DyNAflow: Colonisation dynamics of Arctic endemics across glacial landscapes

Warming in the Arctic is causing glacial retreat, which exposes deglaciated terrains to biotic colonisation. Ecological studies can provide insights into the local processes (microclimate, biotic interactions) driving the development of soil communities after glacier retreat. However, community dynamics are determined not only by local environmental conditions but also by regional dispersal processes. Nevertheless, there is almost no quantification of allogenic sources (i.e. colonisation from ice-free areas adjacent to the glacier foreland) compared to autogenic sources (i.e. within-foreland site-to-site colonisation) because community ecology data cannot differentiate between the two sources. High-throughput sequencing (HTS) technologies provide high-resolution genomic data to infer gene flow between populations at the landscape scale and the origins of populations. HTS paves the way for quantifying allogenic inputs of dispersing organisms, thus determining the multiple drivers (local and regional) of colonisation after glacier retreat. Furthermore, the project will provide the first characterization of the genomic diversity in Midtre Lovénbreen, a biological level of organisation often overlooked in Arctic and glacier systems. Population genomic diversity will be assessed for four key endemic species using ddRAD-seq, a cost-effective approach to perform genomic. For each species, the sampling will cover the foreland, adjacent, and regional pools, for a total of 24 sites. The foreland sites will be collected along three transects to obtain a representative sampling of local environmental variation and of potential barriers to gene flow. A total of nine sites will cover adjacent and regional areas. Tackling the genetic diversity of glacial biotic communities is needed to understand the full scope of colonization dynamics after glacier retreat and better predict the consequences of future climate changes on Arctic biodiversity.