Effects of land use intensity on pollinator health and pollination services

• Applicants: Professor Dr. Manfred Ayasse, since 4/2022; Professorin Dr. Lena Wilfert
• Subject Area: Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions
• Term: from 2020 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 432950060

Roughly 47 percent of Germany’s surface area is used for farming; 90% of this area can be considered as intensively farmed. Intensive farming aims to increase yields per unit of area resulting in monotonous farmland. In such impoverished landscapes, pollinators suffer from reduced availability of food sources and nesting sites, fragmentation of habitats and exposure to pesticides. These factors, alone or in combination, can increase stress levels in individuals and may lead to developmental deficits (e.g. morphological malformation such as asymmetric wing development), physiological changes (e.g. changes in pheromone production) or increasing disease loads (e.g. viruses). Such declines in pollinator health can reduce survival of pollinator individuals, but also affect foraging behavior, activities and preferences and ultimately pollination services. Thus, we need to understand the links between land use intensification, pollinator health and pollination services to potentially mediate negative effects, such as declining pollinator populations, and maintain pollination services in agricultural landscapes. Within our study, we will combine field measurements of pollinator health and pollination services in agricultural landscapes with common-garden experiments to understand how changes in land management and different stressors such as narrow diet, insecticides or pathogens can directly influence health factors and ecosystem functioning, i.e. pollination services. Using Bombus lapidarius and Episyrphus balteatus - representating bees and syrphids as two important pollinator groups - as focal species, we will collect quantitative data on wing asymmetry, cuticular lipids with a pheromone function, fat body size and viral loads as indicators for pollinator health and changes in pollinator behavior such as flight distances, pollen collection or flower constancy and pollen carrying as indicators for pollination services and combine these data with measurements of land use intensity: land use index (LUI), plant diversity, pesticide use and composition of the surrounding landscapes of the 150 grassland plots in the Biodiversity Exploratories. Moreover, we will experimentally simulate different land use intensities by altering food source availability and insecticide exposure and explore the same relationships to disentangle the contribution of both drivers of declining pollinator health. We will thus answer whether declining pollinator health caused by land use regimes results in declining pollinator services and what factors may be the leading driver, providing important information for improving management practice to increase pollinator health and maintain pollination services in agricultural landscapes.

• DFG Programme: Infrastructure Priority Programmes
• Subproject of: SPP 1374: Biodiversity Exploratories
• Ehemaliger Antragsteller: Dr. Jonas Kuppler, until 3/2022