The local experts' perception of environmental change and its impacts on surface water in Southwestern Nigeria

In this study, we investigated whether environmental changes (climatic conditions, deforestation and surface water) in the woodland savanna and rain forest zones of Southwestern Nigeria, as observed by the rural communities' local experts', can be used to evaluate Land cover change (LCC) in the region. LCC was conducted using orthorectified Landsat multi-temporal imagery for 1970/1972, 1986/1987, 2000/2001 and 2006 using maximum likelihood classification and change detection techniques. The results showed a decrease in the forest area and an increase in built-up and cultivation/others (open space, bare land, grassland) areas. Between 1972 and 2006, forest reduced by about 50% while built-up areas increased by about 300%. A Participatory Learning Approach (PLA) involving experienced elderly local experts above 65 years old was conducted to assess their observations in the region on (i) LCC and (ii) the causes of water shortage, and (iii) the associated risk and adaptation/recommendation. The communities' local experts reported that changes in climatic condition, deforestation in the last 30 years and constructions of surface storages (reservoirs) are the major factors responsible for declining surface water in the region. There is thus, a good corroboration between the results of remotely sensed data of LCC assessment and the communities' local experts' observations of land cover changes and changes in surface water resources in the region. The study therefore inferred that LCC map products-information could be used in a participatory approach involving the communities to assess the impact of environmental change on an important service of forest ecosystems such as fresh water resources.