Conference Agenda

Despite agricultural intensification increased global food production for several decades, the benefits of this approach have started to be challenged. For example, although larger amounts of cultivated land have been promoted to raise crop yields, the spatial pattern of land conversion and its effects on biodiversity and crop production have received little attention. Another fundamental, yet often overlooked factor relates to the stability of crop production, as food security will be achieved by high crop yields that are also stable over time. The benefits of agricultural intensification have come at a cost to biodiversity, which is responsible of the provision of important agricultural services, such as crop pollination. In this talk, I will discuss the role of biodiversity on the provision and stability of ecosystem services in agroecosystems. I will introduce the different forms to quantify stability and I will discuss how recent advances in stability theory are applied to agroecosystems and crop production. Using a model of crop yield dynamics, I will explore how changes in biodiversity affect crop pollination. This information is relevant to ensure food security in a world where human population is growing and agriculture is shifting towards more pollinator-dependent food production.

Pollinator declines are predicted to reduce the yield of nutritious crops and increase rates of micronutrient deficiency across the world. However, previous studies have only modelled these effects at a broad global level, making it challenging to predict effects on individuals and identify local solutions. Working in ten smallholder villages in rural Nepal, we use a network approach to quantify the links between insect pollinators, crops, and the nutrients consumed by 200 smallholder families throughout an entire year. We show that approximately 25% of consumed food items are pollinator dependent and substantial proportions of key dietary nutrients including folate and vitamin A are reliant on insect pollinators. The domesticated Asian honeybee (Apis cerana) and various wild pollinators including bumblebees, solitary bees and flies are essential for supporting the production of these nutrients but agricultural specialization is likely to reduce the resilience of pollination services. We identify management options for enhancing the resilience and provisioning of pollination services and predict the resulting benefits for human health and nutrition.

Insect declines have been documented increasingly, with intensive land use being the primary cause. In grasslands, mowing machinery has a strong negative impact on arthropod abundance and diversity. Mowing causes arthropod mortality but also induces consequences such as changes in microhabitats and increased predation. It is therefore important to disentangle the effects of mowing techniques on arthropods in real-world grasslands to improve management for biodiversity.

Using extended data from grasslands in Germany, we analyzed the influence of different mowing techniques on arthropods. We found strong negative effects of mowing on arthropods with the lowest abundances directly after moving. 100 days after mowing, arthropod abundances increased strongly, indicating a potential for recovery over time. Furthermore, different mowing machines caused different levels of damage, with the mulcher being the most detrimental.

Mowing itself has the strongest negative effect on arthropods, while our results show that changes in mowing techniques can also have positive effects. Therefore, to reduce the overall negative effects of mowing, we suggest not only the use of more arthropod-friendly machinery, but also management changes such as less mowing, partial mowing, and extensive grazing.

High biodiversity is thought to increase the resilience of ecosystem services under changing conditions. This is largely because diverse communities host more species that can contribute to ecosystem services (functional redundancy) and because species respond differently to disturbances in their environment (response diversity). As agricultural landscapes become increasingly disturbed, for example through climate change or intensified agricultural management, maintaining or even enhancing the resilience of ecosystem services in agriculture becomes more and more important. However, empirically assessing the resilience of ecosystem functions like biological pest control was formerly challenging as no solid framework existed to do so. However, a new framework linking feeding interactions, metabolic theory and climatic niches made it possible to assess the functional redundancy of predators important for biological pest control in Swedish cereal crops. We expand on this framework by collecting additional feeding interaction and climatic niche data from four countries across a North-South gradient in Europe as well as applying it to existing predator datasets from agricultural landscapes in Sweden. The aim of this work is to improve our understanding of how to best manage agricultural systems to support resilient biological pest control into the future.

Increased agrobiodiversity is expected to provide more resilient ecosystem functions and services in farmland. This is largely because in diverse communities there are more species that can contribute to the functions (functional redundancy), and because different species are likely to respond differently to environmental variation (response diversity). However, attempts to actually measure ecosystem resilience to disturbances, including those related to climate change and agricultural practices, are rare. Notably, to date, we almost entirely lack studies of how farm diversity and landscape complexity contribute to resilience of biological pest control. Here, we present results of an empirical assessment of how natural enemy communities and biological pest control resist and/or recover from disturbance under different agrobiodiversity conditions in cereal fields across Europe. We show that recovery of natural enemy communities and subsequent impacts on biological pest control depend on in-field management practices and may be modulated by surrounding landscape structures. These results are a step towards better understanding the drivers of biological pest control resilience in European agricultural landscapes in order to ensure resilient biodiversity and ecosystem functioning in future landscapes under global change.

Designing pesticide-free agricultural landscapes based on stable provision of ecosystem functions becomes of paramount importance for fostering sustainable crop production. Drawing upon the conceptual framework derived from the stability of plant productivity in natural systems, we formulate some working hypotheses to evaluate how to maximize the stability of ecosystem service provision and underlying ecological communities in heterogeneous agricultural landscapes. Specifically, in this draft, we explore the relationships between the variability of the landscape heterogeneity in terms of composition and configuration and the stability of (i) ecological communities, (ii) intermediate ecosystem service, such as pest control, and ultimately (iii) crop productivity. We also examine the empirical validation of these hypotheses and outline potential avenues for future research.