From degradation to regeneration with ecoremediation: How Turku recognized the second chance provided by nature and decided to do it differently this time around

About the urban biodiversity park as a nature-based solution

The concept of urban biodiversity parks (UBP) was first developed in 2004 at the Centre for Environmental Management of Degraded Ecosystems at the University of Delhi, India. It emerged in response to New Delhi’s pressing need to rehabilitate industrially polluted areas, its commitment to reintroduce nature into urban spaces and enhance the city’s living conditions. Dr. Arbind Kumar Sinha, one of the original researchers, emphasizes that the urban biodiversity park is a living laboratory that enables a better understanding of ecological processes and learning from nature. 

The concept was proven on several case examples, like Yamuna and Aravalli Biodiversity Parks. This success led to the establishment of the Delhi Biodiversity Foundation, an institution responsible for management of all  biodiversity parks in New Delhi today.

From an urban development perspective, UBPs are seen as a new type of neighbourhood-scale urban green infrastructure, employing nature-based solutions to restore degraded and often heavily polluted areas. They help reintroduce or enhance biodiversity while improving the living conditions of the wider urban area.

The key distinction between UBPs and traditional urban nature reserves lies in their proactive approach to biodiversity. Rather than merely protecting and maintaining existing ecosystems, UBPs actively enhance biodiversity. They serve as dynamic spaces where new nature-based solutions are developed, focusing on ecological restoration, habitat creation, environmental monitoring, and learning. Therefore, UBPs should not be regarded as conventional, fully developed urban green spaces but rather as evolving landscapes where human-mediated and ecological processes continuously interact.

In practical terms, this means that UBPs function as urban nature-based solution testing sites. They facilitate small-scale biodiversity development, such as the nurturing of specific species groups and habitats, alongside the creation of new urban green elements that can later be replicated in other neighbourhoods. Moreover, UBPs harness ecological processes to spread local vegetation beyond their boundaries, thereby contributing to biodiversity enhancement across the entire urban area.

Another defining characteristic of UBPs is their integration of natural growth and ecological processes with human activities. By doing so, they become vibrant, multifunctional spaces – green living rooms for urban residents – offering attractive outdoor and recreational areas. This appeal is particularly significant, as it unlocks one of the key added values of urban green spaces: their potential to serve as platforms for environmental awareness and education – reconnecting urban populations with nature.

Based on scientific evidence of their success and the existence of nearly ten UBPs in the New Delhi metropolitan area today, the Urban Biodiversity Parks project partnership concluded that the model is effective. Enabling them to adapt and transfer the concept to Europe, using Skanssi Park as a testing site.

The case of Skanssi Park

The Skanssi Biodiversity Park is situated in the Skanssi district, within an old gravel pit on a sand ridge that runs through Turku. The area was extensively excavated in the 1950s and 1960s, resulting in a valley-like landscape. Since gravel extraction ceased in the 1970s, much of the exposed pit has naturally re-vegetated. Under the influence of a diverse range of local conditions, various habitats have emerged – including forests of different ages, a small lake surrounded by wetlands, steep sandy slopes covered with pioneer species, and more.

Over the past few decades, interventions in the Skanssi area have been minimal, mostly limited to essential maintenance activities. As a result, the site has not been heavily used or widely recognised as a high-quality green space. Today, Skanssi is surrounded by dense and continuously expanding infrastructure. This development dynamic has transformed it into an oasis of diverse nature within an increasingly urbanised environment.

In 2016, new plans emerged, focused on further urbanization of the whole Skanssi district. The plan proposed envelopment of the Skanssi park with a new neighbourhood, while Skanssi park area was seen simply as an attractive green recreational space. However, this plan was never realized.

As urban development trends evolved and started moving into the direction of the New European Bauhaus, Turku’s urban planners began to recognise the true value of Skanssi Park and its unique ecological characteristics. Their understanding was further reinforced by efforts from the Biodiversity Unit at the University of Turku, which employed the BioBlitz approach to engage citizens and decision-makers, raising awareness about the importance of urban biodiversity and potential solutions for its enhancement.

Over time, the City of Turku came to realise that nature had transformed this once-degraded site into a thriving urban biodiversity hotspot. This shift in perception led to the emergence of a new vision: modifying the spatial plan to create a "close-to-nature" and sustainable neighbourhood within the Skanssi district. And, if everything goes according to plans, Skanssi district could become a lighthouse project and a leading example of sustainable urban development.  

The overall approach

Before discussing the proposed solutions, it is essential to understand the overall approach used in developing the Skanssi Biodiversity Park Care and Use Plan, which the partnership formulated at the beginning of the project. This approach is based on the general understanding that there are four distinct ways to promote natural growth in urban areas:

• Free ecological succession allows nature to develop freely, with minimal human intervention. The goal is to preserve or enhance biodiversity through natural processes, enabling species to grow and spread on their own. Although uncommon in urban areas, nature reserves serve as the best examples of this management approach.
• Controlled neglect does not alter the overall direction of natural growth but selectively supports favourable developments while suppressing undesirable ones. Nature evolves through spontaneous species growth and spread, but human intervention – such as clearing, cutting, and weeding – is used to reinforce positive ecological changes in line with specific goals.
• Controlled growth is guided by human-defined objectives, where natural development is directed and often initiated. This approach is commonly used in cities, such as in the management of meadows established by sowing seeds. It also plays a significant role in ecological restoration, where natural processes are carefully managed to achieve desired outcomes.
• Engineered biodiversity involves strict regulation of natural growth. In this method, an area is deliberately transformed into a biodiversity-rich space through interventions such as soil preparation, seeding, and planting. Spontaneous natural growth is limited, and supplementary sowing or planting is used to reinforce targeted vegetation if initial efforts do not yield the desired results.

None of these methods is inherently superior to the others. The most suitable approach must always be chosen based on the specific context and objectives of the site in question.

The logic behind 21 urban biodiversity treatment zones and testing areas

UBPs are large entities with different subareas, each contributing to a rich mosaic landscape. These sub-areas or zones can take the form of points or polygons of varying shapes and sizes, reflecting the complexity of natural environments. Development within biodiversity parks is typically carried out in stages, with each zone managed individually according to specific goals and tailored management regimes. This approach ensures that biodiversity is actively enhanced while maintaining a dynamic balance between conservation, ecological restoration, and sustainable human interaction.

Preliminary biodiversity investigations across 20 hectares of Skanssi Park revealed an exceptionally high diversity of existing habitats, highlighting its strong potential for experimental research. As a result, the park was divided into 21 polygons, each serving as a testing ground for a unique approach to conserving and actively enhancing urban biodiversity, as presented on the map below.

Like all UBPs, Skanssi Park has been designed to support outdoor activities and education too. The plan aims to enhance the existing infrastructure and upgrade it based on the needs of key target groups, including park managers, researchers, teachers, students, families with children, the elderly, and recreation enthusiasts, among others.

However, analysing the needs of these groups quickly revealed overlapping – and even conflicting – interests. While 20 hectares is a significant area, it is not large enough to accommodate all activities without careful planning. Recognising this, the City of Turku identified a clear need to develop a Visitor Management Plan – a strategy to balance diverse interests, prevent conflicts, and ensure that Skanssi Park remains accessible and enjoyable for all.

The local seed accumulation solution  

It is impossible to describe all 21 urban biodiversity treatment zones and testing areas in a single article. However, we can take a closer look at one that is currently being implemented.

At the northernmost point of Skanssi Park lies an open field, situated directly across from the Skanssi shopping mall and alongside one of the major roads leading into Turku. Notably, this area has been reserved for the future expansion of the Turku tramway.

So why invest into urban biodiversity on a location that will inevitably be urbanised? According to the latest information, the City of Turku will not require this land for at least the next ten years, making it a prime example of an urban land reservation with no immediate function – a common situation in many cities across Europe. But from the project’s perspective, an ideal opportunity to create a temporary local plant species seed accumulation area.

In this case, the controlled growth approach was clearly the preferred option. To create the so-called enrichment meadow, the soil was carefully prepared to meet the needs of key target species. Specifically, a 30 cm thick layer of sand (90–95%) mixed with organic matter (5–10%) was spread across the area. Measures were implemented to prevent contamination by invasive species.

Seeds of local wild plants were collected under controlled conditions from verified locations across the Turku region and sown in November 2024. Seeds from the ten rarest plant species were incorporated into the mixture to support their preservation.

Seed collection was based on a set of pre-agreed and tightly followed rules in order to ensure best possible results:

• Only plants collected within the Turku region were used to ensure that the selected species are both genetically adapted and ecologically linked to the local environment.
• Seeds from a diverse range of plant species were gathered from multiple locations within a narrow geographical area to preserve genetic diversity and adaptability.
• The vegetation used was carefully selected to remain within its historic range, helping to restore and strengthen individual plants, populations, and strains of species within their natural phytogeographical boundaries.
• Measures are in place to ensure that collected and cultivated seeds do not spread beyond the Turku region.
• All seed collection and sowing locations will be thoroughly documented to maintain traceability and enable the verification of transferred seeds.

An experienced expert can identify plant species even outside their flowering period. Seed collection is best carried out in uniform and sufficiently large areas, as these provide an abundant and sustainable seed supply. Seeds should not be collected from small or sparse populations, as this could deplete local seed reserves and compromise the vitality of existing plant communities. To ensure responsible and effective seed collection in Skanssi park enrichment meadow, experts have marked and mapped designated collection areas for specific species. If needed, targeted re-sowing will be conducted in the coming years to reinforce and sustain plant populations.

In the initial phase, aggressive species spreading from other areas – such as hogweed, field thistle, and bitter gorse – will need to be eradicated. Organised weeding is planned for the first few years. Over time, new generations of seeds will be collected and transferred to the most suitable habitats within Skanssi Park. The same principle applies to other species, although botanists anticipate that, in the long run, seeds from this meadow will naturally enrich the biodiversity of the wider area through passive dispersal.

Moreover, the collected vegetation can be used to develop a special Turku meadow seed mixture, which could enhance the biodiversity of the city's green areas. This distinct mix of local plant species would not only contribute to urban biodiversity but also strengthen the identity and ecological value of green spaces. The use of native species would further enhance the educational and environmental awareness aspects of urban greenery.

Project partners plan to use this site for seed production over the next ten years, essentially creating an on-site seed bank. When the planned tramway expansion begins, the topsoil will be carefully removed and repurposed to establish new meadows, fields, and green roofs across Turku. The meadow will be closely monitored, not only to assess the effectiveness of this approach but also to ensure the traceability of plant genetic origins in the future.

The awareness raising and educational dimension

 As previously mentioned, Urban Biodiversity Parks (UBPs) are not just about nature – they also have a strong human dimension. This applies even to the creation of a local seed bank.

During the project, partners recognised that few experts are available who can accurately identify local plant species, let alone collect their seeds correctly.

Seed collectors must identify the plant species and their seeds, know how to estimate the appropriate time and methods for seed collection. Collecting seeds may require repeated visits to several different sites, so a certain devotion to the task is a requirement. Seeds, even when gathered in dry conditions, must be properly dried and stored in appropriate conditions until sowing. 

The seeds collection can also be carried out under the guidance of experts, in which case collectors are not required to have as much knowledge of plant species. This is why partners decided to organize a special training for biology students and enthusiasts to learn how to identify targeted species and collect their seeds. This initiative not only strengthens biodiversity conservation efforts but also adds an important awareness-raising, educational, and citizen science element to the project.

For conclusion

Dear reader, we began this article with the statement: “Nothing in nature is fixed.” The same can be said for innovation projects. For now, the Urban Biodiversity Parks project is progressing well. We hope you will continue to follow our journey, celebrate our successes, and learn from our experiences. As we often say, the path to innovation is never straightforward, but it is always inspiring.