Herbaceous Dominant the Changes of Normalized Difference Vegetation Index in the Transition Zone Between Desert and Typical Steppe in Inner Mongolia, China

Abstract

Asymmetric responses of aboveground net primary productivity (ANPP) to precipitation were identified as a signal to predict ecosystem state shifts at temperate grassland zones in Inner Mongolia, China. However, mechanism studies were still lacking. This study hypothesized that the enhanced growth and newly emerged herbaceous after increased precipitation resulted in the highest asymmetry at the transition zone between desert and typical steppe. We monitored the responses of the normalized difference vegetation index (NDVI) of different species to precipitation events using un-manned aerial vehicle technology to test this hypothesis. NDVI and species richness were measured twice at fixed points in July and August with a time interval of 15 days. Results showed that: (1) From July to August, NDVI in the transition zone increased significantly after precipitation (P < 0.05), but NDVI in both the desert and typical steppe showed a non-significant change (P > 0.05). (2) In the transition zone, NDVI increases from the shrub and herbaceous contributed to 37 and 63% increases of the site NDVI, respectively. (3) There was a significant difference in species richness between July and August in the transition zone (P < 0.05), mainly caused by the herbaceous (Chenopodiaceae, Composite, Convolvulaceae, Gramineae, Leguminosae, and Liliaceae), which either emerged from soil or tillers growth from surviving plants. This study demonstrated that herbaceous dominant the changes of NDVI in the transition zone, which provides a scientific basis for the mechanism studies of ANPP asymmetric response to precipitation and warrants long-term measurements.

Characterization and attribution of vegetation dynamics in the ecologically fragile South China Karst: Evidence from three decadal Landsat observations

“…The normalized difference vegetation index (NDVI) constructed by the red and near-infrared spectral bands is considered to be closely related to vegetation coverage and productivity ( Huete et al., 2002 ), which makes it one of the most widely utilized remotely sensed indices to investigate vegetation dynamics across global and regional levels ( Myneni et al., 1997 ; Pinzon and Tucker, 2014 ; Zhou et al., 2020 ; Lv et al., 2022 ). Numerous studies have employed time series of NDVI data to examine the vegetation variations in the South China Karst region since the launch of the ecological engineering around 2000 ( Cai et al., 2014 ; Wang et al., 2015 ; Tong et al., 2016 ).…”

Seasonal Response of the NDVI to the SPEI at Different Time Scales in Yinshanbeilu, Inner Mongolia, China

“…Most of Yinshanbeilu has arid and subarid areas; however, due to global warming, relevant studies have shown that the climate warming trend in this region has already been more pronounced during the last two decades. Moreover, annual precipitation is increasing, which has alleviated the degree of drought in Yinshanbeilu to a certain extent [46,47].…”

Plant biotype interacting grazing activity shapes grassland ecosystem functions

“…In contrast, soil–plant interactions and species coexistence in both desert and typical steppes are mainly affected by water availability (Chen et al, 2022). Precipitation in July and August plays a critical role in driving net primary productivity of grasslands in the typical to desert steppe transition zone (Lv et al, 2022). During the extended drought period, the growth of shallow‐rooted plants can be severely suppressed, and the degree of the influence can vary with soil properties (Tian et al, 2022).…”