Spatio-Temporal Assessment of Vegetation Health across the Nine States of Niger Delta Region of Nigeria Using Landsat and Avhrr/Modis Dataset (Published)
The Niger Delta region of Nigeria since the oil boom era of 1975 has undergone severe eco-environmental alterations associated with negative changes to the natural ecosystem particularly vegetation. This alteration is believed to cause unidentifiable changes in vegetation health, hence, the need for the spatio-temporal assessment of the vegetation health condition of the entire region. Multi-temporal Landsat remote sensing satellite images of 1986, 2002 & 2016 and AVHRR and MODIS dataset were used to generate the normalized difference vegetation index (NDVI) by creating a model in ArcGIS software. The generated NDVI results from Landsat disclosed that the general health condition of vegetation in 2002 was less than 1986 and 2016 poorer than 2002. Also, the inter-annual temporal analysis of the NDVI result showed that Years 2007 and 2008 recorded the healthiest vegetation condition while 1994 recorded lowest and monthly temporal analysis result indicated that lower vegetation condition was recorded in February and August while October recorded the highest. The mean NDVI values for each state of the study area revealed that the vegetation condition of the core oil producing states of Akwa Ibom, Bayelsa, Rivers, and Delta State were the most stressed as result of heavy alteration of the vegetation due to unwholesome activities of oil exploration/exploiting like gas flaring, oil spillage, pipe line vandalism etc. whereas Ondo, Edo, Abia, Cross River, Abia and Imo state that has not had similar heavy alteration had healthier vegetation condition. This study has proved that the oil and gas exploration and exploitation in the region is really altering the vegetation health condition of the region.