When talking about bees, many people first think of honey bees. They are known worldwide as farm animals, and the honey they produce is a popular food. Honey bees are kept by humans in beehives, which are home to a queen and up to 40,000 worker bees. However, the western honeybee (Apis mellifera) is only one of nearly 600 species of bees native to this country. All other species are grouped under the term “wild bees.” These wild bees usually live alone and contribute significantly to the stability of our ecosystem.
Like many other insects, bees are also affected by global insect decline, i.e., the decline in biomass and/or species numbers. As a result, 48% of bee species are already considered endangered or even extinct. There are many reasons for this: rising temperatures and periods of drought caused by climate change, the loss of habitats due to the clearing of the landscape, the use of pesticides, limited food availability due to monocultures, and increasing soil sealing threaten wild bees.
However, the situation is different for honey bees. As they are kept as livestock by humans, they are less affected by these factors. In addition, beekeeping is becoming increasingly popular as a hobby. Since 2007, the number of honey bee colonies in Germany has almost doubled from 670,000 to around one million. However, this rapid increase, combined with increasingly scarce food resources, could become an additional problem for wild bees. Initial studies on food competition between wild bees and honey bees are already available, but the results are inconsistent and often only relevant locally. To date, there has been no systematic spatial analysis of the potential for competition in terms of food availability.
Our goal is therefore to conduct such an analysis for northern Germany (Hamburg, Lower Saxony, Bremen, Schleswig-Holstein). We plan to compare spatially distributed food requirements with the available amounts of nectar and pollen. In this way, we hope to identify possible regional differences and areas with particularly high competition potential. We will publish the results in the form of interactive maps to create a basis for future research projects and measures for sustainable beekeeping in risk areas.
To carry out this project, we first need various data sets. On the one hand, it is important to have the most accurate locations possible for the honeybee colonies kept. Since keeping bee colonies is subject to reporting requirements under Section 1a of the Bee Disease Ordinance, we will request this data from the relevant authorities. We will also contact the beekeeping associations in the federal states to obtain even more detailed information if necessary. Second, we need information about the available food resources, i.e., the plant populations in the region. For this purpose, we will use mapping data from various geoinformation systems, such as the Hamburg biotope register or the street tree register. Finally, we need data on the observed wild bee populations, which, however, are only available selectively from scientific studies.
Since this data is all available in different formats, we first have to merge and clean it. We will do this using the programming language R and various open-source packages such as the “terra” package. For a more sound analysis, we will supplement the data with findings from the scientific literature, e.g., on the pollen and nectar requirements of the various bee species and the food supply of regional plant species. Since both the raw data and the literature data are likely to have gaps, we’ll perform appropriate error estimates and interpolations.