Jo Insu, Fridley Jason D, Frank Douglas A
Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA.
New Phytol. 2016 Jan;209(1):115-22. doi: 10.1111/nph.13619. Epub 2015 Sep 3.
Invaders often have greater rates of production and produce more labile litter than natives. The increased litter quantity and quality of invaders should increase nutrient cycling through faster litter decomposition. However, the limited number of invasive species that have been included in decomposition studies has hindered the ability to generalize their impacts on decomposition rates. Further, previous decomposition studies have neglected roots. We measured litter traits and decomposition rates of leaves for 42 native and 36 nonnative woody species, and those of fine roots for 23 native and 25 nonnative species that occur in temperate deciduous forests throughout the Eastern USA. Among the leaf and root traits that differed between native and invasive species, only leaf nitrogen was significantly associated with decomposition rate. However, native and nonnative species did not differ systematically in leaf and root decomposition rates. We found that among the parameters measured, litter decomposer activity was driven by litter chemical quality rather than tissue density and structure. Our results indicate that litter decomposition rate per se is not a pathway by which forest woody invasive species affect North American temperate forest soil carbon and nutrient processes.
外来物种通常比本地物种具有更高的产量，并且产生的凋落物更易分解。外来物种凋落物数量和质量的增加应会通过加快凋落物分解来促进养分循环。然而，纳入分解研究的入侵物种数量有限，这妨碍了我们概括它们对分解速率影响的能力。此外，以往的分解研究忽略了根系。我们测量了美国东部温带落叶林中42种本地和36种非本地木本植物叶片的凋落物特征和分解速率，以及23种本地和25种非本地物种细根的凋落物特征和分解速率。在本地物种和入侵物种之间存在差异的叶片和根系特征中，只有叶片氮含量与分解速率显著相关。然而，本地物种和非本地物种在叶片和根系分解速率上并没有系统的差异。我们发现，在所测量的参数中，凋落物分解者的活动是由凋落物化学质量而非组织密度和结构驱动的。我们的结果表明，凋落物分解速率本身并不是森林木本入侵物种影响北美温带森林土壤碳和养分过程的途径。
