Urbanization is a landscape transformation process that is manifested by spatial expansion relative to human development. The present study aimed at the characterization of the spatio-temporal dynamics of Niamey city over the past 38 years (1975-2013) through a diachronic analysis of Lands at satellite images and application of landscape ecology principles. It sought to: (i) analyze the spatiotemporal pattern of land use land cover change of Niamey city and (ii) identify the driving forces for the land use land cover change in Niamey and their implications. Thirteen LULC classes were identified and grouped into three broad categories namely "Built-up area", "Agricultural zone" and "Vegetation area". The "Agricultural zone", more specifically the class "Rain-fed farmland" represent the landscape matrix (over 37% of the landscape) throughout the period considered for the study. "Built-up area" dominated by "suburb quarter" experienced its lowest expansion rate during the interim period T2 (1989-1999).Analysis of the landscape spatial structure and configuration revealed that the landscape is fragmentation and highly heterogeneous. In general, urbanization in Niamey could be characterized by progressive densification and sprawl along communication lines.

Balanites aegyptiaca est l'une des plantes à usages multiples au Niger très appréciée par les populations. Cette étude conduite au Centre Régional de Recherche Agronomique de Zinder, vise à étudier la germination et l'évolution des plantules de cette espèce. Les essais de germination ont été effectués dans des planches rectangulaires sur six types de traitements pendant 3 mois et le suivi de croissance des plantules dans des pots plastiques enfouis dans le sol pendant 6 mois. L'étude a montré que l'ingestion des fruits de Balanites aegyptiaca par les chèvres réduit significativement la dormance tégumentaire. Les graines extraites des noyaux qui ont transité par le tractus digestif des chèvres ont le taux de germination le plus élevé (76,87%) et le taux de germination le plus faible a été obtenu avec les fruits entiers (38,12%). Après 6 mois de suivi, la croissance du pivot racinaire des plantules (78,59±9,04 cm) est plus importante que celle de la partie aérienne (61,8±6,2 cm). Cette étude permet d'envisager la production des plants de Balanites aegyptiaca en vue de sa conservation durable.

Prosopis africana is a species of great socio-economic importance, threatened with extinction from its natural habitat in Niger due to overexploitation. The main objective of this study is to determine the potential geographic distribution of P. africana in Niger. Climatic and botanical data has been collected and used to model the distribution, on the basis of principle of maximum entropy (MAXENT) using MAXENT 3.3.3k, DIVA-GIS 7.5, and ArcGIS 10.0. programs. Rainfall and temperature are the most significant variables in the distribution of P. africana in Niger. Thus the southern band of the country (from the sudanian zone to the sahelio-soudanian zone), the wettest, is the area conducive to the development of P. africana (128,692.32 km 2 in total, 10.16% of the territory). Given the extent of this area revealed by this study, a reforestation policy implementation of P. africana would allow to restore its stands in Niger.

Wastewater treatment is a problem with much acuity in the city of Maradi in general, and particularly in the Communal District I of Maradi. It is for this reason that the present study was conducted which deals with wastewater sanitation. The main objective of this study conducted through a survey is to investigate in the domestic wastewater sanitation in the Communal District I of Maradi city. Specifically, the study aims to estimate the amount of wastewater produced by households and to analyze the sanitation system at household and at district levels. The wastewater management practices in this district were assessed through a descriptive cross sectional study in which a total of 129 households were selected by sample distribution technique in the district neighborhoods and studied using interviewer and administered questionnaires at communal and household levels. The results of the study showed that the amount of domestic wastewater generated is quite large, about 32.27 m 3 per person per day, and this comes from several sources including showers, laundry, dishwashing and income generating activities. The results also revealed that the unhealthy state of the Communal District I of Maradi is related to the absence of a wastewater treatment system, the methods and practices used in its management, and the population is also largely responsible for this unhealthy state and not willing to participate to a sanitation project.

This study was undertaken to obtain direct and useful data that support biodiversity awareness and management in two cities of Niger. 800 questionnaires were administrated to the populations of Niamey and Maradi. The results show that 99% of respondents are aware of the importance of biodiversity in urban areas. They assign multiple roles to it; however, climatic and managerial reasons explain why plants are most preferred to animals in these cities. Furthermore, shade and fruits are the criteria for plant species selection, and that explains the abundance of Azadirachta indica A. Juss. and Mangifera indica L. Even though plants are preferred to animals in houses, 47% of the respondents practice animal husbandry. Most of the animals are left wandering with risks of destruction of green areas, road unsafety, and zoonotic contamination. The results of this study also showed the ignorance of 55% of the respondents about the presence of wildlife in urban areas. The proliferation of cockroaches and rats could be an indication of insanitary conditions that are faced in some areas of the cities as mentioned by 81% of the respondents. This study shows the importance of local knowledge in the identification process of urban problems.