Identifying the environmental factors controlling litter decomposition is key to understanding the magnitude and rates of nutrient cycling in tropical forests, and how they may be influenced by climate variability and environmental change. We carried out a leaf litter translocation experiment in mature rain forest over a 2,520 m altitudinal gradient in Costa Rica. Leaf litter decomposition rates (k) of ten tree species, two dominant species from each ecosystem, plus two standard species, were calculated over 540 days in four life zones. k was lowest in montane with 0.83 per year and lower montane forests with 2.21 per year. k did not differ between lowland and premontane forests at 3.12 per year, in spite of the 3℃ difference of mean annual temperature between these life zones. k varied fourfold among species. Species decomposition rates ranked as follows, and were predictably related to leaf economic spectrum traits of the species: Acalypha communis (standard, fast decomposer)» Hyeronima oblonga > Alchornea latifolia, Quercus bumelioides, Jarava ichu (standard, slow decomposer)> Minquartia guianensis > Magnolia sororum > Vochysia allenii > Pourouma bicolor, Carapa guianensis. These two slowest‐decomposing species were native premontane and lowland forest dominants, respectively, with tough, low‐nutrient leaves. The ranking of species by k varied very little among life zones suggesting that decomposer organisms in very different ecosystems and environments react in similar ways to the litter quality in general. We conclude that while k decreases with temperature in rain forests on tropical mountains, bioclimatic zones defined as premontane may be “functionally lowland.” The effects of species identity on decomposition rates on tropical mountains are consistent and independent of environment for both standard and native species. Under climate change on these mountains, if moisture regimes do not change, decomposition rates will increase due to rising temperatures. Soil carbon storage may therefore decrease. Changes in the altitudinal distributions of currently dominant species will also affect this critically important biogeochemical process.

中文翻译：

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海拔和物种同一性驱动新热带雨林在2950 m垂直梯度上10个物种的凋落物分解速率

确定控制凋落物分解的环境因素是了解热带森林中养分循环的程度和速率以及气候变化和环境变化如何影响养分循环的关键。我们在哥斯达黎加的2,520 m海拔梯度上的成熟雨林中进行了凋落物移位试验。在540个生命区域内的540天中，计算了10种树种，每个生态系统的2个优势种以及2个标准树种的凋落物分解率（k）。山地的k最低，每年为0.83，山地较低的森林中的k为每年2.21。ķ尽管这些生活区之间的年平均气温相差3℃，但低地森林和山前森林之间的年均温度没有差异，为每年3.12。k在种间变化四倍。物种分解速率排名如下，并且与该物种的叶片经济谱特征有关，可预测地与该物种相关：阿拉伯沙蝇（Acalypha communis）（标准，快速分解剂）»扁叶天蛾 >  Alchornea latifolia，栎栎，Jarava ichu（标准，慢速分解剂）> Minquartia guianensis  > 玉兰sororum  >  Vochysia allenii  >  Pourouma双色，Carapa花草。这两个分解最慢的物种分别是原生的山前和低地森林优势种，叶片坚韧，营养低。在生活区之间，按k进行的物种排名变化不大，这表明，在非常不同的生态系统和环境中，分解生物对垃圾质量的反应通常相似。我们得出结论，虽然k在热带山区的雨林中，温度随温度降低而下降，定义为前山地带的生物气候区可能是“功能低地”。物种身份对热带山区分解速率的影响是一致的，并且与标准物种和本地物种的环境无关。在这些山脉的气候变化下，如果水分状况不发生变化，则分解速率将因温度升高而增加。因此，土壤碳储量可能减少。当前优势物种的海拔分布的变化也将影响这一至关重要的生物地球化学过程。