Biodiversity

Biodiversity underpins the natural life-support system of cities. For sustainable cities, a key question is why is biodiversity important in cities.

Climate change and biodiversity loss feed each other. Healthy ecosystems (forests, wetlands, soils) absorb carbon and stabilize temperatures, whereas destroying these ecosystems accelerates warming, heatwaves and floods. As the EU’s climate and biodiversity policies emphasize, protecting and restoring urban nature is fundamental to climate adaptation and quality of life.

2. What is Biodiversity?

Biodiversity (biological diversity) is the variety of life on Earth. It includes diversity within species (genetic variation among individuals), between species (the number of different plants, animals, fungi, etc.), and of ecosystems (different habitats like forests, wetlands, rivers).

Urban biodiversity ranges from the tree species in a park and the microbes in the soil, to the birds, insects and mammals that use city habitats. A biodiverse city is one that maintains a rich mix of native species and healthy ecosystem types, rather than a concrete monoculture.

These ecosystems provide ecosystem services, the benefits people get from nature. For example, urban trees and soils store carbon, cooling the city and slowing climate change. Parks and green roofs soak up stormwater, reducing floods; flowering plants feed pollinators like bees and butterflies; and wetlands filter pollutants from water. Biodiversity also yields cultural and health benefits: green spaces for recreation improve mental well-being, and many medicines are derived from plant compound.

The importance of biodiversity

Biodiversity plays a key role in many aspects of life on Earth. Healthy ecosystems with high biodiversity are better able to withstand changes and stresses such as climate change, natural disasters or human activities. Species diversity ensures the stability of ecosystems and contributes to recovery from disturbance. In addition to its ecological benefits, biodiversity is also of economic importance, as many industries such as agriculture, fisheries and tourism depend on healthy ecosystems and a diversity of biological resources.

Measuring biodiversity

Measuring biodiversity is a complex task involving different methodologies and approaches. The most common indicator is to monitor the number of species in a given location, which provides a basic overview of diversity. However, for a comprehensive assessment, it is also important to consider the genetic diversity and functional diversity of ecosystems. Scientists often use various indices, such as the Shannon index, which takes into account not only the number of species but also their relative abundance. These methods allow a more detailed analysis and understanding of biodiversity in different ecosystems and conditions.

Nature-Based Solutions and Biodiversity: Green and Blue Infrastructure

Nature-based solutions (NBS) use ecosystems to address urban challenges.

• Green infrastructure – networks of parks, street trees, green roofs and corridors – is explicitly designed to support biodiversity while providing services. The EU defines green infrastructure as interconnected natural areas that deliver services like water purification, air quality, and climate regulation and enhance biodiversity.
• Blue-green infrastructure combines water elements (blue, e.g. wetlands, restored rivers) with vegetation (green) to manage rainwater and create habitats.

How to increase biodiversity in urban areas: practical measures

Cities and developers can take many practical steps to boost urban biodiversity.

Key measures include:

• Plant native and diverse vegetation. Use a mix of trees, shrubs, perennials and grasses. Native species are better adapted and provide nectar and seeds for local wildlife. Boost vegetation complexity: create layers of plants (groundcover, herb layer, shrub layer, canopy) and include features like deadwood or rocks.
• Create new habitats. Replace or complement manicured lawns with wildflower meadows or clover-rich lawns (prairies, scrub areas). Add bird/bat boxes, pollinator gardens and insect hotels. Install ponds, rain gardens or reed beds to support amphibians and aquatic life. Even small “pocket parks” or green balconies add habitat.
• Green roofs and walls. Encourage green roofs, living walls and garden balconies on buildings. These add green square meters without needing land. T
• Connect and expand green areas. Link isolated parks with green corridors (tree-lined streets, riparian buffers). Corridors allow species to move and pollinate between sites. Studies emphasise that “biodiversity flourishes when cities build connected networks of corridors and stepping-stone habitats”. Preserving existing urban forests and expanding street tree cover also ties habitats together.
• Minimize impervious surfaces. Use permeable paving, unpaved planting strips and soil-friendly design so rain can infiltrate. Protect and improve urban soils – soil holds vast biodiversity (microbes, insects) and stores carbon. Reducing soil sealing (e.g. through “unsealing” initiatives) helps soil organisms and groundwater recharge.
• Limit chemicals and invasive species. Adopt pesticide-free landscaping and control invasive plants. For example, reduce mowing and weedkiller use so wildflowers can thrive.
• Engage the community. Support community gardens, native plant giveaways and citizen-science surveys. Local volunteers can help plant trees, monitor wildlife or maintain rain gardens. Building public support ensures long-term care of green projects.

Biodiversity, Equity and Quality of Life: Urban Access and Justice

Access to nature is also an issue of social equity. A useful guidline for equitable greening is the 3-30-300 rule. Studies show that low-income and marginalized communities often have less and poorer-quality green space in their neighborhoods. This “nature gap” means disadvantaged groups miss out on the health and social benefits of biodiversity. Conversely, green spaces can greatly improve quality of life for those communities: urban parks, gardens and tree-lined streets reduce stress, improve mental health and foster social cohesion.
Urban planners are beginning to address this: WHO and EU guidelines suggest everyone should live within a short walk of a park or green area (see 3-30-300). In summary, integrating biodiversity in cities is not just a technical goal but also a social one: cities must bring nature to people as a public service. Doing so delivers both environmental justice and the direct well-being benefits of nature for all communities

By adopting these practices, European cities can become more sustainable and resilient. The gains are clear: as one planning report concludes, treated as core infrastructure, biodiversity yields “cooler streets, cleaner water, less impactful floods, and richer public life” – in other words, safer, healthier and happier cities. Preserving and enhancing urban biodiversity is thus an investment in climate resilience, public health and quality of life.

UpGreen: Measuring What Matters in Urban Nature

To support cities in building nature-positive infrastructure, ASITIS developed UpGreen – a digital tool that helps municipalities and developers assess the condition, functions and value of urban green infrastructure. UpGreen goes beyond basic mapping: it quantifies carbon sequestration, vegetation stress, tree productivity, tree survival capacity, the cooling potential and habitat quality across different segments of public and semi-public greenery.

By combining satellite data, ecological metrics and urban climate parameters, UpGreen enables cities to prioritize investments where nature delivers the highest climate and biodiversity benefits. Whether identifying heat-vulnerable neighborhoods for tree planting or evaluating the biodiversity potential of green corridors, UpGreen turns data into action.

In this way, it becomes a practical enabler of the EU Biodiversity Strategy and a compass for cities aiming to align spatial development with ecosystem restoration and long-term resilience.