From Grazing Sheep to Flourishing Medians: The Nature Conservancy's Urban Grassland Project in Berlin Charlottenburg-Wilmersdorf

As urban populations grow, the effects of climate change become increasingly apparent. Urban areas, dominated by cars, concrete, and asphalt, absorb heat throughout the day and retain it at night, creating an oven-like effect. Impermeable surfaces not only exacerbate heat waves but also prevent rainwater from seeping into the ground, which can overwhelm drainage systems during heavy downpours. This leads to heat stress for people, animals and plants, while increasing the risk of flooding. So, what's the solution?  

Experts have long advocated for more greenery in cities. Parks, trees and vegetation serve vital functions: they purify the air, cool the surroundings, and absorb and retain stormwater. They also create habitats for small wildlife and insects, boosting biodiversity. Additionally, urban greening has a profound impact on mental well-being, helping people feel more at ease and refreshed.

While there is a broad consensus that our cities must embrace greener solutions, local administrations struggle to find the resources needed to bring these changes to life.

Europe Urban Greening Program

In response, The Nature Conservancy Europe (TNC) launched the Europe Urban Greening Program in 2020. "To assist cities and municipalities in tackling the enormous challenge of climate adaptation, we collaborate closely, integrating practical research with pilot projects," says Program Director Jamie Chan. Partnering with Berlin’s Charlottenburg-Wilmersdorf district office, TNC launched the first urban greening project five years ago. It focuses on creating a scientific framework for urban grassland development, serving as the foundation for designing and enhancing green spaces in the district. Additionally, it fosters pilot projects that can serve as models for other municipalities.

Potential to add green spaces each year

Sounds ambitious? It’s achievable if just one percent of the district’s roofs are greened annually. With 311 hectares of flat rooftops, the potential for new green space is immense. This figure comes from the Urban Grassland Plan, developed with the district office and finalised in 2024. Green roofs bring significant benefits—they absorb rainwater, easing strain on sewers, while evaporation cools the surroundings. Traffic areas also hold promise: 56 medians are identified as prime candidates for improvement, according to the study.

As part of the project, a method was devised to quickly assess green space quality, alongside curated lists of climate-resilient and ecologically valuable plant species—key tools for efficient future planning.  

Which plants should be prioritised in Berlin? 

To explore this, TNC collaborated with district authorities and the Senate Administration to host a series of workshops. Interest in the topic is high - early 2025, around 70 experts from science, administration, and practice discussed "Guidelines and Species Selection for Seeding and Planting in an Urban Context". They assessed species selection based on local conditions, costs, maintenance needs, ecological benefits, aesthetics, and seed availability. The debate over non-native species remains ongoing. 

"We have found that plant selection depends on diverse, site-specific factors. While establishing universal criteria is challenging, continuing the discussion is essential," says Maria Knaus, who is leading the Urban Grassland Project in Berlin. "There may not be a standardised species list, but at least city-wide recommendations within Berlin’s administration could emerge," noted Dr. Ulrich Heink from the Nature Conservation Office Charlottenburg-Wilmersdorf.

Eco-Grazers: How Sheep Are Reviving Biodiversity at Wilmersdorf Stadium

The sheep on Wilmersdorf Stadium’s slopes don't care about selection criteria. They simply eat what they like, benefiting nature in the process. As part of a pilot project, their grazing is being tested as a natural way to enhance the grassland. A few years ago, the stadium looked very different. In 2005, the grandstands were removed, and the slopes became overgrown with ash maple and garden blackberry - dense, species-poor growth that required regular mowing.

To improve ecological value, sheep were introduced in 2021. Their natural grazing helps control shrubs, making room for new species. To further boost biodiversity, drought-resistant plants were introduced in selected grazed areas, with their growth monitored by the Technical University.