@article{MarkovicCarrizoKaercheretal.2017, author = {Markovic, Danijela and Carrizo, Savrina F. and Kaercher, Oskar and Walz, Ariane and David, Jonathan N. W.}, title = {Vulnerability of European freshwater catchments to climate change}, series = {Global change biology}, volume = {23}, journal = {Global change biology}, publisher = {Wiley}, address = {Hoboken}, issn = {1354-1013}, doi = {10.1111/gcb.13657}, pages = {3567 -- 3580}, year = {2017}, abstract = {Climate change is expected to exacerbate the current threats to freshwater ecosystems, yet multifaceted studies on the potential impacts of climate change on freshwater biodiversity at scales that inform management planning are lacking. The aim of this study was to fill this void through the development of a novel framework for assessing climate change vulnerability tailored to freshwater ecosystems. The three dimensions of climate change vulnerability are as follows: (i) exposure to climate change, (ii) sensitivity to altered environmental conditions and (iii) resilience potential. Our vulnerability framework includes 1685 freshwater species of plants, fishes, molluscs, odonates, amphibians, crayfish and turtles alongside key features within and between catchments, such as topography and connectivity. Several methodologies were used to combine these dimensions across a variety of future climate change models and scenarios. The resulting indices were overlaid to assess the vulnerability of European freshwater ecosystems at the catchment scale (18 783 catchments). The Balkan Lakes Ohrid and Prespa and Mediterranean islands emerge as most vulnerable to climate change. For the 2030s, we showed a consensus among the applied methods whereby up to 573 lake and river catchments are highly vulnerable to climate change. The anthropogenic disruption of hydrological habitat connectivity by dams is the major factor reducing climate change resilience. A gap analysis demonstrated that the current European protected area network covers <25\% of the most vulnerable catchments. Practical steps need to be taken to ensure the persistence of freshwater biodiversity under climate change. Priority should be placed on enhancing stakeholder cooperation at the major basin scale towards preventing further degradation of freshwater ecosystems and maintaining connectivity among catchments. The catchments identified as most vulnerable to climate change provide preliminary targets for development of climate change conservation management and mitigation strategies.}, language = {en} } @article{VehKorupvonSpechtetal.2019, author = {Veh, Georg and Korup, Oliver and von Specht, Sebastian and R{\"o}ßner, Sigrid and Walz, Ariane}, title = {Unchanged frequency of moraine-dammed glacial lake outburst floods in the Himalaya}, series = {Nature climate change}, volume = {9}, journal = {Nature climate change}, number = {5}, publisher = {Nature Publ. Group}, address = {London}, issn = {1758-678X}, doi = {10.1038/s41558-019-0437-5}, pages = {379 -- 383}, year = {2019}, abstract = {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.}, language = {en} } @article{SchmidtWalzJonesetal.2016, author = {Schmidt, Katja and Walz, Ariane and Jones, Isobel and Metzger, Marc J.}, title = {The Sociocultural Value of Upland Regions in the Vicinity of Cities in Comparison With Urban Green Spaces}, series = {Mountain research and development}, volume = {36}, journal = {Mountain research and development}, publisher = {American Geophysical Union}, address = {Lawrence}, issn = {0276-4741}, doi = {10.1659/MRD-JOURNAL-D-16-00044.1}, pages = {465 -- 474}, year = {2016}, language = {en} } @article{SchmidtWalzMartinLopezetal.2017, author = {Schmidt, Katja and Walz, Ariane and Martin-Lopez, Berta and Sachse, Rene}, title = {Testing socio-cultural valuation methods of ecosystem services to explain land use preferences}, series = {Ecosystem Services : Science, Policy and Practice}, volume = {26}, journal = {Ecosystem Services : Science, Policy and Practice}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2212-0416}, doi = {10.1016/j.ecoser.2017.07.001}, pages = {270 -- 288}, year = {2017}, abstract = {Socio-cultural valuation still emerges as a methodological field in ecosystem service (ES) research and until now lacks consistent formalisation and balanced application in ES assessments. In this study, we examine the explanatory value of ES values for land use preferences. We use 563 responses to a survey about the Pentland Hills regional park in Scotland. Specifically, we aim to (1) identify clusters of land use preferences by using a novel visualisation tool, (2) test if socio-cultural values of ESs or (3) user characteristics are linked with land use preferences, and (4) determine whether both socio-cultural values of ESs and user characteristics can predict land use preferences. Our results suggest that there are five groups of people with different land use preferences, ranging from forest and nature enthusiasts to traditionalists, multi-functionalists and recreation seekers. Rating and weighting of ESs and user characteristics were associated with different clusters. Neither socio-cultural values nor user characteristics were suitable predictors for land use preferences. While several studies have explored land use preferences by identifying socio-cultural values in the past, our findings imply that in this case study ES values inform about general perceptions but do not replace the assessment of land use preferences. (C) 2017 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.}, language = {en} } @article{ReinhardtLierschAbdeladhimetal.2018, author = {Reinhardt, Julia and Liersch, Stefan and Abdeladhim, Mohamed Arbi and Diallo, Mori and Dickens, Chris and Fournet, Samuel and Hattermann, Fred and Kabaseke, Clovis and Muhumuza, Moses and Mul, Marloes L. and Pilz, Tobias and Otto, Ilona M. and Walz, Ariane}, title = {Systematic evaluation of scenario assessments supporting sustainable integrated natural resources management}, series = {Ecology and society : a journal of integrative science for resilience and sustainability}, volume = {23}, journal = {Ecology and society : a journal of integrative science for resilience and sustainability}, number = {1}, publisher = {Resilience Alliance}, address = {Wolfville}, issn = {1708-3087}, doi = {10.5751/ES-09728-230105}, pages = {34}, year = {2018}, abstract = {Scenarios have become a key tool for supporting sustainability research on regional and global change. In this study we evaluate four regional scenario assessments: first, to explore a number of research challenges related to sustainability science and, second, to contribute to sustainability research in the specific case studies. The four case studies used commonly applied scenario approaches that are (i) a story and simulation approach with stakeholder participation in the Oum Zessar watershed, Tunisia, (ii) a participatory scenario exploration in the Rwenzori region, Uganda, (iii) a model-based prepolicy study in the Inner Niger Delta, Mali, and (iv) a model coupling-based scenario analysis in upper Thukela basin, South Africa. The scenario assessments are evaluated against a set of known challenges in sustainability science, with each challenge represented by two indicators, complemented by a survey carried out on the perception of the scenario assessments within the case study regions. The results show that all types of scenario assessments address many sustainability challenges, but that the more complex ones based on story and simulation and model coupling are the most comprehensive. The study highlights the need to investigate abrupt system changes as well as governmental and political factors as important sources of uncertainty. For an in-depth analysis of these issues, the use of qualitative approaches and an active engagement of local stakeholders are suggested. Studying ecological thresholds for the regional scale is recommended to support research on regional sustainability. The evaluation of the scenario processes and outcomes by local researchers indicates the most transparent scenario assessments as the most useful. Focused, straightforward, yet iterative scenario assessments can be very relevant by contributing information to selected sustainability problems.}, language = {en} } @article{HuberRiglingBebietal.2013, author = {Huber, Robert and Rigling, Andreas and Bebi, Peter and Brand, Fridolin Simon and Briner, Simon and Buttler, Alexandre and Elkin, Che and Gillet, Francois and Gret-Regamey, Adrienne and Hirschi, Christian and Lischke, Heike and Scholz, Roland Werner and Seidl, Roman and Spiegelberger, Thomas and Walz, Ariane and Zimmermann, Willi and Bugmann, Harald}, title = {Sustainable land use in Mountain Regions under global change synthesis across scales and disciplines}, series = {Ecology and society : a journal of integrative science for resilience and sustainability}, volume = {18}, journal = {Ecology and society : a journal of integrative science for resilience and sustainability}, number = {3}, publisher = {Resilience Alliance}, address = {Wolfville}, issn = {1708-3087}, doi = {10.5751/ES-05499-180336}, pages = {20}, year = {2013}, abstract = {Mountain regions provide essential ecosystem goods and services (EGS) for both mountain dwellers and people living outside these areas. Global change endangers the capacity of mountain ecosystems to provide key services. The Mountland project focused on three case study regions in the Swiss Alps and aimed to propose land-use practices and alternative policy solutions to ensure the provision of key EGS under climate and land-use changes. We summarized and synthesized the results of the project and provide insights into the ecological, socioeconomic, and political processes relevant for analyzing global change impacts on a European mountain region. In Mountland, an integrative approach was applied, combining methods from economics and the political and natural sciences to analyze ecosystem functioning from a holistic human-environment system perspective. In general, surveys, experiments, and model results revealed that climate and socioeconomic changes are likely to increase the vulnerability of the EGS analyzed. We regard the following key characteristics of coupled human-environment systems as central to our case study areas in mountain regions: thresholds, heterogeneity, trade-offs, and feedback. Our results suggest that the institutional framework should be strengthened in a way that better addresses these characteristics, allowing for (1) more integrative approaches, (2) a more network-oriented management and steering of political processes that integrate local stakeholders, and (3) enhanced capacity building to decrease the identified vulnerability as central elements in the policy process. Further, to maintain and support the future provision of EGS in mountain regions, policy making should also focus on project-oriented, cross-sectoral policies and spatial planning as a coordination instrument for land use in general.}, language = {en} } @article{WalzSchmidtRuizFrauetal.2019, author = {Walz, Ariane and Schmidt, Katja and Ruiz-Frau, Ana and Nicholas, Kimberly A. and Bierry, Adeline and Lentsch, Aster de Vries and Dyankov, Apostol and Joyce, Deirdre and Liski, Anja H. and Marba, Nuria and Rosario, Ines T. and Scholte, Samantha S. K.}, title = {Sociocultural valuation of ecosystem services for operational ecosystem management: mapping applications by decision contexts in Europe}, series = {Regional environmental change}, volume = {19}, journal = {Regional environmental change}, number = {8}, publisher = {Springer}, address = {Heidelberg}, issn = {1436-3798}, doi = {10.1007/s10113-019-01506-7}, pages = {2245 -- 2259}, year = {2019}, abstract = {Sociocultural valuation (SCV) of ecosystem services (ES) discloses the principles, importance or preferences expressed by people towards nature. Although ES research has increasingly addressed sociocultural values in past years, little effort has been made to systematically review the components of sociocultural valuation applications for different decision contexts (i.e. awareness raising, accounting, priority setting, litigation and instrument design). In this analysis, we investigate the characteristics of 48 different sociocultural valuation applications—characterised by unique combinations of decision context, methods, data collection formats and participants—across ten European case studies. Our findings show that raising awareness for the sociocultural value of ES by capturing people's perspective and establishing the status quo, was found the most frequent decision context in case studies, followed by priority setting and instrument development. Accounting and litigation issues were not addressed in any of the applications. We reveal that applications for particular decision contexts are methodologically similar, and that decision contexts determine the choice of methods, data collection formats and participants involved. Therefore, we conclude that understanding the decision context is a critical first step to designing and carrying out fit-for-purpose sociocultural valuation of ES in operational ecosystem management.}, language = {en} } @article{MarkovicWalzKaercher2019, author = {Markovic, Danijela and Walz, Ariane and K{\"a}rcher, Oskar}, title = {Scale effects on the performance of niche-based models of freshwater fish distributions: Local vs. upstream area influences}, series = {Ecological modelling : international journal on ecological modelling and engineering and systems ecolog}, volume = {411}, journal = {Ecological modelling : international journal on ecological modelling and engineering and systems ecolog}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0304-3800}, doi = {10.1016/j.ecolmodel.2019.108818}, pages = {11}, year = {2019}, abstract = {Niche-based species distribution models (SDMs) play a central role in studying species response to environmental change. Effective management and conservation plans for freshwater ecosystems require SDMs that accommodate hierarchical catchment ordering and provide clarity on the performance of such models across multiple scales. The scale-dependence components considered here are: (a) environment spatial structure, represented by hierarchical catchment ordering following the Strahler system; (b) analysis grain, that included 1st to 5th order catchments; and (c) response grain, the grain at which species respond most, represented by local and upstream catchment area effects. We used fish occurrence data from the Danube River Basin and various factors representing climate, land cover and anthropogenic pressures. Our results indicate that the choice of response grain local vs. upstream area effects and the choice of analysis grain, only marginally influence the performance of SDMs. Upstream effects tend to better predict fish distributions than corresponding local effects for anthropogenic and land cover factors, in particular for species sensitive to pollution. Key predictors and their relative importance are scale and species dependent. Consequently, choosing proper species dependent spatial scales and factors is imperative for effective river rehabilitation measures.}, language = {en} } @article{KaercherFrankWalzetal.2019, author = {K{\"a}rcher, Oskar and Frank, Karin and Walz, Ariane and Markovic, Danijela}, title = {Scale effects on the performance of niche-based models of freshwater fish distributions}, series = {Ecological modelling : international journal on ecological modelling and engineering and systems ecolog}, volume = {405}, journal = {Ecological modelling : international journal on ecological modelling and engineering and systems ecolog}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0304-3800}, doi = {10.1016/j.ecolmodel.2019.05.006}, pages = {33 -- 42}, year = {2019}, abstract = {Niche-based species distribution models (SDMs) have become an essential tool in conservation and restoration planning. Given the current threats to freshwater biodiversity, it is of fundamental importance to address scale effects on the performance of niche-based SDMs of freshwater species' distributions. The scale effects are addressed here in the context of hierarchical catchment ordering, considered as counterpart to coarsening grain-size by increasing grid-cell size. We combine fish occurrence data from the Danube River Basin, the hierarchical catchment ordering and multiple environmental factors representing topographic, climatic and anthropogenic effects to model fish occurrence probability across multiple scales. We focus on 1st to 5th order catchments. The spatial scale (hierarchical catchment order) only marginally influences the mean performance of SDMs, however the uncertainty of the estimates increases with scale. Key predictors and their relative importance are scale and species dependent. Our findings have useful implications for choosing proper species dependent spatial scales for river rehabilitation measures, and for conservation planning in areas where fine grain species data are unavailable.}, language = {en} } @article{NussbaumerSchaubHuggeletal.2014, author = {Nussbaumer, S. and Schaub, Y. and Huggel, C. and Walz, Ariane}, title = {Risk estimation for future glacier lake outburst floods based on local land-use changes}, series = {Natural hazards and earth system sciences}, volume = {14}, journal = {Natural hazards and earth system sciences}, number = {6}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1561-8633}, doi = {10.5194/nhess-14-1611-2014}, pages = {1611 -- 1624}, year = {2014}, abstract = {Effects of climate change are particularly strong in high-mountain regions. Most visibly, glaciers are shrinking at a rapid pace, and as a consequence, glacier lakes are forming or growing. At the same time the stability of mountain slopes is reduced by glacier retreat, permafrost thaw and other factors, resulting in an increasing landslide hazard which can potentially impact lakes and therewith trigger far-reaching and devastating outburst floods. To manage risks from existing or future lakes, strategies need to be developed to plan in time for adequate risk reduction measures at a local level. However, methods to assess risks from future lake outbursts are not available and need to be developed to evaluate both future hazard and future damage potential. Here a method is presented to estimate future risks related to glacier lake outbursts for a local site in southern Switzerland (Naters, Valais). To generate two hazard scenarios, glacier shrinkage and lake formation modelling was applied, combined with simple flood modelling and field work. Furthermore, a land-use model was developed to quantify and allocate land-use changes based on local-to-regional storylines and three scenarios of land-use driving forces. Results are conceptualized in a matrix of three land-use and two hazard scenarios for the year 2045, and show the distribution of risk in the community of Naters, including high and very high risk areas. The study underlines the importance of combined risk management strategies focusing on land-use planning, on vulnerability reduction, as well as on structural measures (where necessary) to effectively reduce future risks related to lake outburst floods.}, language = {en} } @article{FischerBrettinRoessneretal.2022, author = {Fischer, Melanie and Brettin, Jana and Roessner, Sigrid and Walz, Ariane and Fort, Monique and Korup, Oliver}, title = {Rare flood scenarios for a rapidly growing high-mountain city: Pokhara, Nepal}, series = {Natural Hazards and Earth System Sciences}, volume = {22}, journal = {Natural Hazards and Earth System Sciences}, edition = {9}, publisher = {Copernicus Publications}, address = {Katlenburg-Lindau}, issn = {1684-9981}, doi = {10.5194/nhess-22-3105-2022}, pages = {3105 -- 3123}, year = {2022}, abstract = {Pokhara (ca. 850 m a.s.l.), Nepal's second-largest city, lies at the foot of the Higher Himalayas and has more than tripled its population in the past 3 decades. Construction materials are in high demand in rapidly expanding built-up areas, and several informal settlements cater to unregulated sand and gravel mining in the Pokhara Valley's main river, the Seti Khola. This river is fed by the Sabche glacier below Annapurna III (7555 m a.s.l.), some 35 km upstream of the city, and traverses one of the steepest topographic gradients in the Himalayas. In May 2012 a sudden flood caused >70 fatalities and intense damage along this river and rekindled concerns about flood risk management. We estimate the flow dynamics and inundation depths of flood scenarios using the hydrodynamic model HEC-RAS (Hydrologic Engineering Center's River Analysis System). We simulate the potential impacts of peak discharges from 1000 to 10 000 m3 s-1 on land cover based on high-resolution Maxar satellite imagery and OpenStreetMap data (buildings and road network). We also trace the dynamics of two informal settlements near Kaseri and Yamdi with high potential flood impact from RapidEye, PlanetScope, and Google Earth imagery of the past 2 decades. Our hydrodynamic simulations highlight several sites of potential hydraulic ponding that would largely affect these informal settlements and sites of sand and gravel mining. These built-up areas grew between 3- and 20-fold, thus likely raising local flood exposure well beyond changes in flood hazard. Besides these drastic local changes, about 1 \% of Pokhara's built-up urban area and essential rural road network is in the highest-hazard zones highlighted by our flood simulations. Our results stress the need to adapt early-warning strategies for locally differing hydrological and geomorphic conditions in this rapidly growing urban watershed.}, language = {en} } @article{MartinLopezLeisterCruzetal.2019, author = {Martin-Lopez, Berta and Leister, Ines and Cruz, Pedro Lorenzo and Palomo, Ignacio and Gret-Regamey, Adrienne and Harrison, Paula A. and Lavorel, Sandra and Locatelli, Bruno and Luque, Sandra and Walz, Ariane}, title = {Nature's contributions to people in mountains}, series = {PLoS one}, volume = {14}, journal = {PLoS one}, number = {6}, publisher = {PLoS}, address = {San Fransisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0217847}, pages = {24}, year = {2019}, abstract = {Mountains play a key role in the provision of nature's contributions to people (NCP) worldwide that support societies' quality of life. Simultaneously, mountains are threatened by multiple drivers of change. Due to the complex interlinkages between biodiversity, quality of life and drivers of change, research on NCP in mountains requires interdisciplinary approaches. In this study, we used the conceptual framework of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) and the notion of NCP to determine to what extent previous research on ecosystem services in mountains has explored the different components of the IPBES conceptual framework. We conducted a systematic review of articles on ecosystem services in mountains published up to 2016 using the Web of Science and Scopus databases. Descriptive statistical and network analyses were conducted to explore the level of research on the components of the IPBES framework and their interactions. Our results show that research has gradually become more interdisciplinary by studying higher number of NCP, dimensions of quality of life, and indirect drivers of change. Yet, research focusing on biodiversity, regulating NCP and direct drivers has decreased over time. Furthermore, despite the fact that research on NCP in mountains becoming more policy-oriented over time, mainly in relation to payments for ecosystem services, institutional responses remained underexplored in the reviewed studies. Finally, we discuss the relevant knowledge gaps that should be addressed in future research in order to contribute to IPBES.}, language = {en} } @article{SchmidtMartinLopezPhillipsetal.2018, author = {Schmidt, Katja and Martin-Lopez, Berta and Phillips, Peter M. and Julius, Eike and Makan, Neville and Walz, Ariane}, title = {Key landscape features in the provision of ecosystem services}, series = {Land use policy}, volume = {82}, journal = {Land use policy}, publisher = {Elsevier}, address = {Oxford}, issn = {0264-8377}, doi = {10.1016/j.landusepol.2018.12.022}, pages = {353 -- 366}, year = {2018}, abstract = {Whereas ecosystem service research is increasingly being promoted in science and policy, the utilisation of ecosystem services knowledge remains largely underexplored for regional ecosystem management. To overcome the mere generation of knowledge and contribute to decision-making, scientists are facing the challenge of articulating specific implications of the ecosystem service approach for practical land use management. In this contribution, we compare the results of participatory mapping of ecosystem services with the existing management plan for the Pentland Hills Regional Park (Scotland, UK) to inform its future management plan. By conducting participatory mapping in a workshop with key stakeholders (n = 20), we identify hotspots of ecosystem services and the landscape features underpinning such hotspots. We then analyse to what extent these landscape features are the focus of the current management plan. We found a clear mismatch between the key landscape features underpinning the provision of ecosystem services and the management strategy suggested. Our findings allow for a better understanding of the required focus of future land use management to account for ecosystem services.}, language = {en} } @article{PhilipsWalzBergneretal.2015, author = {Philips, Andrea and Walz, Ariane and Bergner, Andreas G. N. and Gr{\"a}ff, Thomas and Heistermann, Maik and Kienzler, Sarah and Korup, Oliver and Lipp, Torsten and Schwanghart, Wolfgang and Zeilinger, Gerold}, title = {Immersive 3D geovisualization in higher education}, series = {Journal of geography in higher education}, volume = {39}, journal = {Journal of geography in higher education}, number = {3}, publisher = {Routledge, Taylor \& Francis Group}, address = {Abingdon}, issn = {0309-8265}, doi = {10.1080/03098265.2015.1066314}, pages = {437 -- 449}, year = {2015}, abstract = {In this study, we investigate how immersive 3D geovisualization can be used in higher education. Based on MacEachren and Kraak's geovisualization cube, we examine the usage of immersive 3D geovisualization and its usefulness in a research-based learning module on flood risk, called GEOSimulator. Results of a survey among participating students reveal benefits, such as better orientation in the study area, higher interactivity with the data, improved discourse among students and enhanced motivation through immersive 3D geovisualization. This suggests that immersive 3D visualization can effectively be used in higher education and that 3D CAVE settings enhance interactive learning between students.}, language = {en} } @article{HeidenreichBuchnerWalzetal.2021, author = {Heidenreich, Anna and Buchner, Martin and Walz, Ariane and Thieken, Annegret}, title = {How to deal with heat stress at an open-air event?}, series = {Weather, climate \& society / American Meteorological Society}, volume = {13}, journal = {Weather, climate \& society / American Meteorological Society}, number = {4}, publisher = {American Meteorological Soc.}, address = {Boston}, issn = {1948-8327}, doi = {10.1175/WCAS-D-21-0027.1}, pages = {989 -- 1002}, year = {2021}, abstract = {Heat waves are increasingly common in many countries across the globe, and also in Germany, where this study is set. Heat poses severe health risks, especially for vulnerable groups such as the elderly and children. This case study explores visitors' behavior and perceptions during six weekends in the summer of 2018 at a 6-month open-air horticultural show. Data from a face-to-face survey (n = 306) and behavioral observations ( n = 2750) were examined by using correlation analyses, ANOVA, and multiple regression analyses. Differences in weather perception, risk awareness, adaptive behavior, and activity level were observed between rainy days (maximum daily temperature, 25 degrees C), warmsummer days (25 degrees-30 degrees C), and hot days (>30 degrees C). Respondents reported a high level of heat risk awareness, butmost (90\%) were unaware of actual heat warnings. During hot days, more adaptive measures were reported and observed. Older respondents reported taking the highest number of adaptive measures. We observed the highest level of adaptation in children, but they also showed the highest activity level. From our results we discuss how to facilitate individual adaptation to heat stress at open-air events by taking the heterogeneity of visitors into account. To mitigate negative health outcomes for citizens in the future, we argue for tailored risk communication aimed at vulnerable groups.
SIGNIFICANCE STATEMENT: People around the world are facing higher average temperatures. While higher temperatures make open-air events a popular leisure time activity in summer, heat waves are a threat to health and life. Since there is not much research on how visitors of such events perceive different weather conditions-especially hot temperatures-we explored this in our case study in southern Germany at an open-air horticultural show in the summer of 2018. We discovered deficits both in people's awareness of current heat risk and the heat adaptation they carry out themselves. Future research should further investigate risk perception and adaptation behavior of private individuals, whereas event organizers and authorities need to continually focus on risk communication and facilitate individual adaptation of their visitors.}, language = {en} } @article{VehKorupWalz2019, author = {Veh, Georg and Korup, Oliver and Walz, Ariane}, title = {Hazard from Himalayan glacier lake outburst floods}, series = {Proceedings of the National Academy of Sciences of the United States of America : PNAS}, volume = {117}, journal = {Proceedings of the National Academy of Sciences of the United States of America : PNAS}, number = {2}, publisher = {National Academy of Sciences}, address = {Washington}, issn = {0027-8424}, doi = {10.1073/pnas.1914898117}, pages = {907 -- 912}, year = {2019}, abstract = {Sustained glacier melt in the Himalayas has gradually spawned more than 5,000 glacier lakes that are dammed by potentially unstable moraines. When such dams break, glacier lake outburst floods (GLOFs) can cause catastrophic societal and geomorphic impacts. We present a robust probabilistic estimate of average GLOFs return periods in the Himalayan region, drawing on 5.4 billion simulations. We find that the 100-y outburst flood has an average volume of 33.5(+3.7)/(-3.7) x 10(6) m(3) (posterior mean and 95\% highest density interval [HDI]) with a peak discharge of 15,600(+2.000)/(-1,800) m(3).S-1. Our estimated GLOF hazard is tied to the rate of historic lake outbursts and the number of present lakes, which both are highest in the Eastern Himalayas. There, the estimated 100-y GLOF discharge (similar to 14,500 m(3).s(-1)) is more than 3 times that of the adjacent Nyainqentanglha Mountains, and at least an order of magnitude higher than in the Hindu Kush, Karakoram, and Western Himalayas. The GLOF hazard may increase in these regions that currently have large glaciers, but few lakes, if future projected ice loss generates more unstable moraine-dammed lakes than we recognize today. Flood peaks from GLOFs mostly attenuate within Himalayan headwaters, but can rival monsoon-fed discharges in major rivers hundreds to thousands of kilometers downstream. Projections of future hazard from meteorological floods need to account for the extreme runoffs during lake outbursts, given the increasing trends in population, infrastructure, and hydropower projects in Himalayan headwaters.}, language = {en} } @article{SchulzVoigtBeuschetal.2016, author = {Schulz, Katharina and Voigt, Karsten and Beusch, Christine and Almeida-Cortez, Jarcilene S. and Kowarik, Ingo and Walz, Ariane and Cierjacks, Arne}, title = {Grazing deteriorates the soil carbon stocks of Caatinga forest ecosystems in Brazil}, series = {Forest ecology and management}, volume = {367}, journal = {Forest ecology and management}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0378-1127}, doi = {10.1016/j.foreco.2016.02.011}, pages = {62 -- 70}, year = {2016}, abstract = {Grazing by domestic ungulates can have substantial impacts on forests in arid and semi-arid regions, possibly including severe loss of carbon from the soil. Predicting net livestock impacts on soil organic carbon stocks remains challenging, however, due to the dependence on animal loads and on soil and environmental parameters. The objective of this study was to better understand grazing effects on soil organic carbon in seasonal tropical dry forests of north-eastern Brazil (Caatinga) by quantifying carbon stocks of the upper soil profile (0-5 cm depth) and greater soil depths (>5 cm depth down to bedrock) along a gradient of grazing intensity while accounting for other influencing factors such as soil texture, vegetation, landscape topography, and water availability. We analysed soil organic carbon, soil clay content, altitude above sea level, soil depth to bedrock, distance to the nearest permanent water body, species diversity of perennial plants and aboveground biomass on 45 study plots located in the vicinity of the Itaparica Reservoir, Pernambuco, Brazil. Livestock (mainly goats and cattle) are unevenly distributed in the studied ecosystem, thus grazing intensity was accounted for based on the weight of livestock droppings per square metre and classified as no or light, intermediate, or heavy grazing. The mean soil organic carbon in the area was 16.86 ± 1.28 Mg ha\&\#8722;1 C with approximately one-quarter found in the upper 5 cm of the soil profile (4.14 ± 0.43 Mg ha\&\#8722;1 C) and the remainder (12.57 ± 0.97 Mg ha\&\#8722;1 C) in greater soil depths (>5 cm). Heavy grazing led to significantly lower soil organic carbon stocks in the upper 5 cm, whereas no effect on soil organic carbon of the soil overall or in greater soil depths was detectable. The soil's clay content and the altitude proved to be the most relevant factors influencing overall soil organic carbon stocks and those in greater soil depths (>5 cm). Our findings suggest that grazing causes substantial release of carbon from Brazilian dry forest soils, which should be addressed through improved grazing management via a legally compulsory rotation system. This would ultimately contribute to the conservation of a unique forest system and associated ecosystem services.}, language = {en} } @article{WalzBraendleLangetal.2014, author = {Walz, Ariane and Braendle, J. M. and Lang, D. J. and Brand, Fridolin Simon and Briner, Simon and Elkin, C. and Hirschi, C. and Huber, R. and Lischke, H. and Schmatz, D. R.}, title = {Experience from downscaling IPCC-SRES scenarios to specific national-level focus scenarios for ecosystem service management}, series = {Technological forecasting \& social change}, volume = {86}, journal = {Technological forecasting \& social change}, publisher = {Elsevier}, address = {New York}, issn = {0040-1625}, doi = {10.1016/j.techfore.2013.08.014}, pages = {21 -- 32}, year = {2014}, abstract = {Scenario analysis is a widely used approach to incorporate uncertainties in global change research. In the context of regional ecosystem service and landscape management where global IPCC climate simulations and their downscaled derivates are applied, it can be useful to work with regional sodo-economic scenarios that are coherent with the global IPCC scenarios. The consistency with the original source scenarios, transparency and reproducibility of the methods used as well as the internal consistency of the derived scenarios are important methodological prerequisites for coherently downscaling pre-existing source scenarios. In contrast to well-established systematic-qualitative scenario techniques, we employ here a formal technique of scenario construction which combines expert judgement with a quantitative, indicator-based selection algorithm in order to deduce a formally consistent set of focus scenario. In our case study, these focus scenarios reflect the potential development pathways of major national-level drivers for ecosystem service management in Swiss mountain regions. The integration of an extra impact factor ("Global Trends") directly referring to the four principle SRES scenario families, helped us to formally internalise base assumptions of IPCC SRES scenarios to regional scenarios that address a different thematic focus (ecosystem service management), spatial level (national) and time horizon (2050). Compared to the well-established systematic-qualitative approach, we find strong similarities between the two methods, including the susceptibility to personal judgement which is only partly reduced by the formal method. However, the formalised scenario approach conveys four clear advantages, (1) the better documentation of the process, (2) its reproducibility, (3) the openness in terms of the number and directions of the finally selected set of scenarios, and (4) its analytical power. (C) 2013 Elsevier Inc. All rights reserved.}, language = {en} } @article{SchneiderWalzAlbertetal.2021, author = {Schneider, Philipp and Walz, Ariane and Albert, Christian and Lipp, Torsten}, title = {Ecosystem-based adaptation in cities}, series = {Land use policy}, volume = {109}, journal = {Land use policy}, publisher = {Elsevier}, address = {Oxford}, issn = {0264-8377}, doi = {10.1016/j.landusepol.2021.105722}, pages = {11}, year = {2021}, abstract = {Extreme weather events like heavy rainfall and heat waves will likely increase in intensity and frequency due to climate change. As the impacts of these extremes are particularly prominent in urban agglomerations, cities face an urgent need to develop adaptation strategies. Ecosystem-based Adaptation (EbA) provides helpful strategies that harness ecological processes in addition to technical interventions. EbA has been addressed in informal adaptation planning. Formal municipality planning, namely landscape planning, is supposed to include traditionally some EbA measures, although adaptation has not been their explicit focus. Our research aims to investigate how landscape plans incorporate climate-related extremes and EbA as well as to discuss the potential to enhance EbA uptake in formal planning. We conducted a document analysis of informal planning documents from 85 German cities and the analysis of formal landscape plans of 61 of these cities. The results suggest that city size does affect the extent of informal planning instruments and the comprehensiveness of formal landscape plans. Climate-related extremes and EbA measures have traditionally been part of landscape planning. Almost all landscape plans address heat stress, while climate change and heavy rain have been addressed less often, though more frequently since 2008. Greening of walls and roofs, on-site infiltration and water retention reveal significant potential for better integration in landscape plans. Landscape planning offers an entry point for effective climate adaptation through EbA in cities. Informal and formal planning instruments should be closely combined for robust, spatially explicit, legally binding implementation of EbA measures in the future.}, language = {en} } @article{VehKorupRoessneretal.2018, author = {Veh, Georg and Korup, Oliver and Roessner, Sigrid and Walz, Ariane}, title = {Detecting Himalayan glacial lake outburst floods from Landsat time series}, series = {Remote sensing of environment : an interdisciplinary journal}, volume = {207}, journal = {Remote sensing of environment : an interdisciplinary journal}, publisher = {Elsevier}, address = {New York}, issn = {0034-4257}, doi = {10.1016/j.rse.2017.12.025}, pages = {84 -- 97}, year = {2018}, abstract = {Several thousands of moraine-dammed and supraglacial lakes spread over the Hindu Kush Himalayan (HKH) region, and some have grown rapidly in past decades due to glacier retreat. The sudden emptying of these lakes releases large volumes of water and sediment in destructive glacial lake outburst floods (GLOFs), one of the most publicised natural hazards to the rapidly growing Himalayan population. Despite the growing number and size of glacial lakes, the frequency of documented GLOFs is remarkably constant. We explore this possible reporting bias and offer a new processing chain for establishing a more complete Himalayan GLOF inventory. We make use of the full seasonal archive of Landsat images between 1988 and 2016, and track automatically where GLOFs left shrinking water bodies, and tails of sediment at high elevations. We trained a Random Forest classifier to generate fuzzy land cover maps for 2491 images, achieving overall accuracies of 91\%. We developed a likelihood-based change point technique to estimate the timing of GLOFs at the pixel scale. Our method objectively detected ten out of eleven documented GLOFs, and another ten lakes that gave rise to previously unreported GLOFs. We thus nearly doubled the existing GLOF record for a study area covering similar to 10\% of the HKH region. Remaining challenges for automatically detecting GLOFs include image insufficiently accurate co-registration, misclassifications in the land cover maps and image noise from clouds, shadows or ice. Yet our processing chain is robust and has the potential for being applied on the greater HKH and mountain ranges elsewhere, opening the door for objectively expanding the knowledge base on GLOF activity over the past three decades.}, language = {en} }