Inter-population variability in seed germination, reproductive ecology and genetic structure of a rare chasmophyte (Campanula raineri, Campanulaceae): insights for conservation purposes

Campanula raineri Perp. is a stenoendemic chasmophyte of the Italian Prealps. A multidisciplinary approach combining seed germination tests and other reproductive ecology traits (e.g. pollen quality, the trade-off between sexual and vegetative reproduction) across populations, population genomics and past-to-future Species Distribution Models (SDMs) will highlight potential threats for this species and support conservation strategies involving plant material produced from seed. Scattered populations at different elevations across the entire distributional range of C. raineri provide data and material (e.g. seeds for in vitro germination tests and pollen for quality assessment) for the analyses. Population structure is currently being defined using a 2b-RAD genotyping approach followed by bioinformatics analyses of SNPs. SDMs are being elaborated to combine presence/absence data with ecological information (bioclimatic variables, elevation and substrate). Seed germination rate and pollen viability exhibited strong positive relationships with elevation, while flower production decreased slightly. Initial results regarding population structure suggest extensive outbreeding across populations and scarce nucleotide diversity within populations. This genetic uniformity hinders the species ability to cope environmental changes, making it particularly threatened. Preliminary models combining only species occurrence localities and bioclimatic variables correctly predict the current distribution area of C. raineri, and are being integrated with elevation and substrate information and extended in time to describe past and future potential distributions. Preliminary genomics results suggest the need of conservation actions for C. raineri. Projections of future species distribution will identify populations at most risk of climate change, and suitable areas for survival and colonization. In vitro production of plants can easily provide material for population reinforcements or reintroductions, even transferring material between populations - suggested by the high gene flow naturally occurring between populations - taking into account that high-altitude populations produce less but higher-quality flowers.