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

Abstract

Abstract:The Grain to Green Program (GTGP) and eco-environmental emigration have been employed to alleviate poverty and control rocky desertification in the Southwest China Karst region. Carbon sequestration and oxygen production (CSOP) is used to indicate major ecological changes, because they involve complex processes of material circulation and energy flow. Using remote sensing images and weather records, the spatiotemporal variation of CSOP was analyzed in a typical karst region of northwest Guangxi, China, during 2000-2010 to determine the effects of the Chinese government's ecological rehabilitation initiatives implemented in 1999. An increase with substantial annual change and a significant increase (20.94%, p < 0.05) in variation were found from 2000 to 2010. CSOP had a highly clustered distribution in 2010 and was correlated with precipitation and temperature (9.18% and 8.96%, respectively, p < 0.05). CSOP was significantly suppressed by human activities (p < 0.01, r =´0.102) but was consistent with the intensity of GTGP (43.80% positive). The power spectrum of CSOP was consistent with that of the gross domestic product. These results indicate that ecological services were improved by rocky desertification control in a typical karst region. The results may provide information to evaluate the efficiency of ecological reconstruction projects.

Karst landscapes of China: patterns, ecosystem processes and services

“…Soil patches may receive nutrients from direct atmospheric deposition and runoff from surrounding areas. When the rock-to-soil patch area ratio is 7:3 or higher, the contribution of rock outcrops on water and nutrients redistribution likely exceeds that of atmospheric deposition (Zhang et al 2016). Consequently, a higher proportion of rock outcrops may be linked to higher soil nutrients (Zhang et al 2006(Zhang et al , 2007b.…”

“…Consequently, landscape pattern may be variable even in areas with a high percentage of rock outcrops. Different combinations of soil patches and rock outcrops create various niches for vegetation communities and, in places, the amount of nutrients available from soil patches may be sufficient to support tree growth (Zhang et al 2016). Given similar vegetation cover, soil water and nutrients are generally higher in soil patches around large rock outcrops because of larger runoff volumes from bare, rock surfaces and shading effects (Hu et al 2018).…”

“…Many comprehensive ES studies have been conducted for KRD ecosystems (e.g., Guo et al 2013;Zhang et al 2014;Gao and Xiong 2015) and individual ES (e.g., vegetation carbon sequestration, water regulation, soil conservation; Zhang et al 2014Zhang et al , 2015aZhang et al , 2016. More regional assessments of ES dynamics have been completed at karst recovery demonstration sites, watershed, county, prefecture and provincial levels (e.g., Zhang et al 2009a;Zhou et al 2011;Tian et al 2016).…”

“…Consequently, the question of the degree to which ecological engineering has contributed to the recovery remains open. As a step forward, residual analysis has been conducted to separate the effects of climate variation from other impacting factors on ES dynamics (e.g., Zhang et al 2016). A dynamic vegetation model (LPJ-GUESS) was used to simulate Leaf Area Index and aboveground biomass carbon dynamics without conservation practices with results compared to reference satellite data (Tong et al 2018).…”

Emergy and Economic Evaluation of Seven Typical Agroforestry Planting Patterns in the Karst Region of Southwest China

“…To reduce the rate of land degradation and to promote ecological and economic development, the government of the People's Republic of China started the nationwide comprehensive management of rocky desertification in 2008 and the Grain for Green Program (GGP) to convert cropland to grassland and forest, in 1999 [6]. Until 2017, a total area of 66,000 km 2 in 451 rocky desertification counties has been subjected to vegetation restoration work, fruit tree planting, forage cultivation, cattle raising, among others [7].…”