Research on the quantitative evaluation of grassland degradation and spatial and temporal distribution on the Mongolia Plateau

In this study, we used remote sensing technology to obtain a quantitative evaluation of the present situation of grassland degradation on the Mongolia Plateau. The time scale investigated was 1982 to 2013. We used NDVI data inversion vegetation coverage, and took vegetation coverage in the period 1982-1985 as the main indicator of ecosystem health. Furthermore, we calculated the grassland degradation index(GDI) and evaluated grassland degradation in the Mongolia Plateau during the period 1986-2013 to gain a quantitative estimate of the Mongolia Plateau grassland degradation time and space distribution characteristics. The results showed that the grassland vegetation coverage reached 14.60% and 18.43%, respectively, in the periods 1986-2000 and 2001-2013, with both showing an increase trend. The areas of significant(P<0.05) and highly significant (P<0.01) increase were 298.86 and 189.67 km2 in the period 1986-1999, respectively, and the areas of significant (P<0.05) and highly significant (P<0.01) increase were 443.32 and 92.46 km2 in the period 2001-2013, respectively. Compared with 1986, the worst grassland coverage was in 2007, whereas it was poor in 2001 and 1995. The best grassland coverage was recorded in 2013. In terms of the GDI, in the period 1986-1999, severely degraded grassland area had the largest area percentage(50.35%), whereas in the period 2000-2013, the percentage areas of moderately and seriously degraded grassland were 39.42% and 30.34%, respectively. Collectively,the results showed that grassland degradation conditions are improving on the Mongolia Plateau, from extremely serious and serious degradation to moderate and light grassland degradation.