The limestone area located in southwestern Guangxi in the south of China is part of a global biodiversity hotspot. As an important habitat of this limestone region, karst wetlands provide birds with necessary water conditions for their survival and reproduction. From 2007 to 2012, bird surveys were conducted in natural wetlands(pools, streams, springs and seasonal flows) in 14 nature reserves and 18 reservoirs in the limestone area of southwestern Guangxi. A total of 365 bird species were recorded in field investigations, including 103 water-dependent birds mainly seen in wetlands. Among these 103 birds, 10 species are globally threatened and 5 species have been placed under national key protection. The birds were selective in their use of the various types of karst wetlands. The number of bird species was the highest in pools and springs, with 304 and 266 respectively, followed by streams with 131 species. Reservoirs are the main wintering habitat for the large Natatores and in the rainy season the importance of seasonal flows is paramount. Seasonal changes in the utilization of karst wetlands by birds were obvious; the number of bird species in the dry season was much higher than during the rainy season. Bird migration and seasonal flows are the main reasons for seasonal variation in the number of water-dependent birds. These natural karst wetlands ensure the drinking water supply for more than 80% of the water-independent birds in the dry season. These karst wetlands are the wintering ground and stopover area for 58 species of migrant birds. At present, threats to the birds in the karst wetlands consist of illegal hunting, habitat changes and eucalyptus plantations. Karst wetlands are important for protecting biodiversity. More attention ought to be directed to these wetlands and protection efforts enhanced.
A specimen of White-spectacled Warbler Seicercus affinis was collected in Diding Nature Reserve in Jingxi County, Southwest Guangxi province in December 2006. It is a new record of bird species in Guangxi. During our field investigation in Diding Nature Reserve from January 2005 to May 2007, Seicercus affinis were observed frequently in the underbrush of the evergreen broad-leaved forest and the shrub around agricultural land at an altitude of 500-700m. There are two subspecies of Seicercus affinis recorded in the world, but only one in China. Through a careful examination, this specimen was identified as Seicercus affinis intermedius. The distribution ofSeicercus affinis in China will be discussed in this paper. The specimen was kept at the College of Animal Sciences and Technology, Guangxi University.
