Maximum Likelihood Linear Calibration of Pollen Spectra in Terms of Forest Composition
Maximum Likelihood Linear Calibration of Pollen Spectra in Terms of Forest Composition
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DOI：
10.2307/2531338
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发表时间：
1983-12
期刊：
影响因子：
1.9
通讯作者：
I. Prentice;R. W. Parsons
中科院分区：
文献类型：
--
作者：
I. Prentice;R. W. Parsons
过去的森林组成原则上可以从泥炭或湖泊沉积物中发现的花粉光谱中重建，但花粉分析师通常使用半定量方法，定量方法需要发展。必须为花粉-植被关系设计模型，必须使用适当的统计方法使这种模型与现代花粉沉积（来自地表样本的花粉光谱）和当代森林组成的数据相吻合。每个分类群的花粉沉积速率被假定为是一个独立的线性函数，其丰度在一个固定的距离内的沉积网站。花粉数据被认为是由相对计数，而不是绝对沉积速率的估计。不同的近似值导致两种替代模型花粉计数相对树丰度。最大似然估计和标准偏差的数值得到的两个模型的参数。通过使用地面花粉数据和森林清查数据从威斯康星州和上密歇根州的模型进行说明和比较，模型解释70-80%的花粉数据的方差，并给出可解释和一致的结果。
SUMMARY Past forest composition may, in principle, be reconstructed from the spectra of pollen found in peat or lake sediment, but pollen analysts normally use semiquantitative methods, and quantitative approaches need development. Models must be devised for the pollen-vegetation relationship, and appropriate statistical methods must be used to fit such models to data on modern pollen deposition (pollen spectra from surface samples) and contemporary forest composition. Each taxon's pollen deposition rate is assumed to be an independent linear function of its abundance within a fixed distance of the depositional site. Pollen data are assumed to consist of relative counts, rather than estimates of absolute deposition rates. Different approximations lead to two alternative models relating pollen counts to relative tree abundances. Maximum likelihood estimates and standard deviations are obtained numerically for the parameters of both models. The models are illustrated and compared by using surface pollen data and forest inventory data from Wisconsin and Upper Michigan; the models explain 70-80% of the variance in the pollen data and give interpretable and congruent results.