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Abstract titles


Assessment of the impact of the influx of Central African refugees on the plant cover between 2002 and 2017 in the localities of Borgop and Ngam

Solange SADJO LABE (1), Innocent Prosper TCHOULI (2), Narcisse TALLA TANKAM (3), Michel TCHOTSOUA (4)
1) Ingénieure géomaticienne, ACAGER – Ngaoundéré
2) Doctorant en géographie, Université de Ngaoundéré
3) Chargé de cours, ENS Bertoua, Université de Ngaoundéré
4) Professeur titulaire des universités (Université de Ngaoundéré)

Abstract. One of the problems with the influx of refugees into a country is its impact on the vegetation cover. The localities of Borgop and Ngam sheltering Central African refugees have not been spared. The temporal dynamics in the two localities were studied from the diachronic analysis of the three Landsat images acquired in 2002, 2013 and 2017 supplemented by ground truths. The results indicate an annual degradation rate of 0.44% between 2002 and 2013 and 2% between 2013 and 2017. This recent dynamic is mainly due to human activities of refugees.
Key words : Evaluation, plant cover, Central African refugees, Borgop and Ngam.


State of Floristic Resources in the Settlement Area of the Nya-Pendé Refugee Camps in October 2012

Robert MADJIGOTO (1), Issa DOUBRAGNE (2), Barnabas Guy-vi GUILOU FACHO (3)
1) Chef du Département de Géographie, Université de N’Djamena
2) Directeur Général de l’Initiative Humanitaire pour le Développement Local (IHDL)
3) Environnementaliste-géomaticien, Expert en gestion des ressources naturelles, Coordonnateur du Projet Produits Forestiers Non Ligneux (PFNL)

Abstract. Due to its geographical location, the Department of Nya-Pendé constitutes a transition zone between the equatorial forest and the Sudano-Guinean savannah. Precipitation exceeds 1000 mm per year. Following conflicts in CAR in 2003, a massive influx of more than 29,000 refugees took place. They are settled in three (3) camps. The sharp increase in the population has put pressure on the resources. Based on the classification of the 2012 satellite image and the analysis of survey data and floristic inventories, this study has highlighted the impact of the presence of refugees on floristic resources. The inventory showed huge amounts of destroyed trees. The wildlife habitat has begun and contributed to its disappearance. A development plan for the refugee settlement area is urgently needed.
Key words : Refugee camp, vegetation, flora, multi-resource inventory, Nya-Pendé.


Exploitation and resilience of Lophira lanceolata, Daniellia oliveri and Hymenocardia acida on the Ngaoundere plateau

1) Université de Ngaoundéré, Département de Géographie
2) Université de Maroua, Institut supérieur du Sahel

Abstract. Logging on the Adamawa plateau is a major issue for the population because of their multiple uses (firewood, charcoal, timber, fodder and source of income). The characteristic species of the region, in particular Lophira lanceolata, Daniellia oliveri and Hymenocardia acida, are the most requested. The present study aims to contribute to the sustainable management of the wood resource through the socio-environmental assessment related to the fuelwood problem and the regeneration capacity of the species in the cutting areas. Different methods were used depending on the information sought: Free lists (Freelisting), the questionnaire and the interview guide enabled the collection of socio-economic data from actors in the timber industry, the diachronic analysis of satellite images from 2000 to 2015, it was possible to assess the rate of degradation of the vegetation cover, which is not only linked to human solicitation but also and above all to the low resilience of these characteristic species of the region. The results of the socio-economic surveys show a specific diversity of forty-five distinct (woody) species used for various purposes. The diachronic analysis of satellite images indicates a significant degradation of tree savannas from 23.25% in 2000 to 21.31% in 2015. The direct consequences of this degradation are the rapid change in the landscape of the savannah landscape and the increase greenhouse gases in nature.
Key words : Tree, firewood, regression of the canopy, regeneration, Ngaoundéré plateau.


Mono and multi specific allometric equations for estimating the above-ground biomass of Western Highlands savannas – Cameroon

Junior Baudouin WOUOKOUE TAFFO (1), Victor François NGUETSOP (2), Théophile FONKOU (3), Samuel Séverin KENFACK FEUKENG (4)
1) Laboratoire de Botanique Appliquée
2) Département de Biologie
3) Faculté des Sciences
4) Université de Dschang, Cameroun

Abstract. Savannas ecosystems are significant terrestrial carbon stocks and their quantification is crucial to understand the total impact of the climate changes. The aim of this study was to formulate the mono and multi-specific allometric equations for evaluating the woody biomass of Western Highlands savannas of Cameroon. Data of aboveground woody biomass were obtained from destructive sampling of 103 trees belonging to seven (07) species of diameter > 5 cm. Proportional relationships between aboveground biomass and diameter at breast height were constructed from 8 allometric models (linear, growth, compound, exponential, quadratic, cubic, power and logarithmic). From the data collected and analysed, two allometric models are suggested based on quadratic and cubic regressions. Carbon stock assessment based on these models gave results with high coefficient of determination (adjusted R² > 0.9). ANOVA tests showed a very low difference between mean values of experimental data and model outputs. The results show that the greatest risks of skew are located at the level of individuals of large diameter (> 21 cm) whereas good prediction of the biomass is on individuals of small diameters (< 21 cm) which are dominant in the ecosystems of savanna. Specific models are more efficient in estimating biomass than models taking in account several species.
Key words : Aboveground biomass, Cameroon, Diameter at breast height, Allometric equations, highland savannas.


The problem of fisheries management in Gabon: between management and organization of maritime fishing territories

Aline-Joëlle LEMBE épouse BEKALE (1)
1) Université Omar BONGO, Département de Géographie, Centre d’Etudes et de Recherches en Géosciences politiques et Prospective (CERGEP)

Abstract. Gabon is now campaigning for greater openness to the sea to enable the fisheries sector to be both competitive and sustainable. The desire to diversify the national economy, which is still largely dependent on oil extraction, encourages the development of other sectors of activity, such as marine fishing. The objective of the present reflection is to take a critical look at the policies aimed at stimulating dynamics of management and sustainable organization of marine fisheries. In this sense, it relies on a methodological approach, on a qualitative approach based on a content analysis of categorical type of official texts in fisheries management in Gabon and annual reports or five-year or ten-year framework studies of the Directorate General Fisheries and Aquaculture (DGPA). To do this, the analysis units selected are essentially fishing licenses, marine parks and biological rest periods. The main results of this research show three levels of dysfunction: a gap between legal texts and production methods; a lack of knowledge of the different fishing territories and their stakeholders; a weak landing and marketing infrastructure. In sum, the conclusions of this research invite to requestionner the more global problematic of the sustainable development of fishing territories in Central Africa and in Gabon in particular. The analysis carried out supports the idea that territorial realities still struggle to be considered in the definition of improvement projects in the fisheries sector.
Key words : Halieutic Policies, Maritime fishing, Territory of fishing, Installation, Sustainable exploitation, Gabon.


Persistence of anarchic exploitation of rônier wood in Loug-Chari (Chad): complicity of role between actors

Blao Martin ZOUA (1), Amane TATALOUM (2)
1) Doctorant, Assistant, Enseignant-chercheur, Département de Géographie, Faculté des Sciences humaines et sociales (FSHS), Université de N’Djamena
2) Maître assistant, Enseignant-chercheur, Département de Géographie (FSHS), Université de N’Djamena

Abstract. Inspite of the prohibition of the abusive cut of the green heart by the State since 2008, the populations continue to exploit fraudulently the wood of borassus. The reading of existing documentation, the investigations of ground and the collected data processing enabled us to identify five categories of actors: oldest members, agents of National Forestry Commission, wood owners of borassus, canvassers and tradesman-conveyors. The monetary search for incomes is the prime motive, which animates each one of them. A part from the canvassers and tradesman-conveyors, the other actors of this die continue to work however for the perenniality of the resource. Considering the stakes, the challenges and the interests, which emanate from the current form of the exploitation of the wood of borassus in Loug-Chari, is there no urgency to establish a consensual structure? These results are interesting for the planning, the stock management, and the comprehension of the strategies of the actors.
Mots clés : Wood of borassus, exploitation, games players, borassus, Chad.


Using mobile GIS and the vertex tool in forest management: an application in the forest of the Mbalmayo National School of Water and Forests

Germain MBOCK (1), Danièle TJOMB (2), Phillipes MBEVO FENDOUNG (3), Gilles Ivan AKAMBA (4)
1) Ecole Nationale des Eaux et Forêts (ENEF) de Mbalmayo, Directeur
2) Ecole Nationale des Eaux et Forêts (ENEF) de Mbalmayo, Enseignante et Géomaticienne
3) Université de Yaoundé, Doctorant en Géographie physique et Géomaticien
4) Professeur des lycées d’enseignement général en Géographie et Géomaticien

Résumé. The advent of space technologies and their multiple applications have significantly reduced the management of the environment. Geographical Information Systems (GIS) and remote sensing offer a wide range of tools commonly used in land use planning and natural resource management. In the field of forestry, georeferenced inventories, sampling plans and forest zoning makes an increasing use of mobile GIS, particularly ArcPad and vertex. These two revolutionary tools intervene respectively in the georeferencing of the trees considering the diameter and the estimation of the height of the trees. The ArcPad is incorporated into another tool called Personal Digital Assistant (PDA) which also englobesembodies the GPS some applications and some features of the ArcMap software. The objective of this research is to apply these two tools in the management of the NFS school forest, in particular in the georeferenced inventory of trees / species and the estimation of the heights of trees. To achieve this, an experimental (study) plot is georeferenced with the help of a GPS and registered in the ArcPad. The inventory is thus done by moving inside the parcel. The collected data is automatically saved in the Shapefile format and easily imported under GIS. With this approach, a certain number of results are obtained. It appears that this portion of forest has a high floristic diversity (Abyzia, Aiele, Azoba, Fraka, Sapeli, Movingui, Ilomba, Iroko, etc.). The diameter of the trees varies between 26 and 120 cm and the heights are between 10 and 38 meters. Three thematic maps are produced to facilitate the management of this forest area. To sustain this technology, 18 NFS teachers are trained and two ecoguards in the handling of these tools. The latter will be responsible for transmitting this know-how to their learners, in order to popularize the technology.
Key words : Mobile GIS, Forest Management, Mbalmayo, Georeferenced Inventory.


Urbanization and socio-spatial inequalities in the city of Bouake in Ivory Coast

Souleymane DIAGABATE (1)
1) Docteur en Géographie, Laboratoire Dynamiques Sociales et Recompositions des Espaces (Ladyss), Université Paris 8 Vincennes Saint Denis (France)

Abstract. The essentially spontaneous urbanization of the city of Bouaké is marked by the phagocytosis of the peripheral villages.To identify this urbanization as well as the actors of the governance of the city, the review of the literature, observations and cartographic field surveys combined with surveys and interviews were conducted. Analysis of the data collected reveals that the urbanized site is located on a slight slope of about 10%. This main feature partly explains the rapid expansion of the city. The rivers Loka and Khan that cross the city have fragmented the urban territory giving it a city aspect difficult to develop. The discontinuities of the urban territory lead to an uneven distribution of the population. The uneven distribution of populations and the development work have introduced socio-spatial inequalities between the meshes of the urban space.
Key words : Ivory Coast, Bouake, urbanization, environment, socio-spatial inequalities.


Problem of drinking water supply in the City of Bouaké (Ivory Coast)

Bêh YEO (1), Egue Alphonse Charles TROTSKY MEL (2), Brou Emile KOFFI (3)
1) Doctorant, Université Alassane Ouattara, Bouaké, Côte d’Ivoire
2) Assistant, Université Jean Lorougnon Guédé, Daloa, Côte d’Ivoire
3) Professeur Titulaire, Université Alassane Ouattara, Bouaké, Côte d’Ivoire

Abstract. In this article, the authors analyze the explanatory factors of the drinking water deficit in Bouaké households. As a result of desk research, tabulation and analysis of the questionnaire surveys, they note that the unequal distribution of infrastructure, the absence or poor maintenance of these infrastructures forces people to resort to other sources of water generally unsuitable for consumption. But these remedies that do not solve the deficit are, for the most part, illegal, costly and expose people to health risks.
Key words : Ivory Coast-Bouaké-drinking water-lack-supply


Geomatics, mobilization and collection of taxes in the Council of Saint Louis du Nord (Haiti)

Félix SAINTERVIL (1), Narcisse TALLA TANKAM (2), Michel TCHOTSOUA (3)
1) Master II en Géomatique Aménagement et Gestion des Ressources
2) Chargé de cours, Université de Ngaoundéré, ENS de Maroua
3) Professeur Titulaire, Université de Ngaoundéré, Département de Géographie

Abstract. The decentralization of State powers in Haiti from the 1987 constitution, amended in 2015, makes the Commune a fully-fledged entity of Local Communities, enjoying administrative and financial autonomy, able to mobilize local resources for increase its tax base. However, communal tax revenues have so far yielded poor returns, including the built-up property tax (CFPB), which is the tax base. So, there are many questions about the ability of this important link of the state at the local level to increase local revenues. Indeed, all is explained by the complexity and the difficulty for the municipality to implement an appropriate instrumentation to identify the local tax revenue sources to carry out the census, contribute to their mobilization and ensure the issuance of roles and their recovery. In the light of the results of this application, geomatics can facilitate the definition of optimal mobilization strategies for local taxes, particularly the development of knowledge and tools that promote the accumulation of precise, practical and technical information about reality. Its contribution is therefore a means to project and better anticipate the effects of a change in local public policy on tax mobilization and management.
Key words :  Haïti, Saint Louis North, Tax Mobilization, CFPB, GIS.


Impact of the maala ecobuage on the physicochemical properties and the productivity of acidic clay soils of the Niari Valley (Congo)

Jean de Dieu NZILA (1), Roland MOREAU (2), Irène MBOUKOU-KIMBATSA (3)
1) Ecole Normale Supérieure (ENS), BP 237 Brazzaville, Congo
2) Institut de Recherche pour le Développement (IRD), Montpellier, France
3) Ecole Nationale Supérieure d’Agronomie et de Foresterie (ENSAF), Brazzaville, Congo

Abstract. Maala-type burning is a variation on slash-and-burn cultivation of long ridges (10-20 m) in which interwoven savannah grass, previously dried and piled in swaths, is buried. Steaming. The burning is studied on a field of traditional cultivation of about 400 m2. The analyzes are carried out on the sieved soil at 2 mm. Determination of the biomass of macroinvertebrate stands in the soil is based on the sampling method recommended by the Tropical Soil Biology and Fertility (TSBF) sampling program (Lavelle, 1988, Anderson and Ingram, 1989, Mboukou-Kimbatsa, 1997). There is an overall decrease of 30% organic matter in the ridged log after combustion. Total nitrogen losses are lower (20%); they would be compensated by an increase of ammoniacal nitrogen. On the other hand, there is a clear increase in exchangeable cations (4.86 to 8.29 cmol.kg-1 soil), the saturation level of the absorbing complex (35 to 65%) and pH (from 5.1 to 6.5). , thus reducing the manganic toxicity observed on these soils. The total phosphorus contents are not very variable in all the samples (close to 3 ‰) whereas those of the assimilable phosphorus increase progressively in the phases subjected to strong rises of temperature (from 0.44 to 1.47 ‰). With a crop time of 3 or 4 years, cassava (22 t.ha-1) and peanut (1.2 t.ha-1) yields on ecobed fields are significantly higher than those obtained by other systems. slash-and-burn or mechanized cultivation.
Key words :  Congo, Niari Valley, burn beating, Ferralsols, soil fertility.