References of "Daïnou, Kasso"
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See detailIdentité et écologie des espèces forestières commerciales d'Afrique Centrale: le cas de Milicia spp.
Daïnou, Kasso ULg; Doucet, Jean-Louis ULg; Sinsin, Brice et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2012), 16

Le terme iroko regroupe les deux espèces du genre africain Milicia et désigne le bois qui en est dérivé. Malgré une importance économique reconnue depuis plus de deux siècles et une diminution sensible ... [more ▼]

Le terme iroko regroupe les deux espèces du genre africain Milicia et désigne le bois qui en est dérivé. Malgré une importance économique reconnue depuis plus de deux siècles et une diminution sensible des densités de population du fait de l'exploitation, les connaissances scientifiques utiles à la gestion durable de l'iroko font défaut, particulièrement en Afrique Centrale. L'existence même d'une spéciation au sein du genre Milicia mérite d'être revérifiée: les caractères utilisés pour séparer les deux taxons M. excelsa (Welw.) C.C. Berg et M. regia (A. Chev.) C.C. Berg sont peu consistants et une révision de ces traits distinctifs permettrait de réétudier le niveau de vulnérabilité des populations de Milicia spp., et donc de revoir les stratégies de gestion de ce groupe taxonomique. M. regia n'a fait l'objet que de rares études écologiques tandis que M. excelsa, plus largement distribuée, a retenu l'attention scientifique en Afrique de l'Ouest, dans une certaine mesure. Dans tous les cas, les traits d'histoire de vie conditionnant la diversité génétique et le taux de régénération naturelle méritent d'être identifiés ou mieux décrits. En particulier, les connaissances existantes sur les populations reproductrices, les facteurs régulant la floraison, les patrons de fructification et de dispersion des diaspores, ainsi que d'autres caractères qui amènent à décrire l'iroko comme un arbre pionnier (besoins en lumière, dormance des graines) devraient être mieux documentés. Enfin, la dynamique même des populations naturelles de juvéniles devra également être mieux caractérisée. En l'absence de données fines en écologie, la durabilité de nombreuses ressources ligneuses commerciales est tributaire d'actions sylvicoles, lesquelles peuvent être coûteuses et ne pas être garanties sur le long terme. [less ▲]

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See detailSylviculture in logging gaps of a Central African rainforest : first synthesis from tests with 11 timber tree species
Daïnou, Kasso ULg; Cerisier, Benjamin; Bourland, Nils ULg et al

in CIRAD Montpellier (Ed.) IUFRO International Conference , Research Priorities in Tropical Silviculture : Towards New Paradigms ?: Abstracts (2011, November 15)

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See detailLe Noisetier d'Afrique (Coula edulis Baill.). Un produit forestier non ligneux méconnu
Moupela, Christian ULg; Vermeulen, Cédric ULg; Daïnou, Kasso ULg et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2011), 15(3), 485-495

Non-timber forest product (NTFP) are of significant nutritional, economic and cultural importance for the people of central Africa. However, many products have not yet been the subject of scientific ... [more ▼]

Non-timber forest product (NTFP) are of significant nutritional, economic and cultural importance for the people of central Africa. However, many products have not yet been the subject of scientific studies; such is the case of Coula edulis. Although very little is known about this species, it has many uses and its fruits are regulary eaten and marketed by various communities. Cultivation of this tree species remains however very limited, mainly because of the low germination potentiel of its seeds. Its wood, renowned for its termite resistance, is used locally for construction. Mechanical tests conducted on the timber have put its technological aptitudes to the fore; it has indeed the potential to become one of the most sought-after commercial species. As in the future, Coula edulis could be managed for its wood as well as its non-timber forest product, in-depth studies aiming at the sustainable development of this natural ressource need to be implemented. [less ▲]

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See detailSoil seed bank characteristics in Cameroonian rainforests and implications for post-logging recovery
Daïnou, Kasso ULg; Bauduin, Aline ULg; Bourland, Nils ULg et al

in Ecological Engineering (2011)

The soil seed bank is considered as an important component for resilience of climacic vegetation. No investigation has ever been conducted in Central African rainforests regarding this topic. We studied ... [more ▼]

The soil seed bank is considered as an important component for resilience of climacic vegetation. No investigation has ever been conducted in Central African rainforests regarding this topic. We studied the soil seed bank characteristics in relation to the standing vegetation in three Cameroonian forest zones with different disturbance regimes. There was no significant difference between sites in terms of density of the seed bank. But dissimilarities of the floristic compositions between sites were high. Overall, seeds came from 43 species including three commercial tree species. Whereas the seedlings emerging from soil samples mostly came from weedy and short-lived pioneer species, climax species predominated in the extant vegetation, leading to a very weak similarity between soil seed flora and the surrounding vegetation. Canopy openness could significantly affect the species richness of soil seed stocks but not the seed density. These results show that the soil seed bank contribution to the resilience of mature tropical forests is low. In particular, very few timber tree species could benefit from soil seed stocks for their regeneration. Therefore, the development of enrichment techniques including use of the soil seed bank as a source of tree regeneration in such a context would be irrelevant. [less ▲]

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See detailDéforestation: des niveaux très variables d'un continent à l'autre
Daïnou, Kasso ULg

Conference (2010, June 02)

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See detailCan Pleistocene refuge theory explain within-species patterns of genetic diversity in African lowland rainforest trees?
Heuertz, Myriam; Savolainen, Vincent; Budde, Katharina et al

Poster (2010)

Pleistocene refuge theory holds that regions which nowadays harbour high numbers of endemic species correspond to forest refuges, where rainforest persisted through periods of adverse climatic conditions ... [more ▼]

Pleistocene refuge theory holds that regions which nowadays harbour high numbers of endemic species correspond to forest refuges, where rainforest persisted through periods of adverse climatic conditions. In order to test this theory, we surveyed geographical patterns of genetic diversity based on chloroplast DNA sequences in 15 rainforest tree species from 12 plant families in Atlantic Equatorial Africa. We found frequent geographic structure in the data sets, but no consistent pattern of genetic structure due to refugia. Species with gravity-dispersed oily seeds display low polymorphism whilst those with divergent lineages or ancient species display high polymorphism. Phylogeographical signals often correspond to taxa with divergent lineages. [less ▲]

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See detailForest refugia revisited: nSSRs and cpDNA sequences support historical isolation in a wide-spread African tree with high colonization capacity, Milicia excelsa (Moraceae)
Daïnou, Kasso ULg; Bizoux, Jean-Philippe ULg; Doucet, Jean-Louis ULg et al

in Molecular Ecology (2010)

The impact of the Pleistocene climate oscillations on the structure of biodiversity in tropical regions remains poorly understood. In this study, the forest refuge theory is examined at the molecular ... [more ▼]

The impact of the Pleistocene climate oscillations on the structure of biodiversity in tropical regions remains poorly understood. In this study, the forest refuge theory is examined at the molecular level in Milicia excelsa, a dioecious tree with a continuous range throughout tropical Africa. Eight nuclear microsatellites (nuSSRs) and two sequences and one microsatellite from chloroplast DNA (cpDNA) showed a deep divide between samples from Benin and those from Lower Guinea. This suggests both that these populations were isolated in separate geographical regions, probably for several glacial cycles of the Pleistocene, and a poor mixture of gene pools despite M. excelsa’s wind-pollination syndrome. The divide can also be related to seed dispersal patterns, which should be largely determined by the migration behaviour of M. excelsa's main seed disperser, the frugivorous bat Eidolon helvum. Within Lower Guinea, a north-south divide, observed with both markers despite weak genetic structure (nuSSRs: FST=0.035, cpDNA: GST=0.506), suggested the existence of separate Pleistocene refugia in Cameroon and the Gabon/Congo region. We inferred a pollen-to-seed dispersal distance ratio of 1.76, consistent with wide-ranging gene dispersal by both wind and bats. Simulations in an Approximate Bayesian Computation framework suggested low nuSSR and cpDNA mutation rates but imprecise estimates of other demographic parameters, probably due to a substantial gene flow between the Lower Guinean gene pools. The decline of genetic diversity detected in some Gabonese populations could be a consequence of the relatively recent establishment of a closed canopy forest which may negatively affect M. excelsa's reproductive system. [less ▲]

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See detailSpatial genetic structure in Milicia excelsa (Moraceae) indicates extensive gene dispersal in a low-density wind-pollinated tropical tree
Bizoux, Jean-Philippe ULg; Daïnou, Kasso ULg; Bourland, Nils ULg et al

in Molecular Ecology (2009), 18

In this study, we analysed spatial genetic structure (SGS) patterns and estimated dispersal distances in Milicia excelsa (Welw.) C.C. Berg (Moraceae), a threatened windpollinated dioecious African tree ... [more ▼]

In this study, we analysed spatial genetic structure (SGS) patterns and estimated dispersal distances in Milicia excelsa (Welw.) C.C. Berg (Moraceae), a threatened windpollinated dioecious African tree, with typically low density ( 10 adults ⁄km2). Eight microsatellite markers were used to type 287 individuals in four Cameroonian populations characterized by different habitats and tree densities. Differentiation among populations was very low. Two populations in more open habitat did not display any correlation between genetic relatedness and spatial distance between individuals, whereas significant SGS was detected in two populations situated under continuous forest cover. SGS was weak with a maximum Sp-statistic of 0.006, a value in the lower quartile of SGS estimates for trees in the literature. Using a stepwise approach with Bayesian clustering methods, we demonstrated that SGS resulted from isolation by distance and not colonization by different gene pools. Indirect estimates of gene dispersal distances ranged from rg = 1 to 7.1 km, one order of magnitude higher than most estimates found in the literature for tropical tree species. This result can largely be explained by life-history traits of the species. Milicia excelsa exhibits a potentially wideranging wind-mediated pollen dispersal mechanism as well as very efficient seed dispersal mediated by large frugivorous bats. Estimations of gene flow suggested no major risk of inbreeding because of reduction in population density by exploitation. Different strategy of seed collection may be required for reforestation programmes among populations with different extent of SGS. [less ▲]

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See detailConsommation de bois dans les zones humides du complexe ouest du Bénin: besoins et gestion locale des formations ligneuses
Daïnou, Kasso ULg; Vermeulen, Cédric ULg; Doucet, Jean-Louis ULg

in Bois et Forêts des Tropiques (2008), (298), 13-24

L’étude propose une estimation de la consommation de bois dans les villages du complexe ouest des zones humides du Sud-Bénin. Les enquêtes ont été réalisées dans dix villages. Les résultats montrent ... [more ▼]

L’étude propose une estimation de la consommation de bois dans les villages du complexe ouest des zones humides du Sud-Bénin. Les enquêtes ont été réalisées dans dix villages. Les résultats montrent l’existence de deux zones distinctes du point de vue de l’intensité de la consommation de bois et des espèces utilisées. Dans la zone 1 composée des villages bordant la mangrove, Cocos nucifera, quoique peu appréciée, est l’espèce la plus consommée des dix-huit ligneux utilisés comme combustible. Soixante-douze espèces de bois d’énergie sont recensées dans la zone 2 regroupant les villages de terre ferme. Azadirachta indica y est l’espèce la plus consommée et appréciée. Les indices de consommation moyens de ces deux zones sont respectivement de 0,88 kg/j/p et de 1,26 kg/j/p. En matière de construction, les espèces précédemment citées sont une nouvelle fois majoritairement utilisées : C. nucifera et Rhizophora racemosa dans la zone de mangrove, A. indica en milieu de terre ferme. En moyenne, une personne dispose d’une surface bâtie de 8,84 m2 nécessitant environ 117 dm3 de bois. Pour le bois d’œuvre, le complexe dépend presque entièrement de l’extérieur. Tenant compte de la population du complexe et de ses besoins, de l’état et de la productivité de ses formations boisées, l’étude prévoit une situation de dégradation sérieuse de la végétation en zone 2. Des mesures de sensibilisation et de reboisement urgentes sont préconisées pour réduire la dépendance de cette région vis-à-vis des autres contrées du pays. [less ▲]

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See detailFitness And Genetic Variation Of Viola Calaminaria, An Endemic Metallophyte: Implications Of Population Structure And History
Bizoux, Jean-Philippe ULg; Daïnou, Kasso ULg; Raspe, O. et al

in Plant Biology (2008), 10(6), 684-693

We investigated variations in genetic diversity and plant fitness in a rare endemic metallophyte of calamine soils, Viola calaminaria, in relation to population size, population connectivity and ... [more ▼]

We investigated variations in genetic diversity and plant fitness in a rare endemic metallophyte of calamine soils, Viola calaminaria, in relation to population size, population connectivity and population history in order to evaluate and discuss potential conservation strategies for the species. Mean population genetic diversity (Hs = 0.25) of V. calaminaria was similar to endemic non-metallophyte taxa. Twenty-one per cent of the genetic variation was partitioned among populations and a low (9%) but significant differentiation was found among geographical regions. Our results did not support the hypothesis that the acquisition of metal tolerance may result in reduced genetic diversity, and suggested that strict metallophytes do not exhibit higher inter-population differentiation resulting from scattered habitats. There were no relationships between population genetic diversity and population size. Significant correlations were found between plant fitness and (i) population size and (ii) connectivity index. Recently-founded populations exhibited the same level of genetic diversity as ancient populations and also possessed higher plant fitness. There was no indication of strong founder effects in recently-established populations. The results suggest that the creation of habitats through human activities could provide new opportunities for conservation of this species. [less ▲]

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See detailEnrichissement des trouées d’abattage à la société Pallisco.
Bourland, Nils ULg; Daïnou, Kasso ULg; Kouadio, Y. L.

Conference given outside the academic context (2007)

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See detailModule de formation - Dynamique des peuplements forestiers d’Afrique Centrale
Doucet, Jean-Louis ULg; Dissaki, A.; Mengome, A. et al

Learning material (2007)

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See detailLa régénération des espèces forestières vulnérables à l'Est du Cameroun : cas de Milicia excelsa
Daïnou, Kasso ULg; Doucet, Jean-Louis ULg; Mahy, Grégory ULg

Conference (2006)

Au Cameroun, le processus de la gestion durable des forêts a conduit une société d'exploitation forestière industrielle à procéder depuis quelques années, en partenariat avec des institutions de recherche ... [more ▼]

Au Cameroun, le processus de la gestion durable des forêts a conduit une société d'exploitation forestière industrielle à procéder depuis quelques années, en partenariat avec des institutions de recherche locales ou internationales, à des études scientifiques d'espèces identifiées comme vulnérable dans ses concessions. A ce titre, la détermination de techniques d'interventions sylvicoles pragmatiques ainsi que l'écologie d'espèces telles que l'iroko, Milicia excelsa sont étudiées afin de comprendre et de remédier au faible niveau de régénération naturelle. Les observations portent d'une part sur les performances de fructification (phénologie, pluie de graine, germination) et de dispersion des semences, et d'autre part, sur la dynamique de populations naturelles de juvéniles. Etant donné qu'une faible performance de régénération peut être due à la consanguinité, elle-même résultant de la raréfaction des populations, il est prévu également une analyse de la diversité génétique locale. Parallèlement, des essais de plantations permettent de juger des effets de différents facteurs abiotiques ou biotiques sur la dynamique des plantules. [less ▲]

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