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基于长白山次生针阔混交林样地,以520个1 m×1 m幼苗样方中胸径小于1 cm的乔木幼苗为研究对象,选取2013年和2014年的幼苗调查数据,运用广义线性混合模型(GLMM)分析了生物邻体和生境异质性对幼苗存活的影响,探讨了次生针阔混交林幼苗存活影响因素及物种共存机制。结果表明:(1)适宜大树生长的局域生境同样也适宜幼苗的存活,幼苗存活率与土壤含水量和有效氮等土壤养分显著正相关。(2)幼苗个体之间存在明显的竞争,较多的幼苗邻体显著降低幼苗的存活率。同种大树邻体和同种幼苗邻体与幼苗存活显著负相关,表明存在负密度制约效应。(3)随着幼苗年龄的增加,生境异质性对幼苗存活的影响逐渐增大。该研究证实了密度制约效应和生境异质性对幼苗存活有着重要影响,其相对重要性随着幼苗年龄级、功能群以及物种种类而变化。
Based on the secondary coniferous and broadleaf mixed forest plots in Changbai Mountain, 520 seedlings of 1 m × 1 m seedlings were selected as tree seedlings with DBH less than 1 cm. The data of 2013 and 2014 seedling surveys were selected and the generalized linear mixed model (GLMM) analyzed the influence of bio-adjacent body and habitat heterogeneity on seedling survival and discussed the influencing factors of seedling survival and species coexistence mechanism in secondary coniferous-broad-leaved forest. The results showed that: (1) The local habitats suitable for the growth of large trees were also suitable for the survival of seedlings. The seedling survival rate was significantly and positively correlated with soil moisture content and soil available nitrogen. (2) There is obvious competition between individual seedlings, more seedling neighbors significantly reduce the survival rate of seedlings. There was a significant negative correlation between the adjacent species of the same kind of tree and the seedling of the same species and the survival of the seedling, indicating that there is a negative density control effect. (3) With the increase of seedling age, the impact of habitat heterogeneity on seedling survival gradually increased. This study confirms that density-constraining effects and habitat heterogeneity have important implications for seedling survival, and their relative importance varies with seedling age class, functional group, and species.