Assessing Future Vegetation Trends and Restoration Prospects in the Karst Regions of Southwest China

Xiaowei Tong,Chujie Liao,Rasmus Fensholt,Yuemin Yue,Kelin Wang,Martin Brandt

doi:10.3390/rs8050357

Abstract

To alleviate the severe rocky desertification and improve the ecological conditions in Southwest China, the national and local Chinese governments have implemented a series of Ecological Restoration Projects since the late 1990s. In this context, remote sensing can be a valuable tool for conservation management by monitoring vegetation dynamics, projecting the persistence of vegetation trends and identifying areas of interest for upcoming restoration measures. In this study, we use MODIS satellite time series (2001–2013) and the Hurst exponent to classify the study area (Guizhou and Guangxi Provinces) according to the persistence of future vegetation trends (positive, anti-persistent positive, negative, anti-persistent negative, stable or uncertain). The persistence of trends is interrelated with terrain conditions (elevation and slope angle) and results in an index providing information on the restoration prospects and associated uncertainty of different terrain classes found in the study area. The results show that 69% of the observed trends are persistent beyond 2013, with 57% being stable, 10% positive, 5% anti-persistent positive, 3% negative, 1% anti-persistent negative and 24% uncertain. Most negative development is found in areas of high anthropogenic influence (low elevation and slope), as compared to areas of rough terrain. We further show that the uncertainty increases with the elevation and slope angle, and areas characterized by both high elevation and slope angle need special attention to prevent degradation. Whereas areas with a low elevation and slope angle appear to be less susceptible and relevant for restoration efforts (also having a high uncertainty), we identify large areas of medium elevation and slope where positive future trends are likely to happen if adequate measures are utilized. The proposed framework of this analysis has been proven to work well for assessing restoration prospects in the study area, and due to the generic design, the method is expected to be applicable for other areas of complex landscapes in the world to explore future trends of vegetation.

Highlights

Vegetation has considerable impacts on almost all land surface energy exchange processes acting as an interface between land and atmosphere
To alleviate the severe rocky desertification in Southwest China, national and local Chinese governments have implemented a series of Ecological Restoration Projects (ERPs) to improve vegetation and ecosystem conditions since the late 1990s
Whereas a positive slope value indicates a positive trend in vegetation, a negative slope value refers to negative vegetation trends which can be an indicator of degradation

Summary

Introduction

Vegetation has considerable impacts on almost all land surface energy exchange processes acting as an interface between land and atmosphere. These fragile karst regions have been reported to undergo severe rocky desertification. This type of land degradation is a process where a karst area covered by vegetation and soil transforms into a rocky barren landscape, which is considered to be one of the most dangerous ecological and environmental problems in China [7,8,9]. To alleviate the severe rocky desertification in Southwest China, national and local Chinese governments have implemented a series of Ecological Restoration Projects (ERPs) to improve vegetation and ecosystem conditions since the late 1990s.

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Methods

Results

Discussion

Conclusion