Responses of spatiotemporal vegetative land cover to meteorological changes in Bangladesh

Quantifying the response of vegetation cover change (VCC) to climatic variables is a gap that is mandatory for the conservation and rehabilitation of natural landscapes to ensure sustainability. Based on temperature and rainfall data, the Normalized Difference Vegetation Index (NDVI) dataset, and district statistical data, we investigated the spatiotemporal variations of temperature, rainfall, urban land, and VCC in all the urban and suburban areas of Bangladesh during 1990-2018. To quantify the impact of urbanization on VCC, two regression models were built between growing-season NDVI (GNDVI) and proportion of urban land (PUL). Linear regression, Pearson's correlation, and Spearman correlation analysis were carried out to identify the temporal correlation among the variables. Results show that the rainfall, temperature, GNDVI, and PUL varied greatly among the districts. The inter-annual GNDVI was found to be closely related to diverse climatic variables, while the inter-annual GNDVI was moderately sensitive to climatic changes. A significant correlation was found between the trend of GNDVI and GP, while a negative correlation between the GNDVI trend and GT, GNDVI and PUL change. The strong sensitivity of GNDVI change to GP was calculated in the precipitation range of 2200-3000 mm and GNDVI to GT change in the temperature range of 300-31 degrees C. Besides, urban expansion was found mostly responsible for VCC in the study area. Unplanned urban developments would persist and accelerate diverse environmental changes and unsustainability. The findings of the study warn us about the need for sustainable landscape management and ecological preservation.