SoNaRR 2025: Urban

Visit Wales

This webpage is part of the State of Natural Resources Report 2025

The urban ecosystem is the built environment - which includes buildings, roads, gardens, parks and informal greenspaces, waste sites and any other structure or space installed for human activities.

Key messages

  • Our towns and cities are struggling to cope with climate change due to increased risk of heat stress and flooding, and we expect this to get worse.
  • Over 80% of Wales’s population live in built-up areas, which provide essential ecosystem services for people and the economy.
  • Pollution is a major pressure on our urban ecosystems and human health, including air, water, soil, noise, and light pollution.
  • We need more street trees, rain gardens and other green infrastructure to keep the places where we live habitable in the face of pollution and climate change.
  • To tell if our actions are working, we need a monitoring network in each urban area to track changes in air pollution, light pollution, rainfall, temperature, and wildlife.

Assessment of SMNR

This urban assessment is one of eight ecosystem and three natural resource assessments that inform the overall SoNaRR2025 report. It builds on the findings of SoNaRR2020, drawing together updated evidence from subject experts, national datasets, and collaborative projects. This assessment is closely linked to the assessments for Air, Water and Freshwater.

The assessment is structured around four interlinked aims that guide Wales’s progress toward the sustainable management of natural resources (SMNR), helping to communicate the relationship between the environment, well-being, and the economy.

Aim 1: Stocks of natural resources are safeguarded and enhanced

Urban ecosystems in Wales face pressures from invasive non-native species (INNS), pests, pollution, and climate change. INNS introduced for ornamental purposes can disrupt native biodiversity and ecosystem functions, while pests like ash dieback and oak processionary moth threaten urban trees. Air pollution trends are mixed, with reductions in SO₂ and NO₂ but rising ozone and PM₂.₅ levels in densely populated areas. Light and noise pollution also damage urban wildlife and human health. Water and soil pollution have historically degraded urban ecosystems, though large improvements in water quality and soil remediation happened during the 20th Century. Climate change intensifies the pressures on the urban environment through increased flooding, heat stress, and sea level rise, particularly affecting coastal urban zones.

Progress includes mandatory Sustainable Drainage Systems (SuDS) for new developments since 2019, improving water management. Wales’s 2024 Clean Air Act sets stricter air quality targets and addresses urban noise. The 20mph speed limit policy aims to reduce traffic emissions and noise. Key actions include controlling INNS, monitoring pests, improving air and water quality, remediating contaminated land, adapting urban green spaces to climate impacts, monitoring urban wildlife, safeguarding existing large trees, and managing urban green spaces for pollinators.

Aim 2: Ecosystems are Resilient to Expected and Unforeseen Change

Urban ecosystem resilience is challenged by limited diversity, low green infrastructure extent, and unknown connectivity. Tree species diversity is low, making urban forests vulnerable to pests and climate stress. Green space extent is constrained, with only 3,721 ha of functional green space and 1,432 ha of blue space. Tree canopy cover averages 17–18% and urban trees face aging and loss. Connectivity remains poorly understood, though hedgerows offer some habitat links. Flooding, pollution, and heat stress further degrade urban ecosystem condition.

Recent initiatives include statutory SUDS on new developments, the Local Places for Nature programme, and pollinator-friendly mowing regimes. These efforts enhance resilience by creating new habitats and improving ecosystem services. Recommended actions include increasing tree diversity and canopy cover, protecting and expanding green and blue spaces, and improving ecological connectivity through green corridors and stepping stones including SUDS.

Aim 3: Healthy Places for people, protected from environmental risk

Urban ecosystems support health through climate regulation, air filtration, noise attenuation, and flood mitigation. Cardiff’s urban forest sequesters nearly 8,000 tonnes of carbon annually, while vegetation cools cities and intercepts pollutants. Urban trees and grasslands remove over 1.6 million kg of air pollutants yearly. Vegetation stabilizes soils, reducing landslip risks, and SuDS retain stormwater, lowering flood hazards. Noise mitigation benefits 12,000 homes, improving mental well-being.

Cultural services include recreation, with over 72 million visits to urban green spaces in 2021/22, though usage declined post-2019. Access varies, with 69% of urban households within 300m of functional greenspace. Deprivation correlates with environmental inequality—less affluent areas have lower tree cover and poorer access. Actions include expanding green infrastructure, improving access, and using nature to foster community cohesion and health.

Aim 4: Contributing to a Regenerative Economy, Achieving Sustainable Levels of Production and Consumption

Urban ecosystems contribute to economic sustainability through climate regulation, flood control, and food production. Green infrastructure reduces business costs by mitigating heat stress and air conditioning needs, valued at £1.45 million annually in Cardiff. SuDS and vegetation manage water flow and purify pollutants. Allotments and gardens produced food worth £10.3 million in 2021, supporting local food security and reducing carbon footprints.

However, reduced land management and urban development threaten green space extent and quality. Garden sizes are shrinking, and densification pressures persist. Nature-based solutions (NbS) offer cost-effective alternatives to grey infrastructure, with added value and job creation potential. Progress includes mandatory SuDS on new developments, updated allotment guidance, and the Local Places for Nature programme. Future actions should integrate NbS into planning, promote urban agriculture, and enhance green infrastructure to support a regenerative economy.

Key changes since SoNaRR2020

Urban areas have been subject to more storms and flooding, but also more heatwaves and droughts as our climate has become more variable.

Investments have been made in making homes more energy efficient, and in building energy efficient homes, but these have been small compared to our total housing stock.

Since January 2019 most new developments in Wales must install Sustainable Drainage Systems. However, these cover a very small proportion of urban areas.

Local Places for Nature funding enabled sites totalling 648 ha to adopt biodiversity-friendly mowing. However, this is around 0.5% of our urban area (126745 ha).

Local government funding for parks and green space management has fallen significantly.

Light pollution has become worse. The picture is mixed for other kinds of pollution.

Some bird and butterfly species have become more common whilst others have declined. We do not collect enough data to understand changes in most urban biodiversity.

Read the full assessment of the Urban ecosystem in our State of Natural Resources Report 2025.

Read this assessment



Underlying evidence

In writing our assessments and to better identify opportunities for action we have gathered evidence that helps us understand these key aspects:

  • the drivers of change and pressures on the urban ecosystem in Wales.
  • the ecosystem resilience of the urban ecosystem in Wales.
  • the benefits, or services, we get from the urban ecosystem and how changes in the state of the urban ecosystem impact on well-being.

Access the detailed evidence through our SoNaRR 2025 Evidence portal.

View full screen version.

Evidence needs

The urban ecosystem needs systematic evidence on air quality, light pollution, biodiversity, and on pollutants in surface water runoff. The data that we have is from a few localities in some urban areas so systematic sampling across each urban area is needed to provide the evidence required to guide the management of the habitat in which most people live. We have systematic mapping of urban green spaces, but we need evidence about which are accessible, and which are managed to an appropriate standard. We need better and more up to date data on the extent of urban tree canopies. Most urban areas still require modelled evidence of the impacts of future heatwaves. We need to collect data on the impact of the changing local authority resources allocated to green infrastructure management, and we need to develop monitoring strategies for new and emerging pollutants such as “forever chemicals” (PFAS and PFOS).

Read SoNaRR 2025 Evidence needs.

Key evidence sources

Explore some of the evidence we have used to inform our assessment:

Case studies

Mapping future heatwaves in Welsh towns and cities

The video describes a study that uses computer simulation to assess the extent of heat stress experienced by pedestrians in three Welsh cities during heatwaves, with a view to identifying implications for urban planning and design practice. Professors Phil Jones of Cardiff University and Jianxiang Huang of the University of Hong Kong worked with colleagues to conduct the study.

Mapping future heatwaves in Welsh towns and cities

 

Local Places for Nature Programme

Local places for nature is not prescriptive in what it supports. It promotes a bottom-up approach where activity is community led. It aims to create areas that support nature within communities, in particular urban and peri-urban areas; encourage a greater appreciation and value of nature; create more green spaces, honouring our commitment to do so; and support wider biodiversity objectives.

Local Places for Nature Programme | GOV.WALES

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