Les indicateurs de la dynamique post-culturale de la végétation des jachères dans la partie savane de la réserve naturelle forestière de Kigwena (Burundi)

Abstract

The indicators of the post-cultural dynamics in fallow vegetation in the savannahs of the Kigwena natural forest reserve (Burundi) Background and aims-A synchronic study has been achieved in fallows distributed in three age classes (0-2 years, 3-5 years and more than five years) in the natural forest reserve of Kigwena (Burundi). The aim was to show that differences in the proportion of plant functional groups could be used as indicators in characterizing the post-cultivation succession stages. Methods-The retained functional groups concerned biological and phytogeographic types, leaf size and diaspores dispersion. Key results-The data analysis gave five floristic associations. The functional group analysis evidences that the young successional stages are often characterized by sclerochorous herbaceous (therophyts) with often anemochorous dispersion, while the aged stages are essentially dominated by sarcochorous phanerophyts with essentially autochorous dispersion. The proportion of species with large distribution decreases with the age of the fallow contrary to species with regional distribution. A progressive increase with the age of species number with large leaves and a reduction of species with small leaves has been observed. Conclusion-The follow-up of the temporal variability of biological traits of species permits to characterize stages of post-cultivation succession.

Variabilité des traits fonctionnels des espèces arborescentes dans la reconstitution de la végétation du Parc National d’Azagny (Côte d’Ivoire)

“…Aussi dans le cas des jachères, compte tenu du statut de protection du parc, les paysans dissimulaient leurs plantations de cultures pérennes dans le couvert forestier existant. Ainsi, des espèces de forêts anciennes sont présentes dans ces biotopes (Koffi et al, 2015 (Bangirinama et al, 2010). En outre, les espèces qui composent les familles des Rubiaceae, Moraceae, Malvaceae, Euphorbiaceae, Fabaceae, Annonaceae qui sont les plus importantes dans les différents biotopes étudiés, ont principalement des feuilles mésophylles, des microphylles et des macrophylles.…”

“…L'abondance des espèces anémochores après est due au fait que ces milieux ont été très ouverts autrefois et par conséquent soumis aux vents. Bangirinama et al (2010) ont souligné que ces espèces anémochores sont plus importantes durant les premiers stades de reconstitution. Dans les forêts anciennes, ce fait est imputable aux perturbations naturelles telles que les chablis qui conduisent à des ouvertures dans l'habitat.…”

Land Use and Plant Diversity of the Dahliafleur Reserve of Bingerville (South of Côte d’Ivoire)

“…The low representativeness of hemicryptophytes, geophytes and therophytes is not only the prerogative of the Dahliafleur Reserve. The low proportions of these biological types, mostly heliophilic species, can be explained by the dominance of phanerophytes which reduce their establishment (Bangirinama et al, 2010). The same observation was also made in evergreen forest by Devineau (1984).…”

Vegetation restoration after abandonment of human activities in soubre hydroelectric dam biodiversity Refugee zone (South-West Cote D'Ivoire)

“…(Kassi and Decocq, 2006) [17] . Indeed, anemochory is a main dissemination strategy for plants in open environments (Bangirinama et al, 2010) [6] . The habitats of the refuge area are open spaces, which justifies the presence of these species after the endozoochories.…”