北京市自然保护地生态效益及其影响因素

自然保护地是生物多样性丰富区域，发挥着水源涵养、防风固沙等重要的生态效益。北京市共5类79处自然保护地，是首都重要生态屏障，但自然因素和人为干扰对自然保护地生态效益具有重要影响。本文核算了北京自然保护地的5种典型的生态效益，使用单因素方差分析比较了不同类型自然保护地生态效益的差异性，并基于冗余分析法（RDA）探究了2种自然因素（年均气温和年降水量）和4种人为因素（人口密度、建设用地比例、耕地比例和道路密度）对生态效益的影响。结果表明：1）北京自然保护地总体生态效益：北京自然保护地生境质量高，生境质量指数均值高达0.88；其它4项可价值化的生态效益中，水源涵养价值最大，固碳价值最低。2）各类自然保护地之间生态效益比较：除生境质量外，其它4个生态效益的总效益，自然保护地和森林公园显著高于其它3类自然保护地；湿地公园的生境质量显著低于其它4类保护地，而这4类保护地之间生境质量并无显著差异；从水源涵养的生态效益来看，风景名胜区和地质公园显著低于其它3类自然保护地。3）人为干扰因素（影响水平为38.92%）对生态效益的影响程度远高于自然因素（影响水平为16.63%）；防风固沙、水土保持和固碳效益主要受人为干扰影响，而生境质量同时受到自然因素和人为因素的影响，水源涵养则主要受到自然因素的影响。4）基于冗余分析，北京自然保护地可分为3个类群：水源涵养型、高质量栖息地型、其它生态效益型（包括防风固沙、水土保持和固碳）。本研究可为服务于北京保护地管理，提升北京自然保护地的生态效益。

Ecological benefit evaluation and influencing factors analysis of the Protected Areas in Beijing

The protected area has high biodiversity and many vital ecological benefits, such as water and soil conservation, sand fixation and windbreak. In Beijing, the protected area plays the core role as ecological barrier in the capital. However, there are still many problems in protected area management, and human disturbance is widespread, which seriously affects the ecological benefits of the protected area, especially the metropolitan as Beijing. And natural factors also have effect on ecological benefits. But there is still a gap to understand the human or natural impacts which is the main driver to affect ecological benefits of protected area in Beijing. We calculated 5 typical ecological benefits of 79 natural protected areas in Beijing, and compared the difference of ecological benefits of 5 types of protected area (natural reserve, forest park, scenic and historical interest area, geopark and wetland park) with one-way ANOVA. The effects of two natural factors (annual average temperature and annual precipitation) and four human impacts (population density, proportion of construction land, proportion of cultivated land and road density) on ecological benefits were investigated based on redundancy analysis. The results showed as follows: 1) In 2020, the value of water conservation per unit area in Beijing''s protected areas was 34,347 yuan/ha, the value of wind prevention and sand fixation was 2774 yuan/ha, the ecological value of soil and water conservation was 1274 yuan/ha, and the carbon fixation value was only 473 yuan/ha. In addition, the mean value of habitat quality per unit area in Beijing''s protected areas was 0.88. 2) While comparing ecological benefits among different types of protected area, except habitat quality, the total benefits of the other four types of ecological benefits, nature reserve and forest parks were significantly higher than the other three types of natural protected areas. The habitat quality of wetland parks was significantly lower than that of the other 4 types of protected area, and there was no significant difference among the 4 types of protected area. In terms of ecological benefits of water conservation, scenic and historical interest area and geoparks are significantly lower than other three types of natural protection area. 3) Compared with natural factors (16.63%), human impacts (38.92%) were the main driver to affect protected area in Beijing, mainly on windbreak and sand fixation, soil and water conservation and carbon sequestration. Habitat quality was affected by both natural and human impacts, and water conservation was mainly affected by natural factors. 4) Based on redundancy analysis (RDA), protected area in Beijing can be divided into three groups: water conservation type, high-quality habitat type, and other ecological benefits (including wind prevention and sand fixation, water and soil conservation and carbon sequestration).The results showed that it is important and urgent to integrate and optimize the protected area in Beijing, and the key point is to reduce the construction and agricultural land in the protected area, and move out the excessive population. This study can serve the management of protected area in Beijing and improve the ecological benefits of protected area in Beijing.