Laboratoire de Systémique, Biodiversité, Conservation de la Nature et Savoirs Endogènes, Département des Sciences de l'Environnement, Faculté des Sciences, Université de Kinshasa, B.P 190 Kin XI, RD Congo
The ecosystems of Kimpolo I village and its surroundings are located 23 km east of Kinshasa on the western edge of the Bateke Plateau. To better understand the contribution of its soils and its relief to the ecological planning of its natural ecosystems, a soil analysis and a geomorphological map of this area have been carried out. This study was conducted using soil samples from environmental ecosystems and satellite geographic data collected in the field. On 15 soil samples from different horizons of four profiles, the analysis indicates that the texture of these soils is more than 85% sandy, the pH-H2O and KCl vary from strongly to moderately acidic, the carbon contents Organic matter levels are low, organic matter levels correspond to very low productivity and the Carbon-Nitrogen ratios indicate that there is either a predominance or a balance between mineralization and nitrogen release in horizons and cation exchange capacities. Reveal that these soils are sandy.
Geomorphologically, spatial data processing informs that contour lines are spaced in the middle of the site, attesting to the existence of the plain and narrowed after watercourses before re-spacing to mark the sinusoidal change in relief. In view of the human activities practiced in the site which have a negative impact on the soils and the relief, particular attention must be given to these degraded ecosystems, with a view to their ecological planning.
The ecosystems of Kimpolo I and its surroundings are located 23 km east of Kinshasa on the western edge of the Bateke Tray. To better understand its floristic richness and its chorological position, an analysis of the florule, autoecological and phytogeographical spectra of the species was undertaken. This study was conducted using floristic material from botanical surveys. On an area of 8.65 km2 surveyed, 219 species were inventoried. They belong to 71 families and 168 genera. The most diverse families in number of species are Fabaceae, Poaceae, Rubiaceae, Euphorbiaceae, Cyperaceae, Apocynaceae and Asteraceae. Ecological spectra show the high representativeness of phanerophyts, geophytes, chamephyts, therophyts and hemicryptophyts. At the phytogeographic level, there is a predominance of regional guineo-Congolese species , followed by those with a very wide distribution and African with a large distribution. From the chorological point of view, this flora is north of the Bas-Congo sector and south of the guineo-Congolese regional center of endemism. In view of the many human activities practiced (shifting cultivation, harvesting and harvesting, irrational exploitation of ecosystems, introduction of exotic species, breeding, hunting, fishing, fish farming, charring of wood, bush fires) in the site whose extent on flora and vegetation is strong, special attention must be given to these threatened ecosystems, for their ecological development and their preservation as a regulator of local climate.
A study on the topography and51 the environmental aspects of the irrational occupations of the urban grounds of the Commune of Kisenso with Kinshasa was undertaken in order to determine the constructible zones on the basis of principle of the ekistics one. With this intention, it laid down two objectives: establishment of level lines on the whole of the surface of the Commune and the determination of the constructible zones. The results obtained make it possible to conclude that: the Commune of Kisenso is built on a hill whose altitudes lie between 325-450 Mr. the proportions of the slopes are variable:0-2 %; 2-4 %; 4-8 %; 8-12 %; 12-15 %.The establishment of the plan of the slopes made it possible to deduce the constructible zones from Kisenso with 40.70% and the unconstructible zones to 59.30%. Their surfaces rise respectively to 659.517334 ha and 962.122670 ha.However, the absence of induced adjustment of the free compartmental occupations of the constructible and marginal zones. The current number of the pieces of the Commune of Kisenso occupied freely is 2168. However, in accordance with the ekistics standards, Kisenso should contain 393 pieces. Thus, the uncontrolled extension of occupations of the grounds of the Commune causes erosions, floods, stranding which constitute recurring calamities at each rain season.
The town of Kinshasa, by its spectacular space extension is confronted with many environmental problems, in particular that relating to the land stock management.
Observations of ground supplemented by a socio-economic and demographic investigation into the management of the urban grounds in the Commune of Kisenso with Kinshasa were undertaken in order to release the repercussions environmental S rising from the dualistic management of the urban administration and usual Heads of the land resources. The results obtained reveal that:
- 60% of the surveyed pieces are directly affected by erosions including 55.2% exposed to erosions;
- 25% of the pieces are affected by floods and 15% by stranding;
Concerning the causes at the base of degradation of the grounds of the Commune, the results indicate the inexistence of networks of drainage of water, the bad topographic orientation of the dwellings as well as the lack of sumps in the pieces is 47.60 %, 19.40% and 16.40% respectively of the questioned people.
Lastly, the investigation into the causes of this ground management of the Commune accuses the absence of a policy of habitat, anarchy in the distribution of pieces and the dualistic administration of the land administration and usual Heads.
On one floristical, chorological and ecological analysis of secondary vegetation forest of Central Africa, one stratifition and phytosociological classification of secondary forests proposed by [1] is revised and extented at whole of the Central Africa. In on, one list of 302 characteristical species of different stages development and theirs majeurs geographical distribution in the Sub-Centers Low-Guinea and Congolian of the Regional Center of endemism Guineo- Congolian is stabilised. One stratification, and sames rules or recommandations of the International Code of Phytosociological Nomenclature 3nd edition 2000[2], three alliances, one sub-alliance and four associations phytosociological new of Central Africa secondary forests, accompanied by theirs diagnoses and types are proposed.