Évolution du couvert végétal du Parc National Mbam et Djerem et sa périphérie entre 2000-2018

International audienceLe Parc National du Mbam et Djerem est situé entre 5°30’ et 6°13’ de latitude Nord, et 12°13’ et 13°10’ de longitude Est dans la zone de transition forêt–savane du Cameroun avec une superficie de 416512 hectares. Il possède un potentiel floristique et faunique très particulier.L’analyse de la dynamique du couvert végétal indique un taux de progression global d’environ 4,90 % et un taux de régression d’environ 0,25 % des formations végétales à l’intérieur du parc entre 2000 et 2018. De façon plus spécifique, en 18 ans, la forêt dense semble avoir pris le pas sur la forêt claire et la savane avec une augmentation de 91230 ha, soit un taux d’évolution de 54,95 % tant dis que les espaces de forêt claire et de savane ont diminué respectivement de l’ordre de -69643,5 ha et -21494 ha, soit des taux de l’ordre de -57,75 % et -15,19 %. Par contre à la périphérie du parc, on constate l’effet inverse avec une diminution de la forêt dense de -86141 ha soit un taux de régression de 15 %, et de la savane avec -27219 ha soit un taux de régression de -4,69 %.Les principaux moteurs de ce dynamisme observé sont l’élevage transhumant, l’extension des agro- industries et des exploitations agricoles familiales, l’exploitation illégale du bois d’œuvre et la collecte des Produits Forestiers Non-Ligneux

The Management of Protected Areas in Seven Countries of West and Central Africa

Note portant sur l’auteur Introduction Africa harbours a great variety of ecosystems and almost one-third of the biological diversity of the world (IUCN, 2005) but it is also the continent that suffers from the highest rates of poverty on the planet. In order to try to protect natural resources while ensuring the development of its people, the creation and management of protected areas is widely practised and recognized at the international level. It could even be said that the conservation o..

Devastating Decline of Forest Elephants in Central Africa.

African forest elephants– taxonomically and functionally unique–are being poached at accelerating rates, but we lack range-wide information on the repercussions. Analysis of the largest survey dataset ever assembled for forest elephants (80 foot-surveys; covering 13,000 km; 91,600 person-days of fieldwork) revealed that population size declined by ca. 62% between 2002–2011, and the taxon lost 30% of its geographical range. The population is now less than 10% of its potential size, occupying less than 25% of its potential range. High human population density, hunting intensity, absence of law enforcement, poor governance, and proximity to expanding infrastructure are the strongest predictors of decline. To save the remaining African forest elephants, illegal poaching for ivory and encroachment into core elephant habitat must be stopped. In addition, the international demand for ivory, which fuels illegal trade, must be dramatically reduced

Quelles aires protégées pour l’Afrique de l’Ouest ?

Concilier conservation dans les aires protégées et développement des populations locales exige une bonne connaissance de la dynamique des systèmes naturels et sociaux. Issu d’un séminaire interdisciplinaire qui a réuni les partenaires de 16 pays, en majorité africains, ce CD-ROM présente les données biologiques et sociales permettant de questionner les pratiques en cours dans les aires protégées d’Afrique de l’Ouest. Il s’adresse aux scientifiques, aux gestionnaires et aux décideurs.Reconciling conservation in protected areas and development for the local people requires a good knowledge of the dynamics of natural and social systems. The result of an interdisciplinary seminar which brought together participants of 16 countries, mostly African, this work presents biological and social data in support of a re-consideration of the practices in progress in the protected areas of West Africa. It is intended as much for scientists as for managers and decision-makers

Estimated change in elephant dung density (/km²) distribution during 2002–2011 across the Central African forests.

<p>Results are shown as a percentage of the total area of potential elephant habitat overall (A & B) and by country (C & D) for the predictive model with variables: (A & C) survey year, Human Influence Index, corruption and the presence/absence of guards, and (B & D) survey year, proximity to road, human population density, corruption and the presence/absence of guards. The dung density (per km²) intervals are unequal and correspond to the following elephant population categories: extremely low density (0–100), very low (100–250), low (250–500), medium (500–1,000), high (1,000–3,000) and very high (3,000–7,500). With the loss of very high elephant populations in 2011, there is a significant shift into the lower density intervals over the nine years.</p

Elephant dung density and range reduction across the Central African forests.

<p>Predictions are shown for (A) 2002 and (B) 2011 for the model with variables: survey year∧, Human Influence Index***, corruption*** and the presence/absence of guards***, and (C) 2002 and (D) 2011 for the model with variables: survey year∧, proximity to road∧, human population density***, corruption*** and the presence/absence of guards*** (P-values are: ‘***’ <0.001 and ‘∧’ <0.1). Increasingly darker shades of green correspond to higher densities, grey represents extremely low elephant density range (the first interval: 0–100 elephant dung piles/km²) and white is non-habitat (80 survey sites outlined in red). Cutpoints are: 0; 100; 250; 500; 1,000; 1,500; 3,000; 5,000; and 7,500 dung piles/km². Countries 1–5 are: Cameroon; Central African Republic; Republic of Congo; DRC; Gabon.</p

Boxplots of indices of elephant abundance and hunting intensity.

<p>Summaries shown are the natural logarithm of: (A) elephant dung encounter rate per 100 km grouped by the presence/absence of wildlife guards, (B) elephant dung encounter rate per 100 km grouped by the level of hunting intensity (group cutpoints are 0.6 and 1.75 hunter sign/km), and (C) hunter-sign frequency per 100 km grouped by the presence/absence of wildlife guards. Box-widths are proportional to the number of observations in each group.</p

Encounter rate of elephant dung per kilometre.

<p>Results are shown for the 80 survey sites in Central Africa included in this study. Grey shading represents forest cover.</p