Tyndall Glacier on Mount Kenya has retreated notably in recent years due to warming atmosphere, i.e., climate change. It was evinced that the fronts of four pioneering plant species have migrated uphill following the retreating glacier. Specifically, the front of Senecio keniophytum, the first to appear in areas exposed by glacier disappearance, migrated a speed similar to that of the glacial retreat. In 2016 and 2017, a species of lichen appeared close to glacier terminus as the first pioneering plant species. A permanent plot that was adjacent to the glacier terminus in 1996 exhibited a drastic increase in Senecio keniophytum population and cover in 2011. Near the terminus of the recently disappeared glacier, the population and cover of vegetation increased notably; however, this increasing trend was slower after the passage of 10 years since the disappearance of the glacier. Helichrysum citrispinum, a plant species which was not previously reported near the glacier terminus, was first confirmed in 2009, and its increasing distribution might be a direct result of increasing temperature. With the passage of years after the disappearance of the glacier, gravels become weathered and soil particles become finer. As the humus of the pioneering species accumulates, nutrient rich soil develops. The development of soil is also affected by the number of years elapsed after the disappearance of glacier and by the degree of plant establishment that stabilizes the soil layer. In 2019, dry leaves were collected from three locations on each of the trunks of two individuals of the large woody rosette plants, Senecio keniodendron. Radiocarbon dating of dry leaves showed that the growth rate of two Senecio keniodendron plants were 3 cm/year and 4.5 cm/year, respectively. The age of Senecio keniodendron, which has a height of 5 m, is likely to be 100 years or more.
Mots clés : Retreating glaciers|Climate change|Plant succession|Pioneer plant species|Large woody rosette plants
A103196KM