Seghieri Josiane, Simier Monique. (2002). Variations in phenology of a residual invasive shrub species in Sahelian fallow savannas South-West Niger. Journal of Tropical Ecology, 18, p. 897-912. ISSN 0266-4674.
Titre du document
Variations in phenology of a residual invasive shrub species in Sahelian fallow savannas South-West Niger
Journal of Tropical Ecology, 2002,
18, p. 897-912 ISSN 0266-4674
The aim of this work was to analyse the phenological variation of a residual invasive semi-evergreen shrub in Sahelian fallows in Niger. This species, Guiera senegalensis (Combretaccae), has benefited from the elimination of other species thanks to its high resistance to the increasing cutting pressure for cultivation. We sought to identify traits of its life cycle that could contribute to its persistence and widespread dominance under such a disturbance regime. Leafing, flowering and fruiting were monitored on seven fallows differing in topographic location, age, shrub density and degradation state, during two rainy seasons and one dry season. Phenological spectra showed similar timing of the three phenophases of the seven populations. Differences were observed mainly in magnitude of the phases. However, there were both a high intra-fallow variability (64.6% of the whole variability) and a statistically significant inter-fallow variability, despite only 35.4% of the total variability being due to differences between fallows. A statistical classification of the fallows was proposed based on shrub phenological course over the two cycles monitored. This classification corresponds to a gradient of life-cycle achievement primarily linked to the topographic situation of the stations, and then to a combination of other factors. The flexibility of the phenology at the individual, population and metapopulation scales, inherent to its specific semi-evergreenness property, appeared as an essential phenological attribute contributing to successful widespread persistence of G. senegalensis in the study area.
Plan de classement
Ecologie végétale [076BOTA05]
Descripteurs
SAVANE ; JACHERE ; ARBUSTE ; INVASION ; PHENOLOGIE ; VARIABILITE ; TOPOGRAPHIE ; DENSITE DE POPULATION ; STRATE LIGNEUSE ; DEGRADATION ; FACTEUR ANTHROPIQUE ; SECHERESSE ; RESSOURCES EN EAU ; PRECIPITATION ; ANALYSE EN COMPOSANTES PRINCIPALES ; SEMI PERSISTANT ; PLANTE RUDERALE
