The conversion of riparian vegetation into monocultures alters the input of allochthonous energy and the heterotrophy of streams. Here, we aimed to assess the implication of leaf litter inputs from plant species of agricultural importance on decomposition in Amazonian streams. We hypothesized that decomposition is low in litter with high concentrations of lignin and cellulose, regardless of the origin of plant species (exotic or native). We incubated leaf litter from plant species of agricultural importance, such as cocoa (native) and oil palm (exotic), as a control, leaf litter of Hymenaea courbaril (native) in four streams for 60 days. Contrary to our initial expectations, the leaf litter from oil palm, which was of higher quality and had lower concentrations of structuring compounds (lignin and cellulose), did not differ in decomposition rates from the lower quality leaf litter of the control species, which presented higher concentrations of structuring compounds. We recorded higher decomposition rate in cocoa, which had intermediate concentrations of structural compounds. Our results indicate a negative effect of the conversion of riparian vegetation into oil palm monocultures (Elaeis guineensis) for the processing of organic matter in Amazonian streams, due to the slower decomposition rate of the leaf litter of this species.

河岸植被转变为单一文化会改变异源能量的输入和河流的异养性。在这里，我们旨在评估来自农业重要植物物种的凋落物输入对亚马逊河流域分解的影响。我们假设，不论植物物种的起源（外来或本地），木质素和纤维素含量高的凋落物分解率都很低。我们将来自农业上重要的植物物种（例如可可（本地）和油棕（外来））的叶片凋落物作为对照，进行了雨生的鬣狗的叶片凋落物的对照研究。（本机）分为四组，共60天。与我们最初的预期相反，来自油棕的叶子凋落物质量较高且结构化化合物（木质素和纤维素）的浓度较低，其分解速率与对照物种的质量较低的叶子凋落物没有差异。较高浓度的结构化合物。我们记录到可可豆的分解速率更高，可可豆具有中等浓度的结构化合物。我们的研究结果表明，由于该物种的叶子凋落物的分解速度较慢，因此将河岸植被转化为油棕单作植物（Elaeis guineensis）对亚马逊河中有机物的处理产生了负面影响。