Challenges in restoring Sweden's urban ecosystems

Urban ecosystems are defined as green areas and water within cities, small towns and suburbs and include trees, shrubs, lawns, gardens, avenues, lichens, mosses, lakes, streams, beaches and more. These places are important habitats for biodiversity.

– The restoration of our urban ecosystems is important not only for biodiversity but also for human health and well-being. There is talk of inclusive and sustainable urbanization – how do we build cities that not only preserve biodiversity but also benefit from the ecosystem services that come with it, says Torbjörn Ebenhardt, research leader at the SLU Centre for Biodiversity.

Ecosystem services can include reduced flood risks, a well-regulated local climate, enhanced water and air filtration, climate change mitigation, and increased recreation and well-being for residents.

Urban ecosystem area boundary

151 of Sweden's 290 municipalities are sufficiently urbanized to be included in the restoration plan. (Cities that already have a high proportion of green space and tree cover may be excluded - the thresholds are 45% green space and 10% tree cover.)

One of the main challenges now is to determine how much of the municipal area should be included in the restoration plan. It is up to each Member State to decide on the delimitation. The Swedish National Board of Housing, Building and Planning (Boverket), which is the lead agency in Sweden for urban ecosystem restoration, has three options.

1. Entire municipality (equivalent to 44% of Sweden's total area)
2. Urban area (equivalent to 1% of Sweden's total area)
3. Urban area with surrounding countryside (equivalent to 2% of Sweden's total area)

– This is one of the big issues. We will need input on how to reason and what the consequences of the various delimitations may be. Dialogue and transparency are a requirement of the regulation. The work is long-term and we are just at the beginning. We therefore need help from the municipalities concerned. What are the possibilities and what are the consequences of the demarcations, says Ulrika Åkerlund, landscape architect at the National Board of Housing, Building and Planning and responsible for dialogue and participation in the project.

– It will also be a challenge to deal with the many landowners who need to take care of and develop their green areas. Half of urban green spaces are owned by individuals and a third by public institutions. We need to map what is being done today and what we need to do more of. And how we can talk about quality and not just quantity, says Ulrika Åkerlund.

Ecological urbanization in practice

Johanna Deak Sjöman, researcher at the Department of Landscape Architecture, Planning and Management at SLU, has in her studies mapped what effects local adaptations in cities can have on the living environment. Using a 3D model, she can predict the effects of specific plantings on the local climate.

– Trees play an important role in providing warmth in urban environments, both in summer and winter. An area with smaller trees can reach a radiant temperature of 40 degrees in summer – while in an area with older trees it is 20 degrees. At the same time, excessive tree canopy cover can reduce ventilation. Urban planning therefore requires site-specific solutions, says Johanna Deak Sjöman.

Site-specific solutions must also consider other factors, such as building heights, surface reflectivity and street angles.

– Often, the broad brushstrokes of general policies seem obvious. But when we zoom in to the neighbourhood scale, they can be difficult to translate into practice. The urban landscape contains many components. What we do in one place can affect another place further away, says Johanna Deak Sjönman and continues:

– Another important issue is financing. Getting initial investment can be relatively easy, but it is more difficult to get a long-term budget for operation and maintenance. We need this to realize the vision of a developed urban ecosystem.

Satisfactory level by 2050

How the development of Sweden's urban green spaces will take place in practice – and which cities and land areas will be affected – remains to be seen. By 2050, we should have reached a satisfactory level. But what is a satisfactory level? And how do we define it? Torbjörn Ebenhardt says it's a difficult question:

– The government has set the requirements at a minimum level. At the same time, a municipality can adopt a higher level of ambition than the government. The question is how much we want to achieve.