The Simen Mountains (Ethiopia): Comments on Plant Biodiversity, Endemism, Phytogeographical Affinities and Historical Aspects

• Published in: Systematics and Geography of Plants 2001-01, Vol.71 (2), p.975-991
• Main Authors: Puff, C., Nemomissa, Sileshi
• Format: Article
• Language: English
• Subjects: Afromontane forests; Fees; Flora; Flowering plants; Highlands; Lowlands; Mountains; Plants; Synonyms; Taxa; The Montane Floras of Africa / Les flores montagnardes d'Afrique
• ISSN: 1374-7886
• DOI: 10.2307/3668732

The Simen Mountains, a U.N. World Heritage Site in N Ethiopia (Gonder Administrative region), include extensive high plateau areas (roughly 3200 m to over 4000 m), steep escarpments and lower-lying parts (locally known as "Kolla" or "Simen lowlands"; below 3000 to below 2000 m) and are known for their high biodiversity. The "Simen lowlands", primarily harbouring afromontane vegetation, are richest in species, whereas the afroalpine belt -- although the most spectacular part of the mountains -- is the poorest. Erica forests of the escarpments and some of the plateaux areas are also rather species-poor. In general, species diversity decreases with increasing altitude. At present, approximately 550 taxa of angiosperms are recorded. The mountains, primarily known to biologists for their rare and endangered animals (including the endemic Walia Ibex, Capra walie), also harbour endemic plant species (at least 12; e.g. Rosularia semiensis: afroalpine, or Maytenus cortii: afromontane). In addition to these, more than 30 taxa occurring in the Simen are Ethiopian endemics (e.g. the spectacular afroalpine Lobelia rhynchopetalum, or the afromontane Polyscias farinosa). Interesting phytogeographical affinities to SW Arabia are noteworthy, e.g. Dianthus longiglumis or Chlorophytum tetraphyllum (only known from the Simen and Ethiopian mountains, respectively, and Yemen). Numerous taxa, both from the afromontane and -alpine zone, show a distribution stretching from the Simen southwards to the tropical E African mountains (e.g. Psychotria orophila, afromontane, or Trifolium cryptopodium, afroalpine), sometimes also with an extension to the W African mountains (e.g. Galium simense). Others (primarily taxa occurring in the afromontane zone of the Simen) show wide distribution ranges extending to S Africa (e.g. Halleria lucida, to the Drakensberg). Widely distributed Sudanian or Sudano-Zambezian species occurring in the "Simen lowlands" include Sterculia setigera and Stereospermum kunthianum, respectively. The Simen is a historic plant collecting locality, and -- according to our present state of knowledge -- type specimens of ca. 220 afromontane and -alpine taxa of flowering plants (out of ca. 550 recorded; i. e. 40%!) originate from the Mountains (primarily collections made by W.G. Schimper in the past century). In the past few decades, however, plant collecting was largely impossible (socio-political problems in the North of the country!), so that the botanical knowledge of