The adaptive significance of a wide altitudinal range for montane species

Summary Species of plants on two mountains in East Africa have wide altitudinal ranges. For example 75% of the afroalpine species on Kilimanjaro have ranges in excess of 650 m. It is suggested that wide range is an adaptation of montane species to long-term climatic fluctuations. Comparison is made with van Steenis' idea of zones of temporary and permanent establishment. The possible role of fluctuating climate in producing the Elevation Effect for montane species is indicated.