Effects of Vegetation Switch and Subsequent Change in Soil Invertebrate Composition on Soil Carbon Accumulation Patterns, Revealed by Radiocarbon Concentrations
Effects of Vegetation Switch and Subsequent Change in Soil Invertebrate Composition on Soil Carbon Accumulation Patterns, Revealed by Radiocarbon Concentrations
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DOI：
10.1017/s0033822200046567
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发表时间：
2010
期刊：
影响因子：
8.3
通讯作者：
A. Toyota;I. Tayasu;R. Fujimaki;N. Kaneko;M. Uchida;Y. Shibata;T. Hiura
中科院分区：
文献类型：
--
作者：
A. Toyota;I. Tayasu;R. Fujimaki;N. Kaneko;M. Uchida;Y. Shibata;T. Hiura
植被类型通过凋落物质量和土壤生物多样性等多种因素对陆地生态系统土壤有机碳（SOC）积累产生强烈影响。然而，土壤动物在有机碳积累中的作用尚不清楚。本研究的目的是：(1)研究连续森林或植被转换林区凋落物类型和土壤动物群落的变化对土壤有机碳积累的影响；(2)探讨土壤动物在森林生态系统有机碳积累中的作用。我们关注的是自1739年火山爆发以来268年里火山灰层顶部积累的土壤。20世纪50年代末和60年代初的放射性碳“炸弹峰值”提供了土壤碳年龄的独特同位素特征。研究了凋落物质量和土壤无脊椎动物功能对土壤14C积累模式的共同影响。为了确定植被类型对碳积累的影响，我们选择了4种寒温带森林，其中2种在1960年左右经历了植被转换（针叶林到阔叶林，CB；阔叶林到针叶林，BC）， 2种为连续林（针叶林，CC；阔叶林，BB）。在CC的深度区间，Δ14C值与预期的bomb-14C剖面一致。相比之下，BB、BC和CB的Δ14C模式与CC不同。与CC相比，其他地点的Δ14C值显示，即使在较深的土层中，14C浓度也相对较高，这表明炸弹诱导的14C已被土壤动物输送到更深的土层。当前阔叶林（BB和CB）的凋落物取食无脊椎动物生物量高于当前针叶林（CC和BC）。这些结果表明，阔叶林凋落叶中的碳被丰富的土壤无脊椎动物垂直转运到更深的土壤层。与预期土壤剖面的不一致表明，过去的植被（阔叶林）影响了当前的有机碳积累模式。
Vegetation types strongly affect soil organic carbon (SOC) accumulation in the terrestrial ecosystem through multiple factors such as litter quality and soil biodiversity. However, the roles of soil fauna in SOC accumulation remain unclear. The objectives of this study were to (1) examine how changes in litter types and soil animal communities affect SOC accumulation in continuously forested or vegetation-switched forest areas; and (2) discuss the role of soil animals in SOC accumulation in forest ecosystems. We focused on soils that have accumulated on top of a volcanic ash layer in the 268 yr since a volcanic eruption in 1739. The radiocarbon “bomb spike”' in the late 1950s and early 1960s provides a unique isotopic signature of soil carbon age. We investigated the combined effects of litter quality and soil invertebrate function on soil 14C accumulation patterns. To determine the effects of vegetation types on SOC accumulation, we selected 4 types of cool temperate forests, 2 of which had undergone a vegetation switch in about 1960 (conifer to broadleaved forest, CB; broadleaved forest to conifer, BC), and 2 that had continuous forests (conifer forest, CC; broadleaved forest, BB). The Δ14C values at depth intervals in CC were consistent with the expected bomb-14C profile. In contrast, Δ14C patterns in BB, BC, and CB differed from that of CC. Compared to CC, Δ14C values of the other sites showed relatively high 14C concentrations even in deeper soil layers, which suggests the bomb-induced 14C has been transported to a greater depth by soil animals. Current broadleaved forests (BB and CB) had higher biomass of litter-feeding invertebrates than in current coniferous forests (CC and BC). These results suggest that carbon from leaf litter was vertically translocated to deeper soil layers by the abundant soil invertebrates in broad-leaved forests. Disagreement with the expected soil profile in BC suggests that past vegetation (broadleaved forest) has affected the present SOC accumulation pattern.