Diversidade, parâmetros estruturais e produtos florestais não madeireiros na reserva florestal de Bonepoupa (Douala, Camarões)

http://dx.doi.org/10.5902/1980509812363In order to come up with a sustainable use of forest ecosystems in Cameroon, its vegetal diversity has been inventoried; the plant potentials and the structural parameters were studied in the forest reserve of Bonepoupa. Ten non-continuous plots of 200 m² were done and the materialization of the lines was done with a topofil put at the centre of the field with ropes at 5 m each of the topofil. In addition, ninety people were interviewed in order to know the potential use of species in this region. Up to 172 individuals with Diameter at Breast Height (DBH) ≥ 5 cm divided into 27 species, 25 genera and 18 families were inventoried and the coefficient of abundance-dominance was determined. The diversity index of Shannon (H’) was H’1 = 4.17 ± 0.45 with H’1max = 4.75 and the evenness was R1 = 0.88. Taking into account herbaceous species, H’ determined by the coefficient of abundance-dominance was H’2 = 4.74 ± 0.56 with H’2max = 5.70 and the evenness  was  R2 = 0.83. The  total  basal  area  was 19.69 m2/ha and the density was 860 individuals/ha. These results indicate that herbaceous significantly modifies the value of the diversity index and that forest reserve of Bonepoupa is experiencing a problem of conservation which is due to a lack of its appropriate management. The knowledge of non-timber forest products and their use as food as well as medicinal resources by local population might be helpful for the sustainable management of resources in this forest reserve.http://dx.doi.org/10.5902/1980509812363A fim de chegar a uma utilização sustentável dos ecossistemas florestais na República dos Camarões, a diversidade vegetal tem sido amostrada com intuito de ressaltar o potencial das plantas; e os parâmetros estruturais que foram estudados na reserva florestal de Bonepoupa. O levantamento foi realizado pelo método de amostragem aleatória, onde foram plotadas dez parcelas de 200 m2, distanciadas por uma linha feita com um “topofil” colocado no centro do campo com cordas de 5 m cada uma. Além disso, noventa pessoas foram entrevistadas com o objetivo de conhecer o potencial de uso das espécies nessa região. No total foram amostrados 172 indivíduos com diâmetro a altura do peito (DAP) ≥ 5 cm, distribuídos em 27 espécies, 25 gêneros e 18 famílias. Determinou-se o coeficiente de abundância-dominância. O índice de diversidade de Shannon (H’) foi H’1 = 4,17 ± 0,45 com H’1max = 4,75 e a equabilidade foi R1 = 0.88. Levando em consideração as espécies herbáceas, o H’ determinado pelo coeficiente de abundância-dominância foi H’2 = 4,74 ± 0,56 com H’2 max = 5,70 e a equabilidade foi R1 = 0,83. A área basal total foi 19,69 m2/ha e a densidade foi 860 indivíduos/ha. Analisando-se os resultados obtidos, pôde-se concluir que as herbáceas modificaram significativamente o valor do índice de diversidade e também que a reserva florestal de Bonepoupa está passando por um problema de conservação por falta de gestão adequada. O conhecimento dos produtos florestais não madeireiros, bem como seus usos alimentares e medicinais pela população local, poderia ser útil para a gestão sustentável dos recursos nesta reserva florestal

Effects of vegetation's degradation on carbon stock, morphological, physical and chemical characteristics of soils within the mangrove forest of the Rio del Rey Estuary: Case study – Bamusso (South-West Cameroon)

This study was conducted to assess the capacity of mangroves soils to stock carbon and how degradation can influence its various properties. Transect method was performed. So, two transects of 100 m length and 10 m wide were established according to the degradation level. Total of 18 Soil samples were taken to be described and analysed. The degraded transect (T1) shows a mean carbon stock value of 2102.06 ± 405 Mg.ha-1 while natural (T2) accumulate 2476.6 ± 409 Mg.ha-1. Colour are more light inside the degraded transect (Brown to grayish) than the natural transect (brown to blackish) while spots are more colored in natural transect (gray and yellow) than degraded one (yellow). pH mean value showed that soils of degraded transect was more acidic than those of natural one. Organic matter amount was very high and proves that these soils can be valorized to agricultural activities without previous enrichment. Total Nitrogen was low in the two transects while the available phosphorus values showed that natural transect has more available phosphorus that can be used by the plants than degraded transect. So, degradation would take along reduction of available phosphorus rate in the soils. According to this result showing important different values of carbon stock and soils properties between natural and degraded transect, it is necessary to implement conservation methods in order to stop degradation and enhance capacity of mangroves soils properties.Keywords: Bamusso, degraded transect, natural transect, soils, value

Assessing forest products usage and local residents' perception of environmental changes in peri-urban and rural mangroves of Cameroon, Central Africa

(IF2011 = 2.392; CHL = 4.4)info:eu-repo/semantics/publishe

Étude ethnobotanique des plantes médicinales commercialisées dans les marchés de la ville de Douala, Cameroun

Objectif: L’objectif de cette étude est d’inventorier et d’identifier les vertus thérapeutiques des plantes médicinales commercialisées dans la ville de Douala (Cameroun).Méthodologie et résultats: Des enquêtes ethnobotaniques ont été conduites de juillet à août 2012, auprès de 54 herboristes dans cinq marchés en utilisant des interviews directes et semi-structurées. L’étude a permis d’identifier 84 espèces réparties en 78 genres et 50 familles dont les plus représentées ont été les Asteraceae (9 espèces), Fabaceae (6 espèces) et Lamiaceae (4 espèces). Les troubles infectieux (66,7 %) et gynécoobstétriques et urologiques ont été majoritairement représentés. La recherche du degré de consensus (ICF) révèle que 3 catégories ont atteint des valeurs élevées : les troubles asthéniques (0,8), dermatologiques (0,6), gynéco-obstétriques et urologiques (0,5).Conclusion et application des résultats: Cette étude montre l’importance des enquêtes ethnobotaniques dans la phytothérapie et les limites des herboristes de la pharmacopée traditionnelle.Mots clés: Ethnobotanique, plantes médicinales commercialisées, maladiesEnglish AbstractObjective: The objective of this study was to make an inventory and to identify therapeutic properties of medicinal plants sold in the city of Douala (Cameroon).Methodology and Results: Ethnobotanical surveys were conducted from July to August 2012 beside 54 herbalists in five markets using direct and semi-structured interviews. The study identified 84 species distributed in 78 genera and 50 families, the most represented were Asteraceae (9 species), Fabaceae (6 species) and Lamiaceae (4 species). Infectious disorders (66.7%) and gyneco-obstetrical and urological disorders were mostly represented. Research on the degree of consensus (ICF) reveals that three categories reached high values: asthenic (0.8), skin (0.6), gyneco-obstetrical and urological (0.5) disorders.Conclusion and applications of results: This study shows the importance of ethnobotanical surveys in herbal medicine and limitations of herbalists of traditional medicine.Keys: Ethnobotany, sold medicinal plants, disease

Ecology of the facultative phytotelmic crab Platychirarma buettikoferi (De Man, 1883) (Decapoda, Brachyura, Sesarmidae)

The mangrove forests surrounding Douala, Cameroon, have a long history of human impact due to rapid urbanization, resulting in patches of true mangrove forest interspersed with areas dominated by the mangrove-associated Pandanus species. A survey carried out to assess the possible shift in crab fauna composition and dominance between mangrove and Pandanus dominated areas revealed an undescribed phytotelmic habitat for Platychirarma buettikoferi. This species was found colonizing the natural reservoirs of fresh water represented by Pandanus spp. Our results show P. buettikoferi to be ecologically dependent upon Pandanus spp., and absent on the mangrove floor and trees, strongly indicating a phytotelmic adaptation. Our data suggest that this species is a facultative phytotelmic species well adapted to Pandanus spp. dominated areas. Further studies on the reproductive biology and feeding behaviour of P. buettikoferi may shed light on this unique phytotelmic lifestyle and its role in mangrove ecosystem functioning

Artificial infestations of Tapinanthus ogowensis (Engler) Danser (Loranthaceae) on three host species in the Logbessou Plateau (Douala, Cameroon)

In Cameroon today, Loranthaceae has become a major pest against which a great "battle" must be launched if food production in the country has to be maintained at a self-sufficient level. However, an effective battle against pests can only be achieved through a better understanding of their geographical distribution and biology. Eight Loranthaceae species (Globimetula braunii, Globimetula dinklagei, Globimetula opaca, Helixanthera mannii, Phragmanthera capitata, Tapinanthus globiferus, Tapinanthus ogowensis, and Tapinanthus preussii) have been identified in the Douala area. Among these species, T. ogowensis is the only one limited to a surface area of about eight hectares in the Logbessou plateau located in a direction of North-East from Douala (Latitude 03°40 -04°11' N, Longitude 09°16' -09°52' E, and at an altitude of 13 m). In this zone, the hemi-parasite infests only one host tree (Dacryodes edulis) in the orchards, gardens and agricultural plantations. The hemiparasite is however common and adapted to all the different ecological regions in the southern part Cameroon where it infests several host trees. In order to study the stages involved in the germination, fixation, as well as the initial stages involved in the development of the seedlings of T. ogowensis, three of the most frequent host species (D. edulis, Mangifera indica and Persea americana) on the plateau were artificially infected. The results revealed that the host species are sensitive to the parasite, T. ogowensis, at least during their early stages of growth and development. D. edulis is the most sensitive host species with a 22% yield of young seedlings as against 5 and 4% for P. americana and M. indica, respectively. This sensitivity of the mango tree to T. ogowensis had never been demonstrated before. The percentages of seeds germinating on the different host species however remained high; 96% on both D. edulis and M. indica and 93% on P. americana. It was also revealed that the development of the young seedlings of T. ogowensis is greatly influenced by the availability of light, a plausible reason why Loranthaceae occupies mainly the uppermost branches of the oldest trees found here

Influence des sols salins et calcaires sur la croissance, la nutrition minérale et les composantes agronomiques du niébé (Vigna unguiculata (L.) Walp.) dans trois zones agro écologiques du Cameroun

Objectif: le présent travail consiste à évaluer les effets des sols salins et calcaires sur la croissance, la nutrition minérale et les composantes agronomiques de cinq variétés de niébé (Vigna unguiculata (L) Walp) var. Garoua PG, Mouola PG, Garoua GG, Mouola GG et Tsacre) dans trois zones agro-écologiques du Cameroun.Méthodologie et résultats: le dispositif expérimental est un bloc complètement randomisé avec cinq répétitions. Les résultats obtenus révèlent que la biomasse sèche des feuilles des variétés Mouola PG a augmenté significativement dans les sols calcaires de Baré comparativement aux sols témoins de Yagoua. Dans les sols salins de Kribi, elle baisse significativement chez les variétés Mouola PG, Garoua GG et Tsacre. Les rendements en graines augmentent significativement chez les variétés Garoua PG et Mouola GG dans les sols de Kribi d’une part et d’autre part chez la variété Mouola PG dans les sols de Baré. Les fortes concentrations en Na+ des sols de Kribi ont entrainé une baisse remarquable des concentrations en K+, Ca2+, Mg2+ et N dans les feuilles des variétés Mouola PG, Garoua GG et Tsacre. Par contre, dans le sol de Baré riche en Ca2+, les concentrations en Na+, K+, Mg2+ et P ont augmenté nettement chez les différentes variétés.Conclusion et application des résultats: l’examen de l’ensemble des paramètres étudiés révèle que la zone agro-écologique à pluviométrie uni-modale aux sols salins serait propice à la culture des variétés Mouola GG et Garoua PG tandis que la variété Mouola PG pousserait mieux dans la zone agro-écologique des hauts plateaux aux sols calcaires.Mots clés: Niébé, croissance, nutrition minérale, rendement, sol salin, sol calcaireEnglish Title:  Effects of saline and calcareous soils on the growth, mineral nutrition and agronomic components of cowpea (Vigna unguiculata (L) Walp) in three agro-ecological areas of CameroonEnglish AbstractObjective: the present work evaluates the effects of saline and calcareous soils on the growth, mineral nutrition and agronomic components of five varieties of cowpea (Vigna unguiculata (L) Walp) var. Garoua PG, Mouola PG, Garoua GG, Mouola GG and Tsacre) in three agro-ecological areas of Cameroon.Methodology and results: the experimental setup is a completely randomized block with five repetitions. The results obtained show that the dry biomass of the leaves of the Mouola PG varieties increased significantly in the calcareous soils (Baré) compared to the control soils of Yagoua. In saline soils of Kribi, the dry biomass decreases significantly in leaves of Mouola PG, Garoua GG and Tsacre. In Kribi soils, seed yields increased significantly in the Garoua PG and Mouola GG varieties, while in Baré, the Mouola PG variety grew better. The high Na+ concentration of Kribi soils resulted in a remarkable reduction of K+, Ca2+, Mg2+ and N concentrations in the leaves of the varieties Mouola PG, Garoua GG and Tsacre. On the other hand, in the soils of Baré rich in Ca2+, the concentrations in Na+, K+, Mg2+ and P increased markedly in the different varieties.Conclusion and application of results: Examination of all the studied parameters reveals that the agroecological zone with a modal rainfall with saline soil would be favorable for the cultivation of the varieties Mouola GG and Garoua PG while the variety Mouola PG would grow better in the ecological highlands plateau with calcareous soils.Keywords: Cowpea, growth, mineral nutrition, yield, saline soil, calcareous soi

Ecological status and sources of anthropogenic contaminants in mangroves of the Wouri River Estuary (Cameroon)

Mangroves are critically threatened by human activities, despite the important ecosystem functions and services they provide. Mangroves in Cameroon represent no exception to the worldwide trend of mangrove destruction, especially around Douala, on the Wouri river estuary. In two sites around Douala, we assessed the presence of sterols, PAHs, PCBs, DEHP, DDT and its metabolite p,p'-DDE and potentially toxic metals in sediment samples. As a proxy of ecological quality, we measured the diversity and abundance of macrobenthos assemblages. We detected p,p'-DDE contamination, with concentrations higher than 3 ?g kg? 1 in 16 out of 26 samples which were attributed to recent widespread use of DDT. The detection of sterols revealed faecal contamination. Significant sensitivity of the macrobenthos to contaminants was revealed, with possible implications on the overall mangrove vulnerability to climate change and on the provision of ecosystem services to local populations

Mangrove spatial structure in a monospecific stand of the black mangrove Avicennia germinans (L.) Stearn in the Cameroon estuary

Présentation avec posterinfo:eu-repo/semantics/publishedHexennial International Conference ‘Meeting on Mangrove ecology, functioning and Management – MMM3’, 2-6 juillet, Galle, Sri Lank

DIVERSIDADE, PAR\uc2METROS ESTRUTURAIS E PRODUTOS FLORESTAIS N\uc3O MADEIREIROS NA RESERVA FLORESTAL DE BONEPOUPA (DOUALA, CAMAR 5ES)

In order to come up with a sustainable use of forest ecosystems in Cameroon, its vegetal diversity has been inventoried; the plant potentials and the structural parameters were studied in the forest reserve of Bonepoupa. Ten non-continuous plots of 200 m2 were done and the materialization of the lines was done with a topofil put at the centre of the field with ropes at 5 m each of the topofil. In addition, ninety people were interviewed in order to know the potential use of species in this region. Up to 172 individuals with Diameter at Breast Height (DBH) 65 5 cm divided into 27 species, 25 genera and 18 families were inventoried and the coefficient of abundance-dominance was determined. The diversity index of Shannon (H\u2019) was H\u20191 = 4.17 \ub1 0.45 with H\u20191max = 4.75 and the evenness was R1 = 0.88. Taking into account herbaceous species, H\u2019 determined by the coefficient of abundance-dominance was H\u20192 = 4.74 \ub1 0.56 with H\u20192max = 5.70 and the evenness was R2 = 0.83. The total basal area was 19.69 m2/ha and the density was 860 individuals/ha. These results indicate that herbaceous significantly modifies the value of the diversity index and that forest reserve of Bonepoupa is experiencing a problem of conservation which is due to a lack of its appropriate management. The knowledge of non-timber forest products and their use as food as well as medicinal resources by local population might be helpful for the sustainable management of resources in this forest reserve.A fim de chegar a uma utiliza\ue7\ue3o sustent\ue1vel dos ecossistemas florestais na Rep\ufablica dos Camar\uf5es, a diversidade vegetal tem sido amostrada com intuito de ressaltar o potencial das plantas; e os par\ue2metros estruturais que foram estudados na reserva florestal de Bonepoupa. O levantamento foi realizado pelo m\ue9todo de amostragem aleat\uf3ria, onde foram plotadas dez parcelas de 200 m2, distanciadas por uma linha feita com um \u201ctopofil\u201d colocado no centro do campo com cordas de 5 m cada uma. Al\ue9m disso, noventa pessoas foram entrevistadas com o objetivo de conhecer o potencial de uso das esp\ue9cies nessa regi\ue3o. No total foram amostrados 172 indiv\uedduos com di\ue2metro a altura do peito (DAP) 65 5 cm, distribu\ueddos em 27 esp\ue9cies, 25 g\ueaneros e 18 fam\uedlias. Determinou-se o coeficiente de abund\ue2ncia-domin\ue2ncia. O \uedndice de diversidade de Shannon (H\u2019) foi H\u20191 = 4,17 \ub1 0,45 com H\u20191max = 4,75 e a equabilidade foi R1 = 0.88. Levando em considera\ue7\ue3o as esp\ue9cies herb\ue1ceas, o H\u2019 determinado pelo coeficiente de abund\ue2nciadomin\ue2ncia foi H\u20192 = 4,74 \ub1 0,56 com H\u20192 max = 5,70 e a equabilidade foi R1 = 0,83. A \ue1rea basal total foi 19,69 m2/ha e a densidade foi 860 indiv\uedduos/ha. Analisando-se os resultados obtidos, p\uf4de-se concluir que as herb\ue1ceas modificaram significativamente o valor do \uedndice de diversidade e tamb\ue9m que a reserva florestal de Bonepoupa est\ue1 passando por um problema de conserva\ue7\ue3o por falta de gest\ue3o adequada. O conhecimento dos produtos florestais n\ue3o madeireiros, bem como seus usos alimentares e medicinais pela popula\ue7\ue3o local, poderia ser \ufatil para a gest\ue3o sustent\ue1vel dos recursos nesta reserva florestal