Spatiotemporal analysis of vegetation cover changes around surface water based on NDVI: a case study in Korama basin, So

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ORIGINAL ARTICLE

Spatiotemporal analysis of vegetation cover changes around surface water based on NDVI: a case study in Korama basin, Southern Zinder, Niger Mohamed Adou Sidi Almouctar1   · Yiping Wu1 · Amit Kumar2 · Fubo Zhao1 · Koroma John Mambu3 · Mohammed Sadek1 Received: 22 June 2020 / Accepted: 20 November 2020 © The Author(s) 2020

Abstract In the modern era, vegetation dynamics is an important aspect of climate change studies. The present study examined spatiotemporal changes of (NDVI) normalized difference vegetation index in the Korama basin (Southern Zinder of Niger) from 2000 to 2018, and their correlation with climatic factors was predicted. To analyze the change of vegetation cover, geographical information system, MODIS_NDVI, remote sensing, and climate variables (e.g., temperature and precipitation) datasets were used. Further, the correlation was performed for different years of vegetation types during the growing season (June–October). Our results show an increasing trend in average maximum annual NDVI across the Korama River Basin in the years 2000 and 2018. Conversely, significantly increasing trends in most of the areas were reported. Moreover, in downstream the vegetation cover is increased in Matameye and Magaria, but with a smaller increase in the upstream rate in Mirriah. Furthermore, a decrease in the surface water was observed in the Tessaoua, Matameye, and Magaria sections of the study region in 2000 and 2018, while a rise in water surface area was observed in Matameye and Magaria in the years 2006 and 2012. During rainy and dry seasons, NDVI correlated differently with temperature and precipitation with strong seasonal variations, while the mean vegetation period of NDVI does not show any significant change. In addition, moderate increase was observed in years 2000 and 2012 (r: 0.22; P: 0.50; R2: 0.05; r: 0.31; P: 0.34, R2: 0.10, respectively), and weak decrease in 2006 and 2018 (r: 0.61; P: 0.04; R2: 0.37; r: 0.58; P: 0.06, R2:0.33, respectively). The analysis indicates that climatic parameters such as precipitation and temperature are the main limiting factors affecting the vegetation growth. Indeed, the trends calculated by the correlation analysis showed that as climate factors increased (July, August, and September), the NDVI value increased at a rate of 0.16, reflecting the best growth in vegetation and rise in water bodies, although significantly decreased during years. This study would be highly useful in choice-making for sustainable water resource management in the Korama watershed in Southern Zinder, Niger. Keywords  GIS · NDVI · Remote sensing · Spatiotemporal changes · Surface water · Zinder Abbreviations NDVI Normalized difference vegetation index GIS Geographic information system

DEM Digital elevation model FVC Fractional vegetation cover CRU​ Climatic research unit

* Mohamed Adou Sidi Almouctar [email protected]

Mohammed Sadek [email protected]

* Yiping Wu [email protected]

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Departement of Earth and Environmental Science, School of Human Settl