Tropical peatlands are highly vulnerable to anthropogenic alterations. In Costa Rica, riverine peatlands are understudied, and most are not included in protected areas. This study aims to generating information useful to assess the anthropogenic pressure in a riverine peatland in Los Robles Sector (LRS) of Medio Queso Wetland (MQW) complex. Evaluations of impacts of fires on vegetation and surface peat chemistry, and the post-2021 fire, makeup of dominant vegetation changes with the Cyperaceae species Scleria melaleuca replacing Eleocharis interstincta as the dominant species are presented. The topsoil (0–20 cm) total C content was quantified as lower than 300 g kg⁻¹ with no significant statistical differences in total C and N content between soil shortly after the fires or two years later. The species E. interstincta is observed to promote higher C stability during the dry season, and has a more recalcitrant composition of the root system compared to the post 2021-fire dominant S. melaleuca. To reduce the impact on C accumulation, measures to prevent grazing-originated fires, especially when the water table is low, are urgent. Hence, this work aims at proving information that can be a baseline for impacts assessment and to inform conservation measures and policies.

热带泥炭地极易受到人为改变的影响。在哥斯达黎加，河流泥炭地的研究不足，而且大多数不包括在保护区内。本研究旨在生成有用的信息，以评估 Medio Queso 湿地 (MQW) 综合体洛斯罗布尔斯区 (LRS) 河流泥炭地的人为压力。评估了火灾对植被和地表泥炭化学的影响，以及 2021 年后火灾、莎草科物种Scleria melaleuca取代Eleocharis interstincta成为优势物种的优势植被组成变化。表土（0-20 cm）总碳含量量化为低于 300 g kg ^-1，火灾后不久或两年后土壤之间的总碳和总氮含量没有显着统计差异。据观察， E. interstincta物种在旱季可促进更高的碳稳定性，​​并且与 2021 年火灾后占主导地位的S. Melaleuca相比，其根系组成更加顽固。为了减少对碳积累的影响，迫切需要采取措施防止放牧引起的火灾，特别是在地下水位较低的情况下。因此，这项工作旨在证明可以作为影响评估基线的信息，并为保护措施和政策提供信息。