国家自然科学基金中英合作重大项目No.41571130083;城市与区域生态国家重点实验室开放基金No.SKLURE2015-2-2;中国科学院青年创新促进会资助项目 Supported by the Major Project of Cooperation between China and Britain of the National Natural Science Foundation of ChinaNo.41571130083,the Open Fund of State Key Laboratory of Urban and Regional Ecology No.SKLURE2015-2-2and the Program of the Youth Innovation Promotion Association CAS