Flood and fire act as ecological filters which can interact to shape forest structure and species composition. Our objective was to investigate how the interaction between fire and flood influences richness, abundance, basal area and species composition of the tree community and the monodominant belts of Attalea phalerata Mart. in forest islets of the Pantanal wetland. We used satellite images to find 12 forest islets without fire events from 1998 to 2014, and 12 forest islets burned only once in the same period in a fire event in 2009. In these forest islets, we set up a transect with 10 to 14 contiguous 5 × 10 m plots and sampled all trees with a diameter at breast height of ≥ 4.7 cm. We also measured the watermark height. Flooding influenced species richness and abundance, increased toward wetter areas of the forest islet flood gradient. In contrast, the interaction between fire and flood inverted that trend, with richness and abundance increasing in flood-free areas. Total basal area increases in the more flooded areas of the gradient. The fire or the interaction between fire and flooding did not influence the basal area. The relative abundance of A. phalerata increased with flood level and even more under the fire-flood interaction. We conclude that the interaction between fire and flood influences forest islet structure and species composition; moreover, it favors A. phalerata monodominance.

洪水和火灾充当生态过滤器，可以相互作用以塑造森林结构和物种组成。我们的目标是调查火灾和洪水之间的相互作用如何影响树木群落的丰富度、丰度、基底面积和物种组成以及Attalea phalerata的单优势带  市场。在潘塔纳尔湿地的森林小岛上。我们使用卫星图像找到了 12 个 1998 年至 2014 年未发生火灾事件的森林小岛，2009 年同一时期发生火灾事件的 12 个森林小岛仅被烧毁一次。 5 × 10 m 地块，并对胸高直径≥ 4.7 cm 的所有树木进行采样。我们还测量了水印高度。洪水影响了物种丰富度和丰度，向森林小岛洪水梯度的湿润地区增加。相比之下，火灾和洪水之间的相互作用逆转了这一趋势，无洪水地区的丰富度和丰度增加。坡度中洪水泛滥的区域的总基础面积增加。火灾或火灾与洪水之间的相互作用不影响基底面积。相对丰度A. phalerata随着洪水水位的增加而增加，在火洪水相互作用下甚至更多。我们得出结论，火灾和洪水之间的相互作用会影响森林小岛结构和物种组成；此外，它有利于A. phalerata 的单一优势。