期刊
JOURNAL OF PALEOLIMNOLOGY
卷 27, 期 4, 页码 393-413出版社
SPRINGER
DOI: 10.1023/A:1020318803497
关键词
linear response models; modern training sets; New Zealand; Otago; phytoliths; transfer functions
An analysis of modern phytolith assemblages is presented. Phytolith assemblages were studied in modern surface soils and sediments of 28 sites from east Otago, New Zealand, within a range of vegetation types and microclimates. No simple distinction could be made between vegetation types on the basis of phytolith assemblage composition. A Principal Components Analysis (PCA) of the phytolith data set revealed that festucoid, chloridoid and spherical phytolith morphotypes formed strong associations with sites from wetland, grassland, and forest vegetation types, respectively. More importantly, a comparison of sample replicates from each field site using Squared Chord Distance (SCD) assemblage analysis showed that wetland and grassland sites tended to produce more internally consistent phytolith assemblages than forest sites. Environmental variables including pH, conductivity, altitude, precipitation and temperature were also gathered for each site. The ability of each environmental variable to reflect variance in the entire phytolith data set was estimated by a series of Redundancy Analyses (RDA) with Monte Carlo permutation tests of statistical significance. After a forward selection process, transfer functions were generated using Partial Least Squares (PLS) regression and calibration with jack-knife validation. The final transfer functions have root mean squared errors of prediction for pH (0.47), log conductivity (0.38 muS cm), average annual precipitation (63 mm), and average annual (0.28degreesC), spring (0.38degreesC) and autumn temperature (0.41degreesC); the smallest group of environmental variables explaining the most variance in the modern phytolith data set. The most useful transfer functions for application to fossil phytolith data and paleoenvironmental interpretation are pH, log conductivity and annual precipitation. The relationship between changes in pH and annual precipitation and phytolith assemblage composition found in this study presents a prima facie relationship with the potential to provide direct proxies for soil weathering and indirectly for paleoenvironmental reconstruction.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据