We study the transition to sustainable ecology-based agriculture by using mixed-cropping systems that combine multiple crop species on a single field. Our team elucidates the ecological processes that make mixed cropping systems sustainably productive and we identify which socio-economic and societal or institutional factor need to be resolved to overcome the lock-in in current conventional farming systems. To allow a broad spectrum of farmers, consumers and stakeholders to reach transition goals, we embrace variation in transition paths. We explicitly compare how existing international value chains require adjustments as well as how new short and local value chains can emerge.

Tundra ecosystems are changing rapidly. The Arctic greening trend of the past decades is generally associated with climate warming-induced shrub expansion, but has recently halted for reasons yet unknown. This proposal addresses shrub decline due to abrupt permafrost thaw (thermokarst), which forms a potential explanation for this trend break. At our long-term research site in Siberian lowland tundra we observe both local shrub expansion and shrub drowning due to local permafrost collapse. In poorly drained lowland tundra such shrub decline due to thermokarst could be a likely alternative for the widely assumed shrub expansion. Moreover, we hypothesize abrupt permafrost thaw to be triggered by extreme wet summers. We propose a combination of landscape and local-scale monitoring with experimentation to assess the dynamics and drivers of shrub decline. We will use a time-series of high-resolution satellite images to assess the balance between shrub decline and shrub expansion at the landscape scale. In field studies we will 1) explore whether the recent thaw pond expansion can be traced back to climatic events using dendrochronology on drowned shrubs and 2) experimentally test if we can trigger permafrost collapse in a novel precipitation experiment. A better understanding of what determines shrub expansion and shrub decline is important as the vegetation shifts and permafrost degradation have important consequences for the climate and greenhouse gas balance. We expect that the proposed research on the drivers of shrub decline and expansion in an understudied Arctic region will generate a novel perspective on Arctic landscape changes.

Although intensive agricultural practices continue to put bumblebee populations under pressure, some common and important crop-pollinating bumblebee species seem to be able to persist even in the most intensive agricultural landscapes. Earlier work suggests that this may be because these populations are annually supplemented by mass-migrating bumblebee queens from far-away locations, which would make current agricultural landscapes hidden population sinks. This research combines intensive field monitoring with novel molecular and isotope methods to unravel the role of mass-migration on bumblebee population dynamics in agricultural landscapes, which can improve effective pollinator conservation and food production.

Accelerated sea-level rise (SLR) seriously threatens coastal areas globally. Sand nourishments – the addition of sand to increase the beach volume – are potentially a key method to sustainably adapt to accelerated SLR and keep the low-lying hinterland protected against coastal flooding. The SOURCE project will deliver the scientific knowledge, models and design tools to develop and evaluate nourishment strategies in a multi-stakeholder co-creation process. These carefully planned sand nourishments will create the required and desired resilient and dynamic multifunctional coastal landscapes of the future.

Many people are concerned about the decline of biodiversity in general and pollinators in particular. Consequently, many initiatives are taken to enhance pollinators. However, we do not yet really know what the most powerful underlying values are that motivate people to conserve pollinators. In this project we examined which values appeal most to people with respect to pollinator conservation, how this differs between countries and whether this differs between farmers and the general pubIic. Additionally this project examined whether the results of butterfly monitoring by citizen scientists can be indicative for other pollinators groups, notably wild bees and hoverflies.