About

The steady growth of many cities in Europe and the increasing sealing of land in rural areas are dramatically changing the landscape and habitats of many animal and plant species: Declines in habitats and wildlife populations are being observed in many places in Europe, and currently the decline of many insect species (especially wild bees) is the focus of public attention.

As the degree of urbanization increases (proportion of sealed surfaces, building density, traffic density, etc.), the diversity and abundance of pollinators decreases, which in urban areas is primarily caused by habitat fragmentation. The genetic exchange of isolated insect populations is often only possible to a limited extent, especially in urban areas.

A sub-area of the “Blooming ribbons in cities” project is therefore concerned with the networking of isolated pollinator populations and aims to give the relevant species better opportunities to migrate along an inner city-periphery gradient. To this end, flowering areas are being created along major traffic axes (inner city-urban fringe) in Munich. Varying distances between areas are intended to show the maximum distances that insects are able to cover.

In addition to their attractiveness for insects, a large-scale use of flowering areas for urban areas is to be tested. The seed mixtures of the planted areas vary in their composition, including rare species, and their suitability for use is being investigated in practical tests.

In addition to biodiversity effects and its aesthetic and spatial planning functions, urban greenery also fulfills the function of climate regulation. In addition to improving the living conditions of pollinators, the planting of flower strips will therefore also be investigated with regard to microclimatic site characteristics in comparison to conventional planting.

The “Colorful Ribbons” project aims to achieve the following scientific and practical goals:

1. Developing and testing the creation of a network of flowering areas along several main urban traffic routes to promote pollinators and urban climate adaptation

2. Evaluation of climate resilience and the attractiveness of different species mixtures for pollinators and other beneficial insects in comparison with existing flowering areas and green spaces

3. Climatic optimization of the size and spacing of flowering areas as corridors for pollinators and other beneficial organisms along an urban-rural gradient based on their movement behavior

4. Improving the quality of life of city dwellers through the microclimatic and aesthetic effects of flowering areas

5. Recommendation for practicable compromises between the requirements of nature conservation and urban greening to increase urban climate resilience and the biodiversity of pollinators

Partner

City of Munich

Green City e.V.

Munich State Collection of Zoology

Chair of Strategy and Management of Landscape Development, TUM (Prof. Dr. Stephan Pauleit)

International Publications

Dietzel S, Rojas-Botero S, Dichtl A, Kollmann J, Fischer C (2024) Winners and losers at enhanced urban roadsides: Trait-based structuring of wild bee communities at local and landscape scale. – Biological Conservation 291, 110480. https://doi.org/10.1016/j.biocon.2024.110480

Rojas-Botero S*, Dietzel S*, Kollmann J, Teixeira LH (2023) Towards a functional understanding of rehabilitated urban road verge grasslands: Effects of planting year, site conditions, and landscape factors. – Flora 309, 152417. https://doi.org/10.1016/j.flora.2023.152417

Dietzel S, Rojas-Botero S, Kollmann J, Fischer C (2022) Enhanced urban roadside vegetation increases pollinator abundance whereas landscape characteristics drive pollination. – Ecological Indicators 147, 109980. https://doi.org/10.1016/j.ecolind.2023.109980

German Publications

Dietzel S, Rojas-Botero S, Fischer C, Kollmann J (2022) Aufwertung urbaner Straßenränder als Anpassung an den Klimawandel und zur Förderung bestäubender Insekten. – ANLiegen Natur 44, 31–42. PDF

Dietzel S, Sauter F, Moosner M, Fischer C, Kollmann J (2019) Blühstreifen und Blühflächen in der landwirtschaftlichen Praxis – eine naturschutzfachliche Evaluation. – ANLiegen Natur 41, 73–86. PDF

Press

Grüne Stadt, kühle Stadt (SZ, 14.07.2023, German)

Interview with Simon Dietzel (Green City, 19.12.2023, German)