The Upper Yellow River is the most important area for water retention and flow production in the Yellow River basin, and the statuses of the ecosystems in this region are related to the ecological stability of the whole Yellow River basin. In this paper, the fractional vegetation cover (FVC), net primary productivity (NPP) of vegetation and water retention, soil retention, and windbreak and sand fixation services of the Upper Yellow River ecosystems were analysed from 2000 to 2019 with the trend analysis method. Ecological restoration degree evaluation indices were constructed to comprehensively assess the ecological restoration situation and restoration potential of the ecosystems in the Upper Yellow River region over the past 20 years and to quantitatively determine the contribution rates of climate factors and human activities to these ecosystem changes. The results showed that the settlement ecosystem area exhibited the greatest increase, while the grassland ecosystem area decreased significantly over the study period. In the Upper Yellow River region, the ecosystem quality and ecosystem services generally remained stable or improved. Areas with moderately, strongly and extremely improved ecological restoration degrees accounted for 32.9%, 21.0% and 2.8% of the entire Upper Yellow River region, respectively. Areas with strongly improved and extremely improved ecological restoration degrees were mainly distributed in the Loess Plateau gully areas and on the eastern Hetao Plain. The contribution rates of climatic factors and human activities to the NPP changes measured in the Upper Yellow River were 81.6% and 18.4%, respectively, while the contribution rates of these processes to soil erosion modulus changes were 77.6% and 22.4%, respectively. The restoration potential index of the FVC in the Upper Yellow River was 22.7%; that of the forest vegetation coverage was 14.4%; and that of the grassland vegetation coverage was 23.0%. Over the past 20 years, the ecosystems in the Upper Yellow River region have improved and recovered significantly. This study can provide scientific support for the next stage of ecological projects in the Upper Yellow River region.

As an important vegetation parameter and ecological index, vegetation net primary productivity (NPP) can intuitively reflect changes in the ecological environment and the level of the carbon budget. However, the change trend of NPP and its recovery potential in China over the past 20 years remain unclear. Here, we used trend analysis, multiple regression analysis and residual analysis methods to analyse the change trend in the NPP of China’s terrestrial ecosystems from 2000 to 2019, as well as the climax background, restoration status and restoration potential of the NPP of forest, grassland and desert ecosystems. The results showed that (1) the change in vegetation NPP in China from 2000 to 2019 showed a continuous upward trend, with a change slope of 2.39 gC/m²/a², and the area with a positive slope of change accounted for 68.10% of the country’s land area. The contribution rates of meteorological conditions and human activities to vegetation NPP changes were 85.41% and 14.59%, respectively. (2) The results obtained by the regression analysis method of meteorological conditions based on nature reserves could reflect the zonal climax vegetation status to a large extent, and the obtained values had a smooth transition within each ecogeographical division and between each ecogeographical division, which truly reflected the law of gradual change in climate, vegetation and natural conditions. The annual total NPP of the climax background vegetation in China’s forest, grassland and desert ecosystems was approximately 2.76 ± 0.28 PgC, and the annual total NPP of the three ecosystems was 1.90 ± 0.2 PgC, 0.80 ± 0.07 PgC and 0.009 ± 0.0005 PgC, respectively. (3) The annual total vegetation NPP of the restoration status of China’s forest, grassland and desert ecosystems was 2.24 PgC, and the annual total vegetation NPP of the three was 1.54 PgC, 0.65 PgC and 0.007 PgC, respectively. Benefiting from the effective implementation of climate warming and humidification and ecological engineering, the agro-pastoral zone, the Loess Plateau, the eastern Sichuan Basin and the Greater Khingan Range had the most significant increases in the past 20 years. (4) The annual total vegetation NPP of China’s forest, grassland and desert ecosystem restoration potential was approximately 0.52 ± 0.28 PgC, which accounted for approximately 19.05% of the annual total NPP of the climax background vegetation. The annual total vegetation NPP of forest, grassland and desert ecosystems restoration status was 0.36 ± 0.2 PgC, 0.16 ± 0.07 PgC and 0.002 ± 0.0005 PgC, respectively; the restoration potential accounted for 18.80%, 9.67% and 23.95% of the climax background vegetation NPP, respectively. The deployment of ecological projects should fully consider the restrictive climate conditions for decision makers and ecological scholars, and the benefits and costs of the projects should be considered comprehensively.

The Three-River Headwaters Region (TRHR) is an important part of the ecological barrier of the Qinghai–Tibet Plateau. Understanding the TRHR’s major ecosystem service trade-offs and synergies is important for scientifically integrating and optimizing ecosystem services. We studied the spatial–temporal changes, trade-offs and synergies of the TRHR’s water retention (WR), soil retention (SR), windbreak and sand fixation (WD) and forage supply (FS) services from 2000 to 2019. The results showed that: (1) The TRHR’s WR, SR and FS services gradually decreased from east to west in space, and showed an increasing trend between years; the WD service gradually decreased from west to east in space, and showed a downward trend between years. (2) The synergistic relationship was the dominant relationship between the TRHR’s grassland regulation and provision services. Future research on ecosystem service trade-offs and synergies should consider both the type of ecosystem services and the ecosystem’s multifunctionality. (3) The improvement of the TRHR’s ecosystem services in the future needs to focus on improving the fraction vegetation coverage (FVC) through ecological engineering measures in Maduo, and other areas near the 400 mm precipitation line, and enhancing the synergy of ecosystem services. (4) The restoration of TRHR FVC needs to consider the difference in natural endowments. It is recommended to adopt near-natural restoration in the northwest of the TRHR, and avoid setting too high restoration targets. Planting high-quality pastures in the southeast of the TRHR with good water and heat conditions and rationally allocating grassland ecological and production functions are recommended measures. (5) The TRHR’s grassland should give priority to the development of the ecological functions of natural grasslands, and then give full play to its production functions. Overgrazing is strictly prohibited, so as to avoid the “over-transformation” of ecosystem regulation services to supply services.

Coastal regions stand as pivotal zones of interaction between the marine and terrestrial environments, holding substantial significance for both ecosystems and human societies. Since the 1980s, China’s coastal zones (CCZ) have undergone rapid economic expansion, a surge in urban development activities, and a considerable population increase, instigating significant alterations in land use along the coast. However, in recent years, studies regarding changes in land use along China’s coastal zones have been notably scarce. Utilizing the Comprehensive Lands Cover Database (CLCD) dataset, this study scrutinized the spatiotemporal patterns of land use along the Chinese coastline since 1985. It delved into the temporal and spatial variations in land use, ecological land transformations, and the spatiotemporal evolution of land use development intensity, examining these facets across provinces, municipalities, and different distance bands from the coastal zone. The research findings indicated: Overall, cropland and forest land predominantly occupied coastal zones, encompassing over 80% of the total area. Between 1985 and 2020, the primary changes involved a decrease in cropland and an increase in construction land, with a reduction of 5.97% in cropland, largely transitioning into construction land (84927.21 km²) and forest land (4218.55 km²), resulting in a 5.98% increase in construction land. Despite the intensification of land development, ecological land exhibited an initial rise followed by a declining trend. There existed distinct disparities in land use patterns among provinces and cities, with cropland and forest land prevailing in all areas except Macau. Construction land and land use development intensity witnessed significant increases, most notably in Macau and least pronouncedly in Guangxi. Variations in ecological land alterations were considerable, with Hebei and Guangdong witnessing increases while other regions tended towards stability or reduction. Each distance band manifests a unique land use pattern. Except for the 100-150 km zone, construction land demonstrates an increasing trend across all bands. Ecological land expanded initially but fluctuated further from the coastline. Land use development intensity decreased initially, then stabilized, with the 0-10 km zone showed the highest development intensity. Analyzing the spatiotemporal changes in land use along China’s coastal zones from 1985 to 2020 can offer valuable insights into the management and sustainable development of China’s coastal zones.

The National Key Ecological Function Zones (NKEFZ) serve as crucial ecological security barriers in China, playing a vital role in enhancing ecosystem services. This study employed the theoretical framework of ecological benefits assessment in major ecological engineering projects. The primary focus was on the ecosystem macrostructure, ecosystem quality, and key ecosystem services, enabling quantitative analysis of the spatiotemporal changes in the ecosystem status of the NKEFZ from 2000 to 2019. To achieve this, remote sensing data, meteorological data, and model simulations were employed to investigate five indicators, including land use types, vegetation coverage, net primary productivity of vegetation, soil conservation services, water conservation services, and windbreak and sand fixation services. The analysis incorporated the Theil–Sen Median method to construct an evaluation system for assessing the restoration status of ecosystems, effectively integrating ecosystem quality and ecosystem services indicators. The research findings indicated that land use changes in NKEFZ were primarily characterized by the expansion of unused land and the in of grassland. The overall ecosystem quality of these zones improved, showing a stable and increasing trend. However, there were disparities in the changes related to ecosystem services. Water conservation services exhibited a decreasing trend, while soil conservation and windbreak and sand fixation services showed a steady improvement. The ecosystem of the NKEFZ, in general, displayed a stable and recovering trend. However, significant spatial heterogeneity existed, particularly in the southern region of the Qinghai–Tibet Plateau and at the border areas between western Sichuan and northern Yunnan, where some areas still experienced deteriorating ecosystem conditions. Compared to other functional zones, the trend in the ecosystem of the NKEFZ might not have been the most favorable. Nonetheless, this could be attributed to the fact that most of these areas were situated in environmentally fragile regions, and conservation measures may not have been as effective as in other functional zones. These findings highlighted the considerable challenges ahead in the construction and preservation of the NKEFZ. In future development, the NKEFZ should leverage their unique natural resources to explore distinctive ecological advantages and promote the development of eco-friendly economic industries, such as ecological industry, ecological agriculture, and eco-tourism, transitioning from being reliant on external support to self-sustainability.