Assessment of in situ nest decay rate for chimpanzees (Pan troglodytes ellioti Matschie, 1914) in Mbam-Djerem National Park, Cameroon : implications for long-term monitoring

Accurate assessment of great ape populations is a prerequisite for conservation planning. Indirect survey methods using nest and dung, and a set of conversion parameters related to nest decay rates, are increasingly used. Most surveys use the standing crop nest count (SCNC) method, whereby nests are counted along transects and the estimated nest density is converted into chimpanzee density using an often non-local nest decay rate. The use of non-local decay rate is thought to introduce substantial bias to ape population estimates given that nest decay rates vary with location, season, rainfall, nest shape, and tree species used. SCNC method has previously been applied in Mbam-Djerem National Park (MDNP) in Cameroon, for chimpanzee surveys using a non-local nest decay rate. This current study aimed to measure a local nest decay rate for MDNP and implications for chimpanzee population estimates in the MDNP. The mean nest decay rate estimated using a logistic regression analysis was 127 [95% CI (100-160)] days. Moreover, the results suggested that rainfall strongly infuenced the nest decay rate over the early stage of the lifetime of the nests. The study confrms that estimates of chimpanzee density and abundance using non-local decay rates should be treated with caution. Our research emphasized the importance of using local nest decay rates and other survey methods which do not depend on decay rates to obtain more accurate estimates of chimpanzee densities in order to inform conservation strategies of these great apes in MDNP

Arthropod Diversity in Lama Forest Reserve (South Benin), a Mosaic of Natural, Degraded and Plantation Forests

Arthropod assemblages were examined in Lama forest reserve, a protected area situated in the Dahomey gap, southern Benin, composed of plantations, degraded forest and remnants of natural forest. The objectives were to compare assemblages in relation to forest type and use, to elucidate the value of forest plantations for biodiversity conservation and to identify indicator species for specific forest habitats. Arthropods were collected over an 11-month period, using standardized sets of traps (pitfall, emergence, Malaise and flight intercept traps). Nine different habitats were studied, including natural and degraded forest, forest plantations (Tectona grandis and Senna siamea) of different age, and isolated forest fragments. Our analysis focused on detritivorous and xylophagous arthropods but also included ground beetles and heteropterans, totalling 393 species. We found no differences in species richness among natural and degraded forest habitats in the centre of the reserve (Noyau central). Outside of the Noyau central, species richness was highest in old teak plantations and isolated forest fragments and lowest in young teak and fuelwood plantations. Detrended correspondence analysis (DCA) separated three main groups: (1) natural forest, (2) degraded forest and young plantations, and (3) old plantations and isolated forest fragments. Multiple regression of DCA scores of the first two axes on environmental variables identified one natural and three disturbance-related predictors of arthropod assemblages in Lama forest: soil type (texture), canopy height, naturalness (proportion of Guineo-Congolian plant species) and understorey vegetation cover. We identified 15 indicator species for six different forest habitats. The highest numbers were found in abandoned settlements and old teak plantations. β-diversity was similar among the three DCA ordination groups (degraded forest excluded). Values for β-diversity were relatively high, suggesting that all major forest habitats contribute significantly to regional species pools and should therefore be protected. To enhance arthropod diversity, we propose that management practices in Lama forest should aim to encourage the development of species-rich understorey vegetation of the Guineo-Congolian phytogeographical regio

The relationship between the abundance of the Nigeria-Cameroon chimpanzee (Pan troglodytes ellioti) and its habitat: a conservation concern in Mbam-Djerem National Park, Cameroon

Background Understanding the relationship between great apes and their habitat is essential for the development of successful conservation strategies. The chimpanzee Pan troglodytes ellioti is endemic to Nigeria and Cameroon, and occupies an ecologically diverse range of habitats from forests to forest-savannah mosaic in Mbam-Djerem National Park (MDNP) in Cameroon. The habitat variation in chimpanzees is poorly understood in MDNP which provides an excellent opportunity to assess ecological factors that shape the abundance and distribution patterns of P. t. ellioti over a small geographic scale. Results We counted 249 nests along 132 km of transects in total. Of these, 119 nests along 68 km occurred in dense forest and 130 nests along 64 km in forest-savannah mosaic. Chimpanzee density was 0.88 [95% CI (0.55–1.41)] individuals/km2 in the dense forest and 0.59 [95% CI (0.19–1.76)] in the forest-savannah mosaic. Nest abundance varied with vegetation type and was higher in areas with dense canopy cover, steeper slopes and relatively higher altitudes. Conclusions Our estimates of chimpanzee densities were lower than reported in other studied populations in the range of the Nigeria-Cameroon chimpanzee. However, we found that habitat features, slope and altitude likely play a role in shaping patterns of chimpanzee nesting ecology. Further studies need to be focused on nest decay rates and phenology of useful plants in order to model chimpanzee abundance and distribution in Mbam-Djerem National Park

IN VITRO BEHAVIOUR OF PLASMODIUM FALCIPARUM STRAINS BY ALKALOIDS AND TANNINS EXTRACTED FROM ROOT OF MITRAGYNA INERMIS, A MEDICINAL PLANT

Objective: Mitragyna inermis (Willd.) O. Ktze is a plant belonging to the Rubiaceae family. It is used in West Africa by traditional healers for treatment of accesses febrile generally bound to access malaria, but also to treat several other pathologies. We have collected a medicinal plant, Mitragyna inermis root, currently used for malaria treatment in Burkina-Faso. Methods: Alkaloids and Tannins were extracted by using conventional methods and antimalarial activities were tested. Results: After extracted Alkaloids and Tannins, the in vitro culture of Plasmodium falciparum strain isolated from infected patients showed that the alkaloids extracts presented an excellent antiplasmodial activity on P. falciparum strain (IC50 = 2.36 and 2.56 µg/ml respectively) after 24 and 48h of incubation at 37 °C. On the other hand, the tannins extract no presented antiplasmodial activity (IC50>100 µg/ml) but presented an important maturity of P. falciparum strains, letting foretell a possible use of the polyphenolic compounds by P. falciparum as a source of cellular carbon and energy. Conclusion: These results although exploratory are of fundamental importance for the research in biochemistry and medicine for find new antimalarial prototypes

Spatial mapping and prediction of Plasmodium falciparum infection risk among school-aged children in Côte d'Ivoire

BACKGROUND: In Côte d'Ivoire, malaria remains a major public health issue, and thus a priority to be tackled. The aim of this study was to identify spatially explicit indicators of Plasmodium falciparum infection among school-aged children and to undertake a model-based spatial prediction of P. falciparum infection risk using environmental predictors. METHODS: A cross-sectional survey was conducted, including parasitological examinations and interviews with more than 5,000 children from 93 schools across Côte d'Ivoire. A finger-prick blood sample was obtained from each child to determine Plasmodium species-specific infection and parasitaemia using Giemsa-stained thick and thin blood films. Household socioeconomic status was assessed through asset ownership and household characteristics. Children were interviewed for preventive measures against malaria. Environmental data were gathered from satellite images and digitized maps. A Bayesian geostatistical stochastic search variable selection procedure was employed to identify factors related to P. falciparum infection risk. Bayesian geostatistical logistic regression models were used to map the spatial distribution of P. falciparum infection and to predict the infection prevalence at non-sampled locations via Bayesian kriging. RESULTS: Complete data sets were available from 5,322 children aged 5-16 years across Côte d'Ivoire. P. falciparum was the predominant species (94.5 %). The Bayesian geostatistical variable selection procedure identified land cover and socioeconomic status as important predictors for infection risk with P. falciparum. Model-based prediction identified high P. falciparum infection risk in the north, central-east, south-east, west and south-west of Côte d'Ivoire. Low-risk areas were found in the south-eastern area close to Abidjan and the south-central and west-central part of the country. CONCLUSIONS: The P. falciparum infection risk and related uncertainty estimates for school-aged children in Côte d'Ivoire represent the most up-to-date malaria risk maps. These tools can be used for spatial targeting of malaria control interventions

IN VITRO BEHAVIOUR OF PLASMODIUM FALCIPARUM STRAINS BY ALKALOIDS AND TANNINS EXTRACTED FROM ROOT OF MITRAGYNA INERMIS, A MEDICINAL PLANT

Mitragyna inermis (Willd.) O. Ktze, is a plant belonging to the Rubiaceae family. It is used in West Africa by traditional healers for treatment of accesses febrile generally bound to access malaria, but also to treat several other pathologies. We have collected a medicinal plant, Mitragyna inermis root, currently used for malaria treatment in Burkina-Faso. After extracted Alkaloids and Tannins, the in vitro culture of Plasmodium falciparum strain isolated from infected patients showed that the alkaloids extracts presented an excellent antiplasmodial activity on P. falciparum strain (IC50 = 2.36 and 2.56 µg/ml respectively) after 24 and 48h of incubation at 37 °C. On the other hand, the tannins extracts no presented antiplasmodial activity (IC50>100 µg/ml) but presented an important maturity of P. falciparum strains, letting foretell a possible use of the polyphenolic compounds by P. falciparum as a source of cellular carbon and energy. These results although exploratory are of a fundamental importance for the research in biochemistry and medicine for find new antimalarial prototypes.Keywords: Mitragyna inermis, Malaria, Roots, Tannins, Alkaloids, Plasmodium falciparum