Nature-based solutions knowledge gaps

The knowledge gap database compiles an evidence base for Nature-based Solutions, to support defining research and innovation avenues, and bolster policy and practitioners’ knowledge and knowledge-implementation. This database, first published in 2021 and updated in June 2024, aggregates knowledge gaps and research needs identified through extensive desk research, drawing from academic and non-academic sources. For a detailed explanation of the methodology and analysis behind the 2024 update, please refer to this NetworkNature report. For more context on the initial database see the NetworkNature report on practical, research, and innovation needs.

The updated database includes additional 619 gaps categorised into 32 broad topics and 11 types of approaches. This marks a significant expansion from the initial database, established in 2021, which contained 172 knowledge gaps. Covering gaps from 2017 to March 2024, this database will be continually updated throughout the duration of NetworkNature+.

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Displaying 551 - 600 of 619

Gap description	Origin of source	Source	Resource	Broad topic	Types of approaches
Further research is also required to strengthen our understanding of the multiple interacting impacts of improved forages at the food system level. An increased understanding of particularly the social dimension has a lot to offer, also in terms of understanding the drivers, underlying causes and impacts of changes linked to the productivity, economic, environmental and human dimensions, while our WoS search results show a low coverage of these issues in the scientific literature.	Desk Study	Scientific literature	Notenbaert, A. M. O., Douxchamps, S., Villegas, D. M., Arango, J., Paul, B. K., Burkart, S., Rao, I., Kettle, C. J., Rudel, T. K., Vazquez, E., Teutscherova, N., Chirinda, N., Groot, J. C. J., Wironen, M. B., Pulleman, M. M., Louhaichi, M., Hassan, S., Oberson, A., Nyawira, S. S., ... Peters, M. (2021). Tapping Into the Environmental Co-benefits of Improved Tropical Forages for an Agroecological Transformation of Livestock Production Systems. Frontiers in Sustainable Food Systems, 5, Article 742842. https://doi.org/10.3389/fsufs.2021.742844	Socio-economic benefits NbS interaction at the landscape scale	Ecosystem-based agricultural management
Concurrently, cultivated forages should be promoted as a versatile and multi-purpose crop through public campaigns (social media, workshops, leaflets, lobbying). However, from the literature search these aspects seem to be understudied which would imply limited innovation in awareness raising. Yet, by highlighting the evidence-based benefits of integrating cultivated forages in agroecosystems, we can increase the visibility of crop-livestock systems and inform the flow of scaling-up investments	Desk Study	Scientific literature	Notenbaert, A. M. O., Douxchamps, S., Villegas, D. M., Arango, J., Paul, B. K., Burkart, S., Rao, I., Kettle, C. J., Rudel, T. K., Vazquez, E., Teutscherova, N., Chirinda, N., Groot, J. C. J., Wironen, M. B., Pulleman, M. M., Louhaichi, M., Hassan, S., Oberson, A., Nyawira, S. S., ... Peters, M. (2021). Tapping Into the Environmental Co-benefits of Improved Tropical Forages for an Agroecological Transformation of Livestock Production Systems. Frontiers in Sustainable Food Systems, 5, Article 742842. https://doi.org/10.3389/fsufs.2021.742847	Awareness and capacity building Communication	Ecosystem-based agricultural management
More research is needed at the food system scale to fully understand the role of forages in agroecology, particularly on sociological and process aspects, which are both at the core of the four principles less documented. This also indicates a yet to be filled opportunity for forage experts to engage more with the agroecological movement and make forages part of sustainable agri-food system transformation.	Desk Study	Scientific literature	Notenbaert, A. M. O., Douxchamps, S., Villegas, D. M., Arango, J., Paul, B. K., Burkart, S., Rao, I., Kettle, C. J., Rudel, T. K., Vazquez, E., Teutscherova, N., Chirinda, N., Groot, J. C. J., Wironen, M. B., Pulleman, M. M., Louhaichi, M., Hassan, S., Oberson, A., Nyawira, S. S., ... Peters, M. (2021). Tapping Into the Environmental Co-benefits of Improved Tropical Forages for an Agroecological Transformation of Livestock Production Systems. Frontiers in Sustainable Food Systems, 5, Article 742842. https://doi.org/10.3389/fsufs.2021.742849	Socio-economic benefits Impact assessment	Ecosystem-based agricultural management
A large body of literature on agroforestry in L&MICs {Low and Middle Income Countries} has accumulated, but systematic understanding of the effects of agroforestry on social and ecological outcomes within and across diverse contexts is missing. This lack of knowledge, in turn, constrains the ability of policymakers, practitioners, and researchers to make effective decisions relating to agroforestry programming and investments.	Desk Study	Scientific literature	Miller, Daniel & Ordonez, Pablo & Castle, Sarah & Forrest, Samantha & Nava, Noé & Hughes, Karl & Baylis, Kathy. (2019). The impacts of agroforestry on agricultural productivity, ecosystem services, and human well‐being in low‐and middle‐income countries: An evidence and gap map. Campbell Systematic Reviews. 16. 10.1002/cl2.1066.	Socio-economic benefits Planning and policy frameworks Effectiveness across socio-ecological contexts	Ecosystem-based water management
A SR {Systematic Review} of the currently available quasiexperimental impact evaluation studies would also be worthwhile. Carrying out such syntheses would provide baseline insights to inform future policy and programming relating to agroforestry interventions and also present an important baseline for future research. This kind of synthetic work is also needed to help address what seems to be a persistent dichotomy in agroforestry research between studies in ecology and agronomy, which tend to focus on the agricultural productivity and environmental outcomes of agroforestry practices, and studies in international development that emphasize human well‐being outcomes of agroforestry interventions.	Desk Study	Scientific literature	Miller, Daniel & Ordonez, Pablo & Castle, Sarah & Forrest, Samantha & Nava, Noé & Hughes, Karl & Baylis, Kathy. (2019). The impacts of agroforestry on agricultural productivity, ecosystem services, and human well‐being in low‐and middle‐income countries: An evidence and gap map. Campbell Systematic Reviews. 16. 10.1002/cl2.1066.	Methodologies and tools for systematic evaluation Impact assessment Awareness and capacity building	Ecosystem-based water management
The results of our study show that there is a significant need for further research on the socioeconomic and ecological effects of agroforestry. This need relates to synthesis of the existing evidence base on the impacts of both agroforestry interventions and practices as well as new primary research on agroforestry interventions.	Desk Study	Scientific literature	Miller, Daniel & Ordonez, Pablo & Castle, Sarah & Forrest, Samantha & Nava, Noé & Hughes, Karl & Baylis, Kathy. (2019). The impacts of agroforestry on agricultural productivity, ecosystem services, and human well‐being in low‐and middle‐income countries: An evidence and gap map. Campbell Systematic Reviews. 16. 10.1002/cl2.1066.	Biodiversity benefits Socio-economic benefits	Ecosystem-based water management
A better understanding of the win‐win scenarios and tradeoffs associated with agroforestry is urgently needed, particularly given the potential of agroforestry to help achieve the SDGs. More robust evidence on the different environment and development objectives agroforestry can advance, including climate change mitigation and adaptation, poverty reduction, and health and nutrition, is needed in its own right, but also to enable analysis of synergies and tradeoffs.	Desk Study	Scientific literature	Miller, Daniel & Ordonez, Pablo & Castle, Sarah & Forrest, Samantha & Nava, Noé & Hughes, Karl & Baylis, Kathy. (2019). The impacts of agroforestry on agricultural productivity, ecosystem services, and human well‐being in low‐and middle‐income countries: An evidence and gap map. Campbell Systematic Reviews. 16. 10.1002/cl2.1066.	Synergies and trade-offs between goals	Ecosystem-based water management
Thus, the evidence backing claims about the potential of for agroforestry to improve agricultural productivity, ecosystem services, and human well‐being is lacking.	Desk Study	Scientific literature	Miller, Daniel & Ordonez, Pablo & Castle, Sarah & Forrest, Samantha & Nava, Noé & Hughes, Karl & Baylis, Kathy. (2019). The impacts of agroforestry on agricultural productivity, ecosystem services, and human well‐being in low‐and middle‐income countries: An evidence and gap map. Campbell Systematic Reviews. 16. 10.1002/cl2.1066.	Impact assessment Impacts for health and well-being	Ecosystem-based water management
Developing connections between existing literature and the NbS concept is necessary to ensure that existing knowledge is recognised and used to expand the current state of NbS research.	Desk Study	Scientific literature	Dunlop, T., Khojasteh, D., Cohen-Shacham, E. et al. The evolution and future of research on Nature-based Solutions to address societal challenges. Commun Earth Environ 5, 132 (2024). https://doi.org/10.1038/s43247-024-01308-8	Communication Awareness and capacity building	-
However, NbS research prioritising economic and social development, human health, food security, and water security, remains limited.	Desk Study	Scientific literature	Dunlop, T., Khojasteh, D., Cohen-Shacham, E. et al. The evolution and future of research on Nature-based Solutions to address societal challenges. Commun Earth Environ 5, 132 (2024). https://doi.org/10.1038/s43247-024-01308-8	Planning and policy frameworks Knowledge base	-
Since the growth of large-scale research funding programs in 2015, NbS research has begun to focus on other societal challenges. For instance, research targeting disaster risk reduction has become prominent in recent years. Nonetheless, four of the adopted IUCN societal challenges tend to remain peripheral to the overall NbS research landscape: (i) economic and social development, (ii) human health, (iii) food security and (iv) water security. Research outputs in these disciplines have been disproportionately skewed towards Europe and North America, despite the greatest vulnerabilities lying outside these regions. This mismatch highlights the need for researchers in vulnerable regions to be included in NbS research stewardship and authorship and for future research to be prioritised and funded in regions where it is needed most.	Desk Study	Scientific literature	Dunlop, T., Khojasteh, D., Cohen-Shacham, E. et al. The evolution and future of research on Nature-based Solutions to address societal challenges. Commun Earth Environ 5, 132 (2024). https://doi.org/10.1038/s43247-024-01308-8	Socio-economic benefits Impacts for health and well-being Effectiveness at different geographical scales	-
Expand NbS research to capture the interdependencies between societal challenges and understand how individual societal challenges can be addressed in an integrated way with other societal challenges.	Desk Study	Scientific literature	Dunlop, T., Khojasteh, D., Cohen-Shacham, E. et al. The evolution and future of research on Nature-based Solutions to address societal challenges. Commun Earth Environ 5, 132 (2024). https://doi.org/10.1038/s43247-024-01308-8	Synergies and trade-offs between goals	-
Complementing previous NbS analyses that have advocated for NbS research to close existing global knowledge gaps, the comparison of NbS research production with global vulnerability indicates that the high overall NbS research production in Europe could be better aligned with economic and social development.	Desk Study	Scientific literature	Dunlop, T., Khojasteh, D., Cohen-Shacham, E. et al. The evolution and future of research on Nature-based Solutions to address societal challenges. Commun Earth Environ 5, 132 (2024). https://doi.org/10.1038/s43247-024-01308-8	Planning and policy frameworks Synergies and trade-offs between goals	-
Achieving resilience in food systems is necessary in regions with the greatest vulnerability, such as in Africa and parts of Asia and North America. Future NbS research should seek to establish methods for creating resilient food systems in these regions and re- establishing those in regions that have suffered the most from the effects of climate change and violent conflicts.	Desk Study	Scientific literature	Dunlop, T., Khojasteh, D., Cohen-Shacham, E. et al. The evolution and future of research on Nature-based Solutions to address societal challenges. Commun Earth Environ 5, 132 (2024). https://doi.org/10.1038/s43247-024-01308-8	Technical references, design standards and guidelines Direct and indirect benefits for climate mitigation and adaptation Knowledge base	Ecosystem-based adaptation
Further scoping reviews are recommended once the NbS research landscape has evolved further to understand the change in focus of these research clusters.	Desk Study	Scientific literature	Dunlop, T., Khojasteh, D., Cohen-Shacham, E. et al. The evolution and future of research on Nature-based Solutions to address societal challenges. Commun Earth Environ 5, 132 (2024). https://doi.org/10.1038/s43247-024-01308-8	Knowledge base Planning and policy frameworks	-
Ways and instruments to form and sustain partnerships amongst scientists, municipalities, businesses, and communities need to be found and adopted to share NBS knowledge, understand societal expectations and needs, design feasible solutions, implement and maintain those solutions, and monitor and assess NBS performance.	Desk Study	Scientific literature	Clive Davies, Wendy Y. Chen, Giovanni Sanesi, Raffaele Lafortezza, The European Union roadmap for implementing nature-based solutions: A review, Environmental Science & Policy, Volume 121, 2021, Pages 49-67, ISSN 1462-9011, https://doi.org/10.1016/j.envsci.2021.03.018. (https://www.sciencedirect.com/science/article/pii/S1462901121000897)	Approaches and governance systems for implementation Stakeholder engagement Awareness and capacity building	-
Thus replicability, scalability (upwards and/or downwards), and transferability need to be carefully examined to streamline NBS knowledge and best practice models into actions on the ground.	Desk Study	Scientific literature	Clive Davies, Wendy Y. Chen, Giovanni Sanesi, Raffaele Lafortezza, The European Union roadmap for implementing nature-based solutions: A review, Environmental Science & Policy, Volume 121, 2021, Pages 49-67, ISSN 1462-9011, https://doi.org/10.1016/j.envsci.2021.03.018. (https://www.sciencedirect.com/science/article/pii/S1462901121000897)	Approaches and governance systems for implementation Awareness and capacity building Upscaling NBS	-
Additionally, NBS might generate inequities associated with how the costs and benefits accruing from NBS initiatives are distributed among the population, thus underpin new gentrification trends. Further research is thus needed to add empirical insights to generate adequate NBS knowledge.	Desk Study	Scientific literature	Clive Davies, Wendy Y. Chen, Giovanni Sanesi, Raffaele Lafortezza, The European Union roadmap for implementing nature-based solutions: A review, Environmental Science & Policy, Volume 121, 2021, Pages 49-67, ISSN 1462-9011, https://doi.org/10.1016/j.envsci.2021.03.018. (https://www.sciencedirect.com/science/article/pii/S1462901121000897)	Cost/benefit evaluations Social cohesion and environmental justice	-
First, the relationship between nature and cities is inversely proportional for its most part. In this regard, there is a need to clearly define all aspects of the city-nature relationship and determine how the trade-offs between these two different ecosystems (urban-nature) can be balanced in terms of service provision and delivery, as well as to understand the negative feedback loops and counteract them.	Desk Study	Scientific literature	Mario J. Al Sayah, Pierre-Antoine Versini, Daniel Schertzer, H2020 projects and EU research needs for nature-based adaptation solutions, Urban Climate, Volume 44, 2022, 101229, ISSN 2212-0955, https://doi.org/10.1016/j.uclim.2022.101229.	Synergies and trade-offs between goals Negative impacts Knowledge base	-
In this context, the resource efficiency (consumption versus generation/conservation potential) of any planned solution should be better investigated as throughout their existence NBaS consume natural capital in their own rights.	Desk Study	Scientific literature	Mario J. Al Sayah, Pierre-Antoine Versini, Daniel Schertzer, H2020 projects and EU research needs for nature-based adaptation solutions, Urban Climate, Volume 44, 2022, 101229, ISSN 2212-0955, https://doi.org/10.1016/j.uclim.2022.101229.	Methodologies and tools for systematic evaluation	Ecosystem-based adaptation
Understanding how NBS-NBaS utilize natural resource and nature is relatively an unexplored line of work.	Desk Study	Scientific literature	Mario J. Al Sayah, Pierre-Antoine Versini, Daniel Schertzer, H2020 projects and EU research needs for nature-based adaptation solutions, Urban Climate, Volume 44, 2022, 101229, ISSN 2212-0955, https://doi.org/10.1016/j.uclim.2022.101229.	NbS interaction at the landscape scale Impact assessment	Ecosystem-based adaptation
In the case of NBaS, current research efforts are mostly focused on green infrastructures, ecological connective functions and ecoservices provision for climate change resilience. However, a significant knowledge gap for assessing the impact of NBaS across a range of climate resilience challenges, and through different geographic levels exists.	Desk Study	Scientific literature	Mario J. Al Sayah, Pierre-Antoine Versini, Daniel Schertzer, H2020 projects and EU research needs for nature-based adaptation solutions, Urban Climate, Volume 44, 2022, 101229, ISSN 2212-0955, https://doi.org/10.1016/j.uclim.2022.101229.	Effectiveness at different geographical scales Impact assessment	Ecosystem-based adaptation
Another gap concerning the assessment of their long-term effectiveness under climate change scenarios is also prevalent. This last point should be particularly focused on as it can help understand the conditions these solutions will face and will have to perform under.	Desk Study	Scientific literature	Mario J. Al Sayah, Pierre-Antoine Versini, Daniel Schertzer, H2020 projects and EU research needs for nature-based adaptation solutions, Urban Climate, Volume 44, 2022, 101229, ISSN 2212-0955, https://doi.org/10.1016/j.uclim.2022.101229.	Effectiveness at different time scales Risks from slow-onset events	Ecosystem-based adaptation
In the case of droughts, research needs are more pronounced as studies on NBS-NBaS for slow onset events and their post-occurrence effects are still limited.	Desk Study	Scientific literature	Mario J. Al Sayah, Pierre-Antoine Versini, Daniel Schertzer, H2020 projects and EU research needs for nature-based adaptation solutions, Urban Climate, Volume 44, 2022, 101229, ISSN 2212-0955, https://doi.org/10.1016/j.uclim.2022.101229.	Risks from slow-onset events	Ecosystem-based disaster risk reduction
Emerging literature on urban NBS-NBaS deals mostly with the ecological, socio-cultural and economic dimensions. The integration of “harder science” insights is still lacking and can be considered as an important line of research to develop. Hence, one might consider that there is a lack of ready-to-apply scientific knowledge.	Desk Study	Scientific literature	Mario J. Al Sayah, Pierre-Antoine Versini, Daniel Schertzer, H2020 projects and EU research needs for nature-based adaptation solutions, Urban Climate, Volume 44, 2022, 101229, ISSN 2212-0955, https://doi.org/10.1016/j.uclim.2022.101229.	Knowledge base Interdisciplinary studies and methodologies	-
If the environmental dimension and science(s) behind NBS-NBaS remain underdeveloped as the concept favors its practical and economic sides, NBS-NBaS risk being lost as buzzwords. To overcome these barriers, significant research efforts are required along with long term visions of resilience (particularly for climate change), instead of short-term research on quality. At this stage, the cross-sectoral nature of NBS-NBaS might be a helpful factor, yet current efforts are compartmentalized (silo approaches), and the concerned disciplines have very limited interactions with each other. Even when solid knowledge exists, it is often scattered across different disciplines.	Desk Study	Scientific literature	Mario J. Al Sayah, Pierre-Antoine Versini, Daniel Schertzer, H2020 projects and EU research needs for nature-based adaptation solutions, Urban Climate, Volume 44, 2022, 101229, ISSN 2212-0955, https://doi.org/10.1016/j.uclim.2022.101229.	Knowledge base Interdisciplinary studies and methodologies Effectiveness at different time scales	-
A solid understanding of nature's and systems' complexity is needed for successfully designing NBS-NBaS. This element is currently one the major gaps for upscaling NBS-NBaS. Once integrated, this understanding can help in complementing the effort of actors of various backgrounds (including ordinary citizens) to ensure the success of any designed/ implemented solution.	Desk Study	Scientific literature	Mario J. Al Sayah, Pierre-Antoine Versini, Daniel Schertzer, H2020 projects and EU research needs for nature-based adaptation solutions, Urban Climate, Volume 44, 2022, 101229, ISSN 2212-0955, https://doi.org/10.1016/j.uclim.2022.101229.	Knowledge base Technical references, design standards and guidelines Upscaling NBS	-
However, relevant evidence and knowledge are still somewhat limited when NBS-NBaS are part of a larger hydrological system. The same applies for watershed scale hybrid solutions that contain both small size or large sized NBS-NBaS. As a result of these factors, most risk assessments target small scales (local to regional approaches) often leaving out the larger matrix. Consequently, large scale NBS for hydrometeorological risk reduction are left out of the picture as the spatial unit of assessment disregards them. Therefore, these solutions are still in serious need for further studies particularly in European reference frameworks. This knowledge gap can be considered as a major bottleneck for holistic risk management and resilience plans where large scale NBS-NBaS interventions are often needed.	Desk Study	Scientific literature	Mario J. Al Sayah, Pierre-Antoine Versini, Daniel Schertzer, H2020 projects and EU research needs for nature-based adaptation solutions, Urban Climate, Volume 44, 2022, 101229, ISSN 2212-0955, https://doi.org/10.1016/j.uclim.2022.101229.	Knowledge base Awareness and capacity building Upscaling NBS	Ecosystem-based adaptation
Arguably, evidence of small scale interventions is more or less established, however similarly to NBS for DRR {Disaster Risk Reduction}, evidence of efficiency is particularly lacking at large scales (landscape or watershed). As the concerned challenges are often multi-scalar, the difficulty of measuring the solutions' multi-benefits and efficiency increases. To this end, sufficient best practices in different settings are still lacking and significant research efforts are still needed.	Desk Study	Scientific literature	Mario J. Al Sayah, Pierre-Antoine Versini, Daniel Schertzer, H2020 projects and EU research needs for nature-based adaptation solutions, Urban Climate, Volume 44, 2022, 101229, ISSN 2212-0955, https://doi.org/10.1016/j.uclim.2022.101229.	Effectiveness at different geographical scales Awareness and capacity building Upscaling NBS	Ecosystem-based disaster risk reduction
The interest of the EC's H2020 program in the urban realm is justifiable. Yet, a deeper approach to other ecosystems is much needed. (...) This is particularly the case of mountainous, forested and marine and coastal environments. While forests are very appreciated as NBS-NBaS, they are rarely targeted as a sensitive media to climate change. In its own right, the mountainous environment is significantly underrepresented despite its importance and relative widespread coverage in Europe. The marine and coastal realms are also underrepresented as both a medium and a source of solutions.	Desk Study	Scientific literature	Mario J. Al Sayah, Pierre-Antoine Versini, Daniel Schertzer, H2020 projects and EU research needs for nature-based adaptation solutions, Urban Climate, Volume 44, 2022, 101229, ISSN 2212-0955, https://doi.org/10.1016/j.uclim.2022.101229.	Knowledge base	-
European findings underlined the need to focus more science on the N {Nature} behind NBS and NBaS. For this purpose, scientific and physical methods are needed to better understand the interaction of nature both with and within the implemented or planned NBS- NBaS. However, this does not come as an alternative to the concept's practical and socioeconomic nature, but rather as supplement. The rationale behind this logic is to have a holistic framework that balances between all the theoretical and fundamental components of NBS and NBaS. This is due to the fact that the introduction of these solutions into ecosystems causes the entry of new systems along with their processes. Yet the investigation of these interactions and their cascading effects is still somewhat limited. This gap could be on the most pronounced challenges for upscaling and outscaling NBS-NBaS as well as for unlocking their full potential.	Desk Study	Scientific literature	Mario J. Al Sayah, Pierre-Antoine Versini, Daniel Schertzer, H2020 projects and EU research needs for nature-based adaptation solutions, Urban Climate, Volume 44, 2022, 101229, ISSN 2212-0955, https://doi.org/10.1016/j.uclim.2022.101229.	Technical references, design standards and guidelines Planning and policy frameworks Upscaling NBS	Ecosystem-based adaptation
The role of uncertainties in NBS and NBaS should be better accommodated and explored through further research. The same can be said for uncertainties and trade-offs. While these are developing lines of work, their current acknowledgment under all projects reflects the attainment of an ample awareness level.	Desk Study	Scientific literature	Mario J. Al Sayah, Pierre-Antoine Versini, Daniel Schertzer, H2020 projects and EU research needs for nature-based adaptation solutions, Urban Climate, Volume 44, 2022, 101229, ISSN 2212-0955, https://doi.org/10.1016/j.uclim.2022.101229.	Synergies and trade-offs between goals Technical references, design standards and guidelines	Ecosystem-based adaptation
Understanding how NBS-NBaS utilize natural resources and nature during their existence is a relatively understudied and unexplored line of work.	Desk Study	Scientific literature	Mario J. Al Sayah, Pierre-Antoine Versini, Daniel Schertzer, H2020 projects and EU research needs for nature-based adaptation solutions, Urban Climate, Volume 44, 2022, 101229, ISSN 2212-0955, https://doi.org/10.1016/j.uclim.2022.101229.	Knowledge base Impact assessment	Ecosystem-based adaptation
Understanding ecosystem tipping points and ecological thresholds is a must. Currently, very few to no efforts focus on these central elements.	Desk Study	Scientific literature	Mario J. Al Sayah, Pierre-Antoine Versini, Daniel Schertzer, H2020 projects and EU research needs for nature-based adaptation solutions, Urban Climate, Volume 44, 2022, 101229, ISSN 2212-0955, https://doi.org/10.1016/j.uclim.2022.101229.	Knowledge base	-
An understanding of the supply and demand of ecosystems and their services in complex multidimensional contexts is still limited.	Desk Study	Scientific literature	Mario J. Al Sayah, Pierre-Antoine Versini, Daniel Schertzer, H2020 projects and EU research needs for nature-based adaptation solutions, Urban Climate, Volume 44, 2022, 101229, ISSN 2212-0955, https://doi.org/10.1016/j.uclim.2022.101229.	Relationship between biodiversity, ecosystem functions and ecosystem services	-
A systematic approach to understand how the different systems, i.e. ecosystem-NBS-NBaS, interact with and influence each other is still limited. Hence the need to provide a more inclusive and holistic evaluation framework for properly understanding combined benefits, co-benefits and disservices.	Desk Study	Scientific literature	Mario J. Al Sayah, Pierre-Antoine Versini, Daniel Schertzer, H2020 projects and EU research needs for nature-based adaptation solutions, Urban Climate, Volume 44, 2022, 101229, ISSN 2212-0955, https://doi.org/10.1016/j.uclim.2022.101229.	NbS interaction at the landscape scale Methodologies and tools for systematic evaluation Negative impacts	-
The results of our review disclose a number of gaps within the research on the assessment of non-market benefits of NBS and NBS-like strategies. First, the literature on this subject has been, until now, only partially integrating the spheres of human and nature benefits and has focused predominantly on single-case studies.	Desk Study	Scientific literature	Martina Viti, Roland Löwe, Hjalte J.D. Sørup, Marzenna Rasmussen, Karsten Arnbjerg-Nielsen, Ursula S. McKnight, Knowledge gaps and future research needs for assessing the non-market benefits of Nature-Based Solutions and Nature-Based Solution-like strategies, Science of The Total Environment, Volume 841, 2022, 156636, ISSN 0048-9697, https://doi.org/10.1016/j.scitotenv.2022.156636.	Biodiversity benefits Socio-economic benefits Impacts for health and well-being	-
First, much evidence of NBS impact is relatively patchy, largely anecdotal in nature, limited to short-term studies, and/or lacking the requisite experimental controls to definitively attribute effect. There is an urgent need for the systematic and integrative compilation and assessment of NBS knowledge. In Europe, outcomes of NBS research are consolidated as NBS case studies on the Oppla platform along with other knowledge platforms.	Desk Study	Scientific literature	Calliari, Elisa & Castellari, Sergio & Davis, Mckenna & Linnerooth-Bayer, Joanne & Martin, Juliette & Mysiak, Jaroslav & Pastor, Teresa & Ramieri, Emiliano & Scolobig, Anna & Sterk, Marjolein & Veerkamp, Clara & Wendling, Laura & Zandersen, Marianne. (2022). Building climate resilience through nature-based solutions in Europe: A review of enabling knowledge, finance and governance frameworks. Climate Risk Management. 37. 100450. 10.1016/j.crm.2022.100450.	Communication Knowledge base	-
In particular, we need to better understand the interdependencies between climate change, ecosystems, biodiversity and the ecosystem services delivered. NBS can concomitantly address the interlinked challenges of climate change and biodiversity loss, but additional scientific evidence regarding the species and habitat types at greatest risk due to climate change is needed. Although the role of NBS in enhancing or preserving biodiversity while tackling climate change is clearly identified, the systematic analysis of biodiversity outcomes following NBS implementation is necessary to inform the development of improved NBS design and implementation guidelines to optimise biodiversity outcomes.	Desk Study	Scientific literature	Calliari, Elisa & Castellari, Sergio & Davis, Mckenna & Linnerooth-Bayer, Joanne & Martin, Juliette & Mysiak, Jaroslav & Pastor, Teresa & Ramieri, Emiliano & Scolobig, Anna & Sterk, Marjolein & Veerkamp, Clara & Wendling, Laura & Zandersen, Marianne. (2022). Building climate resilience through nature-based solutions in Europe: A review of enabling knowledge, finance and governance frameworks. Climate Risk Management. 37. 100450. 10.1016/j.crm.2022.100450.	Relationship between biodiversity, ecosystem functions and ecosystem services Risks from slow-onset events Technical references, design standards and guidelines	-
Finally, the socio-economic benefits of NBS require additional investigation. The health and well-being benefits of NBS are frequently referenced, yet knowledge concerning NBS impacts on mental and physical health, quality of life and social cohesion remains fragmented. Additional evidence is needed to design and implement NBS that deliver the full range of well-being benefits. It is also necessary to gather additional evidence regarding trade-offs associated with NBS implementation. (...) It is essential to understand not only the multitude of benefits delivered by NBS, but also the full scope of potential trade-offs (in space and time) in order to develop effective strategies to reduce or eliminate potential negative consequences.	Desk Study	Scientific literature	Calliari, Elisa & Castellari, Sergio & Davis, Mckenna & Linnerooth-Bayer, Joanne & Martin, Juliette & Mysiak, Jaroslav & Pastor, Teresa & Ramieri, Emiliano & Scolobig, Anna & Sterk, Marjolein & Veerkamp, Clara & Wendling, Laura & Zandersen, Marianne. (2022). Building climate resilience through nature-based solutions in Europe: A review of enabling knowledge, finance and governance frameworks. Climate Risk Management. 37. 100450. 10.1016/j.crm.2022.100450.	Socio-economic benefits Impacts for health and well-being Synergies and trade-offs between goals	-
With respect to the economic benefits of NBS, although the Dasgupta review lays out a convincing argument for the economic value of natural capital, which is enhanced by NBS actions, the costs of NBS in the longer term are not fully understood at present, particularly in comparison with conventional grey infrastructure or hybrid blue-green-grey solutions.	Desk Study	Scientific literature	Calliari, Elisa & Castellari, Sergio & Davis, Mckenna & Linnerooth-Bayer, Joanne & Martin, Juliette & Mysiak, Jaroslav & Pastor, Teresa & Ramieri, Emiliano & Scolobig, Anna & Sterk, Marjolein & Veerkamp, Clara & Wendling, Laura & Zandersen, Marianne. (2022). Building climate resilience through nature-based solutions in Europe: A review of enabling knowledge, finance and governance frameworks. Climate Risk Management. 37. 100450. 10.1016/j.crm.2022.100450.	Effectiveness compared to conventional approaches Effectiveness of hybrid solutions Cost/benefit evaluations	-
Concomitantly, we need to better understand the impacts of the spatial scale of NBS implementation on derived social, economic and environmental benefits. Many NBS practitioners also note a lack of knowledge regarding NBS (co–)management and maintenance needs in the longer term. Longer-term case studies are required to both inform technical (engineering) specifications of NBS as well as management/maintenance processes and guidelines.	Desk Study	Scientific literature	Calliari, Elisa & Castellari, Sergio & Davis, Mckenna & Linnerooth-Bayer, Joanne & Martin, Juliette & Mysiak, Jaroslav & Pastor, Teresa & Ramieri, Emiliano & Scolobig, Anna & Sterk, Marjolein & Veerkamp, Clara & Wendling, Laura & Zandersen, Marianne. (2022). Building climate resilience through nature-based solutions in Europe: A review of enabling knowledge, finance and governance frameworks. Climate Risk Management. 37. 100450. 10.1016/j.crm.2022.100450.	Impact assessment Effectiveness at different time scales Effectiveness at different geographical scales	-
Key knowledge gaps within and beyond the EU context include the relatively patchy and anecdotal nature of NBS evidence, the often short-term nature of studies and/or lacking experimental controls to attribute effect, and the need for an improved understanding of the interdependencies between climate change, ecosystems and the services delivered and the role of biodiversity in increasing NBS resilience.	Desk Study	Scientific literature	Calliari, Elisa & Castellari, Sergio & Davis, Mckenna & Linnerooth-Bayer, Joanne & Martin, Juliette & Mysiak, Jaroslav & Pastor, Teresa & Ramieri, Emiliano & Scolobig, Anna & Sterk, Marjolein & Veerkamp, Clara & Wendling, Laura & Zandersen, Marianne. (2022). Building climate resilience through nature-based solutions in Europe: A review of enabling knowledge, finance and governance frameworks. Climate Risk Management. 37. 100450. 10.1016/j.crm.2022.100450.	Relationship between biodiversity, ecosystem functions and ecosystem services Effectiveness at different time scales	-
Relevant to the EU, and specifically to water management aspects, is a predominance of studies on NBS for flood risk reduction, while less is known about the role of NBS in addressing water scarcity.	Desk Study	Scientific literature	Calliari, Elisa & Castellari, Sergio & Davis, Mckenna & Linnerooth-Bayer, Joanne & Martin, Juliette & Mysiak, Jaroslav & Pastor, Teresa & Ramieri, Emiliano & Scolobig, Anna & Sterk, Marjolein & Veerkamp, Clara & Wendling, Laura & Zandersen, Marianne. (2022). Building climate resilience through nature-based solutions in Europe: A review of enabling knowledge, finance and governance frameworks. Climate Risk Management. 37. 100450. 10.1016/j.crm.2022.100450.	Knowledge base Risks from slow-onset events	Ecosystem-based water management
In particular, there is a need to better understand how the implementation of NBS can reinforce or mitigate existing socio-economic and socio-spatial differences and inequalities, or may contribute to social exclusion through ‘green gentrification’ processes.	Desk Study	Scientific literature	Calliari, Elisa & Castellari, Sergio & Davis, Mckenna & Linnerooth-Bayer, Joanne & Martin, Juliette & Mysiak, Jaroslav & Pastor, Teresa & Ramieri, Emiliano & Scolobig, Anna & Sterk, Marjolein & Veerkamp, Clara & Wendling, Laura & Zandersen, Marianne. (2022). Building climate resilience through nature-based solutions in Europe: A review of enabling knowledge, finance and governance frameworks. Climate Risk Management. 37. 100450. 10.1016/j.crm.2022.100450.	Social cohesion and environmental justice Effectiveness across socio-ecological contexts Approaches and governance systems for implementation	-
Perhaps more importantly, we drew attention not only to the need for investing in NBS but also for divesting from nature-negative projects. This point has only been made in passing in the NBS literature and future research could examine the characteristics of governance mechanisms that create conditions for divesting for dominant solutions and leverage public and private funding for NBS.	Desk Study	Scientific literature	Calliari, Elisa & Castellari, Sergio & Davis, Mckenna & Linnerooth-Bayer, Joanne & Martin, Juliette & Mysiak, Jaroslav & Pastor, Teresa & Ramieri, Emiliano & Scolobig, Anna & Sterk, Marjolein & Veerkamp, Clara & Wendling, Laura & Zandersen, Marianne. (2022). Building climate resilience through nature-based solutions in Europe: A review of enabling knowledge, finance and governance frameworks. Climate Risk Management. 37. 100450. 10.1016/j.crm.2022.100450.	Approaches and governance systems for implementation Technical references, design standards and guidelines	-
Our study revealed that knowledge gaps remain at the policy level, including a lack of indicators, restricted deployment of available information, and limited integration across policy domains.	Desk Study	Scientific literature	Grace, Miriam & Balzan, Mario & Geneletti, Davide & Tomaskinova, Judita & Abela, Ruben & Borg, Duncan & Buhagiar, Giulia & Camilleri, Lorinda & Cardona, Mario & Cassar, Nikolas & Cassar, Ralph & Cattafi, Ivana & Cauchi, Daniel & Galea, Claudia & La Rosa, Daniele & Malekkidou, Eleni & Masini, Maria & Portelli, Paul & Tomaškinová, Judita. (2021). Priority knowledge needs for implementing nature-based solutions in the Mediterranean islands. Environmental Science & Policy. 116. 56-68. 10.1016/j.envsci.2020.10.003.	Planning and policy frameworks Methodologies and tools for systematic evaluation Monitoring tools	-
Another major barrier to improving NbS implementation has been the lack of stakeholder-focused perspectives on the process with NbS research generally focussed on theoretical aspects.	Desk Study	Scientific literature	Grace, Miriam & Balzan, Mario & Geneletti, Davide & Tomaskinova, Judita & Abela, Ruben & Borg, Duncan & Buhagiar, Giulia & Camilleri, Lorinda & Cardona, Mario & Cassar, Nikolas & Cassar, Ralph & Cattafi, Ivana & Cauchi, Daniel & Galea, Claudia & La Rosa, Daniele & Malekkidou, Eleni & Masini, Maria & Portelli, Paul & Tomaškinová, Judita. (2021). Priority knowledge needs for implementing nature-based solutions in the Mediterranean islands. Environmental Science & Policy. 116. 56-68. 10.1016/j.envsci.2020.10.003.	Stakeholder engagement Approaches and governance systems for implementation	-
We call for further research on transformative change in practice that supports the monitoring and evaluation of NbS on the ground.	Desk Study	Scientific literature	Palomo, Ignacio & Locatelli, Bruno & Otero, Iago & Colloff, Matt & Crouzat, Emilie & cuni sanchez, Aida & Gómez-Baggethun, Erik & González-García, Alberto & Grêt-Regamey, Adrienne & Jiménez-Aceituno, Amanda & Martín-López, Berta & Pascual, Unai & Zafra-Calvo, Noelia & Enora, Bruley & Fischborn, Marie & Metz, Rosmarie & Lavorel, Sandra. (2021). Assessing nature-based solutions for transformative change. One Earth. 4. 10.1016/j.oneear.2021.04.013.	Knowledge base Methodologies and tools for systematic evaluation Monitoring tools	-
Further studies about the effect of NbS on the different dimensions of equity are thus needed.	Desk Study	Scientific literature	Palomo, Ignacio & Locatelli, Bruno & Otero, Iago & Colloff, Matt & Crouzat, Emilie & cuni sanchez, Aida & Gómez-Baggethun, Erik & González-García, Alberto & Grêt-Regamey, Adrienne & Jiménez-Aceituno, Amanda & Martín-López, Berta & Pascual, Unai & Zafra-Calvo, Noelia & Enora, Bruley & Fischborn, Marie & Metz, Rosmarie & Lavorel, Sandra. (2021). Assessing nature-based solutions for transformative change. One Earth. 4. 10.1016/j.oneear.2021.04.013.	Social cohesion and environmental justice	-