Vegetation Response to Temperature Change on the Rwenzori Slopes, Western Uganda: Preliminary Results from Pollen Analysis

Abstract

Several climatic periods, cooler than today, were evidenced on the Rwenzori Mountains, by the accumulation of moraines deposited by glaciers that advanced to lower altitudes on the mountain slopes. This paper provides evidence from pollen analysis that between ca. 9300 and ca. 6400 yr. B.P., Hagenia abyssinica and Ericaceae, trees typical of the junction bamboo-zone-ericaceous belt (altitude 3000 m), were distributed in significant abundance in the vegetation surrounding bog 2 (altitude 2500 m). This lowering of vegetation belts suggests climatic conditions cooler than today by about 3 ⁰C. The co-existence of ericaceous vegetation and montane forest evidenced from ca. 9300 to ca. 6400 yr. B.P. is in agreement with the Omurubaho glaciation reported to have occurred on the Rwenzori from ca. 10 000 to ca. 5000 yr. B.P.

Keywords: Rwenzori, Moraines, Lapse rate, Omurubaho glaciation