Is Forest Restoration in the Southwest China Karst Promoted Mainly by Climate Change or Human-Induced Factors?

Abstract

Abstract:The Southwest China Karst, the largest continuous karst zone in the world, has suffered serious rock desertification due to the large population pressure in the area. Recent trend analyses have indicated general greening trends in this region. The region has experienced mild climate change, and yet significant land use changes, such as afforestation and reforestation. In addition, out-migration has occurred. Whether climate change or human-induced factors, i.e., ecological afforestation projects and out-migration have primarily promoted forest restoration in this region was investigated in this study, using Guizhou Province as the study area. Based on Moderate-Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) data, we found general greening trends of the forest from 2000 to 2010. About 89% of the forests have experienced an increase in the annual NDVI, and among which, about 41% is statistically significant. For the summer season, more than 65% of the forests have increases in summer NDVI, and about 16% of the increases are significant. The strongest greening trends mainly occurred in the karst areas. Meanwhile, annual average and summer average temperature in this region have increased and the precipitation in most of the region has decreased, although most of these changes were not statistically significant (p > 0.1). A site-based regression analysis using 19 climate stations with minimum land use OPEN ACCESS Remote Sens. 2014, 6 9896 changes showed that a warming climate coupled with a decrease in precipitation explained some of the changes in the forest NDVI, but the results were not conclusive. The major changes were attributed to human-induced factors, especially in the karst areas. The implications of an ecological afforestation project and out-migration for forest restoration were also discussed, and the need for further investigations at the household level to better understand the out-migration-environment relationship was identified.

Spatio-Temporal Variation and Impact Factors for Vegetation Carbon Sequestration and Oxygen Production Based on Rocky Desertification Control in the Karst Region of Southwest China

“…This study's results suggest that factors affected by humans have important effects on the pattern of CSOP in a typical karst region, and that rocky desertification control measures also had an important impact on the pattern of CSOP, which are similar to previous results for small scale vegetation in karst obtained by sampling [8,9,14,29]. Most of the previous studies showed that spatial variation in vegetation carbon density generally increased in a typical area between 2005 and 2010, and factors associated with human activities had relatively high impacts on the distribution of vegetation carbon density.…”

“…Karst regions are characterized by thin soil depth (generally not more than 10 cm), and poor surface water retention (infiltration coefficient of 0.3-0.6 or even 0.8) [9][10][11]. A degraded karst ecosystem may recover far more slowly than other ecosystems.…”

Increased vegetation growth and carbon stock in China karst via ecological engineering

“…Our results indicate that afforestation and conservation projects in southwest China can have a remarkable impact on vegetation cover and carbon stocks, which is in line with other research 2,[30][31][32][33][34][35] . Analysis shows that the total area of conservation projects impacts on leaf area index (LAI) and aboveground biomass carbon (ABC), with strong positive trends in counties of high conservation efforts and corresponding weaker trends in counties of little efforts.…”

NDVI-Based Analysis on the Influence of Climate Change and Human Activities on Vegetation Restoration in the Shaanxi-Gansu-Ningxia Region, Central China

“…The role of ecological restoration in sustainable development, especially the influence of interactions between climate change and human activities on vegetation growth processes has attracted increasing attention [5][6][7][8][9][10][11][12][13][14]. The Shaanxi-Gansu-Ningxia region is located in the middle of the Loess Plateau in central China.…”