Rock fragments (RFs) are a common feature on the soil surface and in topsoil in mountainous areas. Lack of knowledge of the spatial distribution of the RFs along the hillslopes in karst region of southern China has proved a barrier to better understand the hydrology and soil erosion patterns. 

Researchers from Xishuangbanna Tropical Botanical Garden (XTBG) examined the changes of RF coverage and size at the soil surface and the RF content at shallow depth soil along slopes in three karst ecosystem at a karst in southern China. 

The researchers collected and measured the RF cover, size, and content at the soil surface and within the topsoil of secondary forest, man-made forest, and non-forest land hillslopes in a karst region in Yunnan Province, southwest China. 

The study revealed no obvious relationship between the slope and the mean total RF cover, the median diameter (D₅₀), and RF content in the topsoil of three hillslopes covered with different vegetation types. 

“Our results showing a weak relationship indicated that the dominant factor for the spatial distribution of RFs might not be soil erosion on the three hillslopes”, said Prof. SHEN Youxin, correspondence author of the study. 

The large difference between the RF coverage at the surface and the RF content in the soil on the NF hillslope indicated that underground leakage was greater than surface runoff. 

“We concluded that the RF distribution was affected little by slope position, and the removal/establishment of forest had a limited effect on the RF distribution along karst slopes”, said Prof. SHEN. 

The study entitled “Spatial distribution patterns of rock fragments and their underlying mechanism of migration on steep hillslopes in a karst region of Yunnan Province, China” has been published online in Environmental Science and Pollution Research. 

Contact 

SHEN Youxin  Ph.D 

Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China       

E-mail:  yxshen@xtbg.ac.cn