Refine
Year of publication
Document Type
- Article (103)
- Part of Periodical (64)
- Working Paper (62)
- Book (49)
- Doctoral Thesis (27)
- Contribution to a Periodical (7)
- Review (6)
- Periodical (3)
- Report (2)
- Part of a Book (1)
Language
- German (257)
- English (65)
- Multiple languages (3)
- Spanish (1)
Is part of the Bibliography
- no (326)
Keywords
- Mobilität (18)
- Verkehr (10)
- Frankfurt am Main (6)
- Methodenbericht (5)
- Mobilitätsverhalten (5)
- Personenmobilität (5)
- Region Rhein-Main (5)
- Verkehrsplanung (5)
- Deutschland (4)
- Fahrradverleihsysteme (4)
Institute
- Geographie (326) (remove)
Aim: Recent studies in southern Africa identified past biome stability as an important predictor of biodiversity. We aimed to assess the extent to which past biome stability predicts present global biodiversity patterns, and the extent to which projected climatic changes may lead to eventual biome changes in areas with constant past biome.
Location: Global.
Taxon: Spermatophyta; terrestrial vertebrates.
Methods: Biome constancy was assessed and mapped using results from 89 dynamic global vegetation model simulations, driven by outputs of palaeoclimate experiments spanning the past 140 ka. We tested the hypothesis that terrestrial vertebrate diversity is predicted by biome constancy. We also simulated potential future vegetation, and hence potential future biome patterns, and quantified and mapped the extent of projected eventual future biome change in areas of past constant biome.
Results: Approximately 11% of global ice-free land had a constant biome since 140 ka. Apart from areas of constant Desert, many areas with constant biome support high species diversity. All terrestrial vertebrate groups show a strong positive relationship between biome constancy and vertebrate diversity in areas of greater diversity, but no relationship in less diverse areas. Climatic change projected by 2100 commits 46%–66% of global ice-free land, and 34%–52% of areas of past constant biome (excluding areas of constant Desert) to eventual biome change.
Main conclusions: Past biome stability strongly predicts vertebrate diversity in areas of higher diversity. Future climatic changes will lead to biome changes in many areas of past constant biome, with profound implications for biodiversity conservation. Some projected biome changes will result in substantial reductions in biospheric carbon sequestration and other ecosystem services.
Non-forest ecosystems, dominated by shrubs, grasses and herbaceous plants, provide ecosystem services including carbon sequestration and forage for grazing, and are highly sensitive to climatic changes. Yet these ecosystems are poorly represented in remotely sensed biomass products and are undersampled by in situ monitoring. Current global change threats emphasize the need for new tools to capture biomass change in non-forest ecosystems at appropriate scales. Here we developed and deployed a new protocol for photogrammetric height using unoccupied aerial vehicle (UAV) images to test its capability for delivering standardized measurements of biomass across a globally distributed field experiment. We assessed whether canopy height inferred from UAV photogrammetry allows the prediction of aboveground biomass (AGB) across low-stature plant species by conducting 38 photogrammetric surveys over 741 harvested plots to sample 50 species. We found mean canopy height was strongly predictive of AGB across species, with a median adjusted R2 of 0.87 (ranging from 0.46 to 0.99) and median prediction error from leave-one-out cross-validation of 3.9%. Biomass per-unit-of-height was similar within but different among, plant functional types. We found that photogrammetric reconstructions of canopy height were sensitive to wind speed but not sun elevation during surveys. We demonstrated that our photogrammetric approach produced generalizable measurements across growth forms and environmental settings and yielded accuracies as good as those obtained from in situ approaches. We demonstrate that using a standardized approach for UAV photogrammetry can deliver accurate AGB estimates across a wide range of dynamic and heterogeneous ecosystems. Many academic and land management institutions have the technical capacity to deploy these approaches over extents of 1–10 ha−1. Photogrammetric approaches could provide much-needed information required to calibrate and validate the vegetation models and satellite-derived biomass products that are essential to understand vulnerable and understudied non-forested ecosystems around the globe.
Global water models (GWMs) simulate the terrestrial water cycle on the global scale and are used to assess the impacts of climate change on freshwater systems. GWMs are developed within different modelling frameworks and consider different underlying hydrological processes, leading to varied model structures. Furthermore, the equations used to describe various processes take different forms and are generally accessible only from within the individual model codes. These factors have hindered a holistic and detailed understanding of how different models operate, yet such an understanding is crucial for explaining the results of model evaluation studies, understanding inter-model differences in their simulations, and identifying areas for future model development. This study provides a comprehensive overview of how 16 state-of-the-art GWMs are designed. We analyse water storage compartments, water flows, and human water use sectors included in models that provide simulations for the Inter-Sectoral Impact Model Intercomparison Project phase 2b (ISIMIP2b). We develop a standard writing style for the model equations to enhance model intercomparison, improvement, and communication. In this study, WaterGAP2 used the highest number of water storage compartments, 11, and CWatM used 10 compartments. Six models used six compartments, while four models (DBH, JULES-W1, Mac-PDM.20, and VIC) used the lowest number, three compartments. WaterGAP2 simulates five human water use sectors, while four models (CLM4.5, CLM5.0, LPJmL, and MPI-HM) simulate only water for the irrigation sector. We conclude that, even though hydrological processes are often based on similar equations for various processes, in the end these equations have been adjusted or models have used different values for specific parameters or specific variables. The similarities and differences found among the models analysed in this study are expected to enable us to reduce the uncertainty in multi-model ensembles, improve existing hydrological processes, and integrate new processes.
The calcareous substrate of spring-fed fens makes them unique islands of biodiversity, hosting endangered, vulnerable, and protected vascular plants. Hence, spring-fed fens ecosystems require special conservation attention because many of them are destroyed (e.g. drained, forested) and it is extremely difficult or even impossible to restore the unique hydrogeological and geochemical conditions enabling their function. The long-term perspective of paleoecological studies allows indication of former wetland ecosystem states and provides understanding of their development over millennia. To examine the late Holocene dynamics of a calcareous spring-fed fen (Raganu Mire) ecosystem on the Baltic Sea coast (Latvia) in relation to environmental changes, substrate and human activity, we have undertaken high-resolution analyses of plant macrofossils, pollen, mollusc, stable carbon (δ13C) and oxygen (δ18O) isotopes combined with radiocarbon dating (AMS) in three coring locations. Our study revealed that peat deposits began accumulating ca. 7000 cal. yr BP and calcareous deposits (tufa) from 1450 cal. yr BP, coinciding with regional hydrological changes. Several fire events occurred between 4000 and 1600 cal. yr BP, which appeared to have had a limited effect on local vegetation. The most significant changes in the forest and peatland ecosystems were at 3200 cal. yr BP associated with a dry climate stage and high fire activity, and then between 1400 and 500 cal. yr BP potentially associated with temperature changes during the Medieval Climate Anomaly (MCA) and Little Ice Age. Hydrological disturbances in the peatland catchment from 1400 cal. yr BP were most likely strengthened by human activity (deforestation) in this region. The relationship between the development of this peatland and changes in its catchment area, such as land cover changes or fluctuations in groundwater levels, suggest that protection and restoration of spring-fed fen ecosystems should also include the surrounding catchment. The presence of calcareous sediments, as well as appropriate temperature and local hydrological conditions appear to be the most crucial factors controlling Cladium marisus populations in our site - currently at the eastern limit of its distribution in Europe.
The Sustainable Urban Mobility Plan (SUMP) is a concept of the European Union. The non-binding guidelines formulated within this framework aim to help municipalities and cities to strategically define a local and long term transport and mobility plan. From the European Union's point of view, citizen participation plays a pivotal role during all phases – from the development of the plan until its implementation. This intends to achieve greater support and acceptance from the community for the plan, and to facilitate its implementation.
This paper investigates whether the planning and political SUMP approach guarantees successful participatory processes, and what conclusions can be drawn to amend the SUMP process and general transport planning practice. It discusses how citizen participation is defined in the SUMP guidelines and how these elements are reflected in the SUMP guidelines of 2013 and 2019. In a second step, this paper shows how successful citizen participation is defined in an academic context and to what extent the SUMP reflects these findings. The findings derived from the academic context are then applied to the case studies of Ghent and Limburg in order to evaluate how successfully participation procedures were implemented in these SUMP processes. Finally, the question - what conclusions can be drawn from this to improve the SUMP process and general transport planning practice - is assessed.
Ziel der vorliegenden Studie war es, herauszufinden, in welcher Weise ein im Sommer 2020 durchgeführter Verkehrsinfrastruktureingriff an einer Hauptverkehrsstraße in Frankfurt zu einer Verbesserung der wahrgenommenen Lebensqualität der Anwohnenden beiträgt. Es wurde geprüft, ob der Wegfall einer Fahrspur für den motorisierten Individualverkehr (MIV) und der gleichzeitige Bau eines Radfahrstreifens einen positiven Effekt auf die Lebensqualität der Anwohnenden hat. Insgesamt wurden 445 Haushalte an der Friedberger Landstraße vor und nach dem Umbau befragt. Die Lebensqualität wurde in Bezug auf das Konfliktpotenzial und Sicherheitsempfinden im Verkehr, die Aufenthaltsqualität sowie den wahrgenommenen Lärm und die Luftqualität vor und nach dem Bau der Fahrradspur erhoben. Es zeigt sich, dass die wahrgenommene Lebensqualität nach dem Eingriff in fast all diesen Bereichen positiver bewertet wurde als vor dem Eingriff. Dies deutet darauf hin, dass die reduzierte Infrastruktur für den MIV und die gleichzeitige Errichtung einer Fahrradspur einen positiven Effekt auf die Lebensqualität der Anwohnenden haben.
Die Lincoln-Siedlung, eine ehemalige Housing Area der US-Army im Süden von Darmstadt, wird seit dem amerikanischen Truppenabzug im Jahr 2008 als autoreduziertes Wohnquartier entwickelt. Der Autobesitz der Bewohner*innen wird über eine zentrale Stellplatzvergabe mit einem Stellplatzschlüssel von 0,65 Parkplätzen pro Wohneinheit reglementiert. Gleichzeitig stehen zahlreiche Alternativen, wie eine verbesserte Fuß- und Radverkehrsinfrastruktur, eine eng getaktete ÖPNV-Verbindung in die Innenstadt, mehrere (teils vergünstigte) Carsharing- und Fahrradverleihangebote sowie eine Mobilitätsberatung zur Verfügung. Die vorliegende Studie stützt sich auf eine quantitative Haushaltsbefragung (N = 166), evaluiert die genannten Elemente alternativer Mobilität aus Bewohner*innensicht und untersucht die umzugsbedingten Veränderungen im Mobilitätsverhalten der Bewohner*innen. Diese befürworten die Maßnahmen grundsätzlich, bezweifeln jedoch teilweise deren Wirksamkeit, etwa hinsichtlich der Minderung von Verkehrsaufkommen und Schadstoffbelastung. Im Hinblick auf das Mobilitätsverhalten zeigen die Daten eine signifikante Verringerung von Besitz und Nutzung privater Pkw im Vergleich zum Zeitraum vor dem Umzug in die Lincoln-Siedlung. Die Nutzung von Carsharing-Angeboten sowie Bus und Bahn ist hingegen signifikant angewachsen. Diese Veränderungen sind hinsichtlich der überwiegend kurzen Wohndauer der befragten Personen sowie der andauernden Quartiersentwicklung bemerkenswert. Als künftige Maßnahmen konnten bessere Informationen über das Gesamtkonzept und die einzelnen Mobilitätsangebote sowie die Kommunikation von Visionen der fertiggestellten Siedlung identifiziert werden.
Highlights
• Compares narratives and mobility-related practices of car-reduced neighborhoods.
• Identifies commonalities and differences between the ideal vision and the lived practice of car independency.
• The article concludes that a 'post-car system' requires continuous material and immaterial change.
• This can be fostered by political and planning readiness, as well as local willingness and public acceptability.
• Overall, this study reveals the exemplary role of car-reduced neighborhoods for mobility transition.
Abstract
In the pursuit of sustainability, the concept of ‘car-reduced neighborhoods’ promises to decrease car ownership and increase car-independent mobility. However, mobility is not only designed from ‘above’ by planners and policymakers, but also shaped from ‘below’ by its practitioners and their contexts. Only a few studies currently bring together the perspective from ‘above’ and ‘below’ regarding car-reduced neighborhoods. This article therefore combines both perspectives by contrasting the narratives and the mobility-related practices of two German car-reduced urban residential areas. Firstly, we conduct interviews with various actors involved in the planning and implementation of both neighborhoods to identify the narratives. Secondly, we interview the residents to determine the mobility-related practices. Finally, we compare both empirical investigations to analyze the commonalities and differences of the ‘planning vision’ and the ‘lived practice’ of car-free living, car-independent mobility, and restrictive car parking. Although this study identifies differences between the two perspectives, the discrepancy is smaller than evaluated in earlier studies. After relocating to a car-reduced neighborhood, residents tend to maintain, strengthen, and adapt car-independent mobility practices rather than weakening car-independent mobility practices and maintaining car-dependent ones. Thus, residents seem to be encouraged to drive less and to leave their cars parked for most of the time. However, relocating to a car-reduced neighborhood does not automatically initiate full demotorization. Furthermore, residents' parking practices also sometimes deviate from the planning vision. Consequently, the article concludes that overcoming the ‘system’ of automobility for a ‘post-car system’ requires continuous (i) material and (ii) immaterial change fostered by political and planning readiness, as well as local willingness and public acceptability. In this regard, car-reduced neighborhoods can be seen as blueprints for a mobility transition.
Highlights
- Cost-free ticket increases public transport use even when the share was high beforehand
- Free tickets are more effective than just a price reduction (zero-price effect)
- Low income, female and older employees benefit the most
- Not only travel behaviour but also attitudes change
- Cost-free public transport is one component in a set of travel demand management tools
Abstract
To increase its attractiveness for employees, to save costs regarding parking supply and to foster modal shift away from the car, employers can offer sharply cost-reduced public transport tickets. In the state of Hesse/Germany, public authorities have gone one step further by introducing a cost-free public transport ticket for all state employees. We argue that the step from sharply cost-reduced to cost-free is more than just a monetary difference. The aim of this study is to assess whether the ticket is actually affecting employees and what changed their travel behaviour. Therefore, we have analysed a two-wave survey conducted at Goethe University in Frankfurt: one from before and one from after the introduction of the new ticket. The results show a substantial increase in the use of public transport (pt) for commuting and other trip purposes. Car use and availability, however, did not decrease. In particular, those who had no cost-reduced jobticket beforehand switched to public transport after the introduction. Furthermore, we identified increasing public transport use for low-income employees (inclusion hypothesis) and several indicators pointing towards a more multimodal behaviour (multimodal hypothesis).
Evaluating spatial inequalities using a single walking accessibility measure is quite challenging. In response, the paper proposes combining two accessibility measures (real and potential) to provide additional insights into the identification and mapping of spatial inequalities. The municipality of Getafe in the Madrid Metropolitan Area, Spain serves as a case study. A questionnaire, administered via face-to-face interviews, recorded the resident’s walking preferences for reaching in-store retail. A gravity-based model was used to calculate real and potential accessibilities, which were combined to map four accessibility places that originate spatial inequalities: advantageous, moderately advantageous, moderately disadvantageous, and disadvantageous. The results suggest that potential accessibility values are higher than real accessibility values, and the final map shows the city centre residents (mostly seniors) benefit from the advantageous accessibility places. Disadvantageous places are mainly found in the city’s periphery, where younger people live.