BS 55 129 Composition and species richness of forest plants along the Albertine Rift, Africa AXEL DALBERG POULSEN, DAVID HAFASHIMANA, GERALD EILU, INNOCENT B. LIENGOLA, CORNEILLE E. N. EWANGO AND TERESE B. HART . POULSEN, A.D., HAFASHIMANA, D., EILU, G., LIENGOLA, I.B., EWANGO, C.E.N. & HART, T.B. 2005. Composition and species richness of forest plants along the Albertine Rift, Africa. Biol. Skr. 55: 129-143. ISSN 0366-3612. ISBN 87-7304-304-4. The Albertine Rift is composed of a system of mountains from Lake Albert to Lake Tanganyika and harbours a high proportion of endemic species. In this area, 16 1-ha plots of 20 m × 500 m were placed in semi-evergreen forests between 770 m to 1520 m; 12 in Uganda and four in Congo. In the Ugandan plots, soil samples were taken for analyses and ground herbs (divided into pteridophytes and angiosperms), trees, climbers and epiphytes were inventoried. From the Congolean plots only data for ground herbs and trees are included. Species richness of ground herbs and trees were correlated with altitude but do not conform to simple models on Pleis- tocene refugia and might also be explained by environmental factors of the present. Species com- position matrices calculated on the bases of presence-absence for each of the five plant groups were highly and significantly correlated and thus any of them can be used as a rough indicator of more general floristic patterns, which provides a tool for rapid assessment of species composition in other Albertine forests in the future. The floristic pattern of most plant groups were correlated with patterns in altitude, pH and cation concentrations (which were intercorrelated). Species composition has two components related to altitude: an Albertine submontane and a Congolean lowland. Axel Dalberg Poulsen, Botanical Museum, University of Copenhagen, Denmark. Present address: Royal Botanic Garden Edinburgh, 20A Inverleith Row, Edinburgh EH3 5LR, Scotland. E--mail: axel@dalberg- poulsen.com David Hafashimana, Ministry of Water, Lands and Environment, P.O.Box 7096, Kampala, Uganda. E-mail: davidhaf@hotmail.com or davidhaf2000@yahoo.com Gerald Eilu, Faculty of Forestry and Nature Conservation, Makerere University, P.O. Box 7062, Kampala, Uganda. E-mail: eilu@forest.mak.ac.ug Innocent B. Liengola, Wildlife Conservation Society/ Centre de Formation et de recherche en Conservation Forestiere, Ituri Forest, Democratic Republic of Congo. E-mail: iliengola2002@yahoo.fr Corneille E. N. Ewango, Wildlife Conservation Society/ Centre de Formation et de recherche en Conservation Forestiere, Ituri Forest, Democratic Republic of Congo. E-mail: corneille_ewango@yahoo.com Terese B. Hart, International Programs, NYZS/ The Wildlife Conservation Society, 185th St Southern Blvd, Bronx, NY 10460, U.S.A. E-mail: TereseHart@aol.com