Assessment of Ecosystem Services for Urban Resilience – Case Study in Singapore

SIEBER, Jeannettea, FREMGEN, Leonie and PONS, Manon

a EIFER European Institute for Energy Research, Karlsruhe, Germany, e-mail: sieber@eifer.org

Abstract — Within urban development research, the benefits derived from so-called ecosystem services (ES) should be taken into account. To valuate ES, different methods are applicable, such as Cost-Benefit Analysis and/or Geographical Information System (GIS) based approaches. In 2012, the World Resources Institute published a manual for businesses to account for ES called Ecosystem Services Review (ESR). Therein, a five-step process is illustrated for the assessment of impacts and dependencies. To achieve an integrated evaluation for cities, we conduct a modified Urban-ESR in Singapore as a case study. The expected outcomes are both qualitative and quantitative values, displayed either in GIS with maps as main output or as tables for decision-support.

Keywords — Ecosystem Service Review, GIS-based assessment, Urban Development

1 Introduction

1.1 General Introduction to Ecosystem Services

In the past years, research topics like urban sprawl, ecosystem services and sustainable food, water and energy supply have gained interest in the light of a changing climate and reductions in global biodiversity. With regard to a continuously increasing number of people in fast expanding cities, so-called urban services and ecosystem services may see limitations and need to be subject to further examination. Urban areas are characterized by the fastest expansion rate compared to all other land use types. By now, more than half of the global population lives in cities and urban areas which account for about 3 % of the global land area, making them the main consumers of ecosystem services. The term Ecosystem Services (ES) refers to “the benefits people obtain from ecosystems” (Millennium Ecosystem Assessment, 2005). That is, the environment supplies the inhabitants of cities with four types of ES (see Table 1):

Table 1: Four types of ecosystem services. The supporting services underlie each of the other categories as the basic services that ecosystems can supply (according to Millennium Ecosystem Assessment, 2005).

Provisioning Services, e.g. food, water, raw materials and energy

Regulating Services, e.g. carbon sequestration, climate regulation, air and water purification, waste decomposition Cultural Services, e.g. scientific discovery, recreation, ecotourism
Supporting Services, e.g. nutrient cycle, primary production, soil formation

Within the resilience debate, cities are regarded as made of complex systems or even as a “system of systems” (e.g. Revi et al., 2014; Gómez-Baggethun et al., 2013). These systems include amongst others food and water supply systems, the energy system and other key economic sectors. Therefore, in urban design and safety, flood management or air quality improvement - both being regulating services - are challenges to be tackled. Besides these technical aspects, the supply side of food, water and energy with regard to provisioning services is crucial in urban environments. The aforementioned resources are usually provided by the surrounding areas. While cities are thus dependent on global, regional and local ecosystem services for survival, they also largely benefit from internal urban ecosystem services (Bolund and Hunhammar, 1999; Breuste, Haase & Elmqvist, 2013). ES provision can be substantial within urban areas as they host a number of ecosystem processes, which deliver services for human well-being. Such locally generated ES include air quality regulation or recreational opportunities. Continuing ecosystem degradation and loss of agricultural and natural landscapes will exert greater pressure on the urban environment to provide such ecological, productive and cultural functions. Such changes to the pattern of urban landscapes may fundamentally influence both biodiversity and human well-being. Climate change mitigation and adaptation as well as resilience are thus further topics to be merged into the concept of sustainable (urban) development.

1.2 Introduction to the Ecosystem Services Reviews

Developed by the World Resources Institute (WRI), the Ecosystem Services Review (ESR) is an integrated framework designed to complement standard environmental and social impact assessments. In 2012, the WRI set up a concept on how to proceed in a valuation for businesses (World Resources Institute (WRI) et al., 2012). Originally developed for the corporate sector, the so-called corporate ESR enables the identification of priority ES on different spatial scales and the subsequent determination of risks, opportunities, costs and benefits of measures to address ES. The ESR fills the gap of traditional assessment approaches, which do not generally account for the project´s impact on ecosystem service provision. The structured methodology is seen as a guide for practitioners to integrate ecosystem services and by this, manage dependencies on ecosystems and mitigate impacts on ecosystem service benefits.

The adapted ESR tool was further developed from this corporate ES review and can be applied to urban and suburban settings alike. The focus herein lies on managed landscapes within the urban environment. The publicly available spreadsheets can be easily used to describe ecosystem service impacts qualitatively. The excel-based assessment is typically conducted by landscape managers, landscape sustainability initiatives or local environmental regulating bodies, in close collaboration with relevant stakeholders and decision-makers (Ozment et al., 2013). Several outputs are generated through an ESR (Landsberg et al., 2013):

  • List of ecosystem services, for inclusion in the ESR terms of reference;
  • Identification of priority ecosystem services to be considered and stakeholders to be engaged in further stages of the ESR process, for inclusion in the ESR report;
  • Assessment of project impacts and dependencies on priority ecosystem services, for inclusion in the ESR report.

Only ecosystem services that decision-makers can directly control or influence are considered. These include services, whose impacts may adversely affect human well-being, as well as services upon whose provision the policy or project directly depends.

1.3 TEEB Manual for Cities as a Basis

With regard to the above described challenges for and in cities, the TEEB Manual for Cities (TEEB - The Economics of Ecosystems and Biodiversity, 2011) highlights the analyses of ES as vital for sustainable development. Therein, a valuation approach that includes monetary, quantitative and qualitative values is described. The manual distinguishes between the four types of ecosystem services as proposed by the Millennium Ecosystem Assessment (Millennium Ecosystem Assessment, 2005) and provides numerous city examples. Following this general introduction, the TEEB Manual follows a stepwise approach for decision making in cities combining a classical management approach with a focus on ecosystem services and local challenges. To perform such a valuation, a set of methods (e.g. Cost-Benefit Analysis, SWOT Analysis, GIS-based approaches) may be used.

For the conduction of an Urban-ESR in Singapore, the decision was made to combine the two approaches of a Corporate-ESR as established by the WRI with the city-based approaches described in the TEEB Manual for Cities. An integration of the two approaches is now elaborated in more detail in the following sections referring to the city of Singapore as a case study. Thus, Section 2 deals with the methodology from the Corporate-ESR to the Urban-ESR and highlights the steps (1) of prioritizing ecosystem services in a city and (2) of assessing the aforementioned priority services with GIS-based tools. Section 3 follows with the GIS-based localization and analysis of the priority services of “Aesthetic Quality”, “Recreation”, “Carbon Storage” and “Food and Fresh Water Supply”. By connecting the Urban-ESR of Singapore with the local green plan and the goals to become a sustainable garden city, the aim to implement the assessment into future planning options and decisions is articulated. In Section 4, the preliminary results are discussed and chances for future transferability are shown. The following Section 5 highlights questions on the added value for the post-2015 framework and how Urban-ESR might be implemented into the discussion.

2 Methodology

2.1 From the corporate ESR to the Urban-ESR

Based on the ESR and the approach described in the TEEB Manual for Cities, a methodological framework in five steps to optimize ES provision within cities and improve cities’ sustainability was first developed in 2012. This method has been adapted to practical implementation in 2013 (see Figure 1).

Figure 1: The process of an Ecosystem Services Review (ESR). Left column: Corporate-ESR according to WRI (2008/2012), center column: Urban-ESR as developed by EIFER in 2012, right column: methodological enhancement according to EIFER since 2014 (Sieber & Fremgen, 2014)

Since the scope of the study is set to the cities’ boundaries, the proposed framework starts with the identification and analysis of the priority ES for a city. After the identification of the adapted measures to enhance the priority ES, different scenarios have to be proposed corresponding to a bundle of adapted measures. For each scenario, cost-benefit analyses should be conducted. The final aim consists in maximizing social benefits, improving ecosystem functioning and minimizing municipal costs. The basic improvements of the Urban-ESR in contrast to the corporate ESR are the extensive use of GIS-based tools for localization approaches as well as the constant involvement of stakeholders and decision-makers from the interviews and questionnaire to the scenario building to the final implementation. Moreover, the rough concept of the corporate ESR is enhanced by tools and methods especially effectual for urban environments.

To maintain and promote the provision of ES in the city, urban planning documents are fundamental because they define green infrastructures (both biodiversity reservoirs and ecological connections). Of course, other tools are also available, such as incentives to develop green roofs and walls. In some cases (such as Singapore) with extremely high density, combined with a rate of urbanization of 100 %, and an objective of high quality of life, the ES approach could help fulfil environmental ambitions.

2.2 Using questionnaire and results, including prioritization

The first step of an Urban-ESR includes the conduction of interviews or questionnaires in order to prioritize the most important ES. The concept of the ESR was used as it is a low-cost scoping tool and provides a good entry point for further mapping and localization of ecosystem services. User-friendliness of the rather extensive excel spreadsheets was improved through condensing the most important questions within a single more accessible web-based questionnaire. The questionnaire used in this case study assessed the immediate and long-term interdependences between urban development projects, ecosystems, ecosystem service provision, and human well-being. In the process, 40 different institutions were contacted, among them the universities of Singapore, several ministries and NGOs. The contacted individuals were chosen due to their familiarity with biodiversity conservation, urban development, urban planning or ecosystem services in Singapore. In total, seven questionnaires returned completely filled giving a quota of 17.5 %.

In the questionnaire, each of the respondents was asked to give scores on the impact and dependence scales. Both scales each assign four values ranged from high significance (3) to no significance (0) and high impact (3) to no impact (0), respectively. The final value of each ecosystem service is thus a weighted total, ranking ecosystem services according to their overall significance. Given the number of seven responses, the maximum total value that can be placed on the services is 21. Based on the responses, the most important ecosystem services for the case of Singapore are identified.

For the sake of further prioritization, it was considered that the set of urban ecosystem services chosen comprised the most important services regarding Singapore and provided a manageable number of services to assess, while still representing each of the four categories. It is important to note that although certain ecosystem services were prioritized to produce a more detailed review, this does not necessarily mean that those ecosystem services which were ranked lower by stakeholders are of no importance for humans. However, Singapore is nonetheless set apart by certain local characteristics which should become visible in the course of this analysis, hence the focus on specific ecosystem services.

2.3 GIS-based assessments including the use of InVEST

The “Integrated Valuation for Ecosystem Services and Tradeoffs” (InVEST) tool, which was developed by the Nature Capital Project, enables the assessment of ecological production and subsequent economic valuation. InVEST consists of several open source models to map and evaluate ecosystem services through ArcGIS® (Tallis et al., 2013). The tool is amenable to widespread use and can be independently applied to monitor environmental changes or the provision of ecosystem services (Bagstad et al., 2013). However, the generalizability and time requirements may vary greatly with regard to the availability of underlying data. The model outputs are improved with the amount and quality of spatial data inputs. Compared with other valuation tools, InVEST is extensively used in peer reviewed literature.

The InVEST carbon sequestration tool is applied to estimate the amount of carbon stored or sequestered in a landscape over time. InVEST measures the social value of carbon storage and sequestration, which equals avoided social damage associated with carbon release to the atmosphere. By aggregating the amount of stored carbon in four carbon pools (namely, aboveground biomass, belowground biomass, soil and dead organic matter), the model is able to estimate the net amount of stored carbon and market and social values of sequestered carbon.

The InVEST aesthetic quality tool produces view shed maps to determine the visual footprint of near- or offshore development. Such development projects may affect the visual appeal of natural seascapes. The generated maps may then identify coastal areas that are most likely affected. The recreation tool is able to estimate the spread of person-days of recreation. In the absence of visitation rates, geo-tagged photographs posted to the website flickr were used as proxy indicator. Further necessary data inputs include the locations of natural features, such as urban parks, and other recreational sites as well as of built features and environmental conditions.

3 Case Study

3.1 General Introduction

In the following, the case study for the Urban-ESR in Singapore is described in more detail. After the prioritization of the most important ecosystem services in Singapore, connection is made to the local green plan and the goals of Singapore to become and be the “garden city”. An investigation of the indicators underlining the local green program and label, the priority ecosystem services of “Aesthetic Quality”, “Recreation”, “Carbon Storage” and “Food and Fresh Water Supply” are localized and analyzed with the help of GIS-based tools.

The island state of Singapore covers an area of approximately 71240 ha, after having seen many expansion plans. In the process, the built-up area has doubled between 1965 and 2000, while forest and agricultural land has decreased (Singapore Department of Statistics, 2013). Singapore has replaced its native vegetation with a comparably large amount of managed urban vegetation and as little as 0.28 % of the original land area has remained intact. Only about 0.5 % of the total land area is devoted to agricultural use. The number of licensed farms is diminishing, also mirroring the declining total farming area. The total area of farm land (including farms, farmland, farmyard and fish farms) amounts to only 0.08 hectares.

Managed habitats are thus an important feature in Singapore´s green landscapes, including roadside plantings, public urban parks, community gardens, golf courses or farms. At present, about ten percent of the country is green space, half of which is nature reserves. Park connectors serve as greenways, which link nature reserves, urban parks, open spaces and other points of interests to improve access thereof. Aside from enhanced accessibility, this green matrix creates refuge corridors for birdlife and other fauna. In total, the island state is home to more than 2800 hectares of parks, 2656 hectares of roadside greenery and 3347 hectares of nature reserves. In terms of per capita provision, Singapore´s green cover and park provision ratio lies at a low to moderate level in international comparison (Tan et al., 2013).

The following Figure 2 shows an overview of Singapore including park connector loops and cycling paths, green areas like parks and forest, blue water areas and pink buildings. Dark green dots indicate skyrise greenery, light green dots represent locations of community gardening, additionally, brown dots symbolize heritage trees.

Figure 2: Overview Map of Singapore, data for the display was derived from the Singaporean Government and Open Street Map (OSM) (see data reference section for full record)

3.2 Investigation of indicators and factors underlining the local green program and label

Singapore has in the past years placed great emphasis on environmentally-friendly urban development, which is reflected in several governmental policies. A wide variety of measures have been implemented to maintain and even enhance its environmental sustainability. Singapore calls itself the “Garden City” and has even called for the transformation towards a “City in a Garden” (Ministry of National Development Singapore, 2013). The Singapore Green Plan, issued in 1992, was the country´s first formal environmental blueprint. Besides the Green Plan, Singapore has developed both a Concept Plan and a Master Plan. In 2009, the continuation of Singapore´s sustainable development strategy through 2030 was launched as the Sustainable Singapore Blueprint (Inter-Ministerial Committee on Sustainable Development, 2009).

Along with ministerial frameworks, the Singapore Housing and Development Board (HDB) launched the so-called Greenprint framework in 2012. This framework should foster green urban development and create sustainable homes. It is targeted at three levels: building green neighborhoods, upgrading to green flats and forming green communities (Government of Singapore, 2012).

The web-based ESR questionnaire aimed to assess the immediate and long-term interdependences between urban development projects, ecosystems, ecosystem service provision, and human well-being and to distinguish between priority and non-priority ecosystem services in the case of Singapore. The prioritized ES correspond to several initiatives taken in the Greenprint program in Singapore (Government of Singapore 2012). The following table contrasts the priority ecosystem services according to the questionnaire with undertaken actions in the local Greenprint plan by Singapore´s Housing and Development Board.

Table 2: Overview on the prioritized ecosystem services in Singapore (derived from questionnaire) and corresponding actions in the Housing and Development Board’s (HDB) Greenprint plan
Categories Prioritized Ecosystem Services HDB’s Greenprint action
Provisioning Services Food Community Engagement / Landscaping & Greenery
Fresh Water Water Conservation
Regulating Services Air quality regulation Adaptation and mitigation climate change / Landscaping & Greenery
Waste water treatment Waste Management
Habitat Services Habitat Community Gardening
Cultural and amenity Services Aesthetic quality Greener Living / Landscaping & Greenery
Recreation Community Gardening

The provision of food is represented by the initiatives of Community Engagement as well as the Landscaping and Greenery program while fresh water provision corresponds to the Water Conservation aspect. The regulating services air quality regulation and waste water treatment are regarded as parts of the Adaptation and Mitigation of Climate Change and Waste Management respectively. The habitat service is best described in the Community Gardening program while the cultural services of aesthetic quality and recreation fall into the aspects of Greener Living, Landscaping and Greenery and Community Gardening.

This comparison again shows the close connection between different aspects and programs since Community Gardening and Landscaping and Greenery cover at least two different ES. One significant program relates to the greening of rooftops and also vertical greenery of facades. This is the most prominent example for the complementarity of ES as it leads to cooling of buildings, increased habitats, increased pollination within a city, rainwater retention and – as in the case of Singapore – often offers recreation options as well as urban gardening opportunities.

3.3 Localization and Analysis of Urban Ecosystem Services in Singapore

3.3.1 Aesthetic Quality

For the analysis of aesthetic quality in Singapore, the module of the same name in InVEST was used. The data for the module consists of publically available data on different positive natural impact points in Singapore namely heritage trees, skyrise greenery and community gardens. The datasets were updated in July 2014, August 2014 and May 2011, respectively (see data reference section for full record). To conduct the viewshed analysis, further data of a Digital Elevation Model (SRTM; NASA & NGA, n.d.) was implemented. The calculation runs with a standard refractivity coefficient of 0.13, representing the earth’s curvature correction, and a resolution of 100 m.

Figure 3: Analysis of the Aesthetic Quality of Nature in Singapore including heritage trees, skyrise greenery and community gardens as aesthetically positive impacts points in a viewshed (see data reference section for full record)

Natural impacts regarded as aesthetically positive contain heritage trees, skyrise greenery and community gardens. In the generated viewshed maps, the darker areas suggest a higher visual impact, based on the amount of sites visible. Areas with a highly positive natural aesthetic were distributed relatively evenly across the main island. The analysis shows that per cell a maximum of 390 features can be seen. However, most of the island derives an aesthetically positive impact from ten or less selected features.

3.3.2 Recreation

Recreational services contribute to social connection, quality of life, physical health and other facets of human well-being. In other words, places of recreation within the urban environment are not only important in economic terms (e.g. eco-tourism), but also impact spiritual well-being, facilitate a sense of place and enhance social interactions (Russell et al., 2013). In fact, an increasing segment of recreational activities is nature-based, taking place in the natural environment (Balmford et al., 2009). Many Singaporeans find recreational services in the park connector network.

As described in section 2.3 the recreation analysis takes into account geo-tagged photographs from the flickr database. Furthermore, data of park connector loops, cycling paths and relaxation points are included. The dataset on relaxation areas is derived from the Singaporean Health Promotion Board (Health Promotion Board, 2014) and includes topics like barbeque pits, fitness corners and a diversity of green spaces. The mapping results show that the highest density of visits (usdyav) occurs in the downtown area of Singapore, reflecting monuments, museums and sightseeing experience.

Figure 4: Mapping of the Recreation Analysis in Singapore, visit density is hypothesized from geo-tagged flickr database photographs (see data reference section for full record)

Unsurprisingly, recreational services are predominant around the Marina region, Harbourfront as well as Sentosa Island. Furthermore, an increased number also highlights the paths along the park connectors and cycling loops as well as near the relaxation points. Another spot of high density of visits according to the user per day average seems to be the airport in the eastern part of the island. The benefit of the recreational service should be regarded carefully in this case.

3.3.3 Air Quality Regulation

The ecosystem service of air quality regulation was assessed through a carbon storage analysis in this paper. The assessment is based on the InVEST model including current land cover data, carbon pools and a valuation model with a value of carbon (USD/metric ton), the market discount and the annual rate of change in price. Due to the lack of data, only the biophysical carbon sequestration is calculated.

The following map shows the distribution of carbon sequestration in Singapore based on a land cover with a rough resolution and the basic year 2000 (European Commission Joint Research Center (JRC) dataset see Stibig et al. (2003)). Each land cover class receives a value of carbon stored in aboveground biomass, belowground biomass, soil and dead organic matter adapted from the IPCC (IPCC, 2006).

Figure 5: Carbon Analysis in Singapore, based on the land cover dataset for South East Asia (JRC, Stibig et al. 2003) carbon pools from the year 2000 are linked to tropical and subtropical amounts of carbon stored according to (IPCC, 2006)

Due to the model and land cover data resolution, smaller patches of green and carbon storage are not accounted for. Therefore, the areas with the highest amount of carbon stored are forested and national park areas, such as the MacRitchie Reservoir and the Bukit Timah Nature Reserve, the wetland reserves as well as the green spaces around airports. The results do not reflect smaller parks and community gardens or greenery and trees along streets or skyrise greenery. These might also pool a significant amount of carbon within the city. The unit represented is megagrams (tons) per grid cell.

3.3.4 Provision of Food and Water

The provision of food is of special importance in the Singaporean case and ranked high on both impact and dependence scales. The provision of food includes the production of crops (e.g. grain, vegetables, fruits, and rapeseed) for human or animal consumption. At present, only about 0.5 % of the total land area is devoted to agricultural use and total farming area is steadily declining. This results in a strong dependence on daily food imports from neighboring countries. Food provision within the urban environment is thus enabled through agricultural areas, but also through community gardens or vertical and skyrise greenery.

In order to localize food provision, a definition of all areas suitable for food production is prerequisite. Singapore promotes the development of rooftop and skyrise greenery through several incentive schemes. So far, about 374 buildings had installed either rooftop greenery ( 70 %), vertical greenery ( 22 %) or both ( 8 %) (see data reference section for full record). In 2012, it translated to more than 60 hectares of installed skyrise greenery in and on about 250 buildings (Behm and Hock, 2012).

The “Community in Bloom” program was fostered by the National Parks Board in 2005 which was joined by private persons as well as schools, hospitals and welfare organizations. In 2011, Singaporean food supply was supported by 458 community gardens of which 146 were officially listed with a primary use of fruit trees, herbs and spices or vegetables (National Parks Board, 2011). In the meantime, around 600 gardening groups can be found. Another essential ecosystem service for human well-being is fresh water, which is provided from inland bodies, groundwater or surface waters. Fresh water provision ranked highest on both dependence and impact scales, and can thus be considered to be of very high priority for the Singaporean public. Fresh water provision can be approximated by the surface area of fresh water ecosystems and the annual water flow derived thereof.

4 Discussion

Evaluating spatially explicit indicators as described in the respective analyses allows for the identification of urban areas with low and high provision of ecosystem services. A density analysis of the cultural services, represented by community gardens, heritage trees, skyrise greenery and relaxation points as used in this study for recreation and aesthetic quality, shows the highest density of said services in the Marina Bay, the Central Area but also along the cycling paths and the park connector loops. In terms of facilitating easy access to cultural service, these routes seem well planned.

The analysis of aesthetic quality in Singapore is very much influenced by the aesthetically positive points chosen. Using community gardens, skyrise greenery and heritage trees in this case, the output generated displays a wide spread positive aesthetical quality throughout Singapore with a slight concentration in the Central Area, on Pulau Ubin, an island north east of Singapore dedicated to eco-tourism and wildlife preservation and on Sentosa Island, an island resort south of Singapore.

The recreation analysis allows for several interpretations. Since the recreation tool relies on the flickr database of geo-tagged photographs, results may be improved by including either visitation rates of recreational features or other databases in addition to flickr. In other words, high visitation rates might alter and decrease the recreational aspect. Using this model, it is not possible to distinguish between purely natural recreation facets and also cultural aspects since the photographs taken into account are unknown and might display more cultural features. Additionally, the mapped results have to be seen in the context of a larger landscape, as the artificially generated boundaries may result in clipped and ignored features within the external environment.

Through the installation of park connectors and cycling paths, Singapore controls the spread of visitors (locally) and creates space for natural development, where the environment is less impacted. The park connector network serves several important purposes in the highly fragmented urban landscapes in Singapore. From a conservation point of view, it provides habitat and shelter. The park connectors are also hotspots of social interaction and recreational value. One of the most crucial roles of the park connector roles is, however, that of increasing habitat connectivity.

Regulating ecosystem services are tackled in this paper using a carbon storage analysis. The input data allows for an estimation of several land use classes capability to store carbon aboveground, belowground, in the soil and in dead matter. This does not reflect any small patches of green within the city or the efforts of Singapore to install skyrise greenery. Further research including these carbon storage options is necessary. Still, the highest amounts of carbon are stored in the central parts of the Singaporean Island within the forests and revoir areas.

In the field of provisioning ecosystem services, food and water supply alternatives are discussed. Singapore relies heavily on imports regarding foodstuffs so community gardens, skyrise greenery and other backup capacities are needed. With the program “Community in Bloom”, Singapore already provides support for active private gardeners with the wish for self-supply. While small areas of farmland and fish farms are located exclusively in the Western Water Catchment, community gardens and skyrise greenery are spatially well distributed on the island and provide food but also cultural services very locally.

5 Added Value for the Post-2015 Framework for Disaster Risk Reduction

In general, the assessment of ecosystem services in cities is one way of valuating the benefits of ecosystems for the city’s inhabitants as monetarized values as well as non-monetary benefits. The concept of an Urban Ecosystem Services Review (Urban-ESR) as used here, forms a basis that fits to the concept of critical infrastructures and specifically addresses the sectors of energy supply, water and food supply, urban development and air pollution. Critical infrastructures are defined as being essential for the public security and supply and a critical infrastructure failure leads to massive limitations in public life (e.g. Bundesamt für Sicherheit in der Informationstechnik, 2004). Besides, disaster risk management is regarded during the steps of scenario building and a SWOT-analysis and is part of the ecosystem service type of regulating services. Since the concept of the Urban-ESR includes social, economic and ecological factors, it is most suitable for the framework for disaster risk reduction to include people’s quality of life.

As could be seen in the case of Singapore, which is at the forefront of developing building-integrated vegetation, skyrise greenery projects add several dimensions to the urban ecosystem service concept aside from greening the urban infrastructure. In fact, such projects serve as ‘perfect’ example for nearly every type of ecosystem service. This includes not only provisioning services in terms of food and fresh water provision, but also regulating services for micro-climate, air pollution and indoor energy demand. Moreover, habitat for species is provided through green rooftops. Cultural purposes are fulfilled as well since green roofs may serve as eco-touristic magnet and recreational hotspot.

However, the installations of roof greenery and gardens are in direct competition to PV panels and solar heating devices. Nevertheless, both usages are still partly possible. This would increase the provisioning services of self-reliant energy supply and also the other services as discussed above. The installation of information panels in public skyrise greenery or community gardens could also raise the awareness and acceptance of such measures.

6 Conclusions

The Urban-ESR has offered insight into the current provision of urban ecosystem services as well as of ecosystem services in urban areas in Singapore. Overall, the insights gained through the preceding GIS-based maps and investigations provide urban planners with helpful starting points for distilling the necessary practices. Additional data inputs would allow for analyses of the future or potential provision status. Since governmental assistance is crucial for conservation purposes, the incorporation of the spatial dimension can help arrange such administrative and institutional support. This is particularly valuable for solving environmental management problems in an integrated way.

Ecosystem Services, however, cannot only be regarded as natural benefits for people within the framework of an Urban-ESR but cities must be accepted as a kind of natural environment that provides its inhabitants and visitors with natural as well as cultural goods and services. This becomes especially clear regarding recreation as an ES. The analysis in InVEST already takes into account cultural aspects by reflecting geo-tagged photographs of any kind that are worth visiting. There is no difference being made whether it is nature or culture providing this service.

Discussions with scientists and decision-makers in this field showed a discrepancy in language and use of specific terms. Ecosystem Services are a new concept, with Ecosystem Services Reviews as a framework for their assessment, that needs reflection with known procedures and terms otherwise decision-makers are skeptical whether it is useful and practical. By filling the ESR framework with tools and methods specifically designed for decision support and stakeholder advice in cities such as GIS-based maps, Cost-Benefit-Assessment and the overall integration of decision makers into the processes, an Urban-ESR increases the acceptance and understanding of ecosystem services. Applications like Ecosystem-based Adaptation (EbA) and green/blue infrastructure still lack a common procedure and perception in decision making (e.g. United Nations International Strategy for Disaster Reduction (UNISDR), 2012; European Climate Foundation (ECF), 2014). While EbA is perceived as a soft concept, green and blue infrastructure pools soft and hard measures for a sustainable (urban) development. In 2014, Singapore’s national water agency PUB released an updated version of its ABC waters program. ABC stands for “Active, Beautiful, Clean” and the program was launched in 2006. It includes measures as sustainable storm water management, enhancement of biodiversity and increasing aesthetics and recreation (Public Utilities Board (PUB), 2014). However, terms like management, planning, design and construction predominate the communication side and underline green and blue infrastructures. Contrasting this, EbA is not addressed explicitly. One of the next steps will be an implementation of this program in the Urban-ESR Singapore with regard to the provisioning services.

Understanding the individual needs of different ecosystem service beneficiaries, including their perception and knowledge of services, is crucial particularly for intangible or abstract ecosystem services. Future participatory research should thus focus on the inclusion of different stakeholders at various points throughout the Ecosystem Services Review. A comprehensive and critical involvement of stakeholders will help close the existing knowledge gap concerning the social-cultural need for and acknowledgement of urban ecosystem services. Future studies could assess the similarities and differences of maps of urban ecosystem service provision generated by or for the various stakeholder groups in a comparative way. Only if urban ecosystem services are distributed and provided in an equitable way, they can trigger the positive health benefits for the urban population.

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Acknowledgements

This work was conducted in the frame of the project “Smart and Low Carbon Cities”, a collaboration between Singapore’s Housing and Development Board (HDB) and the research and development department of Electricite de France (EDF).

Citation

Sieber, J., Fremgen L. and Pons, M. (2015): Assessment of Ecosystem Services for Urban Resilience – Case Study in Singapore. In: Planet@Risk, 3(1): 77–86, Davos: Global Risk Forum GRF Davos.