Nexus between nature-based solutions, ecosystem services and urban challenges

Sub-Saharan Africa (SSA) is the region most vulnerable to climate change and related hydro-meteorological risks. These risks are exacerbated in rapidly expanding urban areas due to the loss and degradation of green and blue spaces with their regulating ecosystem services. The potential of nature-based solutions (NBS) to mitigate hydro-meteorological risks such as floods is increasingly recognized in Europe. However, its application in urban areas of SSA still needs to be systematically explored to inform and promote its uptake in this region. We conducted a multidisciplinary systematic review following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) protocol to establish the general patterns in the literature on NBS and hydro-meteorological risk mitigation in SSA. We searched scientific journal databases, websites of 12 key institutions and 11 NBS databases and identified 45 papers for analysis. We found at least one reported NBS in 71 % of urban areas of SSA across 83 locations. 62 % of the papers were clustered in South Africa, Kenya, Tanzania and Nigeria only, while the most studied cities were Dar es Salaam and Kampala. Moreover, 66 NBS practices were identified, most of which (n=44) were for flood mitigation. With only Mozambique (n=2) reporting NBS among the most at-risk countries, we found that NBS are implemented where risks occur but not where they are most severe. Mangrove restoration and wetland restoration, reforestation and urban forests, and agroforestry and conservation agriculture were the most common NBS practices identified for floods, extreme heat and drought mitigation, respectively. Traditional practices that fit the definition of NBS, such as grass strips and stone bunds, and practices more popular in the Global North, such as green roofs and green façades, were also identified. These NBS also provided ecosystem services, including 15 regulatory, 5 provisioning and 4 cultural ecosystem services, while 4 out of every 5 NBS created livelihood opportunities. We conclude that reported uptake of NBS for hydro-meteorological risks in SSA is low. However, there could be more NBS, especially at the local level, that are unreported. Furthermore, NBS can help SSA address major development challenges such as water and food insecurity and unemployment and help the sub-region develop climate-resiliently. We, therefore, recommend that NBS be mainstreamed into urban planning and for knowledge exchange opportunities between SSA and Europe and other regions to be explored to promote uptake.

Rapid urbanization in many parts of the world has increasingly put the environment under pressure, with natural landscapes cleared to make way for built infrastructure. Urban ecosystems, and the services that they provide, can offer nature-based solutions to the challenges of urbanization. There is increasing interest in better incorporating ecosystems into urban planning and design in order to deliver greater provision of ecosystem services and enhance urban liveability. However, there are few examples of built or proposed urban developments that have been designed specifically with ecosystem services in mind–partly because there are few modeling tools available to support urban planners and designers by informing their design workflows. Through using Singapore’s latest nature-centric town as a case study, this article assesses the impacts of nature-based solutions in urban design on ecosystem services performance, through a spatially explicit modeling approach. The proposed future scenario for the nature-centric town was projected to result in substantial declines in the provision of all ecosystem services, as a result of the removal of large areas of natural vegetation cover. However, the future scenario compared favourably against three older towns that have been constructed in Singapore, showing the best performance for four out of six ecosystem services. This simulation exercise indicates that designing towns with ecosystem services in mind, and incorporating nature-based solutions into urban design, can help to achieve enhanced performance in providing ecosystem services. The models developed for this study have been made publicly available for use in other tropical cities.

Trade-offs and synergies between livestock production and other ecosystem services

Ecosystems supply goods and services to humans and are the basis for sustainable development of human society. The study of the supply of ecosystem services and the demand and consumption of ecosystem services by human society, and the analysis of the supply and demand characteristics and flow relationships of ecosystem service flows are of great significance for the management of regional ecosystems and the development of ecological compensation. Taking the Yangtze River Economic Belt as an example, this paper calculates the supply and demand indices of ecosystem services in 2015 and 2020, and determines the ecosystem spatial flow paths and flow volumes from the ecosystem supply area to the demand area based on various methods and models such as the minimum cumulative resistance (MCR) model and distance decay model. The results indicate that 1). In 2015 and 2020, the supply and demand of ecosystem services in the Yangtze River Economic Zone show an increasing trend numerically, and there is spatial heterogeneity in the spatial distribution. In terms of ecosystem service supply per unit area, the midstream region is higher than the upstream and downstream regions. In terms of the demand for ecosystem services per unit area, the downstream is higher than the midstream and upstream. 2). From the supply-demand balance of ecosystem services in the Yangtze River Economic Zone, the midstream region is mainly the area of surplus supply of ecosystem services, and the downstream region is mainly the area of deficit supply. From 2015 to 2020, the number of areas with balanced supply and demand of ecosystem services in the Yangtze River Economic Belt decreases and the number of areas with unbalanced supply and demand increases, which is related to the changes in the level of economic development and land use patterns. 3). The flow of ecosystem services in the Yangtze River Economic Belt shows an increasing trend, from 726.59 billion yuan in 2015 to 1,450.54 billion yuan in 2020, with Jiangxi Province being the main ecosystem service supply area and Zhejiang Province being the main ecosystem service demand area in the Yangtze River Economic Belt.

A just urban ecosystem service governance at the neighbourhood level- perspectives from Sofielund, Malmö, Sweden

Increasing urbanization and climate change challenges are leading to relevant environmental, economic and social pressures on European cities. These include increasing flood hazards and the urban heat island (UHI) effect. Nature-Based Solutions (NBS) are increasingly recognized within strategies to provide multiple ecosystem services to mitigate existing risks and pressures, as well as to make cities more resilient and livable. Although being increasingly addressed within the literature, NBS implementation on the ground still faces many technical and financial barriers. This paper aims to test the potential of selected NBS in mitigating the effects of identified climate change risks, i.e., the UHI effect and urban floods, in the Turin urban area (north-western Italy). Four different intervention NBS-based scenarios are developed. The supply of ecosystem services by NBS in each scenario is assessed using InVEST models and the effectiveness of NBS investments is analyzed by calculating and comparing the associated costs and benefits. Different results in terms of effectiveness and economic viability are observed for each scenario and each NBS. Flood risk mitigation oriented NBS seem to have the most impact, in particular forested green areas and retention ponds. The results are relevant to suggest policy mix strategies to embed NBS in city planning.

Many coastal peri-urban and urban populations in Oceania are heavily reliant on terrestrial and marine ecosystem services for subsistence and wellbeing. However, climate change and urbanisation have put significant pressure on ecosystems and compelled nations and territories in Oceania to urgently adapt. This article, with a focus on Pacific Island Oceania but some insight from Aotearoa New Zealand, reviews key literature focused on ecosystem health and human health and wellbeing in Oceania and the important potential contribution of nature-based solutions to limiting the negative impacts of climate change and urbanisation. The inextricable link between human wellbeing and provision of ecosystem services is well established. However, given the uniqueness of Oceania, rich in cultural and biological diversity and traditional ecological knowledge, these links require further examination leading potentially to a new conceptualisation of wellbeing frameworks in relation to human/nature relationships. Rapidly urbanising Oceania has a growing body of rural, peri-urban and urban nature-based solutions experience to draw from. However, important gaps in knowledge and practice remain. Pertinently, there is a need, potential—and therefore opportunity—to define an urban design agenda positioned within an urban ecosystem services framework, focused on human wellbeing and informed by traditional ecological knowledge, determined by and relevant for those living in the islands of Oceania as a means to work towards effective urban climate change adaptation.

Village Tank Cascade System (VTCS) landscapes in the dry zone of Sri Lanka provide multiple ecosystem services (ESs) and benefits to local communities, sustaining the productivity of their land use systems (LUSs). However, there is a lack of adequate scientific research on the ESs of LUSs, despite the recent land use changes that have greatly impacted the provisioning of ESs. Collection of baseline ESs data is a pre-requisite for decision making on ESs-based ecological restoration and management of the VTCS. Thus, this study aimed at assessing ESs of the Mahakanumulla VTCS (MVTCS) located in the Anuradhapura district of Sri Lanka by using a participatory approach involving the integration of local knowledge, expert judgements and LUSs attribute data to assess the ESs. The methodology was designed to integrate the biodiversity and land degradation status of LUSs in a way that is directly linked with the supply of ESs. The study identified twenty-four ESs of the MVTCS based on community perceptions. The identified ESs were assessed as a function of LUSs to develop an ecosystem service supply (ESS) and demand (ESD) matrix model. The results reveal that the current overall ESD for regulating and supporting ESs is higher than the ESS capacity of MVTCS. The assessment also revealed that land degradation and biodiversity deterioration reduce the capacity to provide ESs. Downstream LUSs of the meso-catchment were found to be more vulnerable to degradation and insufficient to provide ESs. Further, the study established that ESs in the MVTCS are generated through direct species-based and biophysical-based providers. In addition, it emerged that social and cultural engagements also played an important role in association with both providers to generate certain types of ESs. Therefore, it can be concluded that VTCS ecological restoration depends on the extent to which integrated effort addresses the levels of ecological complexity, as well as the social engagement of communities and stakeholders. The results of this study provide a scientific basis that can inform future land use decision making and practices that are applicable to successful ESs-based ecological restoration and management of the VTCSs in the dry zone of Sri Lanka.

Mixture mitigates the effect of climate change on the provision of relevant ecosystem services in managed Pinus pinea L. forests

Under rapid urbanisation and climate change, cities urgently need strategies to enhance resilience and sustainability. Transforming brownfields into green spaces has been widely recognised as a nature-based solution (NbS), yet how to integrate this transformation into urban planning to maximise benefits remains unclear. To address the gap, our study proposes a cross-scale approach for brownfield greening (BG) that links urban-scale prioritisation with site-specific greening interventions. By integrating spatially explicit assessments of ecosystem service (ES) supply, demand and supply-demand balance, the approach identifies not only where BG should occur (where to green), but also how tailored interventions can be implemented within sites (how to green). The proposed approach was tested in Tangshan, a typical resource-exhausted city in China, demonstrating how ES assessments can guide both strategic planning and detailed planning of BG. The findings advance the integration of NbS into spatial planning at multiple levels, offering actionable guidance for policy-makers, urban planners and landscape architects. Beyond the case study, the approach also provides insights into managing land abandonment in shrinking cities worldwide, contributing to more effective and transferable urban greening strategies.

In this chapter we pose two questions: (i) Does land size relates to forests and ecosystem service (ES) provision concentration? (ii) Do these spatial concentration patterns relate to expressions of vulnerability such as poverty, low human development, and natural capital loss at the municipality level? For the entire Chilean Patagonia and neighboring Biobio region, we found strong positive correlations (>0.92) between land holding size, native forest, and ES provision (as measured by the Ecosystem Service Provision Index). At the municipality level (n = 147), spatial cluster analysis identified five groups. Group 1 comprised 12 municipalities with high Gini coefficients (high inequality) for land size, native forest area, ES provision, and income, high poverty rates, low levels of human development, medium level of rural and indigenous population, high deforestation and afforestation rates, and high ES loss rates. In the other extreme, group 3 comprised 13 municipalities characterized by the coincidence of low Gini coefficients for land size, native forest area, ES provision, and income, lower poverty rates, higher levels of human development, higher levels of rural population, lower deforestation and low afforestation rates, and low ES loss rates. The results corroborate (i) a trilogy of inequalities, where larger landholders concentrate on land, native forests, and ES provision and (ii) a “trap”-like pattern in some municipalities, where inequalities are linked to poverty and natural capital loss, which is more prevalent in municipalities with a medium proportion of indigenous population. The results corroborate the great inequalities that prevail in the Chilean Patagonia, which demand a shift in land, rural development, and natural resources policies. Any conservation or management instrument based on ES provision must consider this context, with a view to avoiding further inequalities.

Forecasted scenarios of climate change are expected to result in a dramatic reduction in the provision of Ecosystem Services (ES) from forests. Increasing tree species diversity has been proposed as a measure for adapting forests and warrantee the provision of services, since mixed forests, if compared with monospecific forests, are expected to be more productive, resilient and stable facing disturbances. In the present work we use a modelling approach in order to quantify the provision of different ES under expected climate scenarios, comparing pure forests of Pinus pinea L. with mixed forests where the species grows accompanied by different Quercus and Juniperus species. To this aim we first adapted the existing individual tree level model PINEA2, originally constructed for pure even-aged stands of P. pinea, in order to consider the interspecific interactions acting in mixed forests. In a second step we used the so adapted model for forecasting and comparing the provision of different ES – focusing on stocking, growth, yield, CO2 fixation, economic income and structural diversity – under current climate and expected scenarios RCP 4.5 & 8.5. Our results indicate that although growth and allometry in P. pinea trees is enhanced in mixtures, this effect is currently counterbalanced by the expected reduction in growth in the species occupying the understorey, thus under current climate conditions little differences due to composition are observed in the provision of ES. On the other hand, our simulations point to a generalized decrease in the ES supply under more severe climate change scenarios, being this reduction mitigated – at least in part - in mixed P. pinea forests, which are more competitive under the most restrictive environmental conditions. As a consequence, the promotion of mixtures by under-planting and/or releasing of pre-existing advanced regeneration of complementary species may be postulated as a management concept for adapting these forests to climate change.

Nature-based solutions (NBS) in cities are known to provide numerous ecosystem services that contribute to the well-being of city inhabitants and to climate change attenuation and adaptation. Common services provided by the NBS are urban heat island reduction, provision of habitat for biodiversity, rainwater management, indoor summer comfort, etc. To provide science-based arguments for the choice of the adapted solutions to a specific context, the assessment of those services is necessary. The aim of this paper is to review models assessing the service of rainwater management for three green infrastructures: green roofs, urban trees (stand-alone or micro-forest) and vegetated permeable pavements. The final goal of this work is to help improve the decision aid tools for the environmental assessment of the performance of buildings and districts. The characteristics of each model are presented and analyzed, in terms of robustness, parsimony and operationality. We for example compared the number of required parameters (e.g., plant species, substrate type and depth of green roofs, soil moisture, etc.), the availability of these parameters, etc. The multifunctionality of NBS (i.e., other services provided beyond the contribution to the rainwater management) is also considered in the analysis. In addition, as NBS are living systems, their specific needs (such as water and mineral nutrients), as well as the influence of the local context (e.g., climatic, topographic, cultural) are discussed. Finally, some paths for the implementation of the models into the decision tools are highlighted. The main challenge for the implementation in decision tools could be the harmonization between different expertises and stakes.

Ecosystem services of Hurri hills, a montane woodland ecosystem in the arid lands of northern Kenya

Focusing on urban planning tools and techniques that may incorporate environmental services in urban development should be one of the next frontiers of sustainable cities. Designing natural-based solutions for providing crucial biophysical structures and ecological functions for human well-being and mitigating soil loss could be a crucial milestone. In this paper, we provide a methodology for spatially analysing the effects of various urban planning-generated land-use scenarios on the provision of ecosystem services. The methodology analyses the variation of ecosystem services, considering as starting point the ecosystem services provided by the current status of land use of the study area and their potential changes considering the urban actions planned. One scenario of analysis includes the integration of Natural-based Solutions in urban planning. The case study is represented by a peri-urban area characterized by an agroecosystem planned for urban development in the municipality of Gallipoli, Southern Italy. The analysis highlights a low ecosystem services provision of the agroecosystem for effecting of Xylella fastidiosa bacteria that destroyed important olive trees. So, the integration of Natural-based Solutions and reductions of construction buildings in the sub-urban plan could improve the quantity of ecosystem services in the area. Additionally, taking into account the beginning points, the ecological design of ecosystem services can enhance the typology of ecosystem services supply in the region. As a result, the ability to include ecosystem services analysis into urban planning may be a beneficial tool for ecological urban design to aid in decision-making.