Geospatial Assessment of Forest Fragmentation and its Implications for Ecological Processes in Tropical Forests

摘要

The study assessed the patterns of spatio-temporal configuration imposed on a forest landscape in Southwestern Nigeria due to fragmentation for the period 1986 – 2010 in order to understand the relationship between landscape patterns and the ecological processes influencing the distribution of species in tropical forest environment. Time-series Landsat TM and ETM satellite images and forest inventory data were pre-processed and classified into four landuse/landcover categories using maximum likelihood classification algorithm. Fragstats software was used for the computation of seven landscape and six class level metrics to provide indicators of fragmentation and landscape connectivity from the classified images.The result shows that although deforestation reduced between 2000 and 2010, fragmentation, however intensified during the 24 years period. Fragmentation was highest between 1991 and 2000, leading to significant landscape variability, alteration in the general biotic and abiotic conditions and exchange of material and energy. While it appears that overall forest area increased between 2000 and 2010, connectivity and biodiversity indicators declined the most during this period. The resulting scenario is that forest fragmentation, despite the control of deforestation in the last decade of this study have certainly not receded in the study area. This may continue to have subtle negative impact on exchange of material and energy in the ecosystem, contribute to increased depletion of vital forest resources and the disappearance of wildlife from previously known areas.