生物多样性 ›› 2017, Vol. 25 ›› Issue (1): 11-22.DOI: 10.17520/biods.2016290

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天童常绿阔叶林定居幼苗存活和生长的关联

刘何铭1,2, 马遵平1,2, 杨庆松1,2, 方晓峰1,2, 林庆凯1,2, 宗意1,2, 阿尔达克·阿庆1,2, 王希华1,2,*()   

  1. 1 华东师范大学生态与环境科学学院, 上海 200241
    2 浙江天童森林生态系统国家野外科学观测研究站, 浙江宁波 315114);
  • 收稿日期:2016-10-05 接受日期:2016-11-30 出版日期:2017-01-20 发布日期:2017-02-08
  • 通讯作者: 王希华
  • 基金资助:
    国家自然科学基金重大国际合作项目(31210103920)

Relationships between established seedling survival and growth in evergreen broad-leaved forest in Tiantong

Heming Liu1,2, Zunping Ma1,2, Qingsong Yang1,2, Xiaofeng Fang1,2, Qingkai Lin1,2, Yi Zong1,2, 1,2, Xihua Wang1,2,*()   

  1. 1 School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241
    2 Tiantong National Forest Ecosystem Observation and Research Station, Ningbo, Zhejiang 315114
  • Received:2016-10-05 Accepted:2016-11-30 Online:2017-01-20 Published:2017-02-08
  • Contact: Wang Xihua

摘要:

群落幼苗的更新过程是维持群落物种共存的关键环节, 其中幼苗成功定居后的发展阶段是群落幼苗更新过程的重要组成部分, 对群落可繁殖个体补充格局的形成起着十分重要的作用。然而, 相比于新生幼苗, 群落内定居幼苗短期死亡率相对较低, 需要较长时间的监测才能完整地了解其存活格局, 所以相关的研究还相对较少。本研究假设群落内已经成功定居的幼苗的生长状况能够较好地预测其存活情况, 通过分析影响其生长的外在因素, 尝试间接地估计定居幼苗可能的存活格局, 从而了解定居幼苗的存活和生长过程。为验证该假设, 本文选取浙江天童20 ha森林动态监测样地内的定居幼苗作为研究对象, 利用广义线性混合模型分析其相对生长速率, 以及生物邻体因子(同种/异种成树邻体指数, 同种/异种幼苗邻体密度, 同种/异种成树邻体的凋落叶产量)和微生境因子(冠层开度、草本覆盖率、海拔、坡度、坡向、土壤pH、全氮和全磷含量)对定居幼苗短期存活概率的影响, 并利用线性混合模型分析生物邻体因子和微生境因子对定居幼苗相对生长速率的影响。结果显示, 群落内定居幼苗的相对生长速率对其本身的短期存活概率有显著正影响, 且其影响程度最高; 冠层开度对群落幼苗相对生长速率有显著正影响, 且是唯一有显著影响的因子。上述结果说明, 在群落幼苗成功定居后, 其生长状况能够较好地预测其存活情况, 加之林下较好的光照条件能够促进幼苗的生长, 这可能间接导致在林下光照较好的生境条件下定居幼苗长期存活的可能性相对较高。

关键词: 存活率, 相对生长速率, 广义线性混合模型, 冠层开度, 森林动态样地

Abstract

Community seedling regeneration is a crucial process for maintaining species coexistence. The stage from which an established seedling becomes a new reproductive individual is one of the most important components of community regeneration, and influences the community recruitment pattern. However, the short-term mortality of established seedlings is lower than newly germinated seedlings, and previous studies have not been able to analyze the effect of biotic neighborhoods and abiotic micro-habitat factors on established seedling survival perfectly. Therefore, we suggest that the growth status of established seedlings could predict established seedling survival during development, and analyze the effects of these biotic and abiotic factors on established seedling growth, in order to indirectly estimate their effects on established seedling survival. To test this hypothesis, we selected established seedlings in the 20 ha forest dynamics plot in Tiantong as samples. Then, we used generalized linear mixed models to assess the effects of relative growth rate, biotic neighborhood factors (conspecific/heterospecific adult neighborhood indices, density of conspecific/heterospecific seedling neighbors, the amount of conspecific/heterospecific leaf litter from neighbors) and abiotic micro-habitat factors (canopy openness, herbaceous coverage, elevation, slope, aspect, pH value, total nitrogen and total phosphorus in the soil) on short-term established seedling survival rates. We used linear mixed models to assess the effects of biotic neighborhood factors and abiotic micro-habitat factors on relative growth rates of established seedlings. Results showed that relative growth rates have a significant, positive effect on established seedling survival, and this factor is the most important factor among potential influencing factors. In addition, canopy openness, as only one significant influencing factor, has a positive effect on relative growth rates of established seedlings. These results suggest that the growth status of seedlings could predict established seedling survival during development. Meanwhile, established seedlings prefer to grow in habitat with better light. Therefore, the established seedling survival rate would be higher in the habitat with better light through higher relative growth rates.

Key words: survival rate, relative growth rate, generalized linear mixed models, canopy openness, forest dynamics plot