Evaluating the effect of flowering age and forest structure on pollen productivity estimates
Evaluating the effect of flowering age and forest structure on pollen productivity estimates
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DOI：
10.1007/s00334-012-0373-z
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发表时间：
2012-10
影响因子：
2.5
通讯作者：
Isabelle Matthias;A. Nielsen;T. Giesecke
中科院分区：
文献类型：
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作者：
Isabelle Matthias;A. Nielsen;T. Giesecke
花粉产量估算是定量植被重建必不可少的先决条件。来自欧洲不同地区的估计显示出很大的变化，但不确定这是否反映了气候和土壤的区域差异，还是由于对植被丰度的不同评估造成的。森林是一个特殊的问题，因为它们由多层植被组成，许多树种只有在达到几十年的年龄后才开始产生花粉。本文利用德国东北部详细的森林清查数据，研究了开花年龄和林下乔木对PPEs的影响。选取代表该地区不同森林类型的49个中小型湖泊进行花粉计数。来自马达加斯加封闭森林内湖泊的地表样本产生了不成比例的马达加斯加花粉，增加了其PPE和所有其他估计值的变异性。这些样本从进一步的分析中删除，但表明在Prentice-Sugita花粉扩散和沉积模型中没有考虑到高树干空间成分。限制数据集的结果显示，考虑开花年龄和林下植被位置的PPEs存在显著差异。这种影响对生长缓慢和/或开花较晚的树木（如fagususand carpinus）影响最大，而对像桦树和桤木（betulaand alnus）这样发育较早开花的物种影响最小。本研究获得的大相关花粉源面积（RSAP）为7 km，与该地区的景观结构相一致。
Pollen productivity estimates (PPEs) are indispensable prerequisites for quantitative vegetation reconstructions. Estimates from different European regions show a large variability and it is uncertain whether this reflects regional differences in climate and soil or is brought about by different assessments of vegetation abundance. Forests represent a particular problem as they consist of several layers of vegetation and many tree species only start producing pollen after they have attained ages of several decades. Here we used detailed forest inventory data from north-eastern Germany to investigate the effect of flowering age and understory trees on PPEs. Pollen counts were obtained from 49 small to medium sized lakes chosen to represent the different forest types in the region. Surface samples from lakes within a closed forest ofFagusyielded disproportionate amounts ofFaguspollen, increasing its PPE and the variability of all other estimates. These samples were removed from further analysis but indicate a high trunk-space component that is not considered in the Prentice–Sugita pollen dispersal and deposition model. Results of the restricted dataset show important differences in PPEs based on the consideration of flowering age and understory position. The effect is largest for slow growing and/or late flowering trees likeFagusandCarpinuswhile it is minimal for species that flower early in their development likeBetulaandAlnus. The large relevant source area of pollen (RSAP) of 7 km obtained in this study is consistent with the landscape structure of the region.