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The taxonomy of Rutaceae-Toddalieae of Cameroon is revisited on the basis of fertile samples, images of specimens, and systematic literature. Species identification based on the correlation of morphological characters of leaves, inflorescences and fruits, let to recognize four new species including Vepris adamaouae Onana, sp. nov. with the lamina of the leaflets decurrent on the petiolule, slender inflorescences axes and stamens about twice as long as the petals; V. araliopsioides Onana, sp. nov., with 5-folilated leaves and foveolate fruit exocarp; V. letouzeyi Onana, sp. nov. with winged petioles, finely furrowed foveolate fruits exocarp; and V. montisbambutensis Onana, sp. nov. with smaller leaves and fruit compared to other species of the genus. Moreover the material distinguished by the petiolule reduced to a bulge might represent a new species, not yet validated because of the lack of mature flowers and fruits. Toddaliopsis ebolowensis (Engl.) Onana, comb. nov. is lectotypified, allowing the validation of the new combination V. ebolowensis (Engl.) Onana, comb. nov.. The true identity of Teclea campestris and Vepris tabouensis is proposed: they are conspecific with respectively V. heterophylla (Engl.) Letouzey and V. soyauxii (Engl.) Mziray. A key to distinguish species is proposed. New taxa and those with previously confused identification or taxonomic uncertain position are illustrated and their geographical distributions presented. © Publications Scientifiques du Muséum national d'Histoire naturelle, Paris. Source


Koutsovoulos G.,University of Edinburgh | Makepeace B.,University of Liverpool | Tanya V.N.,Institute Of Recherche Agricole Pour Le Developpement | Blaxter M.,University of Edinburgh
PLoS Genetics | Year: 2014

Wolbachia are common endosymbionts of terrestrial arthropods, and are also found in nematodes: the animal-parasitic filaria, and the plant-parasite Radopholus similis. Lateral transfer of Wolbachia DNA to the host genome is common. We generated a draft genome sequence for the strongyloidean nematode parasite Dictyocaulus viviparus, the cattle lungworm. In the assembly, we identified nearly 1 Mb of sequence with similarity to Wolbachia. The fragments were unlikely to derive from a live Wolbachia infection: most were short, and the genes were disabled through inactivating mutations. Many fragments were co-assembled with definitively nematode-derived sequence. We found limited evidence of expression of the Wolbachia-derived genes. The D. viviparus Wolbachia genes were most similar to filarial strains and strains from the host-promiscuous clade F. We conclude that D. viviparus was infected by Wolbachia in the past, and that clade F-like symbionts may have been the source of filarial Wolbachia infections. © 2014 Koutsovoulos et al. Source


Grant
Agency: Cordis | Branch: FP7 | Program: CP-SICA | Phase: ENV.2008.1.1.5.1. | Award Amount: 4.77M | Year: 2009

The proposal addresses Topic ENV.2008.1.1.5.1 Addressing deforestation in tropical areas: greenhouse gas emissions, socio-economic drivers and impacts, and policy options for emissions reduction. The overall goal of the project is to contribute to the development and evaluation of mechanisms and the institutions needed at multiple levels for changing stakeholder behaviour to slow tropical deforestation rates and hence reduce GHG emissions. This will be achieved through enhancing our understanding of the social, cultural, economic and ecological drivers of forest transition in selected case study areas in Southeast Asia, Africa and South America. This understanding will facilitate the identification and assessment of viable policy options addressing the drivers of deforestation and their consistency with policy approaches on avoided deforestation, such as Reduced Emissions from Deforestation and degradation (REDD), currently being discussed in UNFCCC and other relevant international fora. At the same time, ways of improving the spatial quantification of land use change and the associated changes in GHG fluxes will be developed, thereby improving the accounting of GHG emissions resulting from land use change in tropical forest margins and peatlands. This will allow the analysis of scenarios of the local impacts of potential international climate change policies on GHG emission reductions, land use, and livelihoods in selected case study areas, the results of which will be used to develop new negotiation support tools for use with stakeholders at international, national and local scales to explore a basket of options for incorporating REDD into post-2012 climate agreements. The project will provide a unique link between international policy-makers and stakeholders on the ground who will be required to change their behaviour regarding deforestation, thereby contributing to well-informed policy-making at the international level.


Van Straaten O.,University of Gottingen | Corre M.D.,University of Gottingen | Wolf K.,University of Gottingen | Tchienkoua M.,Institute Of Recherche Agricole Pour Le Developpement | And 4 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2015

Tropical deforestation for the establishment of tree cash crop plantations causes significant alterations to soil organic carbon (SOC) dynamics. Despite this recognition, the current Intergovernmental Panel on Climate Change (IPCC) tier 1 method has a SOC change factor of 1 (no SOC loss) for conversion of forests to perennial tree crops, because of scarcity of SOC data. In this pantropic study, conducted in active deforestation regions of Indonesia, Cameroon, and Peru, we quantified the impact of forest conversion to oil palm (Elaeis guineensis), rubber (Hevea brasiliensis), and cacao (Theobroma cacao) agroforestry plantations on SOC stocks within 3-m depth in deeply weathered mineral soils. We also investigated the underlying biophysical controls regulating SOC stock changes. Using a space-for-time substitution approach, we compared SOC stocks from paired forests (n = 32) and adjacent plantations (n = 54). Our study showed that deforestation for tree plantations decreased SOC stocks by up to 50%. The key variable that predicted SOC changes across plantations was the amount of SOC present in the forest before conversion-the higher the initial SOC, the higher the loss. Decreases in SOC stocks were most pronounced in the topsoil, although older plantations showed considerable SOC losses below 1-m depth. Our results suggest that (i) the IPCC tier 1 method should be revised from its current SOC change factor of 1 to 0.6 ± 0.1 for oil palm and cacao agroforestry plantations and 0.8 ± 0.3 for rubber plantations in the humid tropics; and (ii) land use management policies should protect natural forests on carbon-rich mineral soils to minimize SOC losses. Source


Lezine A.-M.,French National Center for Scientific Research | Assi-Kaudjhis C.,French National Center for Scientific Research | Assi-Kaudjhis C.,University of Liege | Roche E.,University of Liege | And 2 more authors.
Journal of Biogeography | Year: 2013

Aim: Our aims were to provide a detailed chronology of past vegetation changes in the tropical mountains of west-central Africa since the Last Glacial Maximum and to discuss montane forest responses to climate change in terms of distribution and biodiversity. Location: Lake Bambili, western Cameroon (05°56′ N, 10°14′ E, 2273 m a.s.l.). Methods: Fossil pollen was extracted from a long, continuous and well-dated sedimentary sequence extending back 20,000 years. Pollen diversity and evenness estimates were based on rarefaction analysis and on Simpson's (1/D) index. Results: Forest was nearly absent from high elevations during the last glacial period. It expanded gradually from 18.4 cal. kyr bp, interrupted only by reversals coincident with the Heinrich 1 (H1) and Younger Dryas (YD) climatic events, and then suddenly collapsed at 3.3 cal. kyr bp. This switch from forest to grassland communities occurred within a time span of three centuries. After 3.3 cal. kyr bp only short and taxon-poor forest phases are recorded, specifically between 2.7 and 1 cal. kyr bp and in recent centuries. Main conclusions: Our data indicate that the mountain forests of Cameroon are recent, resulting from plant migrations from various sources from 18.4 cal. kyr bp onwards. Their progressive development closely followed intensification of the Atlantic monsoon, leading to the formation of a dense forest between 11.7 and 3.3 cal. kyr bp. The composition of this forest included the co-occurrence of species whose ranges do not overlap today, and indicates the potential for the development of unique iterations of climax forests through time. These forests appear to be very sensitive to Northern Hemisphere climate change, with phases of expansion/contraction coeval with the boreal deglacial signal, including widely recognized events such as H1, the YD and the 8.2 ka event. From 8.2 cal. kyr bp onwards, the progressive opening of the canopy is likely to reflect increased seasonality in rainfall related to more frequent El Niño/Southern Oscillation (ENSO) events. The final step of this history was the collapse of the montane forest at 3.3 cal. kyr bp. During the last millennium, very severe disruptions have meant that only the most rapidly dispersing species could spread, contributing to a drastic loss of forest biodiversity that has been accentuated by human impact in the last few centuries. © 2012 Blackwell Publishing Ltd. Source

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