Governance, institutional and economic frameworks for Urban Forests as a Nature-Based Solution in Europe.

Urban forests as nature-based solutions (UF-NbS) play a crucial role for promoting the health and well-being of urban populations. Despite increasing recognition of their importance, knowledge gaps remain regarding UF-NbS implementation, particularly with respect to their performance, their perception, and on decision-making and governance practices for their implementation and management. Grounded in a project-as-practice approach and based on sixteen UF-NbS case histories, this paper seeks to gain insights into UF-NbS project actualities by an identification of characteristic trends as a function of a projects' scope and purpose, or challenge-orientation, respectively. A particular emphasis is on project structure and coordination, on the scope and depth of participation and stakeholder involvement, and on funding mechanisms. Identified trends reveal centrally coordinated, single-responsible public authorities as the most common project structure, but with certain feature contents, i.e., regeneration and reclamation, as being associated with more decentralised forms of governance. It is concluded that irrespective of challenge-orientation, comparatively broad participation appears to be realised within the UF-NbS framework, however, the depth of participation differs considerably. With respect to funding, a strong reliance on public capital is asserted for the UF-NbS context, however, various forms of private contributions appear reasonably common across the assessed case histories. Recommendations for policy-making and avenues of future research are identified, including the validation of identified trends, the fostering of collaboration, the dispersal of decision-making authority, the encouragement for implementing non-tokenistic modes of participation in UF-NbS governance, and the promotion of potentially under-utilised funds.

Reinforcing nature-based solutions through tools providing social-ecological-technological integration.

While held to be a means for climate change adaptation and mitigation, nature-based solutions (NbS) themselves are vulnerable to climate change. To find ways of compensating for this vulnerability we combine a focused literature review on how information technology has been used to strengthen positive social-ecological-technological feedback, with the development of a prototype decision-support tool. Guided by the literature review, the tool integrates recent advances in using globally available remote sensing data to elicit information on functional diversity and ecosystem service provisioning with information on human service demand and population vulnerability. When combined, these variables can inform climate change adaptation strategies grounded in local social-ecological realities. This type of integrated monitoring and packaging information to be actionable have potential to support NbS management and local knowledge building for context-tailored solutions to societal challenges in urban environments.

A trait-based typification of urban forests as nature-based solutions.

Urban forests as nature-based solutions (UF-NBS) are important tools for climate change adaptation and sustainable development. However, achieving both effective and sustainable UF-NBS solutions requires diverse knowledge. This includes knowledge on UF-NBS implementation, on the assessment of their environmental impacts in diverse spatial contexts, and on their management for the long-term safeguarding of delivered benefits. A successful integration of such bodies of knowledge demands a systematic understanding of UF-NBS. To achieve such an understanding, this paper presents a conceptual UF-NBS model obtained through a semantic, trait-based modelling approach. This conceptual model is subsequently implemented as an extendible, re-usable and interoperable ontology. In so doing, a formal, trait-based vocabulary on UF-NBS is created, that allows expressing spatial, morphological, physical, functional, and institutional UF-NBS properties for their typification and a subsequent integration of further knowledge and data. Thereby, ways forward are opened for a more systematic UF-NBS impact assessment, management, and decision-making.

Deliberating options for nature-based river development: Insights from a participatory multi-criteria evaluation.

To address societal challenges in river landscapes, various options are conceivable that differ in the degree of adopting nature-based solutions (NBS) and the respective impacts on people and nature. Multi-criteria evaluation (MCE) can aid participatory deliberations about the performance and significance of such options. However, little experience and evidence exist from the application of participatory MCE in planning NBS in river landscapes. This study aims to expand the understanding of individual and collaborative judgments of agency representatives about river development options with varying levels of NBS interventions. A process tracing approach with a rigorous participatory MCE for four alternatives to develop an exemplary river in Germany is adopted, as well as weighted linear aggregation, descriptive statistics, principal component analysis, and decision tree modelling for data analysis. The results reveal a wide agreement among participants on the positive impacts of NBS on biodiversity and water quality. Participants also tended to judge those ecological dimensions as more important than non-ecological ones. The rankings of alternatives differed when elicited individually but seemed to converge during the deliberation process. Overall, the results indicate a relative preference of participants for medium NBS interventions, but also shed light on potential implementation hurdles. The study closes by proposing key questions to consider for MCE of NBS.

Creating accessible evidence bases: Opportunities through the integration of interactive tools into literature review synthesis.

The COVID-19 pandemic has shown that an immediate access to relevant information is key for timely interventions and forming of public opinion and discourse. In this regard, dashboards present themselves as invaluable tools for the democratization of data and for the creation of accessible evidence bases. Building on this momentum, it is proposed to integrate interactive means such as dashboards into academic literature review synthesis, in order to support the summarization, narration, and dissemination of findings, and furthermore, to increase transparency and support the transferability and comparability of findings. Exemplified for a systematic literature review on urban forests as nature-based solutions,•Key functionalities, requirements and design considerations for the development of dashboards for use in academic literature reviews synthesis are identified.•An application architecture that embeds dashboard development into an R workflow is presented, with emphasis on the steps needed to transform the data collected during the review process into a structured form.•Technical and methodological means for the actual dashboard implementation are highlighted, considering the identified key functionalities and requirements.

Governance models for nature-based solutions: Seventeen cases from Germany.

Nature-based solutions (NBS) for mitigating climate change are gaining popularity. The number of NBS is increasing, but research gaps still exist at the governance level. The objectives of this paper are (i) to give an overview of the implemented NBS for flood risk management and mitigation in Germany, (ii) to identify governance models that are applied, and (iii) to explore the differences between these models. The results of a hierarchical clustering procedure and a qualitative analysis show that while no one-size-fits-all governance model exists, polycentricism is an important commonality between the projects. The study concludes by highlighting the need for further research on traditional governance model reconversion and paradigm changes. We expect the findings to identify what has worked in the past, as well as what is important for the implementation of NBS for flood risk management in future projects.

Integrative assessment of climate change for fast-growing urban areas: Measurement and recommendations for future research.

Over the 20th century, urbanization has substantially shaped the surface of Earth. With population rapidly shifting from rural locations towards the cities, urban areas have dramatically expanded on a global scale and represent crystallization points of social, cultural and economic assets and activities. This trend is estimated to persist for the next decades, and particularly the developing countries are expected to face rapid urban growth. The management of this growth will require good governance strategies and planning. By threatening the livelihoods, assets and health as foundations of human activities, another major global change contributor, climate change, became an equally important concern of stakeholders. Based on the climate trends observed over the 20th century, and a spatially explicit model of urbanization, this paper investigates the impacts of climate change in relation to different stages of development of urban areas, thus evolving a more integrated perspective on both processes. As a result, an integrative measure of climate change trends and impacts is proposed and estimated for urban areas worldwide. We show that those areas facing major urban growth are to a large extent also hotspots of climate change. Since most of these hotspots are located in the Global South, we emphasize the need for stakeholders to co-manage both drivers of global change. The presented integrative perspective is seen as a starting point to foster such co-management, and furthermore as a means to facilitate communication and knowledge exchange on climate change impacts.

On the Nexus of the Spatial Dynamics of Global Urbanization and the Age of the City.

A number of concepts exist regarding how urbanization can be described as a process. Understanding this process that affects billions of people and its future development in a spatial manner is imperative to address related issues such as human quality of life. In the focus of spatially explicit studies on urbanization is typically a city, a particular urban region, an agglomeration. However, gaps remain in spatially explicit global models. This paper addresses that issue by examining the spatial dynamics of urban areas over time, for a full coverage of the world. The presented model identifies past, present and potential future hotspots of urbanization as a function of an urban area's spatial variation and age, whose relation could be depicted both as a proxy and as a path of urban development.

Flood risk assessment in European river basins--concept, methods, and challenges exemplified at the Mulde River.

Flood risk assessment is an essential part of flood risk management, a concept that is becoming more and more popular in European flood policy and is part of the new European Union flood directive. This paper gives a brief introduction into the general concept and methods of flood risk assessment. Furthermore, 3 problems in the practical application of flood risk assessment, particularly on the river basin scale, are discussed: First, uncertainties in flood risk assessment; second, the inclusion of social and environmental flood risk factors; and third, the consideration of the spatial dimension of flood risk. In the 2nd part of the paper a multicriteria risk mapping approach is introduced that is intended to address these 3 problems.