关键词: 策勒绿洲-沙漠过渡带, 沙埋, 疏叶骆驼刺, 花花柴, 灌草丛沙堆, 分布格局

Abstract: In order to study the effects of sand burial on [Alhagi sparsifolia] Shap. and [Karelinia caspia] （Pall.） Less.，two dominant species in Cele oasis-desert ecotone at the southern rim of the Taklimakan Desert，3 typical sample plots with 50 m×50 m were selected in the semi-fixed sandy land，semi-shifting sandy land and shifting sandy land，representing the slight，moderate and intensive burial conditions，respectively. In each plot the species composition and their spatial positions were investigated，the population characteristics （the number，height and crown area） of the two plant species and morphological parameters of the Phytogenic Mounds （Nebkhas） in the three plots were measured as well. Ripley's K （t） function was used to analyze the spatial point pattern of the plants. The results show as follows：the plant number decreased with the sand burial enhanced，as the plant density was 12.5 clump/100 m2 at the semi-fixed sandy land，6.8 clump/100 m2 at the semi-shifting sandy land and 1.4 clump/100 m2 at the shifting sandy land. The percent of the dead plant increased from 14.5% at the semi-fixed sandy land to 40.3% at the shifting sandy land. The Nebkhas volume increased with increasing sand burial intensity，while the morphological types of Nebkhas changed from coexistence of 4 different types into wind shadow dune type. The plant height and crown area decreased from 56.8 cm and 8 815.2 cm2 for [A. sparsifolia] and 62.9 cm and 9 976.8 cm2 for [K. caspia] at the semi-fixed sandy land，to 49.3 cm and 6 464.6 cm2 for [A. sparsifolia] and 48.0 cm and 5 984.0 cm2 for [K. caspia] at the semi-shifting sandy land，but increased to 66.4 cm and 32 065.1 cm2 for [A. sparsifolia] at the shifting sandy land. The two dominant species show an aggregated distribution and insignificant interspecies relation in the sand burial environment，but a nearly significant positive spatial association at the small scale （<5 m） in the semi-fixed sandy land. Generally speaking，the severe sand accumulation has negative effects on the plant reproduction and growth，[A. sparsifolia] species has a greater tolerance to sand burial. Plants in aggregated distribution are always corresponding to the higher topography as a result of the interaction between the plants growth and wind-blown sand activities.

Key words: Cele oasis-desert ecotone, sand burial, [Alhagi sparsifolia] Shap., Karelinia caspia （Pall.） Less., Nebkhas, spatial pattern