南岭亚高山泥炭地现代有壳变形虫环境指示意义的初步研究——以湖南省大坪泥炭地为例

南岭亚高山泥炭湿地在维持华南亚热地区生态系统和区域水平衡中起关键作用,但在这一区域的古环境定量重建工作还未有系统展开.有壳变形虫是古环境定量重建的有效代用指标.本文以南岭西部的湖南大坪泥炭为例,选取23个样品点,初步开展了该地区现代有壳变形虫的种类组成变化鉴定工作,通过多元统计分析发现,水位埋深(water-table depth, WTD)是影响本地区有壳变形虫种类组成变化的最主要环境因子,这一结果与国外其他地区的研究结果相一致.据此,利用国际上广泛使用的生物-环境因子转换函数模型,初步构建了本研究区域现代泥炭湿地有壳变形虫-水位埋深转换函数关系.研究结果表明,所有转换函数预测的水位埋深与实测水位埋深都呈一定的相关性,但受制于本次采样面积小、鉴定样本量较少和水位环境梯度较窄的条件下,转换函数的预测性能还比较差.此次工作可为将来系统开展华南亚热带地区高山泥炭湿地的古水文定量重建工作奠定宝贵的基础数据.

A Preliminary Study of Environmental Implications of the Modern Testate Amoeba from Subalpine Peatlands in the Western Nanling Mountains:A Case Study of Daping Peatland in Hunan Province

Subalpine peatlands in Nanling Mountains play an important role in maintaining ecosystem and regional water balance in subtropical regions of South China. However, there still have no systematic investigation on the quantitative palaeoenviroment reconstructions in this area. Testate amoebae have been effectively used for paleoenvironmental proxies across a range of geographical locations. In this work, we conducted a preliminary study of the modern distribution of testate amoebae assemblage in Daping peatland from a subalpine peatland in the western Naning Mountains. Testate amoebae assemblages from 23 microsites within the peatland were investigated. Multivariate statistical analysis demonstrated that water-table depth (WTD) was the main environmental factor in influencing the testate amoeba community composition, which was consistent with other research results around the world. Accordingly, testate amoebae-based transfer functions were developed using a variety of commonly used models. Our results showed that all transfer function models performed similarly and produced similar reconstructions, however, with relatively poor performance tested by root mean square error of prediction (RMSEP) and coefficient of determination (r2). The poor performances of the transfer functions were likely due to the relatively small sampling area, insufficient sampling sites, and short sampling gradient of water-table depth. This study can provide a valuable data base, which can be useful for the further systematic research of the quantitative hydrological reconstructions in subalpine peatlands from subtropical regions of South China