土地是自然经济的综合体，也是连接各生态环境要素的纽带。土地利用变化及其带来的生态系统变化对于平衡社会经济发展和生态环境保护具有重要意义。在土地利用变化的研究过程中，生态用地变化是研究的重点。深度解析生态用地变化下的生态系统服务时空变化，识别城镇化下的生态系统服务损益以及自然保护的生态保护成效是地理学、生态学研究的前沿议题，面向社会生态系统集成研究的趋势。论文基于Globe Land 30 数据，明确了生态用地类型，统计分析全国生态用地数量、分布、区域特点及变化情况。在此基础上计算了全国生态系统服务，并探究自然保护区建设和城市扩张对生态系统服务的影响，旨在为国家生态文明建设、生态保护和修复提供全面、准确、及时的基础性信息。主要结论如下：

1. 2020年全国生态用地总量723.03万km²占国土总面积的76.1%，林地、草地、灌木地、湿地、水体、裸地、冰川和永久积雪面积分别为210.22、294.94、8.47、4.27、14.74、188.23和9.44万km²，分别占全国总面积的22.13%、31.04%、0.89%、0.45%、1.55%、19.81%和0.99%。

2. 我国约60%生态用地分布在新疆、西藏、内蒙古和青海四省（区）。从林地看，主要分布在云南、四川、黑龙江、广西和内蒙古等省份，南部省份林地占比较高；草地主要分布在西藏、内蒙古、青海和新疆等地；水体与湿地西北省份分布面积较大，而东部沿海地区占比较高；裸地也主要分布在我国西北地区；冰川及永久积雪主要分布在西藏、新疆、青海、甘肃和四川五省区。

3. 尽管我国生态用地总面积较大，但变化形势不容乐观。2000-2020年期间生态用地总面积由730.31万km²减少到723.03万km²，二十年合计减少72764.82 km²，减少幅度为1.00%。其中草地减少面积最大，为26144.64 km²，减少幅度为8.86%。而林地、灌木地、湿地、水体、裸地和冰川及永久积雪分别增加1876.03、6922.70、2064.96、27432.63、13296.24和17415.27 km²，裸地面积增加最多，而水体和冰川及永久积雪增加幅度最大，分别为18.61%和18.45%。

4. 中西部大量裸地转为林、草地，是生态用地增加的主要来源。从转出看，耕地、建设用地是生态用地减少的主要渠道，尤其是东部经济相对发达省份。生态用地开垦为耕地以弥补耕地减少和建设用地直接占用生态用地，是威胁生态用地总面积的双重要素。

5. 2020年我国土壤保持量、防风固沙量、水源涵养量、净初级生产量分别为10.05亿吨、2365万吨、388 mm/m²、45.15 Pg。其中，土壤保持量主要分布在四川、新疆、青藏、青海四省（区），占全国土壤保持总量的59.11%；防风固沙量主要分布在内蒙古、新疆、甘肃、青海四省（区），占全国总防风固沙量的96.05%；水源涵养量主要分布在云南、四川、广东、广西、江西、湖南、湖北和黑龙江，占全国总水源涵养量的48.79%；净初级生产量主要分布在云南、四川、广东、广西、黑龙江，占全国总净初级生产量的32.11%。

6. 2000-2020年，全国土壤保持量减少1.59亿吨，防风固沙量增加1867万吨，水源涵养量减少60.64 mm/m²，净初级生产量增加0.45 Pg。其中，内蒙古、新疆、湖北等地区土壤保持量增加幅度较大，云南、四川、甘肃、西藏等地区土壤保持量减少幅度较大；内蒙古、宁夏、新疆、甘肃、西藏、陕西、青海等地区防风固沙量增加幅度较大；内蒙古、四川、安徽、湖北等地区水源涵养量增加幅度较大，云南、广东、广西、福建等地区水源涵养量减少幅度较大；云南、内蒙古、四川、山西、河北和陕西等地区净初级生产量增加幅度较大，西藏净初级生产量减少幅度最大。

7. 大多数自然保护区对生态系统服务具有正向的有效性，且生态系统服务有效性及其权衡和协同效应随时间而变化。随着时间的推移，净初级生产力有效性与土壤保持有效性、净初级生产力有效性与防风固沙有效性、土壤保持有效性与防风固沙有效性之间的协同效应逐渐增强。自然保护区高程、降水和周长面积比与生态系统服务有效性的相关性强于距居民点距离和保护区年龄，且其强度和性质随时间的变化呈现出明显的异质性。

8. 中国城市的核心区植被呈现增长态势，其中以环渤海的城市群最为显著。扩张区的植被变化差异明显，扩张区植被下降的区域主要集中于中国南方。全国65%左右的城市城市核心区和扩张区呈现“煎蛋状”，22.02%的城市核心区的植被增加而扩张区植被下降。随机森林的分析表明，降水和温度是影响核心区和扩张区植被变化的主要因素。中国的城市绿化政策促进了城市核心区和扩张区植被的生长，部分城市实现了经济发展和生态保护的协同发展。

Land is a comprehensive entity of the natural economy and serves as a link connecting various elements of the ecological environment. Changes in land use and the resulting changes in ecosystems are of great significance for balancing socio-economic development and ecological environment protection. In the study of land use changes, ecological land changes are a focal point. A thorough analysis of the spatiotemporal changes in ecosystem services under ecological land changes, identification of ecological service gains and losses under urbanization, and assessment of the effectiveness of natural conservation are forefront topics in geography and ecology, aligned with the trend of integrated research on social ecological systems. Based on Globe Land 30 data, this paper clarifies ecological land types, statistically analyzes the national quantity, distribution, regional characteristics, and changes of ecological land, and calculates the national ecosystem services. It explores the impacts of nature reserve establishment and urban expansion on ecosystem services, aiming to provide comprehensive, accurate, and timely foundational information for national ecological civilization construction, ecological protection, and restoration regulation. The main conclusions are as follows:

1. In 2020, the total area of ecological land in China was 7.2303 million km², accounting for 76.1% of the total land area. The areas of forest, grassland, shrubland, wetland, water bodies, bare land, glaciers, and permanent snow were 2.1022, 2.9494, 0.0847, 0.0427, 0.1474, 1.8823, and 0.0944 million km², respectively, constituting 22.13%, 31.04%, 0.89%, 0.45%, 1.55%, 19.81%, and 0.99% of the total national area.

2. About 60% of China's land is distributed in the four provinces (regions) of Xinjiang, Tibet, Inner Mongolia, and Qinghai. Forests are mainly distributed in provinces such as Yunnan, Sichuan, Heilongjiang, Guangxi, and Inner Mongolia, with a higher proportion in southern provinces. Grasslands are mainly found in Tibet, Inner Mongolia, Qinghai, and Xinjiang. Water bodies and wetlands are larger in the northwest provinces, while the eastern coastal regions have a higher proportion. Bare land is mainly distributed in the northwest of China, and glaciers and permanent snow are mainly located in Tibet, Xinjiang, Qinghai, Gansu, and Sichuan.

3. Despite the large total area of ecological land in China, the trend of change is not optimistic. From 2000 to 2020, the total area of ecological land decreased from 7.3031 million km² to 7.2303 million km², a decrease of 72,764.82 km² or 1.00%. Among them, grassland decreased the most by 261,441.64 km², a decrease of 8.86%. Forest, shrubland, wetland, water bodies, bare land, glaciers, and permanent snow increased by 1,876.03, 6,922.70, 2,064.96, 27,432.63, 132,965.24, and 17,415.27 km², respectively. Bare land saw the most significant increase, while water bodies and glaciers and permanent snow increased the most in terms of percentage, by 18.61% and 18.45%, respectively.

4. A significant source of increased ecological land comes from the conversion of bare land into forests and grasslands in the central and western regions. In terms of land conversion, cultivated land and construction land are the main channels of ecological land reduction. This is especially notable in economically developed provinces in the east, where ecological land is converted to cultivated land to compensate for the reduction in farmland and the direct use of ecological land for construction, posing a dual threat to the total ecological land area.

5. In 2020, China's soil retention capacity was 1.005 billion tons, windbreak and sand fixation capacity was 23.65 million tons, water conservation capacity was 388 mm/m², and net primary production was 45.15 Pg. Soil retention is mainly distributed in the provinces (regions) of Sichuan, Xinjiang, the Qinghai-Tibet Plateau, and Qinghai, accounting for 59.11% of the total soil retention capacity in the country. Windbreak and sand fixation capacity are mainly distributed in Inner Mongolia, Xinjiang, Gansu, and Qinghai, accounting for 96.05% of the total national capacity. Water conservation capacity is mainly distributed in Yunnan, Sichuan, Guangdong, Guangxi, Jiangxi, Hunan, Hubei, and Heilongjiang, accounting for 48.79% of the total national capacity. Net primary production is mainly distributed in Yunnan, Sichuan, Guangdong, Guangxi, and Heilongjiang, accounting for 32.11% of the total national capacity.

6. From 2000 to 2020, China's soil retention capacity decreased by 159 million tons, windbreak and sand fixation capacity increased by 18.67 million tons, water conservation capacity decreased by 60.64 mm/m², and net primary production increased by 0.45 Pg. Among them, Inner Mongolia, Xinjiang, Hubei, and other regions experienced a significant increase in soil retention capacity, while Yunnan, Sichuan, Gansu, and Tibet experienced a substantial decrease. Inner Mongolia, Ningxia, Xinjiang, Gansu, Tibet, Shaanxi, and Qinghai experienced a significant increase in windbreak and sand fixation capacity. Inner Mongolia, Sichuan, Anhui, and Hubei experienced a notable increase in water conservation capacity, while Yunnan, Guangdong, Guangxi, and Fujian experienced a significant decrease. Yunnan, Inner Mongolia, Sichuan, Shanxi, Hebei, and Shaanxi saw a substantial increase in net primary production, while Tibet experienced the greatest decrease.

7. Most natural reserves have positive ecological service effectiveness, and the effectiveness, balance, and synergistic effects of ecosystem services change over time. Over time, the synergistic effects between the effectiveness of net primary productivity and soil retention, the effectiveness of net primary productivity and windbreak and sand fixation, and the effectiveness of soil retention and windbreak and sand fixation gradually strengthen. The elevation, precipitation, and perimeter-to-area ratio of natural reserves show stronger correlations with the effectiveness of ecosystem services compared to the distance from residential areas and the age of the reserves, with their intensity and nature exhibiting apparent heterogeneity over time.

8. The core areas of vegetation in Chinese cities are showing a growth trend, with the urban agglomeration around the Bohai Sea being particularly notable. There are significant differences in vegetation changes in expansion areas, with a concentration of vegetation decline in the southern regions of China. Around 65% of urban core areas and expansion areas in China exhibit a "fried-egg" pattern, where vegetation increases in the core area while decreasing in the expansion area. These regions are primarily located in the southern part of China. Random forest analysis indicates that precipitation and temperature are the main factors influencing vegetation changes in core and expansion areas. China's urban greening policies have promoted the growth of vegetation in urban core and expansion areas, enabling some cities to