%0 Journal Article
%T Analyse de la distribution spatiale des Acanthaceae en Afrique Centrale et comparaison avec les th¨¦ories phytog¨¦ographiques de Robyns, White et Ndjele.
%A KJ Koffi
%A D Champluveir
%A D F Neuba
%A C De Canniere
%A T Dossahoua
%A J Lejoly
%A E Robbrecht
%A J Bogaert
%J Sciences & Nature
%D 2008
%I 
%X Cette ¨¦tude a pour but d\'analyser les mod¨¨les de distribution spatiale des Acanthaceae, r¨¦colt¨¦es en R¨¦publique D¨¦mocratique du Congo, au Rwanda et au Burundi et de comparer leur r¨¦partition spatiale avec les syst¨¨mes phytog¨¦ographiques qui couvrent cette zone. Elle porte sur 9181 ¨¦chantillons regroup¨¦s en 48 genres et 310 esp¨¨ces. Un syst¨¨me d\'information g¨¦ographique a ¨¦t¨¦ utilis¨¦ pour r¨¦aliser des cartes de distribution de chaque esp¨¨ce. La m¨¦thode multi vari¨¦e de classification, appuy¨¦e par deux indices de structure spatiale (¨¦quitabilit¨¦ et fragmentation) a permis de stratifier la zone d\'¨¦tude afin de permettre une comparaison visuelle avec les syst¨¨mes phytog¨¦ographiques d¨¦finis par Robyns, White et Ndjele. On note une large distribution spatiale pour certaines esp¨¨ces sur l\'ensemble du territoire, alors que d\'autres sont inf¨¦od¨¦es ¨¤ certains territoires phytog¨¦ographiques bien d¨¦termin¨¦s. Les savanes situ¨¦es au Sud de l\'¨¦quateur contiennent des sites plus riches en Acanthaceae que celles situ¨¦es au Nord. Les centres d\'end¨¦misme Guin¨¦o-Congolais, Zamb¨¦zien et Afromontagnard pourraient ¨ºtre les sources de migration des taxons. Les Acanthaceae suivent relativement bien le syst¨¨me phytog¨¦ographique de White et sont utilisables en tant que bioindicatrices afin de rapprocher la distribution spatiale des communaut¨¦s v¨¦g¨¦tales d¨¦crites par ce syst¨¨me. By means of 9181 samples representing 48 genus and 310 species, the spatial distribution models of the Acanthaceae family in Central Africa (Democratic Republic of Congo, Rwanda and Burundi) were analysed. Consequently, a comparison to existing phytogeographic systems for the study region was executed. Spatial distribution maps for each species were created using a geographic information system. Subdivision of the study area was realised using a multivariate classification analysis. Using two indices of spatial pattern (fragmentation, class size evenness), the classification result was compared to the phytogeographic zones defined by Robyns, White and Ndjele. While certain species showed a distribution throughout the study area, the presence of other species was found to be bound to one single phytogeographic territory in particular, or to a restricted number of them. The savannas situated in the southern part of the study area contained more Acanthaceae species than the zones situated north of the equator. The Guineo-Congolian, the Zambezian and the Afromontane centre of endemism are suggested to be the origins of taxon migration. Since it was observed that the spatial pattern of the Acanthaceae species corresponded up a certain extent to the phytogeographic system proposed by White, it can be concluded that the Acanthaceae could be used as bio-indicators to proxy the spatial distribution of plant communities as described by this system.
%U http://www.ajol.info/index.php/scinat/article/view/42156