Abstract: It is generally accepted that the research of structural diversity of communities can provide scientific basis for monitoring, conservation, and sustainable utilization of biodiversity in more efficient way. In this paper, both extended Shannon index and the structure index based on variance (STVI) were adopted to study the structural diversity of Elaeagnus mollis communities in Shanxi Province, China. The two indices showed a relatively consistent development trend, and thus, could comprehensively reflect the differences in the structural diversity of the communities. Community type, species composition, spatial structure, habitat condition, environmental feature, and human disturbance intensity were the main factors affecting the structural diversity. As compared to extended Shannon index, STVI index minimized the subjectivity in categorizing with diameter and height, and could better describe a wider array of structure, being more available in quantitatively analyzing the structural diversity of communities.

Key words: landscape ecological security pattern, spatial principal component analysis, minimum cumulative resistance, ecological network, Ganzhou District.