MetaComNet: Linking metacommunity dynamics to the structure of ecological networks and ecosystem functioning

Safeguarding biodiversity and ecosystem functioning is one of the greatest challenges of our time. Ecosystem functions often depend on complex interactions between species. Pollination is a classic example of such ecosystem functions, and often entirely or at least partially depends on interactions between plants and pollinator. Securing the pollination of wild plants therefore requires knowledge about which species interact, where they occur, and how environmental change affect their distributions. A challenge is that pollinators can have fragmented populations and not occur in all suitable habitats. The reproduction of plants can therefore be limited by a lack of pollinators, if growing where environmental conditions are unsuitable for pollinators, and if distances to the nearest population of pollinators are beyond the foraging ranges of the pollinators. Tools that identify areas with intact plant-pollinator interactions and predict how environmental change affect these interactions and the degree of pollen limitation in plant populations have the potential to become an important asset towards biodiversity conservation. MetaComNet aims to develop statistical models for producing spatial predictions of the robustness of bee plant interactions and ultimately predict how pollen limitation varies along gradients of land use intensification and habitat isolation. We have developed a methodological framework that uses information about the composition of landscapes, together with other environmental factors, in order to predict and map the number of flower-visiting bee species that different plant species attract. Models like ours require georeferenced data or maps on landscape elements (e.g. grassland, fields, and forests) with a high enough spatial resolution to be ecologically meaningful. Ideally such maps should be semi-automatically updatable so that the composition of landscapes, and the frequency of flower-visitor richness, can be tracked over time. We have therefore produced a satellite-based land cover map with a 10m resolution that covers all of Europe. Because it is satellite-based, the map can be updated as new satellite-images become available. In addition to information about environmental conditions, our models rely on data on which bee species visit different flowers in different landscapes. During the summer of 2020 we have therefore conducted an extensive amount of fieldwork and collected data on bee-flower-interactions along 41 road sides in Norway and 30 comparable habitats in Denmark. We will make use of these data when implementing our modelling-framework to predict flower-visitor richness across Norwegian and Danish landscapes. We have also collected wilted flowers from the 41 Norwegian sites and will use these samples to estimate the degree of pollen-limitation that plant species experience in different environments and to test if our prediction maps can explain parts of the geographic variation in pollen limitation. Prior to using the data collected on the project, we have made use of existing data to verify that our MetaComNet-framework does indeed allow modelling and predicting bee-flower interactions in Norway, Denmark, and northern Germany. Our aim for 2023 is to use the MetaComNet data to produce maps showing the expected bee-flower interaction frequency and to test if variation in the degree of pollination in wild plants between plant populations can be explained by our models of pollination potential. MetaComNet is led by the Norwegian Institute for Nature Research (NINA) by draws upon expertise from our partners at: University of Oslo, Norwegian Institute of Bioeconomy Research (NIBIO), Western Norway Universityof Applied Sciences, and Aarhus University (Denmark). Throughout the project we will maintain a close dialog with partners at the Norwegian Public Roads Administration and the Norwegian Environment Agency to ensure the projects relevance to stakeholders.

One of the greatest challenges of our time is to safeguard biodiversity and associated ecosystem functions. Fundamental ecosystem functions such as pollination are the product of mutualistic interactions between organisms. Our understanding of how these species interactions are influenced by environmental change is hampered by the lack of models for simultaneously predicting effects on the distribution of species, interspecific interactions, and associated ecosystem functions. Given the rate of environmental change, there is an urgent need for modelling frameworks that can quantify the influence of community assembly processes on the structure of interaction networks. The aim of MetaComNet is to develop a modelling framework that predicts the structure of interaction networks and the sustenance of associated ecosystem functions, based on community assembly processes (dispersal, trait-based ecological filtering and neutral processes). To achieve this goal, we will use a combination of simulated data, data from digital repositories, and data from our own ecological surveys. We will use ecological networks consisting of floral visitations by wild bees as a model system because bee-plant interactions can lead to pollination. We will conduct pollen limitation experiments to test if the predicted structure of bee-plant networks corresponds to the actual pollen limitation within plant communities. Considering the complexity of interaction networks and theirs linkages to ecosystem functioning, MetaComNet has a bold objective. The potential for achieving our goal is maximized through the careful selection of the experts constituting the research group, combined with a thoroughly thought through methodological approach. MetaComNet is therefore likely to make a substantial contribution to our understanding of how processes acting at different spatial scales influence species distributions, and interactions, and ultimately affect ecosystem functioning