The effects of glacier retreat on plant diversity and soil development

An emblematic symptom of climate change is the retreat of glaciers worldwide. As glaciers retreat, new ice-free terrain allows the development of plant communities and soil. However, little is known about the joint effects of glacier retreat on plant communities and soil properties and how plant–soil relationships change with glacier retreat. We examined how the structure of plant communities and soil properties covary after glacier retreat over a 140-year chronosequence on a glacier foreland. Plant diversity increases with soil nitrogen content shortly after glacier retreat. In turn, soil stabilization and nutrient availability further increases with plant diversity, reaching a maximum value around 60 years since glacier retreat. After 140 years, soil pH becomes very acidic as it acidifies at a rate of 0.02 units per year while plant communities shift from herbaceous to a coniferous forest. Such a shift is accompanied by an increase in soil carbon content and relative decrease in soil nutrients as C/N ratio increases by fivefold. As climate is warming and glaciers are retreating, plants are enriching soil with nitrogen in pioneer stages, whereas biodiversity decreases, soil acidifies, soil carbon accumulates, and nutrients become scarcer in the long-term.