Sandy beaches are key economic assets worldwide, however, recreational activities are an important source of disturbance in these ecosystems. Intensive human use of beaches has a negative effect on benthic communities as it alters species abundance, diversity, and/or distribution. Here, we report the impacts of recreational activities (trampling and vehicles) on meiobenthic communities and nematode assemblages on Amazonian sandy beaches for the first time. For this purpose, samples were carried out in four consecutive months encompassing a period of high visitation peak (one month Before Vacation, During Vacation, and two months After Vacation) on three contrasting beaches regarding disturbances (Urban: Atalaia; Intermediary: Farol-Velho; and Protected: Corvinas) at seven equidistant sampling stations (50 m apart) from the high tide water mark to the swash zone. At each sampling station, three biological samples and sediments samples were collected haphazardly. Also, in each station, the sediment compaction was determined using a manual penetrometer. Overall, physical sediment variables (grain size, sorting) were constant over time in all beaches, whereas differences in intensity of recreational activities and sediment compaction were found between beaches and months. Sediment compaction was considered the most important factor for the differences observed in meiofauna community structure in the study areas, and it was related to intensity of recreational activities. Variations in density and changes in richness between periods were observed in Atalaia and Farol-Velho beaches. On the other hand, Corvinas beach remained the same throughout the study. In the first month after vacation, density and richness were similar to those in the period before vacation, thus indicating that the beaches had recovered in one month. Furthermore, vulnerabilities of Tardigrada and Copepoda, as well as of the Nematoda genera Daptonema, and Chromadorita, indicate that they might be potential indicators of recreational activities.

沙滩是世界范围内的关键经济资产，但是，娱乐活动是这些生态系统中重要的干扰源。人类大量使用海滩对底栖生物群落有负面影响，因为它改变了物种的丰富度，多样性和/或分布。在这里，我们首次报告了娱乐活动（踩踏和车辆）对亚马逊沙质海滩上的底栖动物群落和线虫群落的影响。为此，在三个相距甚远的海滩上，连续四个月对样本进行调查，包括访问高峰期（休假前一个月，休假期间和休假后两个月）（城市：Atalaia；中介机构：Farol-Velho） ；以及受保护的：从高潮水位到冲积带的七个等距采样站（相距50 m）位于Corvinas）。在每个采样站，随意采集了三个生物样品和沉积物样品。另外，在每个站中，使用手动渗透仪确定沉积物的压实度。总体而言，在所有海滩上，物理沉积物变量（粒度，分类）随时间变化都是恒定的，而在海滩和月份之间，娱乐活动强度和沉积物压实程度却存在差异。沉积物压实被认为是研究区域中小型动物群落结构差异的最重要因素，并且与娱乐活动的强度有关。在Atalaia和Farol-Velho海滩上观察到了不同时期之间密度的变化和丰富度的变化。另一方面，在整个研究过程中，Corvinas海滩保持不变。假期后的第一个月，密度和丰富度与假期前的相似，这说明海滩已在一个月内恢复。此外，Tardigrada和Copepoda以及线虫属的脆弱性Daptonema和Chromadorita表示它们可能是娱乐活动的潜在指标。