Water conservation is a crucial functional aspect of ecosystem service. Revealing the temporal and spatial changes in water conservation and exploring the factors influencing those changes are of great significance for the utilization of water resources and the construction of ecological civilization. In this study, we estimated the water conservation changes in Jiangxi over the 20 years from 2000 to 2020 by the rainfall storage method. Thereafter, the GeoDetector was applied to analyze the contributions from various factors, including climatic variations and ecosystem transformations, to the changes in the water conservation. The results showed three important trends. (1) From 2000 to 2020, farmland, grassland, water and wetland dominated the northern part of the Poyang Lake Basin except for the forests. The transformations of ecosystem types in the study area mainly occurred between forests, farmland and towns in the 20 years. During this period, the urban area showed a significant increase of 92.63%, while the other ecosystem types showed decreasing trends. (2) The province’s water conservation function declined from 2000 to 2020, with a total loss of 97.11×10⁴ m³ km^-2, and in the study area it is characterized as high in the east and west and low in the middle. (3) Factorial analysis showed that the changes in the water conservation were not caused by any one factor alone. The q values of ecosystem type change interactions with the changes in annual precipitation, annual temperature and sunshine hours calculated by the GeoDetector were 0.555, 0.541 and 0.501, respectively. Therefore, the interactions between factors contributed 50% more than the single factors in affecting the changes of water conservation.

Given the high degree of fragmentation and poor resistance to disturbance in karst landscapes, it is important to clarify the spatial and temporal dynamics of landscape patterns in karst areas when designing karst ecological protection strategies. Using the Li River Basin as the study area, the spatial distribution and dynamic evolution of landscape patterns in the basin were analyzed at the levels of landscape utilization, landscape type dynamics and landscape pattern indices based on the Landsat series images for 2000 to 2020 obtained from the GEE platform as the data source. The results show three important aspects of this typical karst watershed. (1) There are large differences in landscape structure and landscape type trends between the karst and non-karst areas in the Li River Basin. (2) The comprehensive landscape type dynamic attitude of the Li River Basin is 0.22%, and the composite index of landscape type use varies from 239.49 to 244.88. The degree of landscape use is higher in karst areas than in non-karst areas, and the rate of landscape change in karst areas is more intense. The integrated index of landscape use in karst areas ranges from 262.32 to 270.50, and in non-karst areas it spans 225.28 to 227.01. The integrated landscape type motility in the karst areas is 0.31%, which is about twice as high as that in non-karst areas. (3) The overall landscape evolution of the Li River Basin shows trends of increasing fragmentation, decreasing connectivity, decreasing dominance and increasing heterogeneity, and these trends are particularly prominent in the karst areas. The results of this study can provide a scientific basis for realizing the construction goals of the National Sustainable Development Innovation Demonstration Zone in Guilin, and a technical reference for the ecological environmental management of the karst watershed.

Based on the land use data of 2000, 2010, and 2018, ArcGIS, Fragstas, and GeoDa software were used to assess the spatial and temporal evolution of ecosystem service value (ESV) and landscape ecological risk (LER) in the Jinsha River Basin from 2000 to 2018. Their relationship was subsequently examined using bivariate spatial autocorrelation and spatial regression models. The results indicate three important aspects of this system. (1) Between 2000 and 2018, the woodland, grassland, water area, and construction land rose, while the cultivated land and unused land declined, among which the decrease in unused land and the increase in construction land were more prominent. (2) From 2000 to 2018, the value of ecosystem services in the study area increased by 73.09 billion yuan, from 2018.89 billion yuan to 2091.98 billion yuan, while the overall landscape ecological risk index decreased from 0.01029 to 0.01021. The areas occupied by both low-risk and high-risk areas increased, indicating that the ecological environment in the region as a whole has been improving. However, there are still localized areas with deteriorating ecological conditions. (3) There is a positive spatial correlation between landscape ecological risk and ecosystem service values in the study area, demonstrating a high-risk-high-value clustering characteristic, and the landscape ecological risk has a positive effect on the value of all ecosystem services, particularly the value of the regulation services. The findings of this study can be used as a guide for reducing regional ecological risks, enhancing ecosystem services, and enhancing the quality of the ecological environment in the basin.

The compensatory effect and deep impact of the fruit tree economic forest on water and soil conservation ecology in a semi-arid region are investigated by exploring the ecological service value and ecological functions of the fruit tree economic forest, and further by analyzing its functional effects on reducing water and soil loss, conserving water and soil, conserving the water source, improving environmental quality and maintaining biodiversity. This analysis provides a theoretical basis and support for coordinating the relationship between economic and social development, ecological protection, agriculture and forestry in the semi-arid area of the Loess Plateau; promoting the systematic management of mountain, water, forest, farmland, lake grass and sand; and promoting the ecological protection and high-quality development of the whole Hulu River Basin. According to the Standards for Evaluation of Forest Ecosystem Service Function (GB/T38582-2020), the forestry industry standard of the People’s Republic of China, the current market method, shadow price method, opportunity cost method, Swedish Carbon Tax law and other methods were adopted. The main functions of the fruit-tree economic forest ecosystem and its eco-economic value in the Hulu River Basin in Pingliang City were quantitatively analyzed, and the existing measured data from domestic ecological stations were combined with quantitative analysis and qualitative evaluation. The calculations included the ecological service values of the fruit tree economic forest ecosystem in water conservation, soil conservation, carbon sequestration, oxygen production, nutrient accumulation, environment purification and biodiversity protection, and the dynamic change characteristics of the ecological function quantity corresponding to its value were systematically analyzed. (1) In the four developmental stages of the fruiting economic forest in the Hulu River Basin in Pingliang City, the ecological function service value showed an increasing trend. Among the stages, the total value contribution of the first stage (2005-2009) is 1.299×10¹⁰ yuan; the second stage (2010-2013) is 2.497×10¹⁰ yuan; the third stage (2014-2017) is 2.662×10¹⁰ yuan; and total value contribution of the fourth stage (2018-2020) is 2.774×10¹⁰ yuan. (2) In the composition of the ecological functional service value of the fruit tree economic forest, the value of water conservation is the highest, accounting for the largest proportion at 32.97% of the total value of ecosystem services. Therefore, it plays an important role in regulating the hydrological balance of the basin in the arid and semi-arid region of the Loess Plateau. The function value of the purifying environment is relatively small, accounting for only 0.19% of the total value, followed by the function value of species conservation, accounting for 5.42%. In order of service value, the ecological function values of water conservation, oxygen release, carbon sequestration, nutrient accumulation, soil conservation, fertility maintenance, species conservation and environment purification accounted for 32.97%, 25.94%, 11.63%, 11.34%, 6.37%, 6.14%, 5.42% and 0.19% of the total value, respectively. The conclusions of this study are basically consistent with other domestic studies. Compared with the annual output value of fruit trees in the same period, the total value of ecological services was 2.42 times of the annual output value of the fruit. Therefore, the fruit tree economic forest not only provides a large amount of fresh fruit products and creates tremendous economic and social benefits for the people, but it also provides a major increase in ecological service value, and the contribution of local GEP is greater than that of GDP. (3) After accounting, the water conservation amount of the fruit tree economic forest (2005-2020) in the Hulu River Basin in Pingliang City was 2.586×10⁹ m³, with 2.135×10⁹ t of soil fixation, 2.264×10⁵ t of fertilizer retention, 9.568×10⁶ t of carbon fixation, 2.562×10⁷ t of oxygen production, 9.278×10⁵ t of nutrient accumulation, and 1.137×10⁵ t of environmental purification function (and within that function, the amount of sulfur dioxide absorbed is 94656.02 t, the amount of fluoride absorbed is 1793.82 t, the amount of nitrogen oxide absorbed is 6406.50 t, and the amount of dust fall is 10794.95 t), and the amount of negative ions provided is 1.564×10²⁵, which greatly regulates and improves the ecological environmental quality of the region.

The investigation of carbon storage in ecosystems and its driving factors is crucial for understanding carbon cycling and achieving the goal of carbon neutrality. The grassland in the Northern Tibetan Plateau is an important grassland ecosystem in China, although the accurate estimation of its carbon stock and our knowledge of its spatial patterns and driving factors in the Northern Tibetan Plateau remain unclear due to insufficient field investigations. In this study, a dataset of 150 measured sample points on the Northern Tibetan Plateau, kriging interpolation and statistical methods were used to estimate the densities of aboveground biomass carbon, belowground root carbon and soil organic carbon at a soil depth of 30 cm, as well as to explore the spatial distribution and the main influencing factors of each carbon pool. The average carbon densities were 0.038 kg C m^-2 in aboveground biomass, 0.284 kg C m^-2 in belowground biomass, and 7.445 kg C m^-2 in the soil. The soil organic carbon accounted for 95.85% of the grassland carbon density. The total carbon storage of the grassland ecosystem in the Northern Tibetan Plateau was about 4.08 Pg C, with a decreasing trend from southeast to northwest. Of the total, the organic carbon stocks of vegetation and soil were 0.58 Pg C (including the aboveground and belowground biomass) and 2.58 Pg C, accounting for 28.29% of the total vegetation carbon and 26.60% of the total soil carbon, respectively, on the Tibetan Plateau, with the remainder stored in the bare land. While the precipitation, temperature and soil texture all affected the ecosystem carbon storage, precipitation played the most significant role and the combination of these three factors explained up to 86.47% of the aboveground carbon density. The aboveground carbon pools in grassland ecosystems of the Northern Tibetan Plateau were most sensitive to climatic factors, while the spatial patterns of belowground and soil carbon storage were more complex. This study provides a spatially accurate assessment of the carbon storage in the grasslands on the Northern Tibetan Plateau.