Today, intensively used landscapes are often very biodiversity-poor areas. Even the smallest semi-natural sites, such as meadow paths, are increasingly disappearing and with them a large number of plant and animal species. Based on the assumption that biodiversity brings multifunctional properties to landscapes, the loss of species also means a loss of ecosystem functions and services such as pollination, water, nutrient and carbon storage.

Incentives to take measures to protect ecosystem functions are difficult to provide, especially in intensively used landscapes. As part of the "greening" component of the CAP (Common Agricultural Policy) and the agri-environmental programs of the federal states, flower strips are currently being increasingly introduced in Europe and are also widely accepted in intensively used areas. Individual flower strips can certainly have a positive effect on pollinators, but there are also many examples without any significant positive effect. How many flower strips would be necessary to maintain pollinator diversity at landscape level? And what properties do flower strips have for other ecosystem functions and the resulting services at landscape level?

In a project "Ecological enhancement in arable fields in the Upper Rhine Plain" of the IFAB Mannheim (Institute for Agroecology and Biodiversity), the effect of a complex of flower strips on an area of 10 % in 50 ha landscape sections on pollinator diversity in intensively used agricultural landscapes was investigated over a period of 6 years. In a further project phase of the same project, the proportion of flower strips will now be reduced to 5% of the area and the effects on pollinator diversity will be determined. With this project, we are expanding the field surveys, analyses and elaborations as follows. We investigate a) the effects of such flower strips of different ages and seeding histories from the past 8 years on their carbon, nutrient and water storage capacity; b) the effect of plowing up such flower strips on these ecosystem functions; c) using trait analyses, what role the distances between the flower strips and the remnants of semi-natural habitats (at 10%, 5%, or control landscape) and their quality play for pollinator diversity and composition of more or less specialized species of bees and butterflies; d) the relevance of such flower strips (10%, 5% or control areas; we d) estimate the relevance at landscape level for water, carbon and nutrient storage and pollination performance. The partner IFAB will then compile simple recommendations for action for farmers and politicians on how to choose the arrangement and area proportion of flower strips in order to promote the greatest possible pollinator diversity and other ecosystem services in the landscape.

As flower strips are currently quite well accepted by farmers, even in intensively farmed areas, the inclusion of flower strip networks in the upcoming reform of the CAP could lead to broad acceptance among farmers and rapid implementation in normal landscapes if appropriately promoted. This could slow down the rapid loss of biodiversity and functionality in the intensively used agricultural landscape in the short term in order to gain time to further develop agricultural production and the use of landscapes in a sustainable way.