Richly structured and variously used landscapes provide essential habitats for a variety of insects, many of which – especially wild bee species – are important for pollination. The occurrence of pollinators contributes to stable yields in agriculture and thus to the food security of the population.
The value of the "potential pollination performance" indicator shows the availability of suitable nesting and foraging habitats for wild bees. To this end, proportions of potential flower availability (i.e. the insects' food) and nesting habitats (their habitat) of small solitary wild bees are estimated as a function of land use and the proportion of near-natural small structures. Based on this, it is determined whether food and nesting habitats are sufficiently close to each other (within the flight radius of the insects). The potential pollination performance is determined from the distance of each land use plot to the areas with high potential pollinator occurrence, i.e. high-quality, nearby food and nesting habitats.
The potential occurrence of pollinators (regardless of the location in relation to the agricultural land that may benefit from it) is a secondary indicator and is described as an ecosystem property.
Areas with medium to high pollination services are mainly found in low mountain ranges, the Alps and diversely structured landscapes in the lowlands. Coniferous forests, e.g. in Brandenburg and Bavaria, received medium values. The intensively farmed landscapes and urban areas stand out with low values. Areas with homogeneous, very large agricultural areas and few woody structures offer hardly good habitat for wild bees. As a result, the Magdeburger Börde and the Thuringian Basin scored particularly low. Cities such as Berlin, Hamburg and Bremen, as well as the heavily populated Ruhr region, all scored poorly. Cities are probably underestimated as suitable habitats in this approach because a large proportion of urban vegetation is not present in the baseline data. For Germany as a whole, this results in an average value of 0.23 (on an ordinal scale from 0 to 1, where 0 stands for no pollination performance and 1 for high pollination performance) for the relative pollination potential for solitary wild bees with a small radius of action for the reference year 2015. Trends cannot yet be derived.
Original methodology: Zulian, G., Maes, J., Paracchini, M. L. (2013a): Linking Land Cover Data and Crop Yields for Mapping and Assessment of Pollination Services in Europe. Land 2(3), 472-492
Adapted to Germany by the following steps: