Above- and below-ground biomass relationships across 1534 forested communities
Above- and below-ground biomass relationships across 1534 forested communities
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DOI：
10.1093/aob/mcl206
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发表时间：
2007-01-01
期刊：
影响因子：
4.2
通讯作者：
Niklas, Karl J.
中科院分区：
文献类型：
--
作者：
Cheng, Dong-Liang;Niklas, Karl J.
背景和目的以前的工作表明，在物种和生态上不同的物种中，单个植物的地上和地下干生物量几乎是等长的。异速生长理论预测，在不同的森林类型中，无论植被组成如何，相似的等长比例关系都是成立的。方法为了检验这一假设，我们检验了两个森林水平上、地下每公顷干生物量的概要(分别为M-A和M-R)，以检验M-A和M-R比例等距比例的假设，并以与报告的单个植物数据相同的方式。模型II回归协议被用来比较组合数据集(n=1534)、两个数据集中的每一个以及被分类为群落和生物群类型以及被子植物或针叶植物为主的群落的总共17个数据子集的MA和MR标度指数(即对数-对数线性关系的斜率)的数值。等距假设在统计学上不能被严格否定；这15个指数中有4个因样本量较小而具有较宽的95%可信区间。由于MA和MR的绝对差异，20条回归曲线的y截距存在显著差异。结论森林和个体植物水平MA与MR的异速生长关系具有非常相似的标度指数，但由于y截距的显著差异而不同。这些结果支持了先前的异速生长理论，并为MA和MR的定标提供了边界条件。
Background and Aims Prior work has shown that above- and below-ground dry biomass across individual plants scale in a near isometric manner across phyletically and ecologically diverse species. Allometric theory predicts that a similar isometric scaling relationship should hold true across diverse forest-types, regardless of vegetational composition.Methods To test this hypothesis, two compendia for forest-level above- and below-ground dry biomass per hectare (M-A and M-R, respectively) were examined to test the hypothesis that M-A vs. M-R scales isometrically and in the same manner as reported for data from individual plants. Model Type II regression protocols were used to compare the numerical values of MA vs. MR scaling exponents (i.e. slopes of log-log linear relationships) for the combined data sets (n = 1534), each of the two data sets, and data sorted into a total of 17 data subsets for community- and biome-types as well as communities dominated by angiosperms or conifers.Key Results Among the 20 regressions examined, 15 had scaling exponents that were indistinguishable from that reported for MA vs. MR across individual plants. The isometric hypothesis could not be strictly rejected on statistical grounds; four of these 15 exponents had broad 95% confidence intervals resulting from small sample sizes. Significant variation was observed in the y-intercepts of the 20 regression curves, because of absolute differences in MA or MR.Conclusions The allometries of forest- and individual plant-level MA vs. MR relationships share strikingly similar scaling exponents, but differ because of considerable variation in y-intercepts. These results support prior allometric theory and provide boundary conditions for the scaling of MA and MR.