"Climate warming promotes intra-continental range shifts of plants, animals and microbes from lower to higher latitudes and altitudes. Plants may shift their ranges independent of their co-evolved aboveground and belowground biota, however little is known about how these communities re-assemble in the new range and how that process influences community dynamics and ecosystem functioning. Thus far, predictions on species occurrences have been based exclusively on how niche conditions shift to higher latitudes and altitudes. Here, I will make the next step towards predicting how terrestrial systems respond to climate warming by evaluating interactions between plants, aboveground and belowground multi-trophic communities in the original and new ranges. My overall aim is to determine how aboveground and belowground multi-trophic level communities become disjointed and concomitantly re-assembled during plant range shifts. I will determine consequences for community dynamics and ecosystem functioning in the new range. My overall hypothesis is that due to time-lags in range shifts between plants, and their aboveground and belowground biota, novel communities may develop in the new range that will alter functioning of ecosystems, their stability and resilience. I will study range shifting plant species and determine: 1) aboveground-belowground multi-trophic community composition, 2) specificity of soil-borne pathogens and root-feeding nematodes, arbuscular mycorrhizal fungi, and decomposer organisms, 3) bottom-up and top-down control of these biota by soil communities, and 4) dynamics, stability and resilience of original and novel communities and ecosystem functions under current and future climate conditions. My results will be the first to show how the disjunction and reassembly of aboveground-belowground communities influences plant performance, community dynamics and ecosystem functioning. This will develop a new perspective on climate warming-induced range shifts."