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Nature-Based Solutions concepts and practices are being used worldwide as part of attempts to address societal challenges but have also been criticised for not dealing with deeper transformations needed to face urgent issues including biodiversity loss, climate change and inclusion. In this paper, we explore how an inclusive, integrated and long-sighted approach, emphasising a more radical integration of nature within cities, might support the transformations needed to endure major contemporary challenges. Addressing important emerging critiques of Nature-Based Solutions, we consider the potential of a more incisive form of Nature-Based Thinking (NBT) in cities, based on more holistic perspectives. The paper draws on a reflective and iterative research process that engaged both the research and practice communities through a symposium and a series of futures workshops that together explored the potential of NBT to develop future nature-cities relations in Europe and Latin America. The results of the reflective process suggest that notions of nature with people—not for people— new organisational structures, and the intention and capacity to apply long-term perspectives, are needed when planning for NBS interventions aimed at sustainable urban development. This includes developing a cultural-structural change based on new and inclusive understandings of human–nature relations, and novel governance paradigms that allow cross-sectoral coordination and engagement of local stakeholders beyond formal organisational structures. [ABSTRACT FROM AUTHOR]

Masked or yellow-faced bees of the genus Hylaeus (Colletidae) differ in their mode of pollen transportation from most other bees in that they ingest the pollen directly on the flowers and carry it back to the nest inside the crop located in the anterior half of the metasoma. Due to this hidden mode of pollen transportation, the examination of pollen collected by Hylaeus females requires the dissection of the metasoma. Although this method has never been applied in Europe, the great majority of the Central European Hylaeus species were supposed to be pollen generalists based on observations of flower visits. The microscopical analysis of pollen removed from 30 crops each of 36 Central European Hylaeus species revealed that the proportion of species exhibiting an exclusive or strong preference for pollen from a single plant taxon is much higher than hitherto assumed and that the current assumption of the genus Hylaeus to largely consist of pollen generalists is wrong. Nineteen of the 36 species examined are strictly or largely dependent on a single plant taxon for collecting pollen, such as Apiaceae (n = 11 species), Rosaceae (n = 3), Reseda (Resedaceae) (n = 2), Allium (Amaryllidaceae) (n = 1), Asteraceae (n = 1) and Melilotus (Fabaceae) (n = 1). The 36 Hylaeus species examined collected pollen from the flowers of 31 plant families, of which the Apiaceae and Rosaceae (particularly Potentilla and Rubus) were by far the most important contributing almost 60% to the pollen host spectrum of the entire genus. The comparison between pollen host spectrum and flower visiting records showed that the pollen generalists use the flowers of the Asteraceae as nectar rather than pollen sources, corroborating earlier findings that the digestion of Asteraceae pollen requires physiological adaptations to cope with its unfavourable or protective properties. In summary, the patterns of pollen host use by bees of the genus Hylaeus do not substantially differ from those of other Palaearctic bee taxa despite the masked bees' unusual habit to ingest the pollen directly on the flowers and to transport it inside their body back to the nest. [ABSTRACT FROM AUTHOR]

Urban areas are increasingly experiencing extreme weather events, especially related to water (e.g., droughts, heatwaves, floods), which are devastatingly impacting infrastructure and human lives. Compact cities, conceived to create more robust, effective, and sustainable environments, are under pressure to increase their resilience by co-producing adaptive strategies mainly focused on the urban public space. However, public space design tends to face environmental challenges without sufficiently exploring their intersection with social issues (citizens living conditions and vulnerability) and political structures (governance). This contribution delves into how urban public space interventions are (not) moving towards achieving urban resilience in an integrated way instead of sectoral. A triple-loop approach has been developed and tested in ten urban public spaces in European compact cities in the last 25 years. The results report how most projects reinforce the social dimension by promoting citizen well-being through new quality standards in public spaces, excluding some citizenry's vulnerable segments (immigrants, women, and disabled). The political dimension reinforces hard adaptation measures to manage water resources, although increasing attention is put on nature-based solutions, and most projects ensure participation processes. Finally, the environmental dimension is the most transversal by increasing land conversion, ensuring flooding mitigation, and enhancing adaptive capacity. [ABSTRACT FROM AUTHOR]

The studies that focus on smart growth obviously show that countries interpret this concept in accordance with their own structures. The aim of smart growth in the US is more about planning the cities, in other words, smart cities. However, the concept is used equivalently to developing an economy based on knowledge and innovation in the EU, as it is mentioned in the Europe 2020 Report. For both of the different concepts of smart growth, the important part is that it has to include green policies to support sustainable development. Based on this fact, greenhouse gas (GHG) emissions is a crucial indicator to analyze the countries' sustainable development policies. This study aims to examine the relationship between smart growth and sustainable development in the EU. By following the EU's smart growth concept; this research mainly analyzes GHG emissions, as it is one of the main indicators of sustainable development. The study first specifies the sectors and countries with the highest share of GHG emissions in the EU, so that the sectors that need priority can be determined for policymakers. The results figure out that the energy sector has the most significant contributions to these emissions. In addition to this, the emissions of greenhouse gases and air pollutants from final use of CPA08 products are classified and their trends are examined. Direct emissions by private households has the largest share with a percentage of 19,04% in 2017. This ranking is followed by electricity, gas, steam and air conditioning with 8,57% and constructions and construction works with 7,22%. Considering all these information and the data, it is concluded that the EU should implement urgent and primary policies to reduce GHG emissions in the energy sector in order to achieve its smart growth, and hence sustainable development. [ABSTRACT FROM AUTHOR]

Mono-centric regions have experienced a progressive transformation towards polycentric structures. Transition to discontinuous and dispersed spatial configurations was particularly evident in formerly compact and dense European cities, as a result of increasingly complex commuting patterns. Under the hypothesis that central locations have a balanced rate of resident population to internal workers and attract workers from neighbouring places, a multivariate analysis of commuting patterns may reveal latent transformations of compact, mono-centric cities towards polycentrism and settlement scattering. A more comprehensive understanding of the intimate nature and implications of urban transitions taking place in the last decades in Athens (Greece), a representative metropolitan region in southern Europe, was carried out using census data analyzed through a framework integrating descriptive statistics and mapping, multivariate exploratory data analysis, non-parametric inference and regression models. The analytical framework was proposed with the aim to assess commuting patterns vis à vis urban hierarchy in a context of (more or less) de-centralized growth. Empirical results for the study area indicate the persistence of a bi-centric spatial structure gravitating on the central cities of Athens and Piraeus, with early formation of employment sub-centres and local-scale alterations of the mono-centric scheme as a result of discontinuous urban expansion. Exurban development was associated with the formation of self-contained sub-centres with an increasing proportion of workers in total resident population. [ABSTRACT FROM AUTHOR]

Changes in urban residential density represent an important issue in terms of land consumption, the conservation of ecosystems, air quality and related human health problems, as well as the consequential challenges for urban and regional planning. It is the decline of residential densities, in particular, that has often been used as the very definition of sprawl, describing a phenomenon that has been extensively studied in the United States and in Western Europe. Whilst these studies provide valuable insights into urbanization processes, only a handful of them have reflected the uneven dynamics of simultaneous urban growth and shrinkage, using residential density changes as a key indicator to uncover the underlying dynamics. This paper introduces a contrasting analysis of recent developments in both de- and re-concentration, defined as decreasing or increasing residential densities, respectively. Using a large sample of European cities, it detects differences in density changes between successional population growth/decline. The paper shows that dedensification, found in some large cities globally, is not a universal phenomenon in growing urban areas; neither the increasing disproportion between a declining demand for and an increasing supply of residential areas nor actual concentration processes in cities were found. Thus, the paper provides a new, very detailed perspective on (de)densification in both shrinking and growing cities and how they specifically contribute to current land take in Europe. [ABSTRACT FROM AUTHOR]

Soil sealing has negative impacts on ecosystem services since urban green and soil get lost. Although there is political commitment to stop further sealing, no reversal of this trend can be observed in Europe. This paper raises the questions (1) which strategies can be regarded as being efficient toward ecologically sustainable management of urban soil sealing and (2) who has competences and should take responsibility to steer soil sealing? The analyses are conducted in Germany. The assessment of strategies is carried out using indicators as part of a content analysis. Legal-planning, informal-planning, economic-fiscal, co-operative, and informational strategies are analyzed. Results show that there is a sufficient basis of strategies to secure urban ecosystem services by protecting urban green and reducing urban gray where microclimate regulation is a main target. However, soil sealing management lacks a spatial strategically overview as well as the consideration of services provided by fertile soils. [ABSTRACT FROM AUTHOR]