Fen mires with cushion plants in Bale Mountains, Ethiopia

In March 2013 we investigated two small peatlands in the Bale Mountains in central Ethiopia. The mires are located on the Sanetti Plateau at an altitude of approximately 4000 metres above mean sea level (a.m.s.l.). Their vegetation is dominated by tussocky Carex species and locally also by a cushion plant Eriocaulon schimperi, which occurs elsewhere in eastern Africa in montane areas at altitudes between 2000 and 4100 m a.m.s.l. We studied the vegetation and pore water at different depths. The pore water chemistry suggested that these mires were groundwater fed, but also received water as precipitation and calcium-poor runoff from adjacent hills. The cushion plants (Eriocaulon schimperi) on the Sanetti Plateau resemble Astelia pumila, a cushion plant that dominates large ‘blanket bog type’ mires in south-west Chile and the south-eastern part of Tierra del Fuego (Argentina). Both species appear to expand in slightly degrading fens or bogs under rather extreme environmental conditions. We also discuss possible evolutionary adaptations within the Eriocaulon family to the harsh environment of mountain mires at high altitudes