干旱区生态环境知识资源中心

Owing to its impact on global ecosystem, climate change and related effects is being perceived as a serious issue worldwide especially in the arid and semi-arid regions. Climatic variability has been considered as a major cause for degradation of natural resources. Desertification caused by climatic or human-induced processes negatively affects the productivity of land within an ecosystem. It is noteworthy that depletion of vegetation cover plays a key role in land degradation; in fact reduction in plants and perennial cover is regarded as an indicator of the onset of desertification. Temporal analysis of satellite-based NDVI is one of the major remote sensing tools which can identify the depletion of vegetation cover. In the present study, rain-use efficiency (RUE) method has been used for monitoring vegetation degradation and, substantially, the process of desertification in western Rajasthan. RUE, the ratio between normalized growing season NDVI and rainfall, has been calculated for individual years (1983-2013). A correlation analysis was carried out by considering yearly RUE as dependent variable and time (years) as the independent variable. It shows that regression slope of RUE mainly depends upon the dynamic condition of integrated NDVI and rainfall. In order to monitor the areas under human-induced desertification, the residual trend method has been adopted. The correlation between rainfall and NDVI was found significant (p < 0.05) except some portion in the middle east. The study reveals that about 35% of the total area has experienced high human-induced desertification process.