Perspectives for sustainable Prunus africana production and trade

This brief documents current knowledge about pygeum (Prunus africana). It aims to inform decision makers in governments in producing and consumer countries, international and civil society organisations and researchers, about sustainable (international) trade and governance of the species

Etat des lieux de la filière écorces de Prunus africana : cas des régions du Nord-Ouest et Sud-Ouest du Cameroun

Résumé Prunus africana autrefois appelé Pygeum africana est une espèce endémique des forêts afro-montagnardes d’Afrique et de Madagascar. Cette espèce de haute altitude revêt une importance économique, sociale et scientifique pour les populations locales et pour la communauté internationale. Localement, elle est source de bois d’œuvre (artisanat), de bois de chauffage, de revenus et contribue à la pharmacopée traditionnelle (Hall et al., 2000). Sur le plan scientifique et au niveau international, ses écorces sont utilisées dans les industries occidentales pour soigner l’hypertrophie bénigne de la prostate (Tasse, 2006 ; Njamnshi et Ekati, 2008). Le Cameroun abrite une bonne partie de la population de cette espèce qui est menacé d’extinction et inscrite en annexe II de la Convention sur le Commerce International des Espèces de la Flore et de la Faune (CITES) (Belinga, 2011). Son milieu écologique se situe généralement entre 900 et 3000 m d’altitude notamment les Hautes Terres de l’Ouest, le Mont Cameroun, l’Adamaoua, les monts Bakossi sans oublier quelques échantillons dans la Région du Centre. Prunus africana est classé par l’ Union Internationale pour la Conservation de la Nature (UICN) comme une espèce rare et vulnérable du fait de la dégradation continue de son écosystème liée à la forte pression exercée sur la ressource et l’application des méthodes de récolte non durables. Son commerce a été régulé depuis 1995 par la Convention CITES. Au Cameroun, l’exploitation de Prunus africana se fait sur la base des quotas attribués annuellement par le Ministère des Forêts et de la Faune (MINFOF) aux détenteurs de permis d’exploitation. En outre, l’exportation de Prunus africana vers l’Occident implique environ 200 récolteurs, 6 entreprises nationales et une vingtaine de forêts communautaires dans la Région du Nord-Ouest ainsi qu’une organisation paysanne spécialisée (MOCAP) de la Région du Sud Ouest. Une moyenne de 1923 tonnes est exportée annuellement. Le Cameroun reste le plus grand exportateur mondial des écorces de Prunus africana (38-48% du volume mondial). Toute la filière au Cameroun a été évaluée à 315 millions de FCFA (630 milles $US) pour 646,5 tonnes pour l’année 2007. Toutefois, pour des raisons évoquées plus haut, l’Union européenne (EU) a suspendu les exportations en provenance du Cameroun en 2007. Cet article procède de plusieurs observations sur le terrain dans ces deux régions doublées des enquêtes socioéconomiques auprès des populations cibles. Malgré les conflits d’usage, les pressions et la maîtrise limitée de la ressource, de nombreuses opportunités telles que la prise de conscience de la régénération et le début des inventaires existent aujourd’hui pour une meilleure valorisation, une bonne gouvernance et une gestion soutenue de Prunus africana au Cameroun. Une exploitation rationnelle et durable de cette ressource fera d’elle une bonne source de revenus pour les populations des Régions productrices. Mots clés : Cameroun, Prunus africana, Ecorce, gestion durable. Abstract Prunus africana formerly called Pygeum africana is an endemic species of the Afro-highlander forest of Africa and Madagascar. This high-altitude species is of economic, social and scientific importance for the local people and the international community. Locally, it is a source of timber (Craft), firewood, income and it contributes to the traditional pharmacy (Hall et al., 2000). Scientifically and internationally, its bark is used by Western industries to treat benign prostate hyperplasia (Tasse, 2006; Njamnshi et Ekati, 2008). Cameroon is home to a large part of the population of this species which is threatened by extinction and therefore, included in Appendix II of the Convention on International Trade in Endangered Species of Flora and Fauna (CITES) (Belinga 2011). Its ecological environment is usually between 900 and 3000 m altitude in the Upper West Lands, Mount Cameroon, Adamawa, the Bakossi Mountains not forgetting some areas in the Center Region. Prunus africana is classified by the IUCN as a rare and vulnerable species due to the increased degradation of its ecosystem linked to the strong pressure on the resource and application of unsustainable harvesting methods. Its sales has been regulated since 1995 by the CITES Convention. In Cameroon, the exploitation of Prunus africana is done on the basis of annual quotas allocated by the Ministry of Forestry and Wildlife (MINFOF) to the holders of operating licenses (permits). In addition, the export of Prunus africana to the West involves about 200 harvesters, 6 domestic enterprises and 20 community forests in the North West Region as well as a specialized peasant organization (MOCAP) in the South West Region. An average of 1923 tons is exported annually. Cameroon remains the world’s largest exporter of Prunus africana barks (38-48$ 630 thousand) for 646.5 tons in 2007. However, for reasons mentioned above, the European Union (EU) suspended exports from Cameroon in 2007. This article focuses on several observations on the ground in two regions using repeated socio-economic surveys of the target populations. Despite the conflicts in use, pressures and limited control of the resource, many opportunities such as awareness of regeneration and early inventories now exist to enhance value, good governance and sustained management of Prunus africana in Cameroon. Rational and sustainable exploitation of this resource will make it a good source of income for the people of the producing regions. Keywords : Cameroon, Prunus Africana, bark, sustainable management

When intensity of deltamethrin resistance in Anopheles gambiae s.l. leads to loss of Long Lasting Insecticidal Nets bio-efficacy : a case study in north Cameroon

Background: In Cameroon, insecticide resistance in Anopheles (An.) gambiae s.l. has been reported in several foci, prompting further investigations on associated patterns of Long-Lasting Insecticidal Nets (LLINs) bio-efficacy. The current study, conducted from June to August 2011, explored the intensity of deltamethrin resistance in An. gambiae s.l. from Pitoa and its impact on the residual bio-efficacy of LifeNet, a LLIN with deltamethrin incorporated into polypropylene nets (PND). Methods: Two-four days old females An. gambiae s.l. reared from larval collections in Pitoa were tested for susceptibility to DDT, permethrin and deltamethrin, using standard World Health Organization (WHO) tube assays. Intensity of deltamethrin resistance was explored using WHO tube assays, but across six working concentrations from 0.001 % to 0.5 %. Bio-efficacy of unwashed and washed PND was assessed using WHO cone test. Species identification and kdr 1014 genotyping were performed on mosquito samples that were not exposed to insecticides, using PCR-RFLP and HOLA methods respectively. The Kisumu reference susceptible strain of An. gambiae s.s. was used for comparisons. Results: A total of 1895 An. gambiae s.l. specimens from Pitoa were used for resistance and PND bio-efficacy testing. This mosquito population was resistant to DDT, permethrin and deltamethrin, with 18-40 min knockdown times for 50 % of tested mosquitoes and 59-77 % mortality. Deltamethrin Resistance Ratio compared with the Kisumu strain was estimated at >= 500 fold. LifeNets were effective against the susceptible Kisumu (100 % knockdown (KD60min) and mortality) and the resistant Pitoa samples (95 % KD60min, 83-95 % mortality). However, the bio-efficacy gradually dropped against the Pitoa samples when nets were washed (X-2 = 35.887, df = 8, p < 0.001), and fell under the WHO efficacy threshold (80 % mortality and/or 95 % KD60min) between 10 and 15 washes. The Pitoa samples were composed of three sibling species: An. arabiensis (132/154, 86 %), An. coluzzii (19/154, 12 %) and An. gambiae s.s. (3/154, 2 %). The kdr L1014F allele was found only in An. coluzzii (N-positive = 13/19), at 34 % frequency and heterozygote stage. No specimen carried the kdr L1014S allele. Conclusions: The current study showed that LifeNet might still offer some protection against the resistant An. gambiae s.l. population from Pitoa, provided appropriate dose of insecticide is available on the nets

Shaping forest safety nets with markets : adaptation to climate change under changing roles of tropical forests in Congo Basin

This study examined the roles of markets in non-timber forest products and services that usually serve as safety nets for forest communities. Forests are considered ‘‘safety nets’’ in that people draw on available natural resources to meet emergency shortfalls and to keep them from being worse off in times of need. Markets should complement rather than substitute forests’ roles for adaptation to climate change: although markets may increase the value of a commodity, wholesalers and retailers reap most of the benefits, and the distribution of market revenue leaves local people with returns much lower than the worth of the commodity

Population genetic structure of the malaria vector Anopheles nili in sub-Saharan Africa

<p>Abstract</p> <p>Background</p> <p><it>Anopheles nili </it>is a widespread efficient vector of human malaria parasites in the humid savannas and forested areas of sub-Saharan Africa. Understanding <it>An. nili </it>population structure and gene flow patterns could be useful for the development of locally-adapted vector control measures.</p> <p>Methods</p> <p>Polymorphism at eleven recently developed microsatelitte markers, and sequence variation in four genes within the 28s rDNA subunit (ITS2 and D3) and mtDNA (COII and ND4) were assessed to explore the level of genetic variability and differentiation among nine populations of <it>An. nili </it>from Senegal, Ivory Coast, Burkina Faso, Nigeria, Cameroon and the Democratic Republic of Congo (DRC).</p> <p>Results</p> <p>All microsatellite loci successfully amplified in all populations, showing high and very similar levels of genetic diversity in populations from West Africa and Cameroon (mean Rs = 8.10-8.88, mean He = 0.805-0.849) and much lower diversity in the Kenge population from DRC (mean Rs = 5.43, mean He = 0.594). Bayesian clustering analysis of microsatellite allelic frequencies revealed two main genetic clusters in the dataset. The first one included only the Kenge population and the second grouped together all other populations. High Fst estimates based on microsatellites (Fst > 0.118, P < 0.001) were observed in all comparisons between Kenge and all other populations. By contrast, low Fst estimates (Fst < 0.022, P < 0.05) were observed between populations within the second cluster. The correlation between genetic and geographic distances was weak and possibly obscured by demographic instability. Sequence variation in mtDNA genes matched these results, whereas low polymorphism in rDNA genes prevented detection of any population substructure at this geographical scale.</p> <p>Conclusion</p> <p>Overall, high genetic homogeneity of the <it>An. nili </it>gene pool was found across its distribution range in West and Central Africa, although demographic events probably resulted in a higher level of genetic isolation in the marginal population of Kenge (DRC). The role of the equatorial forest block as a barrier to gene flow and the implication of such findings for vector control are discussed.</p

Midgut microbiota of the malaria mosquito vector Anopheles gambiae and Interactions with plasmodium falciparum Infection

The susceptibility of Anopheles mosquitoes to Plasmodium infections relies on complex interactions between the insect vector and the malaria parasite. A number of studies have shown that the mosquito innate immune responses play an important role in controlling the malaria infection and that the strength of parasite clearance is under genetic control, but little is known about the influence of environmental factors on the transmission success. We present here evidence that the composition of the vector gut microbiota is one of the major components that determine the outcome of mosquito infections. A. gambiae mosquitoes collected in natural breeding sites from Cameroon were experimentally challenged with a wild P. falciparum isolate, and their gut bacterial content was submitted for pyrosequencing analysis. The meta-taxogenomic approach revealed a broader richness of the midgut bacterial flora than previously described. Unexpectedly, the majority of bacterial species were found in only a small proportion of mosquitoes, and only 20 genera were shared by 80% of individuals. We show that observed differences in gut bacterial flora of adult mosquitoes is a result of breeding in distinct sites, suggesting that the native aquatic source where larvae were grown determines the composition of the midgut microbiota. Importantly, the abundance of Enterobacteriaceae in the mosquito midgut correlates significantly with the Plasmodium infection status. This striking relationship highlights the role of natural gut environment in parasite transmission. Deciphering microbe-pathogen interactions offers new perspectives to control disease transmission.Institut de Recherche pour le Developpement (IRD); French Agence Nationale pour la Recherche [ANR-11-BSV7-009-01]; European Community [242095, 223601]info:eu-repo/semantics/publishedVersio