Tropicultura (Jan 2013)
Structure spatiale des trois espèces les plus abondantes dans la Réserve Forestière de la Yoko, Ubundu, République Démocratique du Congo
Abstract
Spatial Pattern of the Three Most Abundant Species in the Yoko Forest Reserve, Ubundu, Democratic Republic of the Congo. The spatial pattern of species is one of the key parameters studied in ecology for the understanding of the ecological processes and functioning of forest ecosystems. This study analyzes the spatial pattern of three plant species at a local scale: Gilbertiodendron dewevrei (De Wild) J. Léonard, Scorodophloeus zenkeri Harms and Uapaca guineensis Müll. Arg., for which a forest inventory in the Yoko Forest Reserve in the Democratic Republic of the Congo showed that they were characterized by a high abundance. The methods of Clark and Evans and of Hines and Hines, based on the distances between nearest neighbors, were used. The analysis was carried out in two plots of different sizes: 6.25 and 25 ha. The method of Clark and Evans showed a random distribution for the 6.25 ha plot and an aggregated distribution at 25 ha, and this for all three species. The T-Square Sampling Procedure associated with the statistical test of Hines and Hines revealed an aggregated distribution for the two plot sizes and for all three species. It appears from this study that the aggregated distribution is the main spatial pattern observed for the most abundant species of the Yoko Forest Reserve. Environmental conditions combined with the seed dispersal mode characterized by weak distances could explain this aggregated distribution. The method of Clark and Evans proved to be sensitive to the effect of the extent of the plot. Indeed, the random distribution observed for a 6.25 ha plot has changed to an aggregated distribution after the extent was increased to 25 ha. Because less sensible to the plot size, the T-Square Sampling Procedure appears more suitable for spatial pattern analysis of species in this forest.
