@article{KahmenSachseArndtetal.2011,
  author    = {Kahmen, Ansgar and Sachse, Dirk and Arndt, Stefan K. and Tu, Kevin P. and Farrington, Heraldo and Vitousek, Peter M. and Dawson, Todd E.},
  title     = {Cellulose delta O-18 is an index of leaf-to-air vapor pressure difference (VPD) in tropical plants},
  series = {Proceedings of the National Academy of Sciences of the United States of America},
  volume    = {108},
  journal   = {Proceedings of the National Academy of Sciences of the United States of America},
  number    = {5},
  publisher = {National Acad. of Sciences},
  address   = {Washington},
  issn      = {0027-8424},
  doi       = {10.1073/pnas.1018906108},
  pages     = {1981 -- 1986},
  year      = {2011},
  abstract  = {Cellulose in plants contains oxygen that derives in most cases from precipitation. Because the stable oxygen isotope composition, delta O-18, of precipitation is associated with environmental conditions, cellulose delta O-18 should be as well. However, plant physiological models using delta O-18 suggest that cellulose delta O-18 is influenced by a complex mix of both climatic and physiological drivers. This influence complicates the interpretation of cellulose delta O-18 values in a paleo-context. Here, we combined empirical data analyses with mechanistic model simulations to i) quantify the impacts that the primary climatic drivers humidity (e(a)) and air temperature (T-air) have on cellulose delta O-18 values in different tropical ecosystems and ii) determine which environmental signal is dominating cellulose delta O-18 values. Our results revealed that e(a) and T-air equally influence cellulose delta O-18 values and that distinguishing which of these factors dominates the delta O-18 values of cellulose cannot be accomplished in the absence of additional environmental information. However, the individual impacts of e(a) and T-air on the delta O-18 values of cellulose can be integrated into a single index of plant-experienced atmospheric vapor demand: the leaf-to-air vapor pressure difference (VPD). We found a robust relationship between VPD and cellulose delta O-18 values in both empirical and modeled data in all ecosystems that we investigated. Our analysis revealed therefore that delta O-18 values in plant cellulose can be used as a proxy for VPD in tropical ecosystems. As VPD is an essential variable that determines the biogeochemical dynamics of ecosystems, our study has applications in ecological-, climate-, or forensic-sciences.},
  language  = {en}
}
@article{LoefflerAnschlagBakeretal.2011,
  author    = {Loeffler, J{\"o}rg and Anschlag, Kerstin and Baker, Barry and Finch, Oliver-D. and Diekkrueger, Bernd and Wundram, Dirk and Schroeder, Boris and Pape, Roland and Lundberg, Anders},
  title     = {Mountain ecosystem response to global change},
  series = {Erdkunde : archive for scientific geography},
  volume    = {65},
  journal   = {Erdkunde : archive for scientific geography},
  number    = {2},
  publisher = {Geographisches Inst., Univ. Bonn},
  address   = {Goch},
  issn      = {0014-0015},
  doi       = {10.3112/erdkunde.2011.02.06},
  pages     = {189 -- 213},
  year      = {2011},
  abstract  = {Mountain ecosystems are commonly regarded as being highly sensitive to global change. Due to the system complexity and multifaceted interacting drivers, however, understanding current responses and predicting future changes in these ecosystems is extremely difficult. We aim to discuss potential effects of global change on mountain ecosystems and give examples of the underlying response mechanisms as they are understood at present. Based on the development of scientific global change research in mountains and its recent structures, we identify future research needs, highlighting the major lack and the importance of integrated studies that implement multi-factor, multi-method, multi-scale, and interdisciplinary research.},
  language  = {en}
}
@article{GeyerKieferKreftetal.2011,
  author    = {Geyer, Juliane and Kiefer, Iris and Kreft, Stefan and Chavez, Veronica and Salafsky, Nick and Jeltsch, Florian and Ibisch, Pierre L.},
  title     = {Classification of climate-change-induced stresses on biological diversity},
  series = {Conservation biology : the journal of the Society for Conservation Biology},
  volume    = {25},
  journal   = {Conservation biology : the journal of the Society for Conservation Biology},
  number    = {4},
  publisher = {Wiley-Blackwell},
  address   = {Malden},
  issn      = {0888-8892},
  doi       = {10.1111/j.1523-1739.2011.01676.x},
  pages     = {708 -- 715},
  year      = {2011},
  abstract  = {Conservation actions need to account for and be adapted to address changes that will occur under global climate change. The identification of stresses on biological diversity (as defined in the Convention on Biological Diversity) is key in the process of adaptive conservation management. We considered any impact of climate change on biological diversity a stress because such an effect represents a change (negative or positive) in key ecological attributes of an ecosystem or parts of it. We applied a systemic approach and a hierarchical framework in a comprehensive classification of stresses to biological diversity that are caused directly by global climate change. Through analyses of 20 conservation sites in 7 countries and a review of the literature, we identified climate-change-induced stresses. We grouped the identified stresses according to 3 levels of biological diversity: stresses that affect individuals and populations, stresses that affect biological communities, and stresses that affect ecosystem structure and function. For each stress category, we differentiated 3 hierarchical levels of stress: stress class (thematic grouping with the coarsest resolution, 8); general stresses (thematic groups of specific stresses, 21); and specific stresses (most detailed definition of stresses, 90). We also compiled an overview of effects of climate change on ecosystem services using the categories of the Millennium Ecosystem Assessment and 2 additional categories. Our classification may be used to identify key climate-change-related stresses to biological diversity and may assist in the development of appropriate conservation strategies. The classification is in list format, but it accounts for relations among climate-change-induced stresses.},
  language  = {en}
}
@article{DeFrenneBrunetShevtsovaetal.2011,
  author    = {De Frenne, Pieter and Brunet, Jorg and Shevtsova, Anna and Kolb, Annette and Graae, Bente J. and Chabrerie, Olivier and Cousins, Sara Ao and Decocq, Guillaume and De Schrijver, An and Diekmann, Martin and Gruwez, Robert and Heinken, Thilo and Hermy, Martin and Nilsson, Christer and Stanton, Sharon and Tack, Wesley and Willaert, Justin and Verheyen, Kris},
  title     = {Temperature effects on forest herbs assessed by warming and transplant experiments along a latitudinal gradient},
  series = {Global change biology},
  volume    = {17},
  journal   = {Global change biology},
  number    = {10},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {1354-1013},
  doi       = {10.1111/j.1365-2486.2011.02449.x},
  pages     = {3240 -- 3253},
  year      = {2011},
  abstract  = {Slow-colonizing forest understorey plants are probably not able to rapidly adjust their distribution range following large-scale climate change. Therefore, the acclimation potential to climate change within their actual occupied habitats will likely be key for their short-and long-term persistence. We combined transplant experiments along a latitudinal gradient with open-top chambers to assess the effects of temperature on phenology, growth and reproductive performance of multiple populations of slow-colonizing understorey plants, using the spring flowering geophytic forb Anemone nemorosa and the early summer flowering grass Milium effusum as study species. In both species, emergence time and start of flowering clearly advanced with increasing temperatures. Vegetative growth (plant height, aboveground biomass) and reproductive success (seed mass, seed germination and germinable seed output) of A. nemorosa benefited from higher temperatures. Climate warming may thus increase future competitive ability and colonization rates of this species. Apart from the effects on phenology, growth and reproductive performance of M. effusum generally decreased when transplanted southwards (e. g., plant size and number of individuals decreased towards the south) and was probably more limited by light availability in the south. Specific leaf area of both species increased when transplanted southwards, but decreased with open-top chamber installation in A. nemorosa. In general, individuals of both species transplanted at the home site performed best, suggesting local adaptation. We conclude that contrasting understorey plants may display divergent plasticity in response to changing temperatures which may alter future understorey community dynamics.},
  language  = {en}
}
@article{WischnewskiKramerKongetal.2011,
  author    = {Wischnewski, Juliane and Kramer, Annette and Kong, Zhaochen and Mackay, Anson W. and Simpson, Gavin L. and Mischke, Steffen and Herzschuh, Ulrike},
  title     = {Terrestrial and aquatic responses to climate change and human impact on the southeastern Tibetan Plateau during the past two centuries},
  series = {Global change biology},
  volume    = {17},
  journal   = {Global change biology},
  number    = {11},
  publisher = {Wiley-Blackwell},
  address   = {Malden},
  issn      = {1354-1013},
  doi       = {10.1111/j.1365-2486.2011.02474.x},
  pages     = {3376 -- 3391},
  year      = {2011},
  abstract  = {Rapid population growth and economic development have led to increased anthropogenic pressures on the Tibetan Plateau, causing significant land cover changes with potentially severe ecological consequences. To assess whether or not these pressures are also affecting the remote montane-boreal lakes on the SE Tibetan Plateau, fossil pollen and diatom data from two lakes were synthesized. The interplay of aquatic and terrestrial ecosystem response was explored in respect to climate variability and human activity over the past 200 years. Nonmetric multidimensional scaling and Procrustes rotation analysis were undertaken to determine whether pollen and diatom responses in each lake were similar and synchronous. Detrended canonical correspondence analysis was used to develop quantitative estimates of compositional species turnover. Despite instrumental evidence of significant climatic warming on the southeastern Plateau, the pollen and diatom records indicate very stable species composition throughout their profiles and show only very subtle responses to environmental changes over the past 200 years. The compositional species turnover (0.36-0.94 SD) is relatively low in comparison to the species reorganizations known from the periods during the mid-and early-Holocene (0.64-1.61 SD) on the SE Plateau, and also in comparison to turnover rates of sediment records from climate-sensitive regions in the circum arctic. Our results indicate that climatically induced ecological thresholds are not yet crossed, but that human activity has an increasing influence, particularly on the terrestrial ecosystem in our study area. Synergistic processes of post-Little Ice Age warming, 20th century climate warming and extensive reforestations since the 19th century have initiated a change from natural oak-pine forests to seminatural, likely less resilient pine-oak forests. Further warming and anthropogenic disturbances would possibly exceed the ecological threshold of these ecosystems and lead to severe ecological consequences.},
  language  = {en}
}
@phdthesis{Wulf2011,
  author    = {Wulf, Hendrik},
  title     = {Seasonal precipitation, river discharge, and sediment flux in the western Himalaya},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-57905},
  school      = {Universit{\"a}t Potsdam},
  year      = {2011},
  abstract  = {Rainfall, snow-, and glacial melt throughout the Himalaya control river discharge, which is vital for maintaining agriculture, drinking water and hydropower generation. However, the spatiotemporal contribution of these discharge components to Himalayan rivers is not well understood, mainly because of the scarcity of ground-based observations. Consequently, there is also little known about the triggers and sources of peak sediment flux events, which account for extensive hydropower reservoir filling and turbine abrasion. We therefore lack basic information on the distribution of water resources and controls of erosion processes. In this thesis, I employ various methods to assess and quantify general characteristics of and links between precipitation, river discharge, and sediment flux in the Sutlej Valley. First, I analyze daily precipitation data (1998-2007) from 80 weather stations in the western Himalaya, to decipher the distribution of rain- and snowfall. Rainfall magnitude frequency analyses indicate that 40\% of the summer rainfall budget is attributed to monsoonal rainstorms, which show higher variability in the orogenic interior than in frontal regions. Combined analysis of rainstorms and sediment flux data of a major Sutlej River tributary indicate that monsoonal rainfall has a first order control on erosion processes in the orogenic interior, despite the dominance of snowfall in this region. Second, I examine the contribution of rainfall, snow and glacial melt to river discharge in the Sutlej Valley (s55,000 km2), based on a distributed hydrological model, which covers the period 2000-2008. To achieve high spatial and daily resolution despite limited ground-based observations the hydrological model is forced by daily remote sensing data, which I adjusted and calibrated with ground station data. The calibration shows that the Tropical Rainfall Measuring Mission (TRMM) 3B42 rainfall product systematically overestimates rainfall in semi-arid and arid regions, increasing with aridity. The model results indicate that snowmelt-derived discharge (74\%) is most important during the pre-monsoon season (April to June) whereas rainfall (56\%) and glacial melt (17\%) dominate the monsoon season (July-September). Therefore, climate change most likely causes a reduction in river discharge during the pre-monsoon season, which especially affects the orogenic interior. Third, I investigate the controls on suspended sediment flux in different parts of the Sutlej catchments, based on daily gauging data from the past decade. In conjunction with meteorological data, earthquake records, and rock strength measurements I find that rainstorms are the most frequent trigger of high-discharge events with peaks in suspended sediment concentrations (SSC) that account for the bulk of the suspended sediment flux. The suspended sediment flux increases downstream, mainly due to increases in runoff. Pronounced erosion along the Himalayan Front occurs throughout the monsoon season, whereas efficient erosion of the orogenic interior is confined to single extreme events. The results of this thesis highlight the importance of snow and glacially derived melt waters in the western Himalaya, where extensive regions receive only limited amounts of monsoonal rainfall. These regions are therefore particularly susceptible to global warming with major implications on the hydrological cycle. However, the sediment discharge data show that infrequent monsoonal rainstorms that pass the orographic barrier of the Higher Himalaya are still the primary trigger of the highest-impact erosion events, despite being subordinate to snow and glacially-derived discharge. These findings may help to predict peak sediment flux events and could underpin the strategic development of preventative measures for hydropower infrastructures.},
  language  = {en}
}
@phdthesis{Zurell2011,
  author    = {Zurell, Damaris},
  title     = {Integrating dynamic and statistical modelling approaches in order to improve predictions for scenarios of environmental change},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-56845},
  school      = {Universit{\"a}t Potsdam},
  year      = {2011},
  abstract  = {Species respond to environmental change by dynamically adjusting their geographical ranges. Robust predictions of these changes are prerequisites to inform dynamic and sustainable conservation strategies. Correlative species distribution models (SDMs) relate species' occurrence records to prevailing environmental factors to describe the environmental niche. They have been widely applied in global change context as they have comparably low data requirements and allow for rapid assessments of potential future species' distributions. However, due to their static nature, transient responses to environmental change are essentially ignored in SDMs. Furthermore, neither dispersal nor demographic processes and biotic interactions are explicitly incorporated. Therefore, it has often been suggested to link statistical and mechanistic modelling approaches in order to make more realistic predictions of species' distributions for scenarios of environmental change. In this thesis, I present two different ways of such linkage. (i) Mechanistic modelling can act as virtual playground for testing statistical models and allows extensive exploration of specific questions. I promote this 'virtual ecologist' approach as a powerful evaluation framework for testing sampling protocols, analyses and modelling tools. Also, I employ such an approach to systematically assess the effects of transient dynamics and ecological properties and processes on the prediction accuracy of SDMs for climate change projections. That way, relevant mechanisms are identified that shape the species' response to altered environmental conditions and which should hence be considered when trying to project species' distribution through time. (ii) I supplement SDM projections of potential future habitat for black grouse in Switzerland with an individual-based population model. By explicitly considering complex interactions between habitat availability and demographic processes, this allows for a more direct assessment of expected population response to environmental change and associated extinction risks. However, predictions were highly variable across simulations emphasising the need for principal evaluation tools like sensitivity analysis to assess uncertainty and robustness in dynamic range predictions. Furthermore, I identify data coverage of the environmental niche as a likely cause for contrasted range predictions between SDM algorithms. SDMs may fail to make reliable predictions for truncated and edge niches, meaning that portions of the niche are not represented in the data or niche edges coincide with data limits. Overall, my thesis contributes to an improved understanding of uncertainty factors in predictions of range dynamics and presents ways how to deal with these. Finally I provide preliminary guidelines for predictive modelling of dynamic species' response to environmental change, identify key challenges for future research and discuss emerging developments.},
  language  = {en}
}
@misc{Hallermeier2011,
  type      = {Master Thesis},
  author    = {Hallermeier, Larissa Diane},
  title     = {K{\"u}sten und Klimawandel in den Augen von Touristen : eine Wahrnehmungsanalyse an der deutschen Ostsee},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-53855},
  school      = {Universit{\"a}t Potsdam},
  year      = {2011},
  abstract  = {Aufgrund seiner wirtschaftlichen Bedeutung spielt der Tourismus in Mecklenburg-Vorpommern eine große Rolle. Insbesondere die K{\"u}stengebiete sind beliebte Reiseziele. In den letzten Jahren konnte ein kontinuierlicher Anstieg der Ank{\"u}nfte und {\"U}bernachtungen verzeichnet werden. Neben anderen Faktoren werden die regionalen Auswirkungen des Klimawandels jedoch in Zukunft eine Herausforderung f{\"u}r den Tourismussektor darstellen. Die globale Erw{\"a}rmung wird f{\"u}r den Strand- und Badetourismus sowohl negative, als auch positive Folgen haben, auf die reagiert werden muss. Neben vorbeugenden Klimaschutzmaßnahmen werden k{\"u}nftig auch Anpassungsstrategien entwickelt werden m{\"u}ssen, die den zu erwartenden Ver{\"a}nderungen Rechnung tragen. Doch zu welchen tourismusrelevanten Ver{\"a}nderungen wird es {\"u}berhaupt kommen und was geschieht bereits aktuell? Sind die Folgen des Klimawandels durch Touristen schon jetzt wahrnehmbar? Wie reagieren die Urlauber auf eventuelle Ver{\"a}nderungen? Diese und andere Fragen soll die vorliegende Arbeit, die innerhalb des RAdOST-Vorhabens (Regionale Anpassungsstrategien f{\"u}r die deutsche Ostseek{\"u}ste) angesiedelt ist, beantworten. Dazu wurde zum einen eine Literaturrecherche zu tourismusrelevanten Klimawandelfolgen an der deutschen Ostseek{\"u}ste durchgef{\"u}hrt. Zum anderen erfolgte in den Sommermonaten 2010 eine Befragung der Strandg{\"a}ste in Markgrafenheide, Warnem{\"u}nde und Nienhagen an der mecklenburgischen Ostseek{\"u}ste. Im Mittelpunkt der Umfrage stand die Wahrnehmung von Erscheinungen (z.B. viele Quallen oder warmes Ostseewasser) sowie kurz- oder langfristigen Ver{\"a}nderungen an der K{\"u}ste (z.B. schmalere Str{\"a}nde, vermehrter Strandanwurf) durch die Urlauber. Außerdem wurden die Einstellung und der Informationsgrad der G{\"a}ste zum Thema Klimawandel an der Ostseek{\"u}ste analysiert. Ziel war es, aus den Umfrageergebnissen Handlungsempfehlungen f{\"u}r das lokale Strandmanagement hinsichtlich k{\"u}nftiger Anpassungsstrategien abzuleiten. Die Literaturrecherche zeigte, dass in einigen Bereichen schon jetzt Ver{\"a}nderungen (z.B. der Luft- und Wassertemperatur oder des Meeresspiegels) nachweisbar sind und laut verschiedener Modellprojektionen von weiteren Ver{\"a}nderungen ausgegangen werden kann. Wie die Umfrage deutlich machte, sind die Ver{\"a}nderungen momentan durch Touristen jedoch kaum oder gar nicht wahrnehmbar. Dementsprechend gering ist auch ihre Reaktion auf die einzelnen Ph{\"a}nomene. Generell ist die Wahrnehmung der Urlauber sehr subjektiv und selektiv. Manche Gegebenheiten wie beispielsweise existierende K{\"u}stenschutzmaßnahmen werden von einem großen Teil der Touristen gar nicht wahrgenommen. Hinsichtlich anderer Erscheinungen wie Strandanwurf und Quallen sind viele Besucher wiederum sehr sensibel. Es zeigte sich außerdem, dass es f{\"u}r die meisten Urlauber schwierig ist, zu beurteilen, ob bestimmte Gegebenheiten am Strand und an der K{\"u}ste mit der globalen Erw{\"a}rmung in Verbindung stehen oder nicht. Es besteht eine große Unsicherheit zu diesem Thema und oft wird der Klimawandel als Ursache f{\"u}r Erscheinungen genannt, auch wenn der kausale Zusammenhang wissenschaftlich nicht nachzuweisen ist. Es zeigte sich, dass die Urlauber sehr wenig {\"u}ber die regionalen Auswirkungen des Klimawandels informiert sind, sich aber Informationen w{\"u}nschen. Folglich sollte zun{\"a}chst die Aufkl{\"a}rung und Information der Urlauber {\"u}ber die Folgen der Ver{\"a}nderung des Klimas im Vordergrund stehen. Denn manche Aspekte, wie der Verlust von Strandabschnitten durch Erosion oder eine eventuelle Zunahme von Blaualgen in der Sommersaison, k{\"o}nnen nicht g{\"a}nzlich vermieden werden. Durch gezielte Aufkl{\"a}rung k{\"o}nnte jedoch beispielsweise eine Akzeptanz f{\"u}r naturnahe Str{\"a}nde oder f{\"u}r den R{\"u}ckzug aus einzelnen Gebieten geschaffen werden. Dar{\"u}ber hinaus sollte die zu erwartende Saisonverl{\"a}ngerung systematisch genutzt werden, um sowohl die K{\"u}ste, als auch das Hinterland durch gezielte Angebote f{\"u}r Touristen attraktiv zu machen. Auf diese Weise k{\"o}nnte eine Entzerrung der Hauptsaison und eine bessere Auslastung der Beherbergungsbetriebe sowie der touristischen Infrastruktur erreicht werden.},
  language  = {de}
}
@phdthesis{Robinson2011,
  author    = {Robinson, Alexander},
  title     = {Modeling the Greenland Ice Sheet response to climate change in the past and future},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-50430},
  school      = {Universit{\"a}t Potsdam},
  year      = {2011},
  abstract  = {The Greenland Ice Sheet (GIS) contains enough water volume to raise global sea level by over 7 meters. It is a relic of past glacial climates that could be strongly affected by a warming world. Several studies have been performed to investigate the sensitivity of the ice sheet to changes in climate, but large uncertainties in its long-term response still exist. In this thesis, a new approach has been developed and applied to modeling the GIS response to climate change. The advantages compared to previous approaches are (i) that it can be applied over a wide range of climatic scenarios (both in the deep past and the future), (ii) that it includes the relevant feedback processes between the climate and the ice sheet and (iii) that it is highly computationally efficient, allowing simulations over very long timescales. The new regional energy-moisture balance model (REMBO) has been developed to model the climate and surface mass balance over Greenland and it represents an improvement compared to conventional approaches in modeling present-day conditions. Furthermore, the evolution of the GIS has been simulated over the last glacial cycle using an ensemble of model versions. The model performance has been validated against field observations of the present-day climate and surface mass balance, as well as paleo information from ice cores. The GIS contribution to sea level rise during the last interglacial is estimated to be between 0.5-4.1 m, consistent with previous estimates. The ensemble of model versions has been constrained to those that are consistent with the data, and a range of valid parameter values has been defined, allowing quantification of the uncertainty and sensitivity of the modeling approach. Using the constrained model ensemble, the sensitivity of the GIS to long-term climate change was investigated. It was found that the GIS exhibits hysteresis behavior (i.e., it is multi-stable under certain conditions), and that a temperature threshold exists above which the ice sheet transitions to an essentially ice-free state. The threshold in the global temperature is estimated to be in the range of 1.3-2.3°C above preindustrial conditions, significantly lower than previously believed. The timescale of total melt scales non-linearly with the overshoot above the temperature threshold, such that a 2°C anomaly causes the ice sheet to melt in ca. 50,000 years, but an anomaly of 6°C will melt the ice sheet in less than 4,000 years. The meltback of the ice sheet was found to become irreversible after a fraction of the ice sheet is already lost - but this level of irreversibility also depends on the temperature anomaly.},
  language  = {en}
}