关键词: 祁连山, 青杄林, 空间格局, 种内关联性, 多重复取样

Abstract: Aims To reveal the spatial pattern and intraspecific association of Picea wilsonii population in the Datong River Basin of Qilian Mountains. Methods Based on a multiple replicate plot design, we used the paired correlation function g(r) and the bivariate paired correlation function g₁₂(r) within the framework of point pattern analysis to analyze the spatial distribution patterns and associations of individuals at different growth stages. Important findings (1) The static diameter distribution of the P. wilsonii population exhibited an inverse J-shaped, with young individuals accounting for 58.8% of the total, indicating a stable and growing population with good regeneration potential. (2) Young individuals exhibited a clustered distribution across all analyzed scales (0-25 m); middle-aged and adult individuals showed a clustered distribution at scales of 0-21 m and 0-6 m, respectively, and became randomly distributed at larger scales; old individuals displayed a random distribution across all scales. (3) Positive associations were observed between young and middle-aged individuals, and between young and adult individuals at scales of 2-25 m, suggesting a facilitative effect of large trees on young trees. Between middle-aged and adult individuals, no significant association was found at 0-6 m, but a positive association emerged at scales >6 m, with the strength of association gradually weakening as the size difference increased. No significant associations were detected between young and old individuals, nor between middle-aged and old individuals across all scales. A weak positive association was found between adult and old individuals at very short distances. Overall, the P. wilsonii population in the Datong River Basin of the Qilian Mountains exhibited a pattern of “clustered at small size classes, random at large size classes” and positive associations between saplings and medium/large trees, exhibiting clear scale dependence and developmental stage dependence.

Key words: Qilian Mountains, Picea wilsonii forest, spatial pattern, intraspecific association, multiple replicate sampling