Satellite View of Vegetation Dynamics and Drivers Over Southwestern China

Abstract

Background: Vegetation is a key component of terrestrial ecosystems. The dynamics of vegetation can be used as an indicator of vegetation health and ecosystem stability. However, the dynamics and responses of vegetation in Southwestern China remain unclear.Methods: Both monotonic and turning point approaches were used in trend analysis to understand the dynamics of vegetation. We applied partial correlation analysis and the relative importance of climatic factors to determine the drivers of vegetation dynamics. Residual trend analysis was applied to distinguish other drivers.Results: The annual mean NDVI generally increased at a rate of 0.0011 year−1 from 1982 to 2015, but much of the study area showed the opposite trend before and after the turning point during this period. The vegetation in the western part of the study area was degraded and increased significantly in the eastern part of the study area. An increasing trend that continued to an increasing trend (II) and a decreasing trend that changed into an increasing trend (DI) were two of the largest patterns of vegetation trends, and they were mainly distributed in the eastern part of the study area. An increasing trend that changed into a decreasing trend (ID) was mainly distributed in the western part of the study area, where the vegetation types were mainly evergreen needle-leaved and grassland. Temperature was the dominant climatic factor and had a positive correlation with vegetation in the eastern part of the study area. Temperature also had some negative correlations with vegetation in western mountainous areas where surface soils are prone to droughts. Solar radiation had a positive correlation with vegetation in the western part of the study area. In addition, the regions with more intensity human activities than other areas were concentrated in the eastern part of the study area.Conclusions: The spatial distribution and trend showed high heterogeneity over Southwestern China. Temperature was the dominant climatic factor. In the eastern part of the study area, human activities played an important role in vegetation greening.

Analysis of Land Use and Land Cover Changes in Urban Areas Using Remote Sensing: Case of Blantyre City

“…Dynamic models are also used for determining the changes in and patterns of vegetation. Xue et al used dynamic models to show how diffusion and nonlocal delay interact to produce vegetation patterns in semiarid environments [16], Brhane et al used a mathematical model to investigate the effects of fire, rainfall, and competition for space on the dynamics of the savannah ecosystem [26], and Yan et al used least-squares linear regression to investigate vegetation dynamics and their relationships to climatic change in southwestern China [27].…”