Dramatic changes of glaciers and vegetation are taking place in the glacier-covered high mountains of East Africa. The Tyndall Glacier on Mt. Kenya, which retreated at
ca. 3 m yr
-1 from 1958 to 1997, retreated more at
ca. 10 m yr
-1 from 1997 to 2002. Pioneer species such as
Senecio keniophytum, Arabis alpina, mosses, lichen, and Agrostis trachyphylla have advanced over areas formerly covered by the glacier. The rate at which this vegetation was migrated up the former bed of the glacier (2.1-4.6 m yr
-1 from 1958 to 1997) is similar to the rate of glacial retreat (2.9 m yr
-1). In the interval from 1997 to 2002, when the glacier retreated at 9.8 m yr
-1, pioneer species advanced at a rapid rate of 6.4-12.2 m yr
-1. Larger woody plants such as
Senecio keniodendron and
Lobelia telekii, which showed no obvious advances before 1997, have advanced quickly since 1997. Rapid glacial retreat has been accompanied by rapid plant colonization. Pioneer species improve soil conditions and habitat for other plants. The distribution of large woody plants such as
Senecio keniodendron and
Lobelia telekii, which tend to grow in areas that were deglaciated 100 years previously, is not directly controlled by glacial retreat, but reflects different effects of debris flow and outwash, and spatial differences in the clast size of the sedimentary debris at the surface of any given area. For example,
Senecio keniodendron grows most abundantly in areas covered by large debris, such as moraines.
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