期刊名称：Science et changements planétaires / Sécheresse
印刷版ISSN：1147-7806
电子版ISSN：1777-5922
出版年度：2000
卷号：10
期号：4
页码：253-261
出版社：John Libbey Eurotext
摘要：Authors Léonard-Élie Akpo , Michel Grouzis , Fidèle Bada , Roger Pontanier , Christian Floret UCAD/FST, Biologie végétale, BP 5005, Dakar, Sénégal, Mission IRD (ex-ORSTOM), BP 134, Tananarive 101, Madagascar, UNB/FS, Biologie végétale, Campus Abomey-Calavi, Bénin, IRD, BP 1386, Dakar, Sénégal. Page(s) : 253-61 Published in: 2000 The specific composition of the herbaceous layer was studied within and outside of the fallow tree cover in Casamance, a subhumid Sudano-Guinean savanna region in Southern Senegal. These fallow plots were arranged in n classes of different ages, i.e. J1, J3, J5, J10 and J17, respectively corresponding to 1, 3, 5, 10 and 17 years after cultivation was abandoned. The floristic data were processed by multivariate analysis methods (CoA, diversity indexes). CoA made a clear distinction between survey data obtained in shady biotopes and those from open areas and the extent of discrimination index varied with the age of the fallows. There was therefore a tree effect on the herbaceous layer. A characteristic flora list was drawn up for each different biotope. The species richness and diversity indexes were substantially higher under the canopy, indicating that the environmental conditions were better than in open areas. The fallow herbaceous vegetation layer evolved in two directions according to the sciophyllous and heliophilic communities.
