关键词: 拟步甲, 鞘翅目, 阿拉善高原, 气象因子, 空间分布格局

Abstract: To understand the distribution of nutrients in soil profile and their responses to dramatic land use change, four adjacent land use systems, including natural forest, the resultantly converted Chinese fir plantation, Chinese chestnut orchard, and sloping cropland, were chosen. Those ecosystems were located at an identical landscape unit in the hilly region of Daweishan Mount, northeast Hunan Province. Soil samples of 0-100 cm were collected by soil auger with a 20 cm interval. The pH, soil organic matter, total and available macro-elements (total N, P, and K, and alkali-hydrolysable N, available P and K), medium elements (exchangeable Ca, Mg), and micronutrients (available Fe, Mn, Cu, and Zn) in each soil layer were analyzed. The sensitivity of soil nutrients in response to land use change was evaluated using the sensitivity index (SI). Results showed that the contents of soil organic matter and total N at 0-100 cm depth were reduced by 9%-55% and 28%-57%, respectively, while that of total P was increased by 0.3-52 folds following the conversion of natural forest to other land use types, indicating that dramatic human activities (such as fertilization) led to losses of soil organic matter and total N but an accumulation of P in soil profile. Compared with the soil total nutrient contents (with SI ranging from -0.6 to 1.5), available nutrient contents (SI: -0.8 to 51.8) were more sensitive to land use changes. The available P (SI: -0.8 to 51.8), K (SI: -0.5 to 2.9), Fe (SI: -0.6 to 3.1), and Cu (SI: -0.8 to 2.2) mainly presented positive responses to land use changes, indicating the enhanced availability of those nutrients in soil by land use change. The SI of available nutrients, including alkali-hydrolysable N, available P, K, Mn and Zn, in subsoil was generally higher than that in topsoil, implying that results focusing on the topsoil nutrients under various land use types cannot be simply extrapolated to the subsoil. Changes in subsoil nutrients (especially for available nutrients, medium nutrients, and micronutrients) caused by land use change should be received more attention.

Key words: Tenebrionidae, Alxa Plateau, meteorological factor, spatial distribution pattern, Coleoptera