forest fires and rising temperatures. In contrast, mixed and broadleaf forests stored the major part of SOC in the mineral soil. Moreover, these two forest types showed unchanged or even slightly increased mineral SOC stocks with higher temperatures, whereas SOC stocks in mineral soils under coniferous forest were distinctly lower. We conclude that mixed and broadleaf forests are more advantageous for C sequestration than coniferous forests. An intensified incorporation of broadleaf species in extent coniferous forests of Bavaria would prevent substantial SOC losses as a result of rising temperatures in the course of climate change. KW - Tree species effect KW - Soil organic matter KW - Climate change KW - Forest management Y1 - 2013 U6 - https://doi.org/10.1016/j.foreco.2013.01.025 SN - 0378-1127 VL - 295 IS - 10 SP - 162 EP - 172 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Wischnewski, Juliane A1 - Herzschuh, Ulrike A1 - Ruehland, Kathleen M. A1 - Braeuning, Achim A1 - Mischke, Steffen A1 - Smol, John P. A1 - Wang, Lily T1 - Recent ecological responses to climate variability and human impacts in the Nianbaoyeze Mountains (eastern Tibetan Plateau) inferred from pollen, diatom and tree-ring data JF - Journal of paleolimnolog N2 - The Tibetan Plateau is a region that is highly sensitive to recent global warming, but the complexity and heterogeneity of its mountainous landscape can result in variable responses. In addition, the scarcity and brevity of regional instrumental and palaeoecological records still hamper our understanding of past and present patterns of environmental change. To investigate how the remote, high-alpine environments of the Nianbaoyeze Mountains, eastern Tibetan Plateau, are affected by climate change and human activity over the last similar to 600 years, we compared regional tree-ring studies with pollen and diatom remains archived in the dated sediments of Dongerwuka Lake (33.22A degrees N, 101.12A degrees E, 4,307 m a.s.l.). In agreement with previous studies from the eastern Tibetan Plateau, a strong coherence between our two juniper-based tree-ring chronologies from the Nianbaoyeze and the Anemaqin Mountains was observed, with pronounced cyclical variations in summer temperature reconstructions. A positive directional trend to warmer summer temperatures in the most recent decades, was, however, not observed in the tree-ring record. Likewise, our pollen and diatom spectra showed minimal change over the investigated time period. Although modest, the most notable change in the diatom relative abundances was a subtle decrease in the dominant planktonic Cyclotella ocellata and a concurrent increase in small, benthic fragilarioid taxa in the similar to 1820s, suggesting higher ecosystem variability. The pollen record subtly indicates three periods of increased cattle grazing activity (similar to 1400-1480 AD, similar to 1630-1760 AD, after 1850 AD), but shows generally no significant vegetation changes during past similar to 600 years. The minimal changes observed in the tree-ring, diatom and pollen records are consistent with the presence of localised cooling centres that are evident in instrumental and tree-ring data within the southeastern and eastern Tibetan Plateau. Given the minor changes in regional temperature records, our complacent palaeoecological profiles suggest that climatically induced ecological thresholds have not yet been crossed in the Nianbaoyeze Mountains region. KW - Tibetan Plateau KW - Nianbaoyeze Mountains KW - Pollen KW - Diatoms KW - Tree-ring KW - Climate change KW - Human impact Y1 - 2014 U6 - https://doi.org/10.1007/s10933-013-9747-1 SN - 0921-2728 SN - 1573-0417 VL - 51 IS - 2 SP - 287 EP - 302 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Sommer, Robert S. A1 - Kalbe, Johannes A1 - Ekstrom, Jonas A1 - Benecke, Norbert A1 - Liljegren, Ronnie T1 - Range dynamics of the reindeer in Europe during the last 25,000 years JF - Journal of biogeography N2 - Aim To understand the role and significance of the reindeer, Rangifer tarandus (Linnaeus, 1758), as a specific indicator in terms of late Quaternary biogeography and to determine the effects of global climate change on its range and local extinction dynamics at the end of the Ice Age. Location Late Pleistocene/early Holocene range of reindeer over all of central and western Europe, including southern Scandinavia and northern Iberia, but excluding Russia, Belarus and the Ukraine. Methods Radiocarbon-dated subfossil records of R. tarandus from both archaeological and natural deposits younger than 25,000 years were assembled in a database. The distribution area was divided into six representative regions. The C-14 dates were calibrated and plotted chronologically in maps in order to compare presence and absence and regional extinction patterns from one region to another. Main conclusions The late Quaternary record for reindeer in Europe during the last 25 kyr shows a climate-driven dispersal and retreat in response to climate change, with regional variations. The collapse of the mammoth steppe biome did not lead to the local extinction in Europe, as in the case of other megafaunal species. Rangifer tarandus co-existed for about 3000 years during the Late Glacial and early Holocene with typical temperate species such as red deer and roe deer in non-analogue faunal communities. The regional extinction at the end of the Pleistocene coincides with the transition from light open birch/pine forests to pine/deciduous forests. KW - Climate change KW - environmental change KW - extinction KW - global change KW - late Quaternary KW - Pleistocene/Holocene transition KW - Rangifer tarandus KW - reindeer Y1 - 2014 U6 - https://doi.org/10.1111/jbi.12193 SN - 0305-0270 SN - 1365-2699 VL - 41 IS - 2 SP - 298 EP - 306 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Wischnewski, Juliane A1 - Mackay, Anson W. A1 - Appleby, Peter G. A1 - Mischke, Steffen A1 - Herzschuh, Ulrike T1 - Modest diatom responses to regional warming on the southeast Tibetan Plateau during the last two centuries JF - Journal of paleolimnolog N2 - A general mean annual temperature increase accompanied with substantial glacial retreat has been noted on the Tibetan Plateau during the last two centuries but most significantly since the mid 1950s. These climate trends are particularly apparent on the southeastern Tibetan Plateau. However, the Tibetan Plateau (due to its heterogeneous mountain landscape) has very complex and spatially differing temperature and precipitations patterns. As a result, intensive palaeolimnological investigations are necessary to decipher these climatic patterns and to understand ecological responses to recent environmental change. Here we present palaeolimnological results from a (210)Pb/(137)Cs-dated sediment core spanning approximately the last 200 years from a remote high-mountain lake (LC6 Lake, working name) on the southeastern Tibetan Plateau. Sediment profiles of diatoms, organic variables (TOC, C:N) and grain size were investigated. The (210)Pb record suggests a period of rapid sedimentation, which might be linked to major tectonic events in the region ca. 1950. Furthermore, unusually high (210)Pb supply rates over the last 50 years suggest that the lake has possibly been subjected to increasing precipitation rates, sediment focussing and/or increased spring thaw. The majority of diatom taxa encountered in the core are typical of slightly acidic to circumneutral, oligotrophic, electrolyte-poor lakes. Diatom species assemblages were rich, and dominated by Cyclotella sp., Achnanthes sp., Aulacoseira sp. and fragilarioid taxa. Diatom compositional change was minimal over the 200-year period (DCCA = 0.85 SD, p = 0.59); only a slightly more diverse but unstable diatom assemblage was recorded during the past 50 years. The results indicate that large-scale environmental changes recorded in the twentieth century (i.e. increased precipitation and temperatures) are likely having an affect on the LC6 Lake, but so far these impacts are more apparent on the lake geochemistry than on the diatom flora. Local and/or regional peculiarities, such as increasing precipitation and cloud cover, or localized climatic phenomena, such as negative climate feedbacks, might have offset the effects of increasing mean surface temperatures. KW - Diatoms KW - Tibetan Plateau KW - Mountain lake KW - Climate change KW - Lake sediments KW - Palaeolimnology Y1 - 2011 U6 - https://doi.org/10.1007/s10933-011-9533-x SN - 0921-2728 VL - 46 IS - 2 SP - 215 EP - 227 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Fer, Istem A1 - Tietjen, Britta A1 - Jeltsch, Florian A1 - Trauth, Martin H. T1 - Modelling vegetation change during Late Cenozoic uplift of the East African plateaus JF - Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences N2 - The present-day vegetation in the tropics is mainly characterized by forests worldwide except in tropical East Africa, where forests only occur as patches at the coast and in the uplands. These forest patches result from the peculiar aridity that is linked to the uplift of the region during the Late Cenozoic. The Late Cenozoic vegetation history of East Africa is of particular interest as it has set the scene for the contemporary events in mammal and hominin evolution. In this study, we investigate the conditions under which these forest patches could have been connected, and a previous continuous forest belt could have extended and fragmented. We apply a dynamic vegetation model with a set of climatic scenarios in which we systematically alter the present-day environmental conditions such that they would be more favourable for a continuous forest belt in tropical East Africa. We consider varying environmental factors, namely temperature, precipitation and atmospheric CO2 concentrations. Our results show that all of these variables play a significant role in supporting the forest biomes and a continuous forest belt could have occurred under certain combinations of these settings. With our current knowledge of the palaeoenvironmental history of East Africa, it is likely that the region hosted these conditions during the Late Cenozoic. Recent improvements on environmental hypotheses of hominin evolution highlight the role of periods of short and extreme climate variability during the Late Cenozoic specific to East Africa in driving evolution. Our results elucidate how the forest biomes of East Africa can appear and disappear under fluctuating environmental conditions and demonstrate how this climate variability might be recognized on the biosphere level. KW - Dynamic vegetation models KW - Palaeovegetation KW - Evolution KW - Late Cenozoic KW - East Africa KW - Climate change Y1 - 2016 U6 - https://doi.org/10.1016/j.palaeo.2016.04.007 SN - 0031-0182 SN - 1872-616X VL - 467 SP - 120 EP - 130 PB - Elsevier CY - Amsterdam ER - TY - THES A1 - Huang, Shaochun T1 - Modelling of environmental change impacts on water resources and hydrological extremes in Germany T1 - Modellierung der Auswirkungen von Umweltveränderungen auf Wasserressourcen und Extremereignisse in Deutschland N2 - Water resources, in terms of quantity and quality, are significantly influenced by environmental changes, especially by climate and land use changes. The main objective of the present study is to project climate change impacts on the seasonal dynamics of water fluxes, spatial changes in water balance components as well as the future flood and low flow conditions in Germany. This study is based on the modeling results of the process-based eco-hydrological model SWIM (Soil and Water Integrated Model) driven by various regional climate scenarios on one hand. On the other hand, it is supported by statistical analysis on long-term trends of observed and simulated time series. In addition, this study evaluates the impacts of potential land use changes on water quality in terms of NO3-N load in selected sub-regions of the Elbe basin. In the context of climate change, the actual evapotransipration is likely to increase in most parts of Germany, while total runoff generation may decrease in south and east regions in the scenario period 2051-2060. Water discharge in all six studied large rivers (Ems, Weser, Saale, Danube, Main and Neckar) would be 8 – 30% lower in summer and autumn compared to the reference period (1961 – 1990), and the strongest decline is expected for the Saale, Danube and Neckar. The 50-year low flow is likely to occur more frequently in western, southern and central Germany after 2061 as suggested by more than 80% of the model runs. The current low flow period (from August to September) may be extended until the late autumn at the end of this century. Higher winter flow is expected in all of these rivers, and the increase is most significant for the Ems (about 18%). No general pattern of changes in flood directions can be concluded according to the results driven by different RCMs, emission scenarios and multi-realizations. An optimal agricultural land use and management are essential for the reduction in nutrient loads and improvement of water quality. In the Weiße Elster and Unstrut sub-basins (Elbe), an increase of 10% in the winter rape area can result in 12-19% more NO3-N load in rivers. In contrast, another energy plant, maize, has a moderate effect on the water environment. Mineral fertilizers have a much stronger effect on the NO3-N load than organic fertilizers. Cover crops, which play an important role in the reduction of nitrate losses from fields, should be maintained on cropland. The uncertainty in estimating future high flows and, in particular, extreme floods remain high due to different RCM structures, emission scenarios and multi-realizations. In contrast, the projection of low flows under warmer climate conditions appears to be more pronounced and consistent. The largest source of uncertainty related to NO3-N modelling originates from the input data on the agricultural management. N2 - Wasserressourcen werden in Quantität und Qualität von Veränderungen in der Umwelt, insbesondere von Änderungen des Klimas und der Landnutzung, in signifikantem Maße beeinflusst. In dieser Arbeit wurden die Auswirkungen von Klimavariabilität und Klimawandel auf die Wasserressourcen und Extremereignisse wie Hoch- und Niedrigwasser in Deutschland untersucht. Die Analyse erfolgte auf der einen Seite modellgestützt, wobei die Ergebnisse aus verschiedenen regionalen Klimamodellen durch ein ökohydrologisches Modell in Änderungen in den hydrologischen Prozessen transformiert wurden, zum anderen aber auch datengestützt, z.B. durch die statistische Interpretation von beobachteten und simulierten Zeitreihen. Zusätzlich wurden die Auswirkungen von Landnutzungsänderungen auf Umsatz von Stickstoff in der Landschaft und im Wasser untersucht, wobei dasselbe ökohydrologische Modell zum Einsatz kam. Im Rahmen des Klimawandels wird zur Mitte dieses Jahrhunderts die aktuelle Evapotranspiration in den meisten Teilen Deutschlands mit großer Wahrscheinlichkeit zunehmen. Die täglichen Abflussmengen der fünf größten Flussgebiete in Deutschland (Ems, Weser, Elbe, Obere Donau und Rhein) werden dieser Untersuchung zur Folge im Sommer und Herbst um 8%-30% geringer sein als in der Referenzperiode (1961-1990). 80% der Szenariensimulationen stimmen darin überein, dass die 50-jährigen Niedrigwasserereignisse zum Ende dieses Jahrhunderts mit großer Wahrscheinlichkeit häufiger in den westlichen, den südlichen und den zentralen Teilen Deutschlands auftreten werden. Die gegenwärtige Niedrigwasserperiode (August-September) könnte sich zudem dann bis in den späten Herbst ausweiten. Für alle Flüsse werden höhere Winterabflüsse erwartet, wobei diese Zunahme für die Ems am stärksten ausfällt (ca. 18%). Mit größerer Unsicherheit sind dagegen die Aussagen zur Entwicklung der Hochwasser behaftet. Aus den Ergebnissen, die durch unterschiedliche regionale Klimamodelle und Szenarien getrieben wurden, kann jedoch kein allgemeingültiges Muster für die Änderungen der 50-jährigen Hochwässer ausgemacht werden. Eine optimierte Landnutzung und ein optimiertes Landmanagement sind für die Reduzierung der NO3-Einträge in die Oberflächengewässer essentiell. In den Einzusgebieten der Weißen Elster und der Unstrut (Elbe) kann eine Zunahme von 10% in der Anbaufläche von Winterraps zu einer 12-19% höheren NO3 Fracht führen. Mais, eine weitere Energiepflanze, hat hingegen einen mäßigeren Effekt auf die Oberflächengewässer. Die Höhe der Gabe von mineralischen Düngern beeinflußt zudem in starkem Maße die Nitratbelastung von Flüssen. Zwischenfrüchte können den NO3-Austrag im Sommer zusätzlich erheblich verringern. Insgesamt bleibt die Unsicherheit in der Vorhersage von Spitzenabflüssen und im Besonderen von Extrem-Hochwässern als Folge unterschiedlicher regionaler Klimamodelle, Emissionsszenarien und Realisationen sehr hoch. Im Gegensatz dazu erscheinen die Projektionen zu den Niedrigwasserereignissen unter wärmeren Bedingungen sehr viel deutlicher und einheitlicher. Die größte Unsicherheit in der Modellierung von NO3 dagegen sind die Eingangsdaten z.B. für das lokale landwirtschaftliche Management. KW - Climate change KW - Land use change KW - Water resources KW - Hydrological extremes KW - Germany Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-59748 ER -