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Biological and phytogeographical analysis of plant communities infested by Chromolaena odorata and Hyptis suaveolens in the Betecoucou region (Benin) Analyse biologique et phytogéographique des savanes colonisées par Chromolaena odorata et Hyptis suaveolens dans la région de Bétécoucou (Bénin)

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Abstract

The paper presents phytosociological analyses of savannah vegetation infested by Chromolaena odorata and Hyptis suaveolens in the Betecoucou region of the Guinea-Congolia/Sudania regional transition zone of Benin. Some 79 phytosociological plots were analysed according to the Braun-Blanquet method. A total of 199 species of vascular plants have been recorded belonging to 53 families. Hemicryptophytes (4.8%) and geophytes (3.9%) are less abundant in the colonised sites than in the non-colonised ones. The colonised sites are dominated by species that are therophytes (50.8%) or chamaephytes (39.9%). Species that are widely distributed (45.9%), mainly pantropical (26.7%) and paleotropical (18.3%) in distribution, are also more frequent in infested than in non-infested sites. On the contrary, African pluriregional elements, e.g. Sudano-Zambezian species (44.4%) and afrotropical species (16.6%) are more frequent in non-infested than in infested sites. Among the widely distributed species, those that are ruderal or nitrophilous are the most frequent. © 2009 National Botanic Garden of Belgium Permission for use must always be obtained from the National Botanic Garden of Belgium.

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