WHAT BENEFITS DOES GREEN INFRASTRUCTURE IN CITIES OFFER?

Transcription

1 WHAT BENEFITS DOES GREEN INFRASTRUCTURE IN CITIES OFFER? A functional perspective Partners involved: Description: Humboldt Universität zu Berlin team, University of Ljubljana team, and University of Lisbon team The document provides the key messages elaborated in GREENSURGE about green space types and a green space typology as well as their functional ecosystem services impacts on human health, well-being and social cohesion. Copenhagen September 2017

2 INTRODUCTION Cities nature is as diverse as their inhabitants, their activities and the forms of land cover they have created. Diverse and healthy urban green infrastructure (UGI) enables a functioning and diverse urban environment for both humans and other species. In particular, it is offering public green recreational space suited to the needs of the people living in densely builtup cities with a lot of traf ic, noise and air pollution. For a sustainable and effect-oriented planning, it is necessary to understand both structure and the range of often intertwined functions green space has and, what is more, the ecosystem services it can offer to the urban society. Moreover, it is equally important to understand how people perceive and thus use or not use this green space. Being familiar with the many types of green spaces and being aware of human-nature interactions supports urban planners in proposing and implementing adequate landscaping in each urban neighbourhood. Citizens should be involved in planning the local green space so that the design considers scienti ic knowledge just as the needs of the neighbourhood which strengthens green impact effectiveness as well as people s ownership of it (Haase, 2016; McPhearson et al., 2016). Cities are centres of demand for ecosystem services, and with the expected growth in urban populations, this demand will increase (Kabisch et al., 2015). There is an enormous richness of diverse public and private green spaces that provide a wide range of ecosystem services to the people living in cities (Haase et al., 2014; see text box below). Through delivering these services, green spaces provide important environmental, social, health, and also economic bene its (Haase et al., 2014). In GREEN SURGE, we studied relationships between different types of UGI and the ecosystem services and health bene its which these spaces provide to different user and resident groups. While the functional linkages between green spaces and the regulating and cultural ecosystem services which they provide are key arguments for the development and maintenance of UGI, there is a need for further identi ication of the linkages between urban green space, biodiversity, biocultural diversity, human health and social cohesion and social inclusiveness (Nesshoever et al., 2017). Ecosystem services provided by UGI: Provisioning services Raw materials, Fresh water, Food, Medicinal resources Regulating services Local climate and air quality, Carbon sequestration and storage, Moderation of extreme events, Water-waste treatment Cultural services Recreation, physical and mental health, Tourism, Aesthetic appreciation and inspiration for culture, Art and design, Spiritual experience and sense of place Habitat and supporting services Habitats for species, Maintenance of genetic diversity WHAT BENEFITS DOES GREEN INFRASTRUCTURE IN CITIES OFFER? Page 2

3 WHAT MATERIAL DID WE COLLECT AND WHICH METHODS DID WE APPLY? A review of international literature on the ecosystem services provided by UGI and the associated benefits of these services including examples and facts on the biophysical functionality of UGI was undertaken. Based on own experience, literature and spatial data from several European cities, we have been creating a typology of urban green spaces (UGI typology), and which can be linked to existing GIS-formats of Europe-wide Urban Atlas and CORINE Land Cover data. This makes it possible to study local land cover, land cover change and land cover flows to learn from the past and defining targets for the future. We further studied the production and recreation function of allotment gardens, the recreation function of urban parks and urban forests as well as the health impacts of urban green and blue infrastructure (GBI) on kid s well-being. Finally, we built a database summarizing existing evidence on important functional linkages and impacts of UGI on climate regulation, water and soil, habitat quality and human health and wellbeing. WHAT DID WE GET OUT? THE MOST IMPORTANT RESULTS Becoming familiar with the range of green spaces We have developed a typology of urban green spaces (see text box below). This typology distinguishes 44 different urban green elements, distributed across 8 different categories. With this, our typology showcases the diversity and comprehensiveness of UGI. There is likely no inventory of green space which can cover all the distinctive green features that exist in European cities, as the natural conditions (i.e. geomorphologic, climatic, biological), the historical development and the social demand are very different across Europe. No inventory can be final since the environmental and social awareness, technological progress as well as creativity of urban planners, landscape architects, citizens and entrepreneurs evolves. This leads to new types of UGI (e.g., community gardens, roof allotments, rain gardens, bioswales, constructed wetlands but also mobile backyard gardens or different forms of guerrilla gardening). GREENSURGE has compiled a very comprehensive inventory of 44 UGI elements to support urban planners to take the next steps in diversifying the types of green to be seen in cities. GREENSURGE inventory of UGI types (The inventory is categorised into 8 types of green spaces. All 44 elements can be found in Cvejić, R. et al., 2015). 1. Building greens 2. Private, commercial, industrial, institutional urban green space (also connected to grey infra- structure) 3. Riverbank green 4. Parks and recreation 5. Allotments and community gardens 6. Agricultural land 7. Natural, semi-natural and feral areas 8. Blue spaces WHAT BENEFITS DOES GREEN INFRASTRUCTURE IN CITIES OFFER? Page 3

4 Variation of UGI across European cities We observe a large diversity in composition and configuration of different green and blue infrastructure elements across European cities (Haase et al., 2014; Cvejić et al., 2015). There are large variations in the percentage of green space within cities, with northern European cities generally having an above average availability of green spaces compared to southern European cities. We also see large variations in types of urban green spaces, with some cities e.g. having large areas of forests or agricultural land while others having more blue spaces or parks created from former industrial, airport or railway brownfields (such as the well-known Tempelhof Feld or the Gleisdreieck in Berlin). These differences reflect macro-geographical regions, ecological and biophysical settings and the history of land-use and socio-economic development over time (Cvejić et al., 2015; Haase et al., 2016). This UGI-variation across cities results from many complex interactions between urban dwellers and the environment including different planning paradigms polycentric multi-actor or centralized top-down and societal development such as (post- )socialist or western market-oriented ones to list the most important. Benefits by many types of green spaces With our literature review, we highlight evidence on the benefits offered by many types of green spaces. We highlight an enormous wealth of green spaces that can provide important benefits if we care well for them. For example, street trees remove air pollution, house gardens provide stress relief and active recreation, and urban forests can generate local tourism (Haase et al., 2014; Haase et al., 2016). More generally, we highlight a relation between surface temperature and the configuration of green and blue areas, revealing opportunities for cooling through developing and maintaining UGI. We also highlight several links between both health and wellbeing of the urban population and the availability of green spaces in their daily environment (Eler et al., 2016). In cities such as Berlin, Lisbon, Ljubljana and Lódz, we show that green spaces in form of allotment gardens provide important sites for the gathering of food. While positive linkages between UGI and ESS delivery dominate literature, there are some findings on ecosystem disservices such as provoking allergy or danger of falling branches. We should also be aware of potential trade-offs between e.g. recreation and biodiversity (Haase et al., 2016) but also not ignore several challenges that might arise with green implementation such as pollen allergies (Döhren & Haase, 2015) or the newly found insight that NO 2 levels are higher inside greenbelts than in open areas without them, likely due to reduced air flow inside greenbelts (Yli-Pelkonen et al., 2017). Further insights with high relevance for practitioners are summarized in the text boxes below (based on GREEN SURGE policy briefs). Figure 1. Large parks as typical types of UGI provide a full range of benefits for cities and their residents ranging from recreation via air temperature regulation and social cohesion (Photo credits: Dagmar Haase) WHAT BENEFITS DOES GREEN INFRASTRUCTURE IN CITIES OFFER? Page 4

5 RESEARCH EXAMPLE Effects of UGI on reducing air temperature in cities The size and configuration (i.e. species, volume and arrangement of green elements) in green areas influences the effect of the urban heat island (UHI). Among vegetated space, wooded vegetation reduces surface temperature the most. Evenly distributed woody vegetation as opposed to clustered vegetation result in even lower surface temperatures. The reason being is that continuous vegetation provides more shade for surrounding, not overgrown surface. GREEN SURGE found out that Helsinki has a smaller UHI effect and an evenly distributed forest, whilst Berlin and Ljubljana have a clustered forest distribution and a bigger UHI effect. The UHI effect seems to also depend on the land use in the outskirts of a city. If the city is surrounded by open croplands or grasslands, which are less vegetated and shaded, then the temperature differences between city centre and outskirts are lower as the temperatures above open landscapes are generally higher. The temperatures above larger forested areas are on the other hand a lot lower, which results in the UHI effect being bigger. This applies to Berlin and Ljubljana for example (Eler et al., 2015). INSIGHT Policies ensuring the accessibility to green space Some European cities have defined per capita threshold values for urban green space or minimum accessibility for a defined area. For example, the city of Berlin, Germany, aims to provide at least 6 m² of urban green per person, while Leipzig, Germany, aims even higher and wants to achieve 10 m² per capita. The national target in the UK is that urban residents should have access to a natural green space of minimum 2 ha within a distance of 300 m from their home. Berlin also recommends that every resident should have access to urban green of minimum 0.5 ha within a 500 m from their house (Kabisch et al., 2016). RESEARCH EXAMPLE Use of green space and health status GREEN SURGE conducted a study to understand the links between the use of green space and the health status of people in 5 European cities (Bari, Berlin, Edinburgh, Malmö, Ljubljana) with more than 3,000 respondents. The proportion of respondents taking a walk when visiting a green space increased with age, independent of the health status (self-perception of being in good or bad health). There is a slight difference between the health status of respondents younger than 20 years and between 41 and 60 years of age: less people with good health use parks to meet friends and relatives. They instead and that includes all ages practice sports as their main activities. In both health categories, less people with an education at university level reported to relax in parks. Whether in good or in bad health, respondents with migration background answered more often that their main activity was to play with children or to meet friends and relatives while visiting urban parks than persons without migration background. Interestingly, dog walking was indicated for both health categories more often when respondents did not have migration background. GREEN SURGE research results suggest that people s health state leads to them using green space slightly different. Taking this into consideration when designing an urban park and managing its vegetation can help integrate the needs of different user groups (e.g. offering outdoor gyms for elderly residents in the neighbourhood) (Haase et al., 2016). WHAT BENEFITS DOES GREEN INFRASTRUCTURE IN CITIES OFFER? Page 5

6 RECOMMENDATIONS FOR PRACTITIONERS Identifying the proper urban green spaces locally and across the city Urban green is equally diverse and essentially includes all vegetation found in a city in parks, urban forests, roadside green and community gardens or on green roofs or walls. UGI also includes blue space such as rivers, lakes or ponds. GREEN SURGE s inventory of 44 urban green space types showcases the diversity. Urban green spaces all fulfil different environmental and social functions as shown above (e.g., temperature reduction, rainwater retention, neighbourhood gardening, recreation). It is necessary to understand the many, often intertwined functions of these green space types. City planners can then better plan and carry out the most suitable types of green space for each neighbourhood ideally with the community and create a diverse green infrastructure network across the city at the same time. GREENSURGE results on green infrastructure types and their functionality allows decision-makers and urban planners to better understand the proper mix of UGI types for a neighbourhood from an environmental as well as community perspective. The following considerations support local governments in connecting and diversifying the UGI network and matching green space functions with citizens needs. Strategically and continuously analyse size, type and distribution of UGI From an environmental perspective, the UGI of a city can be characterised through its size (land area in km 2 ), shape (perimeter in m), structure (type of green such as trees, shrubs, grass, etc.) and overall composition (UGI types in proportion to total urban area). GREEN SURGE has combined landscape metrics to quantify the diversity of UGI types in cities and has found that four factors influence it: the situation of a city within Europe, its glacial landscape formation, its history of land use and, finally, current planning approaches. Local authorities only have a bearing on how cities are planned of course. Planners therefore need to assess how the proportion and types of green space have changed over time and how they are distributed across the city by analysing land use data. Such an analysis informs planners how UGI diversity and functions have changed over time. Knowing this, planners can identify current and future pressure points, enhance UGI by creating more green space (or specific types thereof) or change management practices. It also supports them in optimising land use policy and implementing UGI hand in hand with urban and regional development plans. Our literature review and the empirical work undertaken highlight a large diversity in green and blue infrastructure elements across European cities. These elements provide a wide range of ecosystem services and associated co-benefits for the urban population. In order to consciously make use of all these services and benefits, UGI-policy should embrace a diverse, inclusive and comprehensive understanding of urban green infrastructure. This can be most effectively realized when green spaces are consciously planned, governed and managed in the long-term with recognition for the multiple ecosystem services which they provide on the one hand and the multiple user groups that have either a stake or an interest. We specifically recommend to plan for green spaces close to peoples daily living environment as such spaces have a high potential to improve public health and wellbeing as well as social inclusion and cohesion. As urban green WHAT BENEFITS DOES GREEN INFRASTRUCTURE IN CITIES OFFER? Page 6

7 spaces provide important places of nature in cities, their maintenance also supports local and regional biodiversity. Last but not least, UGI is key when counteracting heat stress and respective mortality in cities (Weber et al., 2014). Strategies and measures to improve the functional impacts/effects of green have to be tailormade to the local context: Whereas green space maintenance plays the major role in cities that have many high quality green spaces, green space enlargement and creation is crucial in cities with less existing green spaces. Across Europe, green and blue spaces in cities can be planned, managed and designed as an important mechanism for climate change adaptation. Reducing the urban heat island effect has a potential to improve public health and wellbeing. Since urban green spaces often provide the primary contact with local flora and fauna and the natural environment for urban residents, they can also be planned to increase environmental learning. TAKE HOME MESSAGES UGI-policy should embrace a diverse, inclusive and comprehensive understanding of UGI at different scales to make use of all the functionality and the benefits ecosystem processes provide what we have shown above: Target the whole city and single urban neighbourhoods. Effective and inclusive strategies to improve the functional impacts of specific types of urban green depend on the local urban context and, hence, need to be tailor-made to the local context. Foster local stewardship by planning and maintaining green and blue spaces in the long-term and close to peoples daily living environment in order to maximize the gain from nature-based solutions to urban challenges such as heat or social exclusion, and to successfully include local people s interests and user specific demands and activities. Figure 2. Allotment gardens as key elements of UGI in cities bringing young and elderly urban dwellers together exchanging nature experiences while producing local food (Photo credits: Dagmar Haase) WHAT BENEFITS DOES GREEN INFRASTRUCTURE IN CITIES OFFER? Page 7

8 References Cvejić, R., Eler, K., Pintar, M., Železnikar, S., Haase, D., Kabisch, N., Strohbach, M., A typology of urban green spaces, ecosystem provisioning services and demands. University of Copenhagen, GREEN SURGE deliverable 3.1. Döhren, P., Haase, D., Ecosystem disservices research: A review of the state of the art with a focus on cities. Ecological indicators 52: Eler, K., Zeleznikar, S., Cvejić, R., Pintar, M., Haase, D., Kabisch, N., Strohbach, M., Annerstedt van den Bosch, M., Kowarik, I., Fischer, L., Functional linkages between urban green infrastructure, biodiversity and human well-being. University of Copenhagen, GREEN SURGE deliverable 3.2. Haase D Reflections on urban landscapes, ecosystems services and nature-based solutions in cities. Planning Theory & Practice 17(2), Haase, D., Kabisch, N., Pintar, M., Strohbach, M., Železnikar, Š., Cvejić, R., Eler, K., Classification of UGI based on their functionality, services, synergies, trade-offs and spatial conflicts. University of Copenhagen, GREEN SURGE deliverable 3.3. Haase D, Larondelle N, Andersson E, Artmann M, Borgström S, Breuste J, Gomez-Baggethun E, Gren A, Hamstead Z, Hansen R, Kabisch N, Kremer P, Langemeyer J, Lorance Rall E, McPhearson T, Pauleit S, Qureshi S, Schwarz N, Voigt A, Wurster D, Elmqvist T A quantitative review of urban ecosystem services assessment: concepts, models and implementation. AMBIO 43(4), Kabisch, N., Qureshi, S., Haase, D., Human environment interactions in urban green spaces - A systematic review of contemporary issues and prospects for future research. Environmental impact assessment review 50: Kabisch, N., Strohbach, M., Haase, D., Kronenberg, J., Urban green space availability in European cities. Ecological indicators 70: McPhearson T Pickett S, Grimm N, Niemelä J, Elmqvist T, Weber C, Breuste J, Haase D, Qureshi S Ecology for an Urban Planet: Advancing Research and Practice Towards a Science of Cities. BioScience. doi: /biosci/biw002. Nesshoever C, Timo Assmuth; Katherine J Irvine; Graciela M Rusch; Kerry A Waylen; Ben Delbaere; Dagmar Haase; Lawrence Jones-Walters; Hans Keune; Eszter Kovacs; Kinga Krause; Mart Külvik; Freddy Rey; Jiska van Dijk; Marie Vandewalle; Odd Inge Vistad; Mark E Wilkinson; Heidi Wittmer The science, policy and practice of Nature-Based Solutions: An interdisciplinary perspective. Science of the Total Environment 579, Weber N, Haase D, Franck U Zooming into the urban heat island: How do urban built and green structures influence earth surface temperatures in the city? Science of the Total Environment 496, WHAT BENEFITS DOES GREEN INFRASTRUCTURE IN CITIES OFFER? Page 8