Sheffer Efrat, Canham Charles D, Kigel Jaime, Perevolotsky Avi
The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel,
Oecologia. 2015 Apr;177(4):1039-51. doi: 10.1007/s00442-015-3228-3. Epub 2015 Feb 15.
Species affect the dynamics of litter decay through the intrinsic properties of their litter, but also by influencing the environmental conditions imposed by their canopy, roots, and litter layers. We examined how human-induced changes in the relative abundances of two dominant Mediterranean trees-Pinus halepensis and Quercus calliprinos-impact leaf litter decomposition. A reciprocal transplant experiment tested decomposition of pine, oak, and mixed leaf litter in oak woodland and pine forest ecosystems with different relative abundances of pine and oak. Using likelihood methods, we tested the importance and magnitude of the environmental effects of local species abundance, litter layer composition, and soil properties on litter mass loss. Oak litter decomposition was slower than pine, and had an antagonistic effect on mixed litter decay. These results differ from other reported pine-oak associations, and are probably associated with a higher content of tannins and phenols in oak compared to pine litter in our study sites. The environmental effects of the two species were opposite to their litter decomposition dynamics. An increased proportion of pine in the oak woodlands and a higher content of pine needles in the litter layer of pine forests reduced decay rates. The presence of more oak and broadleaf litter in the litter layer accelerated decomposition in pine forests. Our results highlight the importance of considering multidimensional species effects mediated by both chemical and physical properties, and imply that man-made changes in the composition and configuration of plant communities may result in complex unpredicted consequences to ecosystem biogeochemistry.
物种通过其凋落物的内在特性影响凋落物分解动态，同时也通过影响其树冠、根系和凋落物层所营造的环境条件来发挥作用。我们研究了人类活动导致的两种地中海优势树种——阿勒颇松（Pinus halepensis）和地中海栓皮栎（Quercus calliprinos）相对丰度的变化如何影响树叶凋落物的分解。一项相互移植实验测试了在松树和橡树相对丰度不同的橡树林地和松树林生态系统中，松树叶、橡树叶及混合树叶凋落物的分解情况。我们使用似然方法，检验了当地物种丰度、凋落物层组成和土壤性质对凋落物质量损失的环境影响的重要性和程度。橡树叶分解比松树叶慢，并且对混合凋落物分解有拮抗作用。这些结果与其他报道的松树 - 橡树组合不同，可能与我们研究地点的橡树凋落物中单宁和酚类物质含量高于松树凋落物有关。这两个物种的环境影响与其凋落物分解动态相反。橡树林地中松树比例增加以及松树林凋落物层中松针含量增加会降低分解速率。松树林凋落物层中更多的橡树和阔叶凋落物的存在加速了分解。我们的结果强调了考虑由化学和物理性质介导的多维物种效应的重要性，并暗示植物群落组成和结构的人为变化可能对生态系统生物地球化学产生复杂的不可预测的后果。
