Nature-based Solutions Research Articles

Milder, wilder, drier: Understanding preferences for urban nature-based solutions in China

Nature-based solutions have gained recognition for their potential to address urban environmental challenges, particularly in rapidly urbanising countries such as China. However, financial and spatial constraints hinder their widespread adoption. Here we explore urban residents' preferences for nature-based solutions targeting stormwater management, urban heat island reduction, and biodiversity support through monetary, time, and space contributions. We carried out three choice experiment surveys with 1536 Chinese respondents, employing three payment vehicles: willingness to pay (WTP), willingness to contribute time (WTCT), and a novel metric, willingness to contribute space (WTCS). The WTCS metric assesses individuals' willingness to voluntarily convert sealed surfaces on private land into greenspace. We found strong preferences for temperature and flooding reduction across all payment vehicles, reflecting substantial challenges of urban heat islands and flooding in China. Additionally, we reveal a preference for moderate greenspace management intensity, highlighting the potential for biodiversity benefits through reduced management intensities. The introduction of the WTCS payment vehicle expands the methodological toolkit for choice experiments and offers a novel approach to assess citizen support for nature-based solutions. These findings have practical implications for designing effective nature-based solutions programs to address urban environmental challenges and meet the preferences of urban residents in China and beyond.

Estimation on Individual-Level Carbon Sequestration Capacity of Understory Perennial Herbs

AbstractThe carbon sequestration capacity of plants has been used as a nature-based solution to reduce carbon emissions. Perennial herbs potentially contribute to carbon sequestration by allocating carbon to belowground parts as well as trees. As individual-level estimations have mainly been carried out for tree species, individual-level carbon sequestration for understory perennial herb species is poorly understood. To estimate the below- and aboveground carbon sequestration capacity, ten perennial herb species were planted for field experiment. Individual carbon sequestration by biomass was calculated by measuring the aboveground- and estimating belowground biomass gain at harvest. We further measured non-destructive aboveground parameters, such as photosynthesis and leaf area, to estimate the belowground biomass. Four species (Aconitum jaluense Kom., Aquilegea oxysepala Trautv. & C.A.Mey., Disporum smilacinum A.Gray, and Polygonatum odoratum var. pluriflorum (Miq.) Ohwi) showed the positive belowground carbon sequestration level during the experimental period. Correlation analyses indicated that the aboveground biomass and leaf area at senescence stage could be used as non-destructive estimates of belowground carbon sequestration. The perennial herb species habitat suitability for use as additional carbon sinks in urban forests and for forest restoration should be assessed based on the increase in belowground biomass.

Effects of Climate and Weeds on the Establishment of Thyme-Based Living Mulch Systems in Drylands of Cyprus

Backround: Mulching systems are at the spotlight of sustainable soil management as nature-based solutions for combating desertification.
 Aims: We tested how living mulch systems based on rainfed Thymbra capitata [(L.) Cav.], can be established under different pressure from drought and weeds in dryland carob plantations.
 Study design: 10 thyme plots in semi-arid climate (SKR); 11 plots in arid climate (VRY); different weed competition intensity (60 thymes per plot).
 Place and Duration of the Study: South-eastern Cyprus, between December 2019 and 2022.
 Methodology: Survival and soil cover for 1260 T. capitata seedlings (3-5 cm tall, 16 seedlings per m2) was assessed at the end of 3 dry seasons (d.s.) together with weed community composition, weed abundance (w.a.) and biomass. Climate data and De Martone’s Aridity Index (DMAI) were used to assess drought severity.
 Results: Around 80% of the thymes survived at the end of the first d.s, that followed a very rainy year (ca. 600 mm annual precipitation; P; ca. +50% than normal; ca. 19 DMAI). Thyme survival appeared unaffected by w.a. in both sites. After a severe drought that occurred the second year (ca. 300 mm P; ca. -22% than normal; ca. 9.5 DMAI) thyme survival rates dropped at the end of the d.s. to ca. 20% at the site with 3 times higher w.a./ biomass (mostly from Avena sp.). However, they were unaffected under low w.a. creating a 29% soil cover (vs.7% in VRY). These results remained till the end of the third d.s.
 Conclusions: To combat desertification and drought intensification under climatic change, rainfed T. capitata as living mulch appears unaffected by weeds during wet years, or in very dry years under low w.a. However, under high w.a., a weed management system is required if climate is arid.

Habitats Heterogeneity Affects Bee Species Assemblage in an Urban Green Space: A Case Study of Nairobi Museum Botanic Garden, Kenya

The conversion of natural landscapes into human-dominated areas has been identified as one major threat to the existence of biodiversity. However, properly managed anthropogenic biomes can act as areas of biodiversity conservation with the potential to provide ecosystem services similar to those obtained in natural habitats. Classic examples are botanic gardens that have become popular in urban centres as examples of nature-based solutions to landscape loss and degradation. To assess the importance of botanic gardens as biodiversity habitats, a study was carried out in the Nairobi Museum Botanic Garden (NMBG). Bees were sampled using pan traps and sweep nets in four habitats classified as gardens, including the Herbal Garden (HG), Memorial Garden (MG), Succulent Garden (SG), and Quarry Garden (QG). A total of 286 individual bees were collected, with MG having 83 individuals, QG (75), SG (66), and HG (62). Though HG recorded the lowest abundance of bees, it recorded the highest number of bee species (14), MG (13), SG (12), and QG (5). The diversity of bees was highest in the HG (H’=1.89), SG (1.88), MG (1.67), and QG (1.15). Meanwhile, high bee abundances and richness were strongly correlated with diverse flowering plants per habitat, with HG having the highest number of flowering plants (23), MG (16), SG (13) and QG (7). The study found that different flowering plants provided habitats that supported unique assemblages of bee communities, a scenario attributed to enhanced habitat heterogeneity. The findings demonstrated that botanic gardens can act as important habitats and refugia for bees in human-dominated landscapes. Therefore, the establishment and conservation of botanic gardens in urban areas is one way to contribute to Sustainable Development Goal 11 of ensuring sustainable cities and human settlements

Animals and Cities: A Reflection on Their Potential in Innovating Nature-Based Solutions.

In recent decades, nature-based solutions (NBSs) have spread in scientific research, and they are increasingly deployed in cities' strategic planning. While the number of nonhuman animals in cities is growing, a specific reflection on the advantages of human-animal interactions as potential NBSs is still lacking. This article aims to provide an overview of the current situation of animals in cities and to explore the roles of animals and their interactions with humans in such a context. These topics are crucial to the European project IN-HABIT in Lucca (Italy), which aims to codify an integrated policy on the relationship between people and animals; its outputs will then be transferred and replicated in other cities. This article concludes by highlighting the need for the involvement of different stakeholders in public-private-people partnerships to implement actions that aim to valorize human-animal relationships and their positive effects. This study presents a perspective on the relevance of animal NBSs to increase the quality of life in cities, both for citizens and for animals living in cities, and to also introduce the opportunity to develop an integrated animal urban policy able to valorize human-animal interactions in cities.

Blueprint for Blue Carbon: Lessons from Seychelles for Small Island States

Blue carbon has been proposed as a nature-based solution for climate change mitigation; however, a limited number of published works and data and knowledge gaps hinder the development of small island developing states’ (SIDS) national blue carbon resources globally. This paper reviews the blue carbon ecosystems of Seychelles as a case study in the context of SIDS, comparing estimations by the Blue Carbon Lab and recent blue carbon (mangrove and seagrass) evaluations submitted to the Seychelles national government. Mangroves (2195 ha, 80% in Aldabra Atoll) and seagrasses (142,065 ha) dominate in Seychelles, with coral reefs having the potential for carbon sequestration (169,000 ha). Seychelles is on track to protecting its blue carbon, but these systems are threatened by rising sea levels, coastal squeeze, erosion, severe storms, and human activities. The importance of carbon inventories, accounting institutions, and continuous monitoring of blue carbon systems is discussed. Blue accounting is necessary for accurate accounting of carbon sequestration and carbon storage, generating carbon credits, and representing impactful reductions in greenhouse gases for NDCs. Challenges and opportunities include policy legislation regarding ownership rights, accreditation and certification for carbon credits, sustainable financing mechanisms like natural asset companies and blue tokens, local engagement for long-term success, and carbon market dynamics following COP27. The restoration and regulation of blue carbon resources for optimal ecosystem services delivery, carbon inventories, and blue carbon policy are recommended development priorities. Blue carbon ecosystems have the potential to contribute to NDCs of SIDS while simultaneously offering sustainable development pathways for local communities through the multiple ecosystem services they provide.

Carbon and nitrogen stock in soils of subtropical urban forests: Isotopic δ13C and δ15N indicators for nature-based solutions in a megacity

Urban forest soils play a pivotal role in enhancing the environmental sustainability of cities, contributing to various natural processes, including plant–microbe interactions, microbial activity, and the decomposition of organic matter. Consequently, urban forest soils emerge as effective NBS, underscoring their potential to mitigate environmental challenges and foster sustainable urban ecosystems. In these sense, this manuscript aimed at evaluating how soil attributes of the urban forests of São Paulo, Brazil, with different adjacent land uses, influence the capacity to store the excess of C and N from anthropogenic emissions, making this ecosystem an important reservoir of urban anthropogenic emissions. Three hundred urban forest soil samples were collected from the surface to a depth of 50 cm. All samples were analyzed for C and N content (and their stable isotopes). In addition, granulometric tests were also carried out to classify the soils. It was found that the most central forest fragment has the highest C and N contents at all analyzed depths, probably due to the association with physical aspects of soil texture. For all layers, the most central fragment soil sample, the only one with a clay soil, presented approximately twice as many elements when compared to the soil samples of the other sites. In general, C and N stocks (and their stable isotopes, δ13C and δ15N, respectively) varied significantly in forests located in the center-periphery direction (%N - F = 24.58, p < 0.05; %C - F = 22.48, p < 0.05; δ15N - F = 4.27, p < 0.05; δ13C - F = 19.8, p < 0.05; C/N - F = 14.56, p < 0.05). This more central forest fragment with higher vehicle emissions showed greater potential to store these atmospheric elements and with greater neutralizing efficiency than the other forest fragments. δ13C and δ15N contents together with the C:N ratio indicated the efficiency of biogeochemical cycling, through decomposition, in different urban forest fragments. More peripheral fragments showed high efficiency in C and N cycling along the analyzed soil profiles, while in the most superficial layer, the most central fragment was highly efficient. These shed light results how integrating NbS principles into strategic urban planning and city-level climate policies can bolster the effectiveness of urban green areas. The integration not only promotes carbon sequestration and efficient nutrient cycling in the soil but also fosters sustainable practices, contributing to a more resilient urban landscape.

Efficiency analysis of best management practices under climate change conditions in the So-okcheon watershed, South Korea

Best management practices (BMPs) are widely applied to address water quality degradation issues attributed to non-point source pollutants. The objective of this study was to assess the efficiency of two types of BMPs, vegetation filter strips (VFS) and wetlands, in reducing total nitrogen (TN) and total phosphorus (TP) in a watershed, and to investigate whether the efficiency of the two BMPs is maintained under future climate scenarios by employing the Soil and Water Assessment Tool (SWAT). A set of parameters was calibrated using the SWAT Calibration and Uncertainty Program (SWAT-CUP) to ensure acceptable simulation results. Three BMP scenarios were developed by applying VFS and wetlands individually and in combination. Projected climate data from 18 global circulation models under Shared Socioeconomic Pathways (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5) were used to depict climate change conditions. VFS demonstrated 18.2% and 22.9% greater reduction efficiency for TN and TP, respectively, relative to wetlands. When the two BMPs were simultaneously applied, the reduction efficiency was even greater than that of single-BMP implementation (by 7.4% for TN and 6.8% for TP compared to VFS alone and by 25.5% for TN and 29.7% for TP compared to wetlands alone). To assess the effect of climate change, the model simulated results for the period of 2021–2,100. The differences in efficiency between the combined BMP scenario and the individual BMPs increased with greater intensity of climate change, especially in the distant future. Therefore, this study supports the effectiveness of nutrient pollution control by applying multiple BMPs rather than by applying individual BMPs. Furthermore, this research underscores the adaptability and reliability of natural-based solutions in mitigating non-point source pollution in a changing climate, which is essential for effective ecological restoration in complex urban-agricultural landscapes. The study provides valuable insights for watershed managers and policymakers seeking effective strategies to combat nutrient pollution in the face of a changing climate within the unique landscape of South Korea.

An Assessment Framework for Mapping the Air Purification Service of Vegetation at the Regional Scale

Efficiently mitigating the severe air pollution resulting from rapid progress is crucial for the sustainable development of the socio-ecological system. Recently, concerns about nature-based solutions have emerged in the research on the treatment of air pollution. Studies on the purification of PM2.5 using vegetation currently concentrate on the individual scale of tree species or urban vegetation, ignoring the regional scale, which could better assist ecological governance. Therefore, taking the Fenwei Plain of China as the study area, an assessment framework of the air purification service’s spatial distribution reflecting regional vegetation was constructed. The dry deposition model and GeoDetector were used to quantify the spatial-temporal pattern and explore natural driving factors on the removal of PM2.5. The results showed that (1) the PM2.5 purification services offered by various types of vegetation exhibit notable variations. The average removal rates of PM2.5 by vegetation were 0.186%, 0.243%, and 0.435% in 2000, 2010, and 2021, respectively. (2) Meanwhile, a wide range of spatial mismatch exists between the PM2.5 concentration and PM2.5 removal. Insufficient supply regions of PM2.5 purification services account for 50% of the Fenwei Plain. (3) PM2.5 removal was strongly influenced by the types of vegetation and the Normalized Vegetation Index (NDVI), followed by the Digital Elevation Model (DEM), and less affected by meteorological factors; a strong joint effect was shown among the factors. The findings in this research provide a new perspective on regional air pollution management at the regional scale.

Bioenergy and Biopesticides Production in Serbia—Could Invasive Alien Species Contribute to Sustainability?

The critical role of energy in contemporary life and the environmental challenges associated with its production imply the need for research and exploration of its novel resources. The present review paper emphasizes the continuous exploitation of non-renewable energy sources, suggesting the transition toward renewable energy sources, termed ‘green energy’, as a crucial step for sustainable development. The research methodology involves a comprehensive review of articles, statistical data analysis, and examination of databases. The main focus is biomass, a valuable resource for bioenergy and biopesticide production, highlighting not only its traditional diverse sources, such as agricultural waste and industrial residues, but also non-edible invasive alien plant species. This study explores the utilization of invasive alien species in circular economy practices, considering their role in bioenergy and biopesticide production. The potential conflict between bioproduct acquisition and food sector competition is discussed, along with the need for a shift in approaching non-edible biomass sources. The paper emphasizes the untapped potential of under-explored biomass resources and the necessity for policy alignment and public awareness. Species with a significant potential for these sustainable strategies include Acer negundo L., Ailanthus altisima (Mill.) Swingle., Amorpha fruticosa L., Elaengus angustifolia L., Falopia japonica (Houtt.) Ronse Decr., Hibiscus syriacus L., Koelreuteria paniculata Laxm., Paulownia tomentosa Siebold and Zucc., Partenocissus quenquefolia (L.) Planch., Rhus typhina L., Robinia pseudoacacia L. and Thuja orientalis L. In conclusion, the paper highlights the intertwined relationship between energy, environmental sustainability, and circular economy principles, providing insights into Serbia’s efforts and potential in adopting nature-based solutions for bioenergy and biopesticides acquisition.

The Raw Material Challenge of Creating a Green Economy

Clean technologies and infrastructure for our low-carbon, green future carry intense mineral demands. The ambition remains to recycle and reuse as much as we can; however, newly mined resources will be required in the near term despite the massive improvements in the reuse and recycling of existing end-of-use products and wastes. Growth trends suggest that mining will still play a role after 2050 since the demand for metals will increase as the developing world moves toward a per capita usage of materials comparable to that of the developed world. There are sufficient geological resources to deliver the required mineral commodities, but the need to mine must be balanced with the requirement to tackle environmental and social governance issues and to deliver sustainable development goals, ensuring that outcomes are beneficial for both the people and planet. Currently, the lead time to develop new mines following discovery is around 16 years, and this needs to be reduced. New approaches to designing and evaluating mining projects embracing social, biodiversity, and life cycle analysis aspects are pivotal. New frontiers for supply should include neglected mined wastes with recoverable components and unconventional new deposits. New processing technologies that involve less invasive, lower energy and cleaner methodologies need to be explored, and developing such methodologies will benefit from using nature-based solutions like bioprocessing for both mineral recovery and for developing sustainable landscapes post mining. Part of the new ambition would be to seek opportunities for more regulated mining areas in our own backyard, thinking particularly of old mineral districts of Europe, rather than relying on sources with potentially and less controllable, fragile, and problematic supply chains. The current debate about the potential of mining our deep ocean, as an alternative to terrestrial sources needs to be resolved and based on a broader analysis; we can then make balanced societal choices about the metal and mineral supply from the different sources that will be able to deliver the green economy while providing a net-positive deal for the planet and its people.

Diatom-mediated food web functioning under ocean artificial upwelling

Enhancing ocean productivity by artificial upwelling is evaluated as a nature-based solution for food security and climate change mitigation. Fish production is intended through diatom-based plankton food webs as these are assumed to be short and efficient. However, our findings from mesocosm experiments on artificial upwelling in the oligotrophic ocean disagree with this classical food web model. Here, diatoms did not reduce trophic length and instead impaired the transfer of primary production to crustacean grazers and small pelagic fish. The diatom-driven decrease in trophic efficiency was likely mediated by changes in nutritional value for the copepod grazers. Whilst diatoms benefitted the availability of essential fatty acids, they also caused unfavorable elemental compositions via high carbon-to-nitrogen ratios (i.e. low protein content) to which the grazers were unable to adapt. This nutritional imbalance for grazers was most pronounced in systems optimized for CO2 uptake through carbon-to-nitrogen ratios well beyond Redfield. A simultaneous enhancement of fisheries production and carbon sequestration via artificial upwelling may thus be difficult to achieve given their opposing stoichiometric constraints. Our study suggest that food quality can be more critical than quantity to maximize food web productivity during shorter-term fertilization of the oligotrophic ocean.

Conceptualising nature-based solutions: addressing environmental challenges in the city of Amman, Jordan

ABSTRACT This article explores the conceptualisation and applicability of nature-based solutions (NBS) in the semi-arid context of Amman, Jordan. Through a Delphi survey, interviews and literature review, it investigates local experts’ views, concluding that NBS are a viable approach, even in context of water scarcity and high urban temperatures. Our results advocate for a paradigm shift towards a balanced relationship between urbanisation and nature, the integration of nature-based thinking into educational systems and continuous development and training for planners and local officers. Cross-sector collaboration, a solid participatory framework, and financial mechanisms for pilot cases are essential for this transformative shift.

Potential for the complementary and integrative use of citizen science and modern science in flood risk reduction: A case study from Sri Lanka

This study sheds light on the complementation of citizen science, powered by indigenous knowledge and self-experience and modern science to reduce the flood risk. A questionnaire survey was conducted to recognize the perception of the community residing in the Kalu river basin which is frequently flooded, on floods, its impacts, causes, spatio-temporal changes and the possible solutions for mitigating the flood impacts. Data were analysed using statistical methods along with GIS and RS techniques and compared with scientific literature. The results exposed that the insights of the residents on the occurrence of high impact floods and Land Use Land Cover changes matched with scientific information. The indigenous knowledge gained throughout many centuries, influences on the attitudes and makes the residents prepare for floods. Also, the residents practice many measures to reduce risk. However, the residents prioritize engineering solutions over Nature-based solutions in flood risk reduction which can be attributed to the lack of awareness on ecosystem services. We conclude that the joint use of citizen science and scientific information is necessary to improve better understanding on the flood risk. Nevertheless, it is important to re-consider whether such outcomes reach the policy makers and the communities effectively.

Wave transformation across impermeable and porous artificial reefs

Porous artificial reefs can function as nature-based solutions for coastal protection, due to their ability to dissipate wave energy while providing habitat for marine species. However, due to the lack of quantitative understanding of wave interactions with porous artificial reefs, there is uncertainty in how to optimize design for coastal protection applications. To address this gap, physical modelling experiments were conducted in a wave flume to investigate wave transformation across both porous and impermeable artificial reefs exposed to a range of regular wave conditions and submergence depths. The results highlight how key changes to wave kinematics (e.g., wave celerity, wave breaking) and wave energy (through reflection, dissipation and transmission) differ considerably between impermeable and porous artificial reefs. These differences in wave kinematic properties and energy balances across each reef can be well characterized by consideration of the effective crest depth (i.e., the total height of water at a point on the reef, including that in the voids) that accounts for the porosity of the reef structure, rather than the actual depth of the reef crest. The ratio of the effective crest depth to the incident wave height, termed the ‘relative effective crest depth’, was used to develop robust formulations to accurately predict wave reflection and transmission coefficients across both reefs over the range of wave and water depth conditions. The new formulations were also compared to other datasets reported in the literature, and were found to provide accurate predictions of both wave reflection and transmission for the broad range of submerged porous coastal structures considered (including artificial reefs and submerged breakwaters).

Home-buying decisions influenced by the implementation of nature-based solutions: The case of Sponge City, Guiyang SW China

Urban floods induced by the compound effects of climate change and rapid urbanisation are one of the key challenges facing many Chinese cities. In 2013, China initiated the Sponge City Program (SCP) to address this issue via constructing/restoring green-blue infrastructure as Nature-Based Solutions (NBS). Various green and blue spaces have been integrated into traditional grey facilities to mitigate urban floods, provide recreational venues, and enhance the natural aesthetics of urban landscapes. While housing development has been actively included in NBS provision, it remains unclear whether and how homebuying decisions might be influenced by NBS implementation under the framework of the Sponge City Program. Our study uses Guiyang, one of the pilots selected by the central government for the construction of “Sponge City” via implementing NBS. In-depth semi-structured interviews (n = 25) were used to examine whether the multiple benefits generated by newly established green-blue (sponge) facilities would affect residents’ home-purchasing preferences/decisions. We found that the provision of a green and blue facility, and whether it is part of the SCP or not, significantly influences a homebuyers’ choice. This study sheds additional light on the nexus of end users (homebuyers) and NBS provision (developers) under the framework of the Sponge City Program, generating practical implications for stakeholder engagement for NBS implementation to achieve sustainable urbanization.

Nature for resilience reconfigured: global-to-local translation of frames in Africa

Globally, various frames of urban nature circulate, each emphasising particular challenges and natural solutions in the climate context. Yet which actors and dynamics shape their translation to the African context remains unclear. This paper explores the global-to-local translation process of frames through interventions funded by transnational actors, conceptualised as agents of policy transfer. Critical scholarship has observed that urban adaptation and resilience interventions in Africa are often characterised as technocratic and top-down approaches, hence it is vital to understand whether these are replicated through proliferating nature-based solutions (NBSs). The study of a resilience-building intervention in Lilongwe, Malawi, reveals that transnational actors play important roles by deploying frames of urban nature through funding projects. However, rather than involving a top-down imposition of particular solutions, this sets in motion dynamics: in the competition for resources that frames generate, various actor constellations of transnational actors, subnational governments and local NGOs reconfigure or relabel strategies and associated (nature-based) practices to suit global frames and the resources they generate. This shapes who is included or not, and what kinds of NBS are being developed, for and by whom. There is a risk that priorities of communities get lost in translation. Policy relevance Frames of urban nature shape global agendas but also matter locally in the design of programmes and projects. This study provides key insights of relevance for policymakers. First, external funding for climate and resilience is unpredictable and insufficient to address manifold urgent local priorities. It is important that actors at all levels strive to align resources to holistic strategies of local governments and do not impose certain visions for urban nature. For this to happen, and second, it is key that local governments and communities are empowered to create forms of nature that are built around diverse forms of local knowledge and expertise, to cater to values and priorities of the communities. Third, proponents of NBSs highlight their potential to address interlinked climate-, biodiversity- and society-related challenges. However, unless funding allocation puts emphasis on the interlinkage of goals, the potential for NBSs to reach multiple goals can get lost. Fourth, there is a need to disrupt the persisting scepticism concerning the feasibility of NBSs in informal settlements and forge collaborations that realise interventions closely linked to the priorities of disadvantaged groups in African cities, to leverage the power of nature for more just societies.

Large-scale environmental signals in seagrass blue carbon stocks are hidden by high variability at local scales

Increasing focus on nature-based climate change mitigation and adaptation strategies has led to the recognition of seagrasses as globally significant organic carbon (Corg) stocks. However, estimates of carbon stocks have been generally confined to a few regions, with few African studies represented in global datasets. In addition, the extent to which biogeographical and environmental variation shape carbon stocks in marine vegetated environments remains uncertain. For South Africa, Zostera capensis is the dominant seagrass species with limited mapping and quantification of its Corg stocks. Here, we measured Z. capensis Corg stocks at six South African estuaries spanning ∼1800 km of the cool-temperate to subtropical marine environmental gradient. Targeting the intertidal zone of the upper and lower estuary reaches, we collected Z. capensis sediments to a depth of 50 cm and measured the Corg, with the median Corg stock estimated at 24.11 Mg C ha−1 (40.4 ± 53.02; mean ± SD). While this is lower than the global average, these data demonstrate that Z. capensis ecosystems are important contributors to blue carbon stocks in the region. Measured Corg stocks showed significant differences between sampling sites for estuaries; however, we did not detect significant differences between estuaries due to high intra-estuarine Corg variability. Examination of biogeographical regions, terrestrial and marine environmental variables as drivers of Corg variability revealed that annual mean sea surface temperature may explain variation in Corg stocks. Furthermore, we found evidence of signals of biogeographical regions and precipitation driving some of the variability in Corg stocks; however, this requires further investigation. Overall, our estimates for Z. capensis add to ongoing national and global efforts to quantify seagrass Corg stocks across environmental and biogeographic gradients to better determine their contributions as nature-based solutions to climate change.

Zoning, Land Use Management and Nature-Based Solutions in Urban Planning, Where Sri Lanka is Standing

Urbanization rapidly changes the land use pattern in Sri Lanka. Cities are important economic centers and provide opportunities for quality of life. Zoning creates prospering urban planning environments, improves construction permit efficiency, enables agency coordination, and provides widespread participation in urban planning. A comprehensive zoning plan with environmentally conscious zoning contributes to the conservation of natural resources, enhances the ability of climate change adaptation and mitigation, fosters a greener urban environment, and ensures urban sustainability. Nature-based Solutions (NbS) are incorporated by nature; use, or mimic, natural processes to contribute to improvement in given landscapes, small or large scale. Attention to NBS has significantly increased in the recent past and is trying to mainstream NbS into a wide range of policies, and urban planning. This study aimed to explore how zoning and NbS can be incorporated in an urban setting to increase urban resilience in water-born cities. The administrative capital of Sri Lanka, Sri Jayawardhanapura-Kotte was selected due to unique inland urban wetland characteristics and vulnerability to wetland ecosystem due to rapid development in the area. Sri Jayawardhanapura-Kotte is rich with its unique landscape and is a part of Ramsar-Colombo wetlands. The Sri Jayawardhanapura-Kotte Capital City Development Plan (the Plan) 2020 and other relevant national policies were assessed in terms of zooning and application of NbS as a strategy of a sustainable and resilient city. Environmental changes and disaster risk areas were assessed (spatial and temporal changes) utilizing earth observation and GIS techniques, and secondary data were obtained from official records and reports. Sri Jayawardhanapura-Kotte covers 78% of the Greater Colombo flood retention area, and 55% of the area is suitable for flood retention. However, 40% of Colombo wetlands have been lost during the last 30 years due to urbanization. Data shows that most of the wetlands are being filled for infrastructure development, including housing, and it is critically important to conserve remaining wetlands in the area with strict regulations including zoning. The Plan has no signs of incorporating or recognizing NbS in the objectives, strategies, and actions for restoration wetlands, proper zoning system for flood mitigation. Analysed policies lack recognition or incorporation of zoning for environmental conservation and disaster risk reduction. The importance of urban areas for future cannot be underestimate and proper urban planning is a necessity in Sri Lanka for mitigate precent anthropogenic climate change impacts ranging but not limited to urban flooding to public health.&#x0D; &#x0D; Keywords: Urban planning, Zoning, Nature-based Solutions, Resilience, water-born cities&#x0D;

Adapting to climate change through nature-based solutions and indigenous knowledge: the case for landscape-scale ecosystem regeneration in the Rokohouia Delta

ABSTRACT This study explores the potential of nature-based solutions and indigenous knowledge in climate change adaptation. It focuses on the Rokohouia Delta located in Aotearoa, New Zealand where Ngāi Tūāhuriri, the Indigenous People of the region, employ strategies deeply rooted in their understanding of the interdependencies between humans and ecosystems, to improve environmental quality. The paper underscores the potential of nature-based solutions (NbS), closely aligned with indigenous ways of thinking, in mitigating hydro-meteorological risks associated with the impacts of climate change. While the study was initially focused on the role of indigenous-informed approaches to NbS on lessening climate change risks, it became apparent that NbS has important potential for cultural revitalisation and decolonisation through the regeneration of mahinga kai (wild food gathering areas), addressing long-held Ngāi Tūāhuriri grievances associated with the destruction of deltaic ecosystems on which it’s culture depends. The findings underscore the potential of NbS in complementing conventional infrastructure (responses/decisions in mitigating hydro-meteorological risks), enhancing social cohesion, and promoting ecological consciousness. The study also concludes that indigenous knowledge can potentially play a crucial role in informing infrastructure choices that integrate nature-based solutions, and thereby facilitate both cultural revitalisation and climate change adaptation.