Vegetos

Abstract

Based on the field survey, spatial distribution patterns of five species of Calligonum L. were analyzed with dispersion coefficient (C), average crowded degree (t), clumping index (I_t), aggregation index (m*/m), Cassie index (C_a), Morisita index (I_δ), and negative binomial indexes (K). The results showed that, (1) Calligonum roborovskii A. Los., Calligonum kuerlese Z. M. Mao, Calligonum yingisaricum Z. M. Mao and Calligonum takuoqiangense B. R. Pan were all aggregated distribution at both scales 10m×10m and 20m×20m. Calligonum ruoqiangense Liou f. presented aggregated distribution at the larger scale of 20m×20m, but tended to uniform distribution at the smaller scale of 10m×10m. (2) The aggregated strength of five species of Calligonum L. were lower, they were C. kuerlese Z. M. Mao, C. roborovskii A. Los., C. yingisaricum Z. M. Mao, C. ruoqiangense Liou f. and C. takuoqiangense B. R. Pan in the order from great to small.