绢毛匍匐委陵菜与土壤有效磷的小尺度空间相关分析

SMALL-SCALE SPATIAL CROSS-CORRELATION BETWEEN RAMET POPULATION VARIABLES OF POTENTILLA REPTANS VAR. SERICOPHYLLA AND SOIL AVAILABLE PHOSPHORUS

许多学者认为植物空间分布是由在小尺度上起作用的某些土壤因子控制,但对克隆植物种群与土壤变量进行空间格局比较的研究相对较少。该研究主要探讨小尺度上克隆植物与土壤有效磷之间的空间相关性,特别是它们的相似性。土壤和植物样品取自北京东灵山的绢毛匍匐委陵菜（Potentilla reptans var.sericophylla）种群,样方大小为336cm×96cm;采用半方差函数和交互相关图来分析空间分布特征。结果表明,土壤有效磷含量空间分布的斑块性结构明显,空间自相关尺度为37.8cm。绢毛匍匐委陵菜的各项测定指标与土壤有效磷的空间格局多数在75-110cm尺度上显著负相关,在110-165cm尺度上相关性不显著;分株数、叶数和匍匐茎生物量在小于50cm尺度上以及根生物量在小于30cm尺度上与土壤有效磷含量的空间格局显著正相关。资源共享和选择性放置克隆分株是绢毛匍匐委陵菜利用小尺度异质性土壤资源的重要生态对策。

Aims Comparison of spatial patterns of clonal plant populations and soil variables has received little attention in ecological studies, although many papers implicitly assume that plant spatial distribution is controlled by soil variables acting at small scales. Our main aim was to investigate small-scale spatial crosscorrelation between population variables of clonal plant species and soil available phosphorus. Methods We investigated a ramet population of Potentilla reptans var. sericophylla in Dongling Mountain Area in Beijing to investigate the degree and scales of patchiness of soil available phosphorus and to determine spatial similarities between population variables and available phosphorus. Spatial soil and plant samples were collected in a plot of 336 cm × 96 cm. Semivariogram and cross-correlogram were applied to characterize spatial patterns. Important findings Soil available phosphorus had clear patchy structure with the spatial autocorrelation range of 37.8 cm. Cross-correlation between measured variables of the ramet population of P. reptans var. sericophylla and soil available phosphorus was negatively significant at a lag interval of 75 - 110 cm, but not significant at a lag interval of 110- 165 cm. There was significant positive correlation between soil available phosphorus and number of ramets and leaves and biomass of stolons at a lag interval 〈 50 cm and for biomass of roots at a lag interval 〈 30 cm. Resource sharing and selective placement of ramets in favorable micro-habitats may be important ecological strategies for Potentilla reptans var. sericophylla to exploit small-scale soil resources that are heterogeneously distributed.