Remote sensing investigation to the distribution and change of karst rocky desertification from 2003 to 2015 in the Nayong area of Guizhou based on Landsat-X GEVI

Karst rocky desertification is a fragile ecological environment that puzzles the development of karst areas in southwest China. In order to understand the improvement of karst rocky desertification in the Nayong area of Guizhou, the authors extracted the scale information of karst rocky desertification in 2003 and 2015 by using the improved enhanced vegetation index model (GEVI) method based on Landsat data, which is 540.06km2 and 390.99 km2, respectively. Comparison of data over these two periods shows that the area of karst rocky desertification in this area has been reduced by 149.07 km2, and the improvement rate has reached 12.88%, especially in the areas of severe rocky desertification (such as Chaoyanggu, Lanba and Maochang), which have been distributed in vast swaths previously. It is also found that the karst rocky desertification in this area is migrating from southwest to northeast, with an area of 289.47 km2, dominated by a moderate degree. It indicates that the control and destruction are synchronized, and the control task remains a great challenge. Nevertheless, the total area of karst rocky desertification is reduced and ecological conditions show a benign development trend, reflecting the effectiveness of comprehensive efforts in recent years.