Community-specific impacts of exotic earthworm invasions on soil carbon dynamics in a sandy temperate forest
Community-specific impacts of exotic earthworm invasions on soil carbon dynamics in a sandy temperate forest
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DOI：
10.1890/12-1555.1
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发表时间：
2013-12-01
期刊：
影响因子：
4.8
通讯作者：
Nadelhoffer, Knute J.
中科院分区：
文献类型：
--
作者：
Crumsey, Jasmine M.;Le Moine, James M.;Nadelhoffer, Knute J.
外来物种的引入可以改变温带森林的地上和地下特性，但对森林土壤碳（C）动态的净影响知之甚少。我们使用了一个围隔实验来研究属于三个不同生态组的昆虫物种的影响（蚯蚓[anecic]，Aporrectodea peculides [endogeic]，和蚯蚓[epigeic]）对碳分布和储存在重建的土壤剖面从一个桑迪温带森林土壤通过测量CO2和溶解有机碳（DOC）的损失，凋落物碳纳入土壤，以单种和物种组合为处理，研究土壤碳库。土壤CO2损失是30%以上的Endogeic x Epigeic治疗比对照组（无蚯蚓）在第一个45天; CO2损失从单种治疗没有不同的控制。DOC损失比CO2损失低三个数量级，并且在不同的群落处理中相似。群落中有非优势种的群落使凋落物C的质量损失增加了31-39%，不同凋落物类型的质量损失差异（红槭>大齿杨>水青冈>红栎>白松）表明群落对落叶的偏好。洞穴系统的体积，连续性和大小分布不同，但不影响累积CO2或DOC的损失。然而，洞穴系统结构通过调节凋落叶对A层C和N库的贡献来控制C的垂直再分配，这表现在：（1）由anecic物种形成的地下垂直洞穴，加速凋落叶质量损失（P. strobus除外）;和（2）A层中密集的洞穴网络与这些库的C和N特性之间的强相关性。最终的土壤碳储量略低，在CO2处理，表明增加的落叶碳输入到土壤中的CO2和DOC跨CO2社区治疗的损失超过抵消。
Exotic earthworm introductions can alter above- and belowground properties of temperate forests, but the net impacts on forest soil carbon (C) dynamics are poorly understood. We used a mesocosm experiment to examine the impacts of earthworm species belonging to three different ecological groups (Lumbricus terrestris [anecic], Aporrectodea trapezoides [endogeic], and Eisenia fetida [epigeic]) on C distributions and storage in reconstructed soil profiles from a sandy temperate forest soil by measuring CO2 and dissolved organic carbon (DOC) losses, litter C incorporation into soil, and soil C storage with monospecific and species combinations as treatments. Soil CO2 loss was 30% greater from the Endogeic x Epigeic treatment than from controls (no earthworms) over the first 45 days; CO2 losses from monospecific treatments did not differ from controls. DOC losses were three orders of magnitude lower than CO2 losses, and were similar across earthworm community treatments. Communities with the anecic species accelerated litter C mass loss by 31-39% with differential mass loss of litter types (Acer rubrum > Populus grandidentata > Fagus grandifolia > Quercus rubra Pinus strobus) indicative of leaf litter preference. Burrow system volume, continuity, and size distribution differed across earthworm treatments but did not affect cumulative CO2 or DOC losses. However, burrow system structure controlled vertical C redistribution by mediating the contributions of leaf litter to A-horizon C and N pools, as indicated by strong correlations between (1) subsurface vertical burrows made by anecic species, and accelerated leaf litter mass losses (with the exception of P. strobus); and (2) dense burrow networks in the A-horizon and the C and N properties of these pools. Final soil C storage was slightly lower in earthworm treatments, indicating that increased leaf litter C inputs into soil were more than offset by losses as CO2 and DOC across earthworm community treatments.