Augmented Nature-Based Solutions: A Possible Taxonomy of Technologies “in” and “for” Urban Greening Strategies

The discipline of implementing Nature-Based Solutions (NBS) at architectural, urban planning, and landscape levels is supported by numerous experiences and several European projects and case studies (Bulkeley 2020; European Commission 2020). The concept of NBS is based on green or blue engineering solutions that replace more traditional gray solutions. The presence of technology in NBS is, therefore intrinsic and fundamental, no matter how low or high-tech this technology is (Andersson et al. 2022). Technology is directly embedded in NBS or applied as an essential component of all technological NBS generally. With NBS, nature is, in fact, “augmented” using technology to improve performance and increase the co-benefits of nature itself in the built environment.

Recent literature on NBS shows a strong interest in possible demonstrations and applications with a technologically embedded approach towards better solutions implementation (Tsekeri et al. 2022; Scheuer et al. 2022; Wellmann et al. 2022). Lately, technologies related to the possible integration of NBS into urban planning are coming to light towards execution scopes in order to increase the environmental performance and social impact of NBS.

However, a systemic insight into the role of technology in supporting the spread of NBS has not yet been conducted (Ahlborg et al. 2019). In this paper, a new proposed NBS taxonomy based on the technology-nature relationship is presented, supported by an extensive overview of the implementation of various technologies within case-study settings of NBS in urban greening strategies and European projects.

The proposed taxonomy is discussed from a twofold perspective: technology embedded “in” green, and technology “for” supporting the flourishing of green in the built environment, i.e., applied externally to NBS. In particular, the following explorations around technology in and for NBS are significant:

This paper originates from an investigation into several applications of NBS in real settings, where we looked explicitly for scientific methods and innovative products and services to enhance the potential of NBS in urban contexts while using technology. An initial literature review on the analysis of “Technology” and “Nature-based Solutions” was carried out in Scopus,¹ whereas 259 articles and scientific products have resulted more prominent since 2016, with a noticeable peak in the years 2021 and 2022.

In addition, our sampling was increased by the session at the Smart and Sustainable Planning for Cities and Regions Conference² (SSPCR 2022) held in July 2022, where the contributions and discussions offered “food for thought” for the content of this paper. The research questions are related to the main session topic on Augmented Nature-based solutions in urban planning and embedded technologies to improve NBS performance and foster social inclusion in urban greening strategies. In contrast, scientific contributions came from different countries, mainly: Italy, Spain, Austria, and Germany. Lastly, we relied on the ongoing application of two European Projects funded by the Horizon 2020 Programme to consolidate the proposed taxonomy, namely CLEVER Cities and VARCITIES, in which the authors are currently involved in.

The CLEVER Cities³ project (June 2018–September 2023) aims to co-create, co-design, co-implement, and co-manage locally tailored NBS to deliver tangible social, environmental, and economic improvements for urban regeneration. It gathers 36 international partners and involves three front-runner cities (Hamburg, Germany, London, United Kingdom, and Milan, Italy) and six fellow cities (Madrid, Larissa, Belgrade, Malmo, Quito, Sfantu Gheorghe). CLEVER Cities applies a place-based approach, starting with key urban regeneration challenges and employs strong local partner clusters to foster sustainable and socially inclusive urban regeneration locally, in Europe, and globally. The CLEVER Cities project co-creates, co-designs, co-implements, and co-manages locally tailored NBS to deliver tangible social, environmental, and economic improvements for large-scale urban regeneration processes. Particular attention in the implementation of NBS within CLEVER Cities is given to shared governance mechanisms and collaborative pathways of co-creation aimed at advancing the cities’ adaptation to a more bottom-up approach to urban planning (Borsboom-Van Beurden et al. 2023; Bradley et al. 2022; Mahmoud and Morello 2021).

The VARCITIES project⁴ (September 2020–February 2025) bridges the NBS approach traditionally characterized by low-tech solutions devoted to enhancing environmental quality with high-tech devices more familiar with the smart city approach to increase the health and well-being of citizens around Europe. It gathers 28 international partners and involves seven pilot cities (Castelfranco Veneto—Italy, Gzira—Malta, Skellefteå—Sweden, Novo Mesto—Slovenia, Dundalk—Ireland, Chania—Greece and Leuven—Belgium) willing to test and implement a series of innovative initiatives on urban green/public spaces. Digitally advanced NBS are therefore implemented through a co-design, co-creation, and co-implementation process, bearing in mind local stakeholders’ social and cultural perspectives. Urban spaces are envisioned as people-centered areas that support creativity, inclusivity, health, and happiness for citizens.

Initial understanding of the technology “in” green urban strategies topic includes different types of sensors that could be used to measure the NBS health status or remote sensing methods to enhance ecosystem services delivery in people’s everyday lives (Li and Nassauer 2021). Gudowsky and Peissl (2016, pp. 5–6) highlight the importance of technology in corresponding citizens’ visions and social needs by using it as a support and catalyst for change in public engagement processes. In the meantime, Maes and Jacobs (2017, p. 123) call for the need to use NBS with low-technological impact to increase the social empowerment of local communities.

Meanwhile, understanding of the technology “for” green urban strategies topic incorporates all the technological support to enhance NBS functionality, durability, and diffusion (Dick et al. 2020). Among others, technologies for green include the use of digital platforms and efficient software to visualize, analyze, and integrate data for NBS deployment in urban planning, such as drones and GIS modeling and mapping methods (Rakha et al. 2021). For instance, recent developments in technology and integration into the human-built environment could help develop the redesign of certain NBS and green infrastructures while increasing their co-benefits and improving ecosystem services (O’Hogain and McCarton 2018). This broad concept is related to the diversity in scales of implemented NBS. Nonetheless, some scholars argue that even “low-tech” or “no-tech” green—also considered as traditional urban greening measures—would still need data elaboration, especially if it relates to vegetation performance against natural and water management capacities to enhance the possibility for urban planners, architects, and landscape designers to reclaim valuable urban spaces correctly (Snep et al. 2020).

Based on this ideation, the resulting taxonomy for Augmented NBS with technologies “in” and “for” green is divided into two main subcategories: sensing with technologies and citizen engagement methods. Other technological aspects are also related to NBS, like structural technologies that sustain and support nature. However, in this taxonomy, we only focus on those technologies that help to give nature a voice and enhance it through sensors or collaboration with people.

On one side, sensing “in” green refers to all the technologies directly embedded in NBS to detect the health of natural elements or surrounding environmental aspects (e.g., air, water, soil). On the contrary, sensing “for” refers to all the technologies that are situated outside the NBS, hence remote sensing devices (mounted on drones, satellites to collect LiDAR, thermal data, and similar technology) to monitor the health of natural NBS performance.

On the other side, citizen engagement “in” green refers to technologies placed inside or around NBS that directly involve human activities in detecting, mapping, and assessing the direct social impact of people on nature or the environmental impact of nature on people. Detaching ourselves from NBS, the engagement of people “for” green, i.e., to promote urban nature, is undoubtedly very vast and can take place in a variety of ways: from low-cost technologies, such as participation models and protocols (from co-design and co-maintenance) of greenery, to more advanced technologies to facilitate collaboration in the creation of NBS (digital fabrication, applications and social media, wearable technologies, etc.).

A further category that structures the taxonomy refers to the phase in which the technologies are employed, i.e., in the planning, design, construction or monitoring and evaluation (M&E) of NBS. This categorization is important to understand the planning phase of technologies themselves and the duration of their use in relation to NBS. The last category refers to the low-tech or high-tech level of technology as considered its readiness level.

Table 1 summarizes the above-mentioned categories, enriched with references to tangible examples from research and practice to emphasize the importance of technology in different phases of urban planning.

Based on the above-mentioned taxonomy, we can report some examples that use similar technologies to evaluate NBS performance while using technology “in” green and “for” green.

In this paper, we propose a taxonomy to organize and frame how NBS improve their environmental performance and social impact through technology. We, therefore, introduced the concept of “Augmented NBS” to highlight technological support in and around green measures. This technological support can take the form directly on NBS or externally to it. Research projects’ experiments and products on the market already show a rich variety of solutions, mostly adopting high-tech solutions as reported in Table 1 as well. An overview of these augmented NBS opens up a series of theoretical, ethical, and practical reflections on the use of technology in nature, thus posing new challenges in the triangulation of the relationship between human, nature, and technology.

“Tech-assisted NBS” or “smart green infrastructure” is becoming trend in a growing market that focuses on combining green and high-tech solutions, and the ambition towards the combined use of natural elements and innovative technological solutions challenges cities to rethink their governance structures and practices, calling for integrated approaches and the mobilization of competencies and skills across institutional sectors (Bisello et al. 2022). Numerous examples are already on the market for outdoor and indoor NBS and products. Embedding sensors in green infrastructure, according to the concept of Internet of Nature (IoN) proposed by Galle (2019), is adding a layer of complexity to the materialization of the digital world or, on the contrary, to the digitalization of living systems. For instance, there are many examples of capillary and widespread applications of sensors in forests (Internet of Trees, IoTr), to monitor the spread of fires, drought, and the health of trees. Hence, “technological prostheses” applied to green solutions allow us to take care of nature with greater attention and effectiveness. Technology, therefore, supports the diffusion of NBS, often criticized for their maintenance costs, given that they are living and constantly evolving solutions, unlike corresponding gray solutions. Robots for the automated maintenance of vertical and horizontal green surfaces and systems to monitor the water and humidity content of plants and soil using sensors or thermal imaging cameras are already widely used examples that testify to the mature hybridization between technology and nature. However, all this smartness is not regulated and there are no shared protocols for the collection and transmission of data collected from the plant world. This aspect opens up a debate linked to the ethical aspects of exploiting nature and to the rights of nature itself in terms of protection and treatment of data produced through the IoN. Going further, nature can enhance the production of energy, opening up important and promising perspectives for research and development. Energy production through nature like bio-photovoltaic modules is the latest frontier of technology integrated with living organisms. Again, ethical questions are even more relevant in this case.

On the other hand, we have citizens and their willingness to protect and enhance nature, especially in urban areas. In this relationship to nature mediated by technology, awareness about nature’s needs and impact is increased. Co-Diverse technologies can be deployed to facilitate participation and e-participation around nature and NBS. A closer and deeper human-nature relationship is enabled through digital (ubiquitous and connected) technology, which gives nature a voice and makes its needs visible to all. Digital technologies support improvements to this relationship in many ways, mainly increasing awareness of nature, shared governance, and democracy around nature and a sense of belonging and caring for nature. Firstly, Augmented Reality and Virtual Reality tools mounted on mobile or wearable devices help to make the invisible visible, represent nature and NBS in the current state or anticipate future urban greening scenarios and support monitoring, evaluation, and decision-making as part of design and co-design activities. Secondly, digital applications are excellent tools for building loyalty and establishing a caring relationship with nature by monitoring its health and state of conservation. In some cases, apps even initiate a dialogue between people and plants which transmit their state of health as recorded by the sensors. Finally, low-tech participation protocols can facilitate the inclusion of nature and NBS as stakeholders. For instance, nature enters decision-making processes by right, through different tools, e.g., role-playing and immersion in nature, or figures enlisted with the task of acting as guarantors of nature itself. It is, therefore, crucial to sensitize people to understand the multiple benefits (Zilio et al. 2022) related to these innovative NBS solutions and to translate them into values (societal, ecological, governance, and economic ones).