Effects of glacier retreat on plant–soil relationships

Background and Aims An emblematic symptom of climate change is the retreat of glaciers worldwide. As glaciers retreat, new ice-free terrains allow the development of plant communities and soil. However, little is known about how plant–soil relationships change with glacier retreat over space-time. Methods We examined the direct and indirect relationships between structure of plant communities (life-forms composition, richness, ecological indicators) and soil properties (pH, organic carbon, total nitrogen, C/N ratio, texture, available and major elements) along a 120-years glacier foreland chronosequence. Results Plant diversity increases with soil nitrogen content shortly after glacier retreat. In turn, soil stabilization and nutrient availability further increases plant diversity, reaching a maximum value around 60 years since glacier retreat. After 120 years, soil pH becomes very acidic as it acidifies at a rate of 0.02 units per, and plant communities shift from herbaceous to a coniferous forest. Such shift is accompanied by an increase in soil carbon and relative decrease in soil nutrients as C/N ratio increases by five folds. As a result, biodiversity decreases in our study area while organic matter accumulation and soil acidity become more pronounced. Conclusion Plants enrich soil nitrogen in pioneer stages while carbon accumulates in the soil and nutrients become scarcer in late stages. As climate is warming and glaciers are retreating at increasing rates, local plant–soil interactions should be the target of biodiversity conservation efforts and landscape management plans aimed at mitigating the impact of glacier retreat on biodiversity and soil functioning.