The 15 ha (500 × 300 m) Nonggang Karst Seasonal Rainforest Dynamics Plot was established in 2011. It is located in the Nonggang National Nature Reserve of the Guangxi Zhuang Autonomous Region, south China, and adjacent to northeastern Vietnam.
The region has a tropical monsoon climate. Mean annual temperature in the region is 22℃, mean annual precipitation is 1,150–1,550 mm. This region is characterized by the highly vulnerable and spectacular limestone karst systems. The karst geomorphological type is “peak-cluster deeply incised round depression (valley)”, which is composed of a plurality of mountain peaks and depressions. The tops of peak clusters are 400–500 m above sea level, the bottoms of depression valleys are 150–200 m above sea level. These karsts support a very high level of endemic species of plants, vertebrates, and invertebrates and are recognized as highly important biodiversity hotspots.
The elevation of the plot varies from 184 to 374 m, with a mean of 262.7 m. The slope varies from 3.7° to 78.9°, with a mean of 41.7°. The rock exposed rate is more than 95% around the peak, about 20% around the depression; the mean rock exposed rate of the plot is 68.8%. The pH value of the plot ranges in 7.5–8.6.
A total of 68,010 individual trees (95,471 individuals with branch) with a dbh of more than 1 cm, belonging to 223 species, 157 genera, and 56 families, were recorded in the plot. Among them, 25,851 individual trees (39,604 individuals with branch), belonging to 60 species, 57 genera, and 37 families, are karst endemic tree species. Tropical families account for 70.45% of the total families, and the tropical genera account for 88.39% of the total genera.
The most dominant families are Euphorbiaceae, Verbenaceae, Sterculiaceae, Moraceae, Tiliaceae, Rubiaceae, and Meliaceae. Dominant species at different habitats vary sharply in the plot: Boniodendron minus, Diospyros siderophylla, Memecylon scutellatum, Sinosideroxylon pedunculatum var. pubifolium, and Pistacia weinmannifolia are the dominant species around the mountain peaks; Excentrodendron tonkinense, Cephalomappa sinensis, Diplodiscus trichosperma, Cleistanthus sumatranus, Sterculia monosperma, and Vitex kwangsiensis are the dominant species at the middle slopes; Archidendron guangxiensis, Saraca dives, Erythrina stricta, Antidesma japonicum, and Ficus hispida are the dominant species at the valley bottoms.
Principal Investigator: Xiankun Li, Professor of Guangxi Institute of Botany, CAS. His research focuses on the karst vegetation succession and correlation with environment.
Research Team: Xiang Wusheng, Guo Yili, Wang Bin, Wen Shujun, Bai Kundong, Ding Tao, Lu Shuhua, Huang Yusong, Liu Yan, Huang Fuzhao, Li Dongxing