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Abstract Wildlife in cities divides people, with some animals bringing positive benefits and others causing conflict, for example due to property damage. Urban wildlife professionals from municipal administration, nature conservation, and hunting associations have a crucial role in shaping human‐wildlife relationships in cities and fostering conflict‐free coexistence. While many studies on urban wildlife have focused on the views of citizens, few have investigated the perspectives of experts to date. To address this knowledge gap, we interviewed 36 urban wildlife professionals giving guidance in the context of urban wildlife management, either in one of the four largest German cities by population (Berlin, Hamburg, Munich and Cologne) or at the national level. Red foxes, wild boars, raccoons, stone martens and Eurasian beavers were the five mammal species most frequently highlighted in interviews to cause human‐wildlife conflicts. The interviewees saw wild boars and raccoons as the most controversial urban wild mammals but emphasized the need to create refuges for beavers and better inform the public about foxes. Management in terms of public outreach, urban planning and population control, as well as establishing official contact points and stricter fines of activities violating regulations were highlighted as important elements of a toolkit to manage urban wildlife conflicts. Read the free Plain Language Summary for this article on the Journal blog.

Future cities have the potential to be biodiverse areas in which humans and wildlife can coexist. However, the success of creating or maintaining wildlife-inclusive future cities can be challenged by management actions that are solely based on ecological research, while overlooking research on human perspectives. Despite the growth of literature on human-wildlife interactions, which complements the breadth of urban ecology research, the overlap between these two research areas is still uncommon. In this study, we reviewed the literature of wild mammals in urban areas to identify patterns and gaps in the literature. We found 848 published journal articles, of which 480 articles focused on wildlife ecology, 269 articles focused on human dimensions and 99 articles had interdisciplinary combinations of both. Ecology-centered publications tended to be about habitat, rather than behavior, diet, health, reproduction and inter-species-relations, and literature on human dimensions was more evenly divided into management, perception, conflict and coexistence. Most ecology studies reported on specific taxonomic families, mainly canids and murids, but in human-dimension studies, “wildlife” was considered more as a general community of species. The most studied interdisciplinary combination of research themes was wildlife habitat and human-wildlife conflicts (n = 22), while only nine studies incorporated perception with ecological research. Even though studies on human dimensions of wildlife in cities are increasing, interdisciplinary research is lacking, which limits the knowledge on how to manage and shape urban areas to achieve coexistence of humans and wild mammals. For future cities to successfully become biophilic and support human-wildlife coexistence, we outlined five key elements for a research agenda: 1) Investigate urban mammal research through an interdisciplinary lens; 2) Explore ecological dynamics beyond habitat selection; 3) Conduct research for coexistence; 4) Disentangle what is “urban wildlife”; 5) Study a diverse array of urban wild mammals.

Abstract While reintroductions of regionally extinct native species usually benefit ecosystems, reintroduced animals often struggle to locate appropriate habitats where they can establish themselves without conflict with humans. European beavers (Castor fiber) were successfully reintroduced to Germany almost 60 years ago and have reached high abundances again. As beavers can damage trees and change landscapes, they are increasingly in conflict with humans. We investigated human perceptions of beavers in Germany using an online survey, as they are an example of a reintroduced species with an expanding population and potential conflicts with humans. We asked participants about their emotions (anger, fear, interest, joy) towards beavers and what they consider to be acceptable beaver habitats. Of nearly 1500 survey participants, 803 (53%) were from the general public, 475 (32%) from the agricultural sector and 219 (15%) from forestry. People in these sectors had very different perspectives: beavers were positively perceived by the general public, but negatively by stakeholders working in agriculture and forestry. Independently of stakeholder groups, we also found regional differences, as participants from Bavaria—the German state with the highest beaver densities—viewed beavers more negatively than those from the rest of Germany. Zoos and wildlife parks, as well as urban and nature conservation areas, were considered to be the most acceptable habitats for beavers, whereas survey participants did not accept private gardens and cultivated areas as beaver habitats. We discuss the sources of negative emotions towards beavers and how ecologically suitable habitats differ from those that appear acceptable by humans. Even 60 years after their reintroduction, beavers in Germany are still being recognized as both a novelty and a nuisance. Our findings highlight the need for active beaver management and increased public engagement to enable positive coexistence between beavers and humans in Germany. Read the free Plain Language Summary for this article on the Journal blog.

Abstract Soils, just like all other ecosystem compartments, change over time and, consequently, conditions for soil‐inhabiting organisms are also changing, affecting their composition and diversity. Soil biodiversity is a critical component of ecosystems that supports many essential ecosystem functions and services, such as nutrient cycling, carbon sequestration, water regulation and biomass production for food, fodder, fibre and energy. However, and despite the importance of soil biodiversity for ecosystem health and human well‐being, neither current state, drivers, potential consequences for ecosystem services nor options for sustainable governance of soil biodiversity are well understood. Here, we provide a framework for and argue that conducting a national assessment of soil biodiversity, albeit being a complex endeavour, is fundamental to building a baseline to understand the current state and trends of soil biodiversity, but also to identify the main drivers of change, the impacts of soil biodiversity loss and the potential pathways for conservation and sustainable governance of soil biodiversity.

As natural habitats decline and wildlife adapts to increasing anthropogenic disturbance, it is crucial to understand human-wildlife relationships in residential areas. However, relevant studies are limited and mostly focused on single cities. To address this knowledge gap, we investigated people’s preferences for seeing wild mammals in residential areas by conducting and analyzing an online survey distributed across Germany (n = 2997 participants). Our results revealed that preferred species (squirrels, hedgehogs, hares, roe deer) were frequently encountered, whereas unpreferred species were those encountered frequently (rats, martens), as well as those encountered rarely (wild boar, coypus, raccoons). We also found a moderately positive correlation between the number of encounters with mammals and them being preferred by humans. Finally, some socio-demographic variables, particularly gender, garden access, and urbanity, are significantly related to human preferences. Based on our results, we propose tailoring wildlife management in residential areas to promote the positive attributes of preferred wildlife as biodiversity ambassadors, while also addressing ways to mitigate encounters and negative perceptions associated with unpreferred species.

Abstract Gardens in cities have been the focus of a wider public health debate in Europe's polluted and dense cities, for the elderly and considering the current COVID‐19 pandemic. Many cities report rising demand for allotment gardens by people from all age groups including young couples and families. This study aims at quantitatively examining the bundle of ecosystem services provided by allotment gardens in Berlin, Germany. It assesses the values related to those ecosystem services' benefits for gardeners and the wider urban public and compares perceptions of the social–environmental value of allotment gardens by gardeners and non‐gardeners. We also compare the frequency of garden visits and the perception of gardens as a crucial element of the urban ecosystem by men and women. We carried out a web‐based survey, additionally a part of the questionnaires was handed out in paper form for respondents who did not have internet access. The resulting sample of 466 gardeners and 80 non‐gardeners shows that urban allotment gardens play an important role in food production, biodiversity conservation, but also social–environmental interactions. The variety of environmental management practices, such as installation of artificial nests for insects, sowing of special flower mixtures, leaving areas with wild vegetation, use of organic fertilizers, including crop residues, shows that most respondents among gardeners are aware of the methods aimed at maintaining biodiversity and soil fertility in their allotment. The sample's analysis further states that benefits are not only perceived by gardeners but also by non‐gardeners. We discuss our findings against the background of the savings and sustainable enhancement of ecosystem services benefits that are created by allotment gardens for all. Read the free Plain Language Summary for this article on the Journal blog.

The impacts of the availability and spatial configuration of urban green spaces (UGS) on their cooling effects can vary with background climate conditions. However, large-scale studies that assess the potential heterogeneous relationships of UGS availability and spatial configuration with urban thermal environment are still lacking. In this study, we investigated the impacts of UGS availability and spatial configuration on urban land surface temperature (LST) taking 306 cities in China as a case study covering a multi-biome-scale. We first calculated the availability of surrounding UGS for urban built-up pixels in each city using a distance-weighted approach, and its spatial configuration was quantified through the Gini coefficient. Then, we employed various regression models to explore how the impacts of UGS availability and the Gini coefficient on LST varies across different LST quantiles and between day- and nighttime. The results revealed that UGS availability was negatively associated with both daytime and nighttime LST, while the Gini coefficient showed a positive impact solely on daytime LST, indicating that an adequate and equally distributed UGS contributes to lower environmental temperatures during the daytime. Furthermore, the impact of UGS availability on LST decreased during both day- and nighttime with increased background LST quantiles. Whereas the impact of the Gini coefficient increased only with daytime LST quantile levels, with its effect remaining almost insignificant during the night. Our findings provide new insights into the impacts of UGS on urban thermal environment, offering significant implications for urban green infrastructure planning aiming at lowering the urban heat island.

Community-supported agriculture (CSA) has the potential to reduce food loss and waste (FLW) due to a direct connection between consumers and producers, lower standards regarding product aesthetics and consumer-related values. Accordingly, CSA could compensate for possible yield gaps compared to conventional agriculture. Here, FLW and yields were assessed for one year in four CSA initiatives in the area of Leipzig, Germany, and compared to reference data. The results show that FLW during production, distribution and consumption were on average 22–70% lower compared to reference data. On average, due to lower FLW, the CSA initiatives could compensate for yield gaps of 32%, which reflects yield gaps typically observed between organic and conventional agriculture. Actual yield gaps in CSA might be lower, as agroecological approaches to increase productivity are widely adopted. The co-evaluation of the results with CSA gardeners showed that FLW could be further reduced in all stages. Reducing FLW was mentioned as an important sustainability goal of the investigated CSA initiatives, yet they also indicated a focus on biodiversity, education, food quality or the reduction of fossil fuels. This pilot study indicates that CSA can contribute to the transition towards sustainable and resilient food systems.

Book review

Abstract Spatio-temporal density trends are considered key indicators of urban development. However, similar density trends may hide different drivers. This study investigates the density trends of 331 European cities between 2006 and 2018 and the underlying trends in residential area and population, broken down into natural change and net migration. The analysis captured a shift in the predominant trend from de-densification (2006–2012) to densification (2012–2018). Two main drivers determined the shift: (i) a more diffused growth of urban population, and (ii) a slowdown of land take for residential use after the global financial crisis of 2008. A clear acceleration in net migration rates, with immigration pushing population growth, occurred in most cities turning from de-densification to densification. Despite path dependencies and enduring differences across regions and city sizes, the distribution of these trends partly redesigned the traditional European East-West dichotomy into a novel center-periphery division.

Abstract Human–wildlife interactions (HWIs) are increasingly common human disturbances as development continues to remove wildlife habitats. Documenting HWI is critical for environmental protection agencies to develop strategies and management decisions that meet the needs of both people and wildlife. However, evaluation of the frequency and types of HWI at broad spatial scales (e.g., national or regional level) can be costly and difficult to implement by managers. In this study, we apply a novel method for the evaluation of patterns of HWI in urban areas by using publicly available data from emergency calls (ECs) placed by inhabitants of Romania's urban areas. We used information from 4601 ECs placed at the Romanian National Emergency Call System 112, which consisted of (1) wildlife species, (2) spatial location, (3) date and time, and (4) a short description of the emergency. Of the 318 analyzed cities, 300 cities documented ECs on HWI between 2015 and 2020, with roe deer and brown bear being the most frequently mentioned species. We recorded an increasing trend in HWI‐related ECs in 73% of the urban areas over the five‐year period. We mapped the large‐scale distribution of HWI by species and type of interactions in order to capture variations at the national level. Further, we analyzed the social and the biophysical factors potentially influencing the occurrence and frequency of HWI. The results showed that social factors have the same effect on all species, while the effect of the biophysical factors varied between species. Particularly, the presence of large natural habitats, represented by forests, influenced the number of calls only for brown bears. Seminatural landscapes with agricultural land have a different influence in terms of effect and significance for the considered species. Our results suggest that publicly available data from ECs can be used for the rapid assessment of HWI and for evaluating trends and predictors of HWI at broad spatial scales.

Hunting and its impacts on wildlife are typically studied regionally, with a particular focus on the Global South. Hunting can, however, also undermine rewilding efforts or threaten wildlife in the Global North. Little is known about how hunting manifests under varying socioeconomic and ecological contexts across the Global South and North. Herein, we examined differences and commonalities in hunting characteristics across an exemplary Global South-North gradient approximated by the Human Development Index (HDI) using face-to-face interviews with 114 protected area (PA) managers in 25 African and European countries. Generally, we observed that hunting ranges from the illegal, economically motivated, and unsustainable hunting of herbivores in the South to the legal, socially and ecologically motivated hunting of ungulates within parks and the illegal hunting of mainly predators outside parks in the North. Commonalities across this Africa-Europe South-North gradient included increased conflict-related killings in human-dominated landscapes and decreased illegal hunting with beneficial community conditions, such as mutual trust resulting from community involvement in PA management. Nevertheless, local conditions cannot outweigh the strong effect of the HDI on unsustainable hunting. Our findings highlight regional challenges that require collaborative, integrative efforts in wildlife conservation across actors, while identified commonalities may outline universal mechanisms for achieving this goal.

Mining in general, and particularly mining for energy resources such as coal and lignite, results in massive impacts on the surrounding landscape and ecosystems. Post-mining reclamation that takes account of the disturbed ecosystem services requires a research approach that links the mining impact to ecosystem functions and ecosystem service potentials. The method used in this paper combines the Driving Forces–Pressures–State–Impact–Response (DPSIR) framework and the ES cascade approach by complementing the limitations of each approach with the strengths of the other. The DPSIR framework is extended to a causal network to account for the multiple interconnected causal chains of coal and lignite mining impacts. The presented causal network supports the identification of ES indicators for the assessment, planning, and monitoring of post-mining reclamation in coal/lignite mining landscapes. The presented approach can also inform political and administrative decisions by identifying the ecosystem elements at risk of being degraded from mining.

An urban agglomeration is the engine of regional and national economic growth, but also causes many ecological and environmental issues that emerge from massive land changes. In this study, the spatiotemporal evolution of an urban agglomeration was quantified and its impacts on the urban and regional landscape patterns were evaluated. It showed that the urbanized land area of the Pearl River Delta Urban Agglomeration (PRDUA) in China nearly quadrupled, having linearly increased from 1819.8 km2 to 7092.2 km2 between 1985 and 2015. The average annual growth rate presented a bimodal wave-like pattern through time, indicating that the PRDUA has witnessed two rounds of the urbanization process. The growth modes (e.g., leapfrog, edge-expansion, infilling) were detected and they exhibited co-existing but alternating dominating patterns during urbanization, demonstrating that the spatiotemporal evolution of the urban development of the PRDUA follows the “spiral diffusion-coalescence” hypothesis. The morphology of the PRDUA presented an alternating dispersal-compact pattern over time. The city-level and regional-level landscape patterns changed synchronously with the spatiotemporal evolution of the PRDUA over time. The urbanization of the PRDUA increased both the complexity and aggregation of the landscape, but also resulted in an increasing fragmentation and decreasing connectivity of the natural landscape in the Pearl River Delta region. These findings are helpful for better understanding how urban agglomerations evolve and in providing insights for regional urban planning and sustainable land management.

Trees are one of the most important elements of green infrastructure in cities. Climate change is specifically affecting trees in many European cities. Trees are experiencing negative impacts from the increase in heat waves and droughts, both of which begin, in some cases, early in the year and continue through the growing season. Current studies on the regionalization of climate change indicate that important water reservoirs such as soil and tree canopies have been drying out for years/decades, and these impacts can be observed in various parts of Europe. Trees react to stress as they age through mechanisms such as crown defoliation, early wilting, shedding of branches and, ultimately, lowered resistance to pests. As a result, massive tree death, both in park trees and street trees, can be observed in many cities. The present study provides a current inventory of street tree damage caused by heat and drought in the city of Leipzig, Germany, in 2020, the third extreme dry year after 2018 and 2019. The field maps focus on different age groups of Quercus, Tilia, Aesculus, Platanus, Fraxinus and Acer along a periurban-urban gradient. The results are clear: significant damage was found in all tree species. Older trees and newly planted trees are most likely to die as a result of extreme conditions, while younger trees with narrow trunks and crowns that have not yet expanded cope better with both heat and drought. Four out of five mapped street trees showed recognizable damage, indicating severe impacts of climate change on important elements of green infrastructure in cities.

Payments for ecosystem services (PES) gained an increasing importance in science and politics within the last decades. Although the enthusiasm about PES is particularly high in Environmental Economics, opponents criticize the market-based character of PES and the associated commodification as well as privatization trends. By means of a systematic literature review we aim at shedding light on the complex and controversial debate about how to define commodification and related privatization processes and how they are linked to PES outcomes. We do so by setting a particular focus on the potentials and challenges of community-based and collective PES (C-PES), also in contrast to PES targeting land under private land tenure (P-PES). Our results reveal that C-PES show promising results when targeting local communities with a high level of social capital. However, there is a lack of studies that systematically assess the relations between different degrees of commodification and the ecological and social outcome of PES programs. For this reason, we provide a new conceptual framework of commodification by highlighting two interrelated spheres, where PES-related commodification processes take place: The first sphere relates to the commodification of ES-providing land, which greatly depends on the land tenure regime in place. The second sphere addresses the commodification of ecosystem services (ES). Our review indicates that C-PES show rather low degrees of commodification in the first sphere because the ES-providing land is often less embedded into private land markets. This is due to often missing alienation rights, more complex decision-making processes, and a potentially lower profit-orientation of the landowners. Empirical long-term studies are needed to investigate changes in both spheres of commodification over time, their potential interactions, and how they affect the outcome of C-PES and P-PES programs.

Abstract Efforts to curb the unsustainable wildlife trade in tropical forests conceptualize bushmeat as a generic resource, exploited by a homogeneous group. However, bushmeat is composed of miscellaneous species differing in risks of zoonotic disease transmissions, sensitivity to hunting and abundance. If people choose these species for varying reasons, mitigation approaches that neglect specific drivers would likely target abundant species, e.g. rodents. Meanwhile, rare species of greater conservation relevance, like many primates, would be overlooked. Additionally, if reasons vary between user groups, their responsiveness to interventions may differ too. We assessed this possibility for three common strategies to mitigate bushmeat use, which are: development‐based—reducing reliance on bushmeat; educational—increasing environmental and school education; and cultural—promoting environmentally friendly habits. We interviewed 348 hunters, 202 traders and 985 consumers of bushmeat around Taï National Park, Côte d'Ivoire, and tested if factors related to the above strategies affected selection for primates, duikers and rodents. Our analyses revealed that people chose taxa for very different reasons. Users with shared characteristics favoured similar taxa; hunters economically reliant on bushmeat income targeted primates and duikers, while hunters and consumers nutritionally reliant on wildlife protein preferred rodents. Different groups used the same taxa for varying reasons. For example, hunting of primates was associated with economic needs, while their consumption appeared a matter of status. Meanwhile, cultural habits, like religion, specifically affected consumption and taboos inhibited the use of primates; environmental awareness was linked to lower utilization of most taxa within most user groups. Our results demonstrate that educational‐, cultural‐, and development‐based strategies may address different needs and taxa. Consumers may present a key target group, as they rejected rare species for multiple cultural and educational reasons. Notably, the widespread effect of environmental awareness could facilitate large‐scale demand‐reduction approaches. Nevertheless, there is no one‐size‐fits‐all solution and campaigns need to be tailored to specific taxa and user groups. Ultimately, clear target definitions, prior in‐depth research, community‐driven solutions and tools from marketing and psychology may help to design novel strategies that encompass the diversity of bushmeat species and its users. A free Plain Language Summary can be found within the Supporting Information of this article.

Compared to rural environments, cities are known to be extraordinarily rich in plant species. In particular, the proportion of alien plant species is higher in urban areas. This is attributed to specific urban conditions, which provide a large variety of habitats due to high geological heterogeneity. It can also be attributed to the role of cities as centres for plant introductions and the consequential increased propagule pressure. Neophytes, alien plant species introduced after the discovery of the Americas, appear to contribute especially strongly to the increased proportion of alien plants in cities. To investigate whether the plant traits of neophytes can be explained by environmental variables, we modelled the composition of their pollination types and growth forms as well as their diaspore weight and the onset of flowering in response to a selection of climatic, geological, land cover and traffic network variables with data from Germany. To test for a specific urban effect, we included their interactions with the area of urban land use. In general, we found that climatic variables were the most important predictors for all traits. However, when considering interactions with urbanisation, non-climatic variables, which often were not significant as the main effect, remained in the final models. This points to an existing ‘urban effect’. However, it is much smaller compared to the purely climatic effects. We conclude that interferences and alterations mainly related to urbanisation and human activity in general are responsible for the different ecological processes found in cities compared to rural areas. In addition, we argue that considering functional traits is an appropriate way to identify the ecological mechanisms related to urbanisation.

Urban nature reserves in Poland are precious relics of ancient nature with preserved biodiversity. They consist of valuable trees several 100 years old, are biodiverse, and are valuable recreational spaces right in and around cities. It is therefore critical to manage tradeoffs between visitor safety due to, e.g., falling dead branches and the need for old-grown trees for biodiversity conservation. This study aimed to determine whether airborne laser scanning data (LiDAR) can confirm that trees exhibiting the worst crown defoliation are the first to be damaged in storms. Our results show that during Storm Eunice in 2022, the detected defoliated trees, in fact, were damaged the most. Despite such evidence available to the city, no targeted changes to the management of the reserves were taken after the storm. One of the forests was completely closed to visitors; in the other forest, areas with damaged trees were fenced off, and then, the remaining branches and fallen trees were removed to make the forest available for recreation. Using available evidence such as LiDAR data, we propose more targeted and nuanced forms of managing biodiversity conservation in conjunction with visitor safety. This includes the establishment of priority areas, visitor information, and visitor management. This way, airborne laser scanning and Geographic Information Systems can be used to balance management needs accounting for both biodiverse old-grown forest structures while at the same time providing added safety for visitors.

The connectivity of green infrastructure facilitating the movement of organisms is the key to strengthening biodiversity in cities. Brownfields are a valuable land resource, with their revitalisation as a Nature Based Solution high on the policy agenda. In supporting cities which simultaneously aim for densification and the maintenance or further development of greenery, this paper develops a model for identifying and prioritising the role of revitalised and prevailing brownfields for the connectivity of green infrastructure using the example of Leipzig, Germany. Comparing metrics between land use categories, brownfields have a central role as stepping stones, with a value of 13%, while revitalised brownfields substantially contribute to global connectivity, with a value of 87% being equally important, for example, with Leipzig’s central parks. This paper’s spatial-explicit network approach provides a complementary planning tool for prioritising brownfields and the added value of their renaturing by identifying (a) strategic functional corridors formed by brownfields, (b) the connectivity relevance and exposure of individual brownfields, and (c) how renatured brownfields would strengthen existing corridors and form alternative paths. This paper presents an approach using freely available software tools and high-resolution canopy data as a proxy for functional connectivity which serves as a standardised and comparable ex-ante evaluation of NBS strategies being implemented in other cities.

In remote sensing (RS), shadows play an important role, commonly affecting the quality of data recorded by remote sensors. It is, therefore, of the utmost importance to detect and model the shadow effect in RS data as well as the information that is obtained from them, particularly when the data are to be used in further environmental studies. Shadows can generally be categorized into four types based on their sources: cloud shadows, topographic shadows, urban shadows, and a combination of these. The main objective of this study was to review the recent literature on the shadow effect in remote sensing. A systematic literature review was employed to evaluate studies published since 1975. Various studies demonstrated that shadows influence significantly the estimation of various properties by remote sensing. These properties include vegetation, impervious surfaces, water, snow, albedo, soil moisture, evapotranspiration, and land surface temperature. It should be noted that shadows also affect the outputs of remote sensing processes such as spectral indices, urban heat islands, and land use/cover maps. The effect of shadows on the extracted information is a function of the sensor–target–solar geometry, overpass time, and the spatial resolution of the satellite sensor imagery. Meanwhile, modeling the effect of shadow and applying appropriate strategies to reduce its impacts on various environmental and surface biophysical variables is associated with many challenges. However, some studies have made use of shadows and extracted valuable information from them. An overview of the proposed methods for identifying and removing the shadow effect is presented.

Cities face growing challenges and urban greenspaces (UGS) play a key role in improving cities liveability. UGS are complex socio-ecological systems and evidence-based and context-sensitive tools are needed to assist planning and manage environmentally sound and socially inclusive UGS. In this paper, we propose an innovative indicator-based tool to operationalize the biocultural diversity (BCD) framework in urban contexts, deriving from its three conceptual layers – materialized, lived and stewardship. Indicators proposed are bundled in themes representing essential components when assessing and analyzing urban BCD from a contextual and sensitizing perspective. The set of indicators highlight key features of socio-cultural and ecological systems, theirs links and interactions, both material and non-material, to capture the essence of biocultural diversity at site-level. By offering a uniform scoring system with the possibility to set site-specific benchmarks, these can be used in any type of greenspace of any city, while allowing different communities/neighborhoods/city councils to embrace different approaches to meet their objectives towards larger scale goals. Twelve urban parks in Lisbon were used as a test-bed for the indicator-based tool and proved its feasibility to gather an overall snapshot of all parks and to demonstrate the possibility to deepen the study to only two parks uncovering self-exclusion processes that otherwise would have remained hidden. The BCD tool brings together essential information scattered over several quality and good practices assessment tools and protocols and, by including indicators specifically addressing governance and stewardship, offers a policy-driven instrument able to capture trade-offs and/or synergies between ecological, social and political domains.

The understanding of urban social-ecological systems requires integrated and interdisciplinary methods. This paper explores differences in the accessibility of urban green spaces (UGS) based on urban morphology. In contrast to other comparative analyses that followed simplified quantification of UGS provision and/or omitted the impact of morphological properties of urban space, this study proposes three improvements. First, it uses the share of UGS in the service area of 300 m walking distance around each residential building in a city as a measure of UGS provision. Second, it includes the potential physical accessibility of UGS as warranted by key actors, such as owners or managers, who decide whether UGS are open or not to potential users. Third, it links UGS accessibility and heterogeneous urban structures. We developed a mixed-methods analysis that combines multiple data sources regarding UGS, the spatial distribution of residential buildings, and street networks. We conducted our analysis in five case-study cities (Barcelona, Halle, Lodz, Oslo, and Stockholm). Our findings suggest that the urban structures where the human–environment interaction transformed the space (such as in the core city areas) are characterized by limited UGS in the service area. Urban structures that are less transformed by human activity (especially suburbia) have the highest share of selected UGS in the service area. In addition, even if the share of UGS in the service area is high, many of them might have limited physical accessibility. In the broader sense, this highlights that social-ecological processes are linked to urban form and cannot be separated in an analysis. Therefore, social-ecological systems could be better understood through the lens of urban morphology.

Summary: Record climate extremes are reducing urban liveability, compounding inequality, and threatening infrastructure. Adaptation measures that integrate technological, nature-based, and social solutions can provide multiple co-benefits to address complex socioecological issues in cities while increasing resilience to potential impacts. However, there remain many challenges to developing and implementing integrated solutions. In this Viewpoint, we consider the value of integrating across the three solution sets, the challenges and potential enablers for integrating solution sets, and present examples of challenges and adopted solutions in three cities with different urban contexts and climates (Freiburg, Germany; Durban, South Africa; and Singapore). We conclude with a discussion of research directions and provide a road map to identify the actions that enable successful implementation of integrated climate solutions. We highlight the need for more systematic research that targets enabling environments for integration; achieving integrated solutions in different contexts to avoid maladaptation; simultaneously improving liveability, sustainability, and equality; and replicating via transfer and scale-up of local solutions. Cities in systematically disadvantaged countries (sometimes referred to as the Global South) are central to future urban development and must be prioritised. Helping decision makers and communities understand the potential opportunities associated with integrated solutions for climate change will encourage urgent and deliberate strides towards adapting cities to the dynamic climate reality.

Urban green spaces (UGS) provide important ecosystem services in cities as they support human health and wellbeing with fresh and cool air, beauty and space for physical activities. To benefit from the positive effects, citizens need access to UGS. Multi-layered barriers can restrict accessibility to green–blue infrastructure (GBI) and accompanying benefits. This study aims to quantify and visualize physical barriers to public and semi-public UGS in the city of Halle, Germany, focusing on three spatial dimensions regarding UGS. For each dimension, three indicator classes are defined as proxies for varying aspects of accessibility: inside, boundary, and outside. A barrier index was calculated for all public and semi-public UGS of the city that cumulated the ratings of each indicator class. The aggregation of all ratings for all three dimensions creates a final barrier index that illustrates all physical barriers of, to and within UGS. We can show to which degree UGS accessibility might be restricted in Halle. As the results show, inside barriers exhibit the highest barrier index indicating that accessibility is most restricted on this dimension of UGS throughout the city. Comparatively low barrier indices in the inner city indicate the best accessibility to UGS in the five districts. Moreover, semi-public UGS like gardens or cemeteries show higher levels of physical barriers than public ones. Linking the barrier index to current urban planning and examining how the indicators defined in this study are addressed in planning documents concerning the improvement of accessibility can be a useful tool for spatially identifying potential planning measures that can reduce physical UGS barriers.

Recently, pocket green spaces (PGS), i.e., small green spaces, have attracted growing attention for their various ecological and social services. As a crucial part of urban green spaces in high-density urban areas, PGS facilitates recreation and relaxation for neighborhoods and thus improves the livability of cities at the local scale. However, whether and how the PGS cools the urban heat island effect is still unclear. This research was performed in the highly developed areas of the city of Shanghai during hot summer daytime. We applied a set of cooling effect indicators to estimate the cooling extent, cooling intensity, and cooling efficiency of PGS. We further examined whether and how landscape features within and surrounding the PGS influence its cooling effects. The results showed that 90% of PGS are cooler than their surroundings. Among the landscape features, the land surface temperature of PGS logarithmically decreased with its area, and the maximum local cool island intensity and maximum cooling area logarithmically increased with the area of PGS. The vegetation types and their composition within the PGS also influenced their surface temperature and the cooling effect. The PGS dominated by tree-shrub-grass showed the highest cooling efficiency. The surrounding landscape patterns, especially the patch density and the landscape shape index, influence the cooling effect of PGS at both class and landscape levels. These findings add new knowledge on factors influencing the cooling effect of PGS, and provide the biophysical theoretical basis for developing nature-based cooling strategies for urban landscape designers and planners.

Two of the dominant processes shaping today’s European cities are the ageing and diversification of the population. Given that the range of action usually decreases in later life, the living environment around the place of residence plays an important role in the social integration of the older generation. Hence, spatial patterns of residence indicate the extent of opportunities for the older population to engage in urban life and, therefore, need to be addressed by urban planning and policy. The aim of this article is to study the interrelation between diversity in later life—in terms of migrant history, gender, social class, and age—as well as planned and actual (past) movements of elders. We have chosen Berlin as a case study and draw from a quantitative survey with elders (age 60+) from diverse backgrounds (N = 427). Our results from descriptive analysis and statistical hypothesis tests show that age impacts people’s past and planned movement; we observe a peak in the decisions to move at the age of 65–75 and a drop in the inclination to move among people over 80. None of the other factors is similarly influential, but we observe appreciable tendencies regarding the impact of gender and social class on planned movements. Our study suggests that variables other than classic socio-demographic data, such as apartment size, rent, social networks, and health, and their interrelations may offer a promising starting point for achieving a full picture of older people’s movement behaviour.

Although potential urban green space accessibility is being discussed widely, specific barriers that affect accessibility are often under-estimated. They do not equate to limited or uneven accessibility nor are they exclusively related to physical settings. Rather, the range of barriers and their complex interactions, including people’s perceptions, personal conditions, and institutional frameworks, make this topic less clear cut and difficult to put into practice for planning purposes. Given the importance of barriers when people make decisions, we present a conceptual framework to capture the cumulative and interactive effects of different barriers on realizing recreational benefits of urban green spaces. The framework classifies physical, personal, and institutional barriers and highlights their interactions based on three case studies: Stockholm, Leipzig, and Lodz. We argue that constraints to the accessibility of urban green spaces are not so much the interactions between various physical, personal, and institutional barriers, but more the significance that beneficiaries assign to them as perceived barrier effects. Studying barriers seeks to improve the knowledge about the non-use of urban green spaces and to enable us to draw conclusions about the actual accessibility of recreational benefits. Deduced from the conceptual framework, three pathways are contrasted for improving accessibility to the recreational benefits of urban green spaces: the environment, knowledge, and engagement. We argue that these pathways should not be a diffuse objective, but a sensitive and scale-dependent re-balance of individual, physical, and institutional factors for considering justice in environmental and green space planning and management. Our systematic conceptualization and classification of multidimensional barriers enables a more comprehensive understanding of individuals’ decisions in terms of accessing recreational benefits.

This article presents a pilot study investigating the multidimensional diversity of cemeteries as an important element of cultural heritage and green infrastructure within the urban landscape. We studied the state and diversity of nature, perceptions, and activities of visitors. As religion is an important aspect that differentiates cemeteries from each other, we studied a sample of four multi-confessional urban cemeteries in Łódź (Poland) and Leipzig (Germany) by using site observation and a questionnaire survey. We found that cemeteries are far undervalued as public green resources that can perform important functions in sociocultural life and the mental well-being of the general public, as the perceptions of silence- and contemplation-seeking visitors tell us. The perception of cemeteries depends on the level of secularization, varying from a sacrum sphere up to specific recreational and touristic opportunities; findings that should be considered by town planners when optimizing the cultural ecosystem services of green spaces.

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.

Cities that begin to regrow after a long period of decline and land abandonment are under pressure to provide comfortable housing conditions in preferred neighborhoods for their residents. On the other hand, these cities should preserve interim green spaces that result from decline because these spaces are a real treasure for densifying cities. Using the case of the city of Halle in post-socialist Eastern Germany, we explore four land use alternatives for neighborhood development close to what might happen: (1) urban densification, (2) spacious housing, (3) the green city, and (4) the edible city. We seek to discover opportunities for regrowth and sustainable land use development by applying the ecosystem services and green points frameworks to a set of land use transition rules. Land use change has been defined for strategic development areas according to the Master Plan and complementary visions of land change. The results of the study provide highly interesting insights into how both regrowth and greening can be enabled in densifying neighborhoods and what types of green are most effective in providing carbon storage and summer heat regulation. Moreover, gardens, as central elements of the edible city concept, were found to be flexible in implementation in very differently dynamic neighborhoods by providing multi-functional spaces for ecosystem services such as climate regulation, local food production, daily recreation, and nature experience. Results demonstrate that ecosystem services benefit flows increase only in districts where real estate pressure is low. In districts with growing population numbers, green spaces are reduced. This may result in increased injustice in green space availability seeing as we have modeled a recreational space per capita of < 9 m² in the Southern Suburb, whereas an increase to almost 70 m² was simulated in the shrinking, prefabricated Newtown. Most importantly, modeling the narratives of the Master Plan in a spatially explicit way demonstrates unused potential for greening in Halle. Thus, we conclude that urban planning should make regular use of such land use alternative to look for hidden combined visions of green and growth in a formerly shrinking city.

The impervious surface area (ISA) is a key indicator of urbanization, which brings out serious adverse environmental and ecological consequences. The ISA is often estimated from remotely sensed data via spectral mixture analysis (SMA). However, accurate extraction of ISA using SMA is compromised by two major factors, endmember spectral variability and plant phenology. This study developed a novel approach that incorporates phenology with Fisher transformation into a conventional linear spectral mixture analysis (PF-LSMA) to address these challenges. Four endmembers, high albedo, low albedo, evergreen vegetation, and seasonally exposed soil (H-L-EV-SS) were identified for PF-LSMA, considering the phenological characteristic of Shanghai. Our study demonstrated that the PF-LSMA effectively reduced the within-endmember spectral signature variation and accounted for the endmember phenology effects, and thus well-discriminated impervious surface from seasonally exposed soil, enhancing the accuracy of ISA extraction. The ISA fraction map produced by PF-LSMA (RMSE = 0.1112) outperforms the single-date image Fisher transformed unmixing method (F-LSMA) (RMSE = 0.1327) and the other existing major global ISA products. The PF-LSMA was implemented on the Google Earth Engine platform and thus can be easily adapted to extract ISA in other places with similar climate conditions.

Within CONNECTING Nature, we are dealing with developing innovative nature-based solutions (NBS) for climate change adaptation, health and well-being, social cohesion and sustainable economic development in European cities. In order to enable “learning by comparing” and “generating new knowledge” from multiple NBS related studies, a novel data and knowledge base is needed which requires a specified methodological approach for its development. This paper provides conceptual and methodological context and techniques for constructing such a data and knowledge base that will systematically support the process of NBS monitoring and assessment: • A methodology presents the comprehensive, multi-step approach to the NBS data and knowledge development that helps to guide work and influence the quality of an information included. • The paper describes the methodology and main steps/phases for developing a large data and knowledge base of NBS that will allow further systematic review. • The suggested methodology explains how to build NBS related databases from the conceptualization and requirements phases through to implementation and maintenance. In this regard, such a methodology is iterative, with extensive NBS stakeholders’ and end-user's involvement that are packaged with reusable templates or deliverables offering a good opportunity for success when used by practitioners and other end-users. • The NBS data and knowledge base gathers information about different NBS models and generations into one easy-to-find, easy-to-use place and provides detailed descriptions of each of the 1490 NBS cases from urban centers in Europe. • The data and knowledge base thus helps users identify the best and most appropriated NBS model/type for addressing the particular goals and, at the same time, considers the local context and potential. • The data obtained can be used for the further meta-analysis by applying statistics or searching for specific sample cases and thus enables to generate and expand the knowledge from multiple NBS related studies, in both qualitative and quantitative ways.

Urban green space (UGS) has gained much attention in terms of urban ecosystems and human health. Measures to improve green space in compact cities are important for urban sustainability. However, there is a knowledge gap between UGS improvement and planning management. Based on the integration of quantity and quality, this research aims to identify UGS changes during urban development and suggest ways to improve green space. We analyse land use changes, conduct a hotspot analysis of land surface temperature (LST) between 2005 and 2015 at the city scale, and examine the changes in small, medium and large patches at the neighbourhood scale to guide decision-makers in UGS management. The results show that (i) the redevelopment of urban brownfields is an effective method for increasing quantity, with differences depending on regional functions; (ii) small, medium and large patches of green space have significance in terms of improving the quality of temperature mitigation, with apparent coldspot clustering from 2005 to 2015; and (iii) the integration of UGS quality and quantity in planning management is beneficial to green space sustainability. Green space improvement needs to emphasize the integration of UGS quantity and quality to accommodate targeted planning for local conditions.

In comparison to the study of green space use, the study of its non-use or rejection is greatly understudied. Neighborhood managers and members of local gardening initiatives of Halle-Newtown, Germany, state that residents ignore local green-blue infrastructure (GBI) for recreational use. Halle-Newtown is a former showcase, large prefabricated socialist housing estate that is now facing an increase of households deprived in multiple ways. We are interested in the question of why people of Halle-Newtown refuse to use local GBI. In order to uncover potential barriers to the enjoyment of the ecosystem service benefits of local GBI, we have chosen the method of mental mapping to explore place attachment in Halle-Newtown. In summer 2018, about 100 residents of Halle-Newtown described the places they prefer when relaxing from a stressful and hot summer day. The results were surprising. Local GBI, be it created in socialist times or recently, was completely absent from their mental maps. Instead, people would overcome longer distances and cover higher costs to reach central green spaces. Tacit knowledge, namely the untold general rejection of the entire neighborhood by the residents, was found to be the deeper reason behind non-use of GBI and missing place attachment. The results uncovered that both neighborhood neglect and the multi-scalar character of urban recreational ideas/behavior are factors that help us to understand non-use of urban GBI, two key insights for urban planning.

Present and future urbanization together with climate change and other uncertainties make urban quality of life a critical issue, and one that will need constant attention and deliberation. Across cities and contexts, urban ecosystems in the form of green and blue infrastructure, have the potential to contribute to human well-being as well as supporting biodiversity, and to do so under diverse conditions. However, the realization of this potential depends not only on the green and blue infrastructure itself, the well-being benefits are outcomes of the structures and processes of the entire urban system. Drawing on theory and insights from social-ecological-technological systems (SETS) research and resilience assessments, we describe how a systemic understanding of the generation and delivery of green and blue infrastructure benefits may inform cross-sectoral strategies and interventions for building resilience around this particular aspect of human well-being. Connecting SETS to non-academic discourse and practice, we describe the urban system in terms of three systemic controlling variables: infrastructure, institutions, and the perceptions of individual beneficiaries, which we call filters, and how these can be used in different participatory processes to assess and build resilience around green and blue infrastructure and its benefits. To ground the conceptual and theoretical framework in real world complexity and make it operational in practice we discuss three case studies applying the framework in Barcelona, Halle, and Stockholm. All cases share the same general three-step process but their individual combinations of methods and adaptions of the filters framework are designed to fit with three necessarily unique collaborative, transdisciplinary processes. The cases are discussed in terms of outcomes and output, the ways they made use of the conceptual framework, and the challenges they faced. This exploratory work points to a new way of engaging with urban resilience - the strength of the approach is that it is not limited to the identification of specific interventions or policy options, nor trying to prevent change; rather it focuses on how to move with change and build resilience through constant balancing of different types of SETS change. Our study reinforces the growing understanding of how well-being benefits positioned as emergent outcomes of internal SETS interactions offers leverage for mainstreaming green and blue infrastructure throughout diverse governance processes and sectors.

Inter- and transdisciplinary research projects bring with them both challenges and opportunities for learning among all stakeholders involved. This is a particularly relevant aspect in social-ecological research projects, which deal with complex real-world systems and wicked problems involving various stakeholders' interests, needs, and views, while demanding expertise from a wide range of disciplines. Despite its importance in such research efforts, the learning process is often not the primary focus of investigation and therefore the knowledge about it remains limited. Here, we put forward an analytical framework that was developed to assess the learning process of both the research team and other participating stakeholders within the scope of an international transdisciplinary project dealing with urban green and blue infrastructure. The framework is structured around five dimensions of the learning process: "Why learn?" (the purpose of knowledge generation and sharing); "What to learn about?" (the types of knowledge involved); "Who to learn with?" (the actors involved); "How to learn?" (the methods and tools used); 'When to learn?' (the timing of different stages). We developed an interview protocol to operationalize the framework and tested our approach through interviews with project researchers. Based on our empirical results, we draw main lessons learned that can inform other transdisciplinary projects. These include capitalizing on what already exists, addressing trade-offs inherent to different types of knowledge, fostering inter- and transdisciplinarity, engaging stakeholders, supporting a learning environment and fostering reflexivity. Besides the empirical insights and the lessons we present, the main contribution of this research lies in the analytical framework we developed, accompanied by a protocol to apply it in practice. The framework can capture the learning process taking place in transdisciplinary research more comprehensively than similar existing frameworks. The five intertwined dimensions it covers are essential to understand and plan such learning processes.

Today’s cities increasingly serve as the nexus between nature and people in times of strong urban growth and, in some cases, urban decline [...]

The relationship between urban green spaces (UGS) and residential development is complex: UGS have positive and negative immediate impacts on residents’ well-being, residential location choice, housing, and land markets. Property owners and real estate agents might consider how prospective clients perceive UGS and act accordingly, while urban planners influence UGS location and management as well as aim at steering the built environment. Typically, studies focus on one of these perspectives at a time. Here, we provide a synopsis of results from studies, taking different perspectives for a single case study: Leipzig, Germany. We summarise and discuss the findings of eight studies on UGS and residential development. In detail, these studies focus on spatial pattern analysis, hedonic pricing analysis, mixed-methods studies on experts’ perspectives, surveys, and choice experiments exploring residents’ perceptions of UGS. We reflect on the feasibility of deriving a synthesis out of these independent studies and to what extent context matters. We conclude that both triangulating of data and methods, as well as long-term and context-sensitive studies are needed to explain the interlinkages between UGS and residential development and their context dependency.

Understanding opportunities as well as constraints for people to benefit from and take care of urban nature is an important step toward more sustainable cities. In order to explore, engage, and enable strategies to improve urban quality of life, we combine a social-ecological-technological systems framework with a flexible methodological approach to urban studies. The framework focuses on context dependencies in the flow and distribution of ecosystem service benefits within cities. The shared conceptual system framework supports a clear positioning of individual cases and integration of multiple methods, while still allowing for flexibility for aligning with local circumstances and ensuring context-relevant knowledge. To illustrate this framework, we draw on insights from a set of exploratory case studies used to develop and test how the framework could guide research design and synthesis across multiple heterogeneous cases. Relying on transdisciplinary multi- and mixed methods research designs, our approach seeks to both enable within-case analyses and support and gradually build a cumulative understanding across cases and city contexts. Finally, we conclude by discussing key questions about green and blue infrastructure and its contributions to urban quality of life that the approach can help address, as well as remaining knowledge gaps both in our understanding of urban systems and of the methodological approaches we use to fill these gaps.

Urban green and blue space interventions may bring about unintended consequences, involving trade-offs between the different land uses, and indeed, between the needs of different urban inhabitants, land users, and owners. Such trade-offs include choices between green/blue and non-green/blue projects, between broader land sparing vs. land sharing patterns, between satisfying the needs of the different inhabitants, but also between different ways of arranging the green and blue spaces. We analyze investment and planning initiatives in six case-study cities related to green and blue infrastructure (GBI) through the lens of a predefined set of questions - an analytical framework based on the assumption that the flows of benefits from GBI to urban inhabitants and other stakeholders are mediated by three filters: infrastructures, institutions, and perceptions. The paper builds on the authors' own knowledge and experience with the analyzed case-study cities and beyond, a literature overview, a review of the relevant city documents, and interviews with key informants. The case studies indicate examples of initiatives that were intended to make GBI benefits available and accessible to urban inhabitants, in recognition of GBI as spaces with diverse functionality. Some case studies provide examples of trade-offs in trying to plan and design a green space for multiple private and public interests in densely built-up areas. The unintended consequences most typically resulted from the underappreciation of the complexity of social-ecological systems and - more specifically - the complexity of the involved infrastructures, institutions, and perceptions. The most important challenges addressed in the paper include trade-offs between the different ways of satisfying the residents' different needs related to the benefits from ecosystem services, ensuring proper recognition of the inhabitants' needs and perceptions, ecogentrification, caveats related to the formalization of informal spaces, and the need to consider temporal dynamics and cross-scale approaches that compromise different goals at different geographical scales.

The economic conservation instrument of payments for ecosystem services (PES) enjoys an increasing popularity among scientists, politicians, and civil society organizations alike, while others raise concerns regarding the ecological effectiveness and social justice of this instrument. In this review article, we showcase the variety of existing PES definitions and systematically locate these definitions in the range between Coasean conceptualizations, which describe PES as conditional and voluntary private negotiations between ES providers and ES beneficiaries, and much broader Pigouvian PES understandings that also assign government-funded and involuntary schemes to the PES approach. It turns out that the scale at which PES operate, having so far received very little attention in the literature, as well as critique of PES must be considered in the context of the diversity of definitions to ensure the comparability between studies researching PES programs. Future research should better target linkages between global, regional, and local scales for the development of PES programs, while taking local collective governance systems for a sustainable use of resources into account more seriously.

There is a rapidly growing body of literature on the theory about the ecosystem service concept and the practical assessment of ecosystem services in different contexts ranging from natural to urban environments. Yet, where does the concept reach its limits? This paper critically reflects the application of the ecosystem service concept in urban environments illustrating the handling of urban structures (incl. built-up areas) and the risk that the normative principle of the concept could be missed. It is shown that in theory urban structures refer to a variety of ecosystem concepts. As a starting point for ecosystem service assessments, these could be classified into natural, managed, constructed and overbuilt systems. Since ecosystem service concepts do not directly refer to a specific ecosystem definition, but to biophysical structures and processes, all of these classes could be included. However, the dependency on context and scale makes a differentiation in practical ecosystem services assessment challenging. We conclude that the ecosystem service concept does not reach its limits in urban environments, but urban environments represent an extreme case characterized by multifunctionality and a high degree of modification that enables to uncover research challenges applying in any environment. There is a need for a more transparent reporting of theoretical and methodological assumptions to facilitate the comparability between ecosystem service assessments. Comprehensive approaches that consider multiple ecosystem services and include human input, human modification, the ecosystem status as well as their interactions are required to understand the spatial relations between ecosystem services delivered by different ecosystems.

Urban growth in and around European cities affects multiple aspects of the environment including green spaces. On the one hand, many cities struggle with environmental problems, overcrowding and overuse resulting from high population densities. On the other hand, high densities result in better access to public green spaces, effective public transport, or less demand for resources. Consequently, finding a balance between density and high liveability in a green and sustainable urban environment is a major challenge for urban planning. Although many studies report and discuss the provision of green spaces in European cities, they fail to relate green space provision to the potential demand by urban dwellers, and to the extent differences can be detected between types of green. Against this background, this paper develops a systematic understanding of green space supply and its relation to the residential density of cities. In so doing, it detects turning points of green space supply in 905 European cities. The results show that green space supply is sensitive to the type of green space, population size and location of cities. Particularly the relation between residential density and the supply with urban green spaces covering parks, public gardens or cemeteries, indicate turning points: at certain residential densities the urban green space supply is decreasing. At a certain residential density, the urban green space supply is highest and cities have a high potential to optimize the balance between sustainability and liveability. However, there is no single optimal residential density. Rather, turning points are different between cities of different density and location in Europe and between different types of neighborhoods within cities. Therefore, different optimum values need to be defined sensitive to these characteristics. For most of the European cities, a decrease of population or built-area cannot be expected in the future. In this situation, the approach to identifying the turning points for green space supply as presented in this paper can be used as a comparative method. This informs green space policies for defining acceptable densities of urban development and corresponding standards for the provision of urban green space.

The changing climate has introduced new and unique challenges and threats to humans and their environment. Urban dwellers in particular have suffered from increased levels of heat stress, and the situation is predicted to continue to worsen in the future. Attention toward urban climate change adaptation has increased more than ever before, but previous studies have focused on indoor and outdoor temperature patterns separately. The objective of this research is to assess the indoor and outdoor temperature patterns of different urban settlements. Remote sensing data, together with air temperature data collected with temperature data loggers, were used to analyze land surface temperature (outdoor temperature) and air temperature (indoor temperature). A hot and cold spot analysis was performed to identify the statistically significant clusters of high and low temperature data. The results showed a distinct temperature pattern across different residential units. Districts with dense urban settlements show a warmer outdoor temperature than do more sparsely developed districts. Dense urban settlements show cooler indoor temperatures during the day and night, while newly built districts show cooler outdoor temperatures during the warm season. Understanding indoor and outdoor temperature patterns simultaneously could help to better identify districts that are vulnerable to heat stress in each city. Recognizing vulnerable districts could minimize the impact of heat stress on inhabitants.

Urbanization rate in Central America is the second fastest worldwide and its major cities face challenges regarding urban sustainability. Urban Green Fabric (UGF) is an important material condition for the urban quality of life and, therefore, key to planning processes. We performed an analysis of the UGF of Guatemala City including the identification and classification of UGF, their spatial pattern analysis, construction of ensembles of districts (zones) and revealing citizen’s interactions with UGF. We used remote sensing and land use mapping techniques, spatial metrics and a questionnaire survey. Main results are the UGF map of Guatemala City and six ensembles of zones based on a set of indicators. We further revealed citizens’ recognition of green spaces, their perceptions about green space amount and availability as well as their support for UGF future interventions. Finally, we discuss the implications for planning promoted by our results and suggest three actions for UGF sustainability: Creation of new green spaces, protecting existing green spaces and enhancing the mosaic with different green spaces types. UGF is an essential decision support tool for a diversity of actors.

The status, changes, and disturbances in geomorphological regimes can be regarded as controlling and regulating factors for biodiversity. Therefore, monitoring geomorphology at local, regional, and global scales is not only necessary to conserve geodiversity, but also to preserve biodiversity, as well as to improve biodiversity conservation and ecosystem management. Numerous remote sensing (RS) approaches and platforms have been used in the past to enable a cost-effective, increasingly freely available, comprehensive, repetitive, standardized, and objective monitoring of geomorphological characteristics and their traits. This contribution provides a state-of-the-art review for the RS-based monitoring of these characteristics and traits, by presenting examples of aeolian, fluvial, and coastal landforms. Different examples for monitoring geomorphology as a crucial discipline of geodiversity using RS are provided, discussing the implementation of RS technologies such as LiDAR, RADAR, as well as multi-spectral and hyperspectral sensor technologies. Furthermore, data products and RS technologies that could be used in the future for monitoring geomorphology are introduced. The use of spectral traits (ST) and spectral trait variation (STV) approaches with RS enable the status, changes, and disturbances of geomorphic diversity to be monitored. We focus on the requirements for future geomorphology monitoring specifically aimed at overcoming some key limitations of ecological modeling, namely: the implementation and linking of in-situ, close-range, air- and spaceborne RS technologies, geomorphic traits, and data science approaches as crucial components for a better understanding of the geomorphic impacts on complex ecosystems. This paper aims to impart multidimensional geomorphic information obtained by RS for improved utilization in biodiversity monitoring.

This opinion paper discusses urban lawns, the most common part of open green spaces and urban green infrastructures. It highlights both the ecosystem services and also disservices provided by urban lawns based on the authors’ experience of working within interdisciplinary research projects on lawns in different cities of Europe (Germany, Sweden and Russia), New Zealand (Christchurch), USA (Syracuse, NY) and Australia (Perth). It complements this experience with a detailed literature review based on the most recent studies of different biophysical, social, planning and design aspects of lawns. We also used an international workshop as an important part of the research methodology. We argue that although lawns of Europe and the United States of America are now relatively well studied, other parts of the world still underestimate the importance of researching lawns as a complex ecological and social phenomenon. One of the core objectives of this paper is to share a paradigm of nature-based solutions in the context of lawns, which can be an important step towards finding resilient sustainable alternatives for urban green spaces in the time of growing urbanisation, increased urban land use competition, various user demands and related societal challenges of the urban environment. We hypothesise that these solutions may be found in urban ecosystems and various local native plant communities that are rich in species and able to withstand harsh conditions such as heavy trampling and droughts. To support the theoretical hypothesis of the relevance of nature-based solutions for lawns we also suggest and discuss the concept of two natures—different approaches to the vision of urban nature, including the understanding and appreciation of lawns. This will help to increase the awareness of existing local ecological approaches as well as an importance of introducing innovative landscape architecture practices. This article suggests that there is a potential for future transdisciplinary international research that might aid our understanding of lawns in different climatic and socio-cultural conditions as well as develop locally adapted (to environmental conditions, social needs and management policies) and accepted nature-based solutions.

The concept of a nature-based solution (NBS) has been developed in order to operationalize an ecosystem services approach within spatial planning policies and practices, to fully integrate the ecological dimension, and, at the same time, to address current societal challenges in cities. It exceeds the bounds of traditional approaches that aim ‘to protect and preserve’ by considering enhancing, restoring, co-creating, and co-designing urban green networks with nature that are characterized by multifunctionality and connectivity. NBSs include the main ideas of green and blue infrastructure, ecosystem services, and biomimicry concepts, and they are considered to be urban design and planning tools for ecologically sensitive urban development. Nowadays, NBSs are on their way to the mainstream as part of both national and international policies. The successful implementation of NBSs in Europe and worldwide, which is becoming increasingly common, highlights the importance and relevance of NBS for sustainable and livable cities. This paper discusses the roles, development processes, and functions of NBSs in cities by taking Leipzig as a case study. Using data from interviews conducted from 2017 to 2019, we study the past and current challenges that the city faces, including the whole process of NBS implementation and successful realization. We discuss the main drivers, governance actors, and design options of NBSs. We highlight the ecosystem services provided by each NBS. We discuss these drivers and governance strategies by applying the framework for assessing the co-benefits of NBSs in urban areas in order to assess the opportunities and challenges that NBSs may have. This way, we are able to identify steps and procedures that help to increase the evidence base for the effectiveness of NBS by providing examples of best practice that demonstrate the multiple co-benefits provided by NBSs.