Species composition of a middle altitude forest in Moukalaba-Doudou National Park, Gabon

Abstract

Although the Congo River Basin contains the second largest tropical rainforest in the world, tropical Africa has fewer tree census plots than tropical Asia or America. Thus, more data are needed to describe species richness and diversity. We conducted a tree census to reveal the species richness and composition of a middle-altitude forest in Moukalaba-Doudou National Park, Gabon. We set a 150×150-m plot (2°3.2’S, 10°25.0’E) at an altitude of 220m. All trees >10cm in diameter at breast height (DBH) were marked, and the DBH of each was measured. We recorded 988trees, 692 (70.0%) of which were fully identified to 63species. Among the rest, 267trees (27.0%) were classified into 27genera, and 22trees (2.23%) were classified into 10 families. The 6most common species accounted for 50.6% (500trees) of the total number of trees: Dichostemma glaucescens (Euphorbiaceae), Diospyros sp. 1 (Ebenaceae), Strombosia pustulata (Olacaceae), Synsepalum longecuneatum (Sapotaceae), Staudtia kamerunensis var. gabonensis (Myristicaceae) and Pausinystalia macroceras (Rubiaceae). The remaining 86species had <10trees per ha, and 42species of these had <1tree per ha on average. These low-density species reflect a high-diversity forest.