![Sample our Environment & Sustainability journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5935/TOC-Subject-Sample-2021-Environment-Sustainability.jpg"})
Résumé
Cette étude compare les pâturages sous et hors couvert ligneux d'une savane à Combretaceae de la zone soudano-sahélienne de Thyssé Kayemor (Sénégal). L'analyse des paramètres floristiques et de production de ces herbages permet de distinguer nettement les biotopes couverts de ceux découverts. Il existe donc un effet couvert, caractérisé par une plus importante richesse spécifique de la végétation pastorale, liée aux espèces exclusives. La production de matières sèches, bien que significativement plus élevée sous couvert, ne varie pas selon l'espèce ligneuse assurant l'ombrage. L'abondance relative des espèces apparaît toutefois plus faible sous les arbres que dans les milieux découverts.
Il presente studio mette a confronto la vegetazione erbacea con quella arborea a prevalenza di Combretaceae di una savana della zona sudano-saheliana del Thyssé Kayermar (Sénégal). L' analisi della componente floristica e della produzione erbacea permettono di discriminare nettamente le due coperture di vegetazione. Esiste un effetto-copertura caratterizzatoda ima maggiore ricchezza floristica specifica della vegetazione erbacea legata a specie esclusive.
Summary
The specific composition and the herbages production had been studied inside and outside the tree crown in sudano-sahelian zone of Thyssé Kayemor (Senegal). The woody vegetation, with isolated trees and clumbs of bushes (primarily Combretaceae) covers 6 741 m2 per hectare, that is to say 67.4%. The floristic data were treated with methods of multivariate analysis and they separate distinctly the relevés of shady biotop of them in open zone. Thus there is a tree crown effect, accompanied by characteristic floristic list for each biotop. Under the tree canopy, the specific richness and the herbage production are significantly more important but this herbaceous cover is less high than in open grassland.
Key words: