[ Phytodiversité et paramètres de structure de la forêt péri-urbaine de la Djoumouna (Brazzaville - Congo) ]
Volume 37, Issue 1, June 2018, Pages 90–110
Victor Kimpouni1, Jean de Dieu Nzila2, Charme Maïdet Massamba Makanda3, Yallo Mouhamed Salisou4, and Jean-Pierre Kampe5
1 École normale supérieure, Université Marien Ngouabi, BP 237 Brazzaville, Republic of the Congo
2 École normale supérieure, Université Marien Ngouabi, BP 237 Brazzaville, Republic of the Congo
3 École normale supérieure, Université Marien Ngouabi, BP 237 Brazzaville, Republic of the Congo
4 Institut national de recherche forestière (IRF), BP 177, Brazzaville, Republic of the Congo
5 Institut national de recherche forestière (IRF), BP 177, Brazzaville, Republic of the Congo
Original language: French
Copyright © 2018 ISSR Journals. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
The Djoumouna periurban forest, in Brazzaville, was studied according to three plots of one hectare each. With an original area of 8.5 ha in the 1990s, this forest has declined by 49%, following human activities, in twenty years. The floristic inventory revealed 898 trees of dbh ≥ 10 cm, either 299 ± 18.68 trees.ha-1 on average; Specific diversity reveals 106 species corresponding to 36 families, the most important of which, following IVF are: Fabaceae (78%); Rubiaceae (41.2%); Euphorbiaceae (35.2%). According to the IVI, the dominant species are: Pentaclethra eetveldeana (22%); Elaeis guineensis (15%); Pentaclethra macrophylla (14%); Plagiostyles africana (13.5%); Hymenocardia ulmoides (10.5%). The Shannon index averages is 3.44 ± 0.10 for maximum diversity average of 4.14 ± 0.03. The Pielou index average is 0.83 ± 0.02, no dominance is found within the phytocenoses. Data from biological indices coupled with floristics show that this ecosystem has a high specific diversity, against a low floristic richness. The diametric structure coupled with the skewness reveal a bad natural regeneration of the ligneous trees. The similarity coefficients of Jaccard (30-47%) and Sørensen (46-64%) show a difference floristic composition. This heterogeneity is the appearance of the area-species curve. The analysis of diaspores shows the importance of sarcochores (73% of species and 62% of individuals), hence zoochoria as the main mode of dissemination. This mesophilic and tropophilous forest is characterized by the Fabaceae of which Pentaclethra eetveldeana and Pentaclethra macrophylla are the markers.
Author Keywords: Congo, periurban forest ecosystem, floristic diversity, bio-ecological indices, structural parameters, phytogeography, dissemination.
Volume 37, Issue 1, June 2018, Pages 90–110
Victor Kimpouni1, Jean de Dieu Nzila2, Charme Maïdet Massamba Makanda3, Yallo Mouhamed Salisou4, and Jean-Pierre Kampe5
1 École normale supérieure, Université Marien Ngouabi, BP 237 Brazzaville, Republic of the Congo
2 École normale supérieure, Université Marien Ngouabi, BP 237 Brazzaville, Republic of the Congo
3 École normale supérieure, Université Marien Ngouabi, BP 237 Brazzaville, Republic of the Congo
4 Institut national de recherche forestière (IRF), BP 177, Brazzaville, Republic of the Congo
5 Institut national de recherche forestière (IRF), BP 177, Brazzaville, Republic of the Congo
Original language: French
Copyright © 2018 ISSR Journals. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
The Djoumouna periurban forest, in Brazzaville, was studied according to three plots of one hectare each. With an original area of 8.5 ha in the 1990s, this forest has declined by 49%, following human activities, in twenty years. The floristic inventory revealed 898 trees of dbh ≥ 10 cm, either 299 ± 18.68 trees.ha-1 on average; Specific diversity reveals 106 species corresponding to 36 families, the most important of which, following IVF are: Fabaceae (78%); Rubiaceae (41.2%); Euphorbiaceae (35.2%). According to the IVI, the dominant species are: Pentaclethra eetveldeana (22%); Elaeis guineensis (15%); Pentaclethra macrophylla (14%); Plagiostyles africana (13.5%); Hymenocardia ulmoides (10.5%). The Shannon index averages is 3.44 ± 0.10 for maximum diversity average of 4.14 ± 0.03. The Pielou index average is 0.83 ± 0.02, no dominance is found within the phytocenoses. Data from biological indices coupled with floristics show that this ecosystem has a high specific diversity, against a low floristic richness. The diametric structure coupled with the skewness reveal a bad natural regeneration of the ligneous trees. The similarity coefficients of Jaccard (30-47%) and Sørensen (46-64%) show a difference floristic composition. This heterogeneity is the appearance of the area-species curve. The analysis of diaspores shows the importance of sarcochores (73% of species and 62% of individuals), hence zoochoria as the main mode of dissemination. This mesophilic and tropophilous forest is characterized by the Fabaceae of which Pentaclethra eetveldeana and Pentaclethra macrophylla are the markers.
Author Keywords: Congo, periurban forest ecosystem, floristic diversity, bio-ecological indices, structural parameters, phytogeography, dissemination.
Abstract: (french)
La forêt périurbaine de la Djoumouna, à Brazzaville, est étudiée suivant trois relevés d’un hectare chacun. D'une superficie originelle de 8,5 ha dans les années 1990, cette forêt a régressé de 49%, suite aux activités anthropiques, en une vingtaine années. L'inventaire floristique a révélé 898 arbres de dbh ≥ 10 cm, soit 299 ± 18,68 arbres.ha-1 ; La diversité spécifique révèle 106 espèces correspondant à 36 familles dont les prépondérantes, suivant les FIV, sont : Fabaceae (78%) ; Rubiaceae (41,2%) ; Euphorbiaceae (35,2%). En fonction des IVI, les espèces dominantes sont : Pentaclethra eetveldeana (22%) ; Elaeis guineensis (15%) ; Pentaclethra macrophylla (14%) ; Plagiostyles africana (13,5%) ; Hymenocardia ulmoides (10,5%). L'indice de Shannon est en moyenne de 3,44 ± 0,10 pour une diversité maximale moyenne de 4,14 ± 0,03. L’équitabilité moyenne est de 0,83 ± 0,02. Les données des indices biologiques couplées aux floristiques montrent que cet écosystème présente une forte diversité spécifique, contre une faible richesse floristique, d’une part, et d’autre part, aucune dominance n’est relevée au sein des phytocénoses. La structure diamétrique couplée au skewness révèlent une mauvaise régénération naturelle des ligneux. Les coefficients de similarité de Jaccard (30-47%) et de Sørensen (46-64%) montrent une composition floristique différence. Cette hétérogénéité est traduit l’allure de la courbe aire-espèces. L'analyse des diaspores ressort l'importance des sarcochores (73% d’espèces et 62% d’individus), d'où la zoochorie comme principal mode de dissémination. Cette forêt mésophile et tropophile est caractérisée par les Fabaceae dont Pentaclethra eetveldeana et Pentaclethra macrophylla sont les marqueurs.
Author Keywords: Congo, écosystème forestier périurbain, diversité floristique, indices de diversité bioécologique, paramètres de structure, phytogéographie, dissémination.
How to Cite this Article
Victor Kimpouni, Jean de Dieu Nzila, Charme Maïdet Massamba Makanda, Yallo Mouhamed Salisou, and Jean-Pierre Kampe, “Phytodiversity and structural parameters of the Djoumouna peri-urban forest (Brazzaville - Congo),” International Journal of Innovation and Scientific Research, vol. 37, no. 1, pp. 90–110, June 2018.
