Nonadditive effects of leaf litter species diversity on breakdown dynamics in a detritus-based stream
Nonadditive effects of leaf litter species diversity on breakdown dynamics in a detritus-based stream
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DOI：
10.1890/06-0674
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发表时间：
2007-05-01
期刊：
影响因子：
4.8
通讯作者：
Hunter, M. D.
中科院分区：
文献类型：
--
作者：
Kominoski, J. S.;Pringle, C. M.;Hunter, M. D.
由于预计物种的消失是非随机的，因此了解我们预计会消失的物种如何与其他物种相互作用以影响生态系统功能是很重要的。我们测试了凋落物物种多样性（以丰富度和组成来衡量）是否会影响以碎屑为基础的河流中的分解动力学。利用单种和混合种叶包的全因子分析（4种优势凋落物种的15种可能组合：红枫[Acer rubrum]、郁金香白杨[Liriodendron tulipifera]、栗树[Quercus prinus]和杜鹃花[rhododendron maximum]），我们测试了单种存在/缺失（加性）或物种相互作用（非加性）对叶包分解率、凋落物化学变化以及微生物和大型无脊椎动物生物量的影响。总体而言，我们发现凋落物物种多样性对叶包分解率有显著的非加性影响，这可以用丰富度和组成来解释。凋落物种类丰富度较高的叶包分解速率较快，且凋落物种类组成的拮抗效应在任意2种或3种凋落物混合时均存在。在凋落物化学、微生物和大型无脊椎动物生物量的变化方面，得到的结果不太一致。研究结果表明，凋落物物种多样性的丧失会减少调节生态系统功能的物种相互作用。为此，东部铁杉等物种的消失。（Tsuga canadensis），同时预测美国东南部河岸树种组成的变化可能对景观尺度上的凋落物分解产生非加性效应。
Since species loss is predicted to be nonrandom, it is important to understand the manner in which those species that we anticipate losing interact with other species to affect ecosystem function. We tested whether litter species diversity, measured as richness and composition, affects breakdown dynamics in a detritus-based stream. Using full-factorial analyses of single- and mixed-species leaf packs (15 possible combinations of four dominant litter species; red maple [Acer rubrum], tulip poplar [Liriodendron tulipifera], chestnut oak [Quercus prinus], and rhododendron [Rhododendron maximum]), we tested for single-species presence/absence (additive) or species interaction (nonadditive) effects on leaf pack breakdown rates, changes in litter chemistry, and microbial and macroinvertebrate biomass. Overall, we found significant nonadditive effects of litter species diversity on leaf pack breakdown rates, which were explained both by richness and composition. Leaf packs containing higher litter species richness had faster breakdown rates, and antagonistic effects of litter species composition were observed when any two or three of the four litter species were mixed. Less-consistent results were obtained with respect to changes in litter chemistry and microbial and macro invertebrate biomass. Our results suggest that loss of litter species diversity will decrease species interactions involved in regulating ecosystem function. To that end, loss of species such as eastern hemlock. (Tsuga canadensis) accompanied by predicted changes in riparian tree species composition in the southeastern United States could have nonadditive effects on litter breakdown at the landscape scale.