Interactions between landscape structure and combined agri-environmental measures on the diversity, population development and health status of wild and honey bees. (ComBee)

The scientific objective of ComBee is to investigate the direct and indirect interactions of the main causes of pollinator insect losses identified in the literature (i.e. land use change, bee diseases). In particular, the focus is on the interactions between different agri-environmental measures and landscape structure, as well as their effects on pollinator species communities, population development of wild and managed bees, prevalence of pathogens and natural counterparts, resource use and trophic interactions between plants, pollinators, pathogens and counterparts.
Organic farming generally has a positive effect on bees, but this effect depends on the landscape structure. To analyse how organic farming can promote healthy and stable honey bee and wild bee populations, we will conduct landscape ecology and genetic studies, and in particular investigate the combination of different agri-environmental measures. We will select a total of 32 landscapes with independent gradients of the proportion of organic farming and semi-natural habitats, and then sample landscape pairs with and without flowering areas within these gradients. Within each landscape, we will use transect surveys and nesting surveys to investigate the diversity and abundance of bees and the flowering resources present. Innovative sound recordings will also be used, providing a non-invasive monitoring method of bee activity. Honey bee and bumblebee colonies will be placed in each landscape and colony growth analysed. We will also record the occurrence and transmission of pathogens, e.g. viruses, using modern genetic analysis methods. Further, we will investigate whether diseases are transmitted from honey bees to wild bees and whether these effects can be mitigated by various agri-environmental measures such as organic farming or flowering areas, individually or in combination. We will examine how high densities of honey bees affect the diversity and abundance of wild bees, their interactions with plants, and their health in different landscapes. We will apply population genetics methods to bumblebees and determine their genetic diversity and colony density.