Characterising changes in urban landscape of Nairobi city, Kenya.

摘要

Landscapes in urban areas especially in developing countries are under pressure due to increasing population of urban dwellers and un-directed spread of city boundaries. Sound urban environment plays important aesthetic, ecological, cultural, social and engineering roles beneficial to the people. To support better management of vegetated sites, it is necessary to understand the spatial configuration at the landscape scale and changes that have occurred. We studied the change in landscape characteristics of the Nairobi city's metropolitan region, using Landsat satellite data for the last three decades. Image data were processed on GIS platform and classified into categories of land use/land cover types. Using the classified images as input for analysis, landscape change was evaluated to characterize the landscape change trends. Significant changes were observed in the spatial configuration of the landscape between 1976 and the year 2000 status. Land uses related to human activities such as built areas increased to the detriment of wetland and vegetated areas. It is expected that if the current trend of development continues, the landscape will experience more pressure and get more fragmented. Such human-mediated alterations may significantly affect the way ecosystem processes within the landscape will respond and how they will impact on peoples' lives. To safeguard the natural greenery, the city planning authorities need to enforce regulatory measures to direct spread of the city in a more strategic way.