Variations in phenology of a residual invasive shrub species in Sahelian fallow savannas, south-west Niger
| Autor: | Monique Simier, Josiane Seghieri |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
INVASION
Population ved/biology.organism_classification_rank.species Metapopulation Biology SAVANE RESSOURCES EN EAU Shrub FACTEUR ANTHROPIQUE Invasive species PHENOLOGIE Dry season Dominance (ecology) STRATE LIGNEUSE education Ecology Evolution Behavior and Systematics education.field_of_study SECHERESSE Phenology ved/biology Ecology VARIABILITE ANALYSE EN COMPOSANTES PRINCIPALES ARBUSTE DEGRADATION SEMI PERSISTANT TOPOGRAPHIE biology.organism_classification Guiera senegalensis JACHERE DENSITE DE POPULATION PRECIPITATION PLANTE RUDERALE |
| Zdroj: | Journal of Tropical Ecology. 18:897-912 |
| ISSN: | 1469-7831 0266-4674 |
| Popis: | 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 (Combretaceae), 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. |
| Databáze: | OpenAIRE |
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