Amazon palm swamp peatlands are major carbon (C) sinks and reservoirs. In Peru, this ecosystem is widely threatened owing to the recurrent practice of cutting Mauritia flexuosa palms for fruit harvesting. Such degradation could significantly damage peat deposits by altering C fluxes through fine root productivity, mortality, and decomposition rates which contribute to and regulate peat accumulation. Along a same peat formation, we studied an undegraded site (Intact), a moderately degraded site (mDeg) and a heavily degraded site (hDeg) over 11 months. Fine root C stocks and fluxes were monthly sampled by sequential coring. Concomitantly, fine root decomposition was investigated using litter bags. In the experimental design, fine root stocks and dynamics were assessed separately according to vegetation type (M. flexuosa palm and other tree species) and M. flexuosa age class. Furthermore, results obtained from individual palms and trees were site-scaled by using forest composition and structure. At the scale of individuals, fine root C biomass in M. flexuosa adults was higher at the mDeg site than at the Intact and hDeg sites, while in trees it was lowest at the hDeg site. Site-scale fine root biomass (Mg C ha−1) was higher at the mDeg site (0.58 ± 0.05) than at the Intact (0.48 ± 0.05) and hDeg sites (0.32 ± 0.03). Site-scale annual fine root mortality rate was not significantly different between sites (3.4 ± 1.3, 2.0 ± 0.8, 1.5 ± 0.7 Mg C ha−1 yr−1 at the Intact, mDeg, and hDeg sites) while productivity (same unit) was lower at the hDeg site (1.5 ± 0.8) than at the Intact site (3.7 ± 1.2), the mDeg site being intermediate (2.3 ± 0.9). Decomposition was slow with 63.5−74.4% of mass remaining after 300 days and it was similar among sites and vegetation types. The significant lower fine root C stock and annual productivity rate at the hDeg site than at the Intact site suggests a potential for strong degradation to disrupt peat accretion. These results stress the need for a sustainable management of these forests to maintain their C sink function.

中文翻译：

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秘鲁亚马逊棕榈沼泽泥炭林细根碳储量、生产力、死亡率和分解率的退化驱动变化


亚马逊棕榈沼泽泥炭地是主要的碳 (C) 汇和水库。在秘鲁，由于经常砍伐毛里求斯棕榈树以收获水果，这一生态系统受到广泛威胁。这种退化可能会通过细根生产力、死亡率和分解速率来改变碳通量，从而显着损害泥炭沉积物，从而促进和调节泥炭积累。沿着同一泥炭地层，我们在 11 个月的时间里研究了未退化地点 (Intact)、中度退化地点 (mDeg) 和严重退化地点 (hDeg)。每月通过连续取芯对细根碳库和通量进行采样。同时，使用垃圾袋研究细根分解。在实验设计中，根据植被类型（M.flexuosa棕榈树和其他树种）和M.flexuosa树龄等级分别评估细根茎和动态。此外，通过使用森林组成和结构，对从单个棕榈树和树木获得的结果进行了场地缩放。在个体尺度上，M. flexuosa 成虫的细根碳生物量在 mDeg 位点高于 Intact 和 hDeg 位点，而在树木中，细根 C 生物量在 hDeg 位点最低。 mDeg 站点 (0.58 ± 0.05) 的站点规模细根生物量 (Mg C ha−1) 高于完整站点 (0.48 ± 0.05) 和 hDeg 站点 (0.32 ± 0.03)。站点之间的站点规模年度细根死亡率没有显着差异（完整、mDeg 和 hDeg 站点的 3.4 ± 1.3、2.0 ± 0.8、1.5 ± 0.7 Mg C ha−1 yr−1），而生产率（相同单位） hDeg 位点 (1.5 ± 0.8) 低于完整位点 (3.7 ± 1.2)，mDeg 位点处于中间 (2.3 ± 0.9)。分解缓慢，300 天后剩余质量为 63.5−74.4%，并且不同地点和植被类型之间的分解相似。 hDeg 地点的细根碳储量和年生产率显着低于完整地点，这表明强烈退化可能破坏泥炭增生。这些结果强调需要对这些森林进行可持续管理，以维持其碳汇功能。