图3. 北京市域受胁鸟类丰富度的空间分布格局。一级关键栖息地分别是: 1: 密云水库; 2: 官厅水库; 3: 怀柔水库; 4: 十三陵水库; 5: 沙河水库; 6: 崇青水库; 7: 海子水库; 8: 大宁水库及其周边的滩地;9: 潮白河; 10: 温榆河; 11: 永定河; 12: 大石河; 13: 拒马河; 14: 泃河; 15: 妫水河等河渠;16: 颐和园; 17: 圆明园; 18: 奥林匹克森林公园; 19: 朝阳公园; 20: 玉渊潭公园; 21: 中南海、北海和后海; 22: 龙潭西湖公园; 23: 麋鹿苑; 24: 汉石桥湿地市级自然保护区; 25: 白浮泉公园; 26: 翠湖国家城市湿地公园等城市绿地水体。

Fig. 3. A map of richness pattern of 30 threatened bird species and the habitat classification. The 1st level key habitats are as follows. 1, Miyun Reservoir; 2, Guanting Reservoir; 3, Huairou Reservoir; 4, Shisanling Reservoir; 5, Shahe Reservoir; 6, Chongqing Reservoir; 7, Haizi Reservoir; 8, Daning Reservoir; 9, Chaobai River; 10, Wenyu River; 11, Yongding River; 12, Dashi River; 13, Juma River; 14, Juhe River; 15 Guishui River; waters in urban green spaces, 16, The Summer Palace; 17, The Yuanmingyuan Park; 18, Olympic Forest Park; 19, Chaoyang Park; 20, Yuyuantan Park; 21, Zhongnanhai, Beihai and Houhai; 22, Longtan West Lake Park; 23, Miluyuan Park; 24, Hanshiqiao Municipal Wetland Nature Reserve; 25, Baifuquan Park; 26, Cuihu National Urban Wetland Park.