The provision of valuable ecosystem services by tropical swamp forests (mainly carbon sequestration and storage in biomass and soil) explains their ecological importance. Current efforts toward the conservation of these ecosystems, however, face strong limitations as their spatial variation is largely unknown, particularly in regions where they occur over large areas. Here, we analyze the α-diversity (i.e., effective number of species or true diversity) and community structure variability of three tropical swamp forest communities distributed along an approximately 300 km long portion of the Usumacinta River Basin, southern Mexico. We sampled eighty-three 625-m² plots to characterize the diversity and structural attributes of the woody plant communities. We recorded 2302 individuals belonging to 60 species and 25 families. Both α-diversity and structural attributes differed significantly among the three communities. The most inland community stood out for having the highest α-diversity for three true diversity values. Interestingly, the mangrove Rhizophora mangle L. was one of the dominant species, both in the swamp forest located closest to the coast and in the community farthest away from the sea. Basal area and density of individuals also had their maxima in the most inland swamp forest. The diversity and structural differences observed among the examined swamp forests seem to be related to contrasting environmental conditions, such as water salinity, distance to the coastline, and the hydrological dynamics of the Usumacinta River. We emphasize the urgency to conserve R. mangle populations in the swamp forest located farthest away from the coast due to its unusual habitat association, which appears to be a relictual condition.

中文翻译：

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墨西哥乌苏马辛塔河流域300 km长样带热带沼泽森林空间变异性评估

热带沼泽森林提供的有价值的生态系统服务（主要是碳固存和生物质和土壤中的储存）说明了其生态重要性。但是，目前在保护这些生态系统方面的努力面临着很大的局限性，因为它们的空间变化在很大程度上是未知的，特别是在大面积分布的地区。在这里，我们分析了墨西哥南部乌苏马辛塔河流域长约300公里的三个热带沼泽森林群落的α多样性（即有效物种数或真实多样性）和群落结构变异性。我们采样了八十^二个625 m ²描绘木本植物群落多样性和结构特征的地块。我们记录了2302个个体，分别属于60个物种和25个科。在三个社区中，α多样性和结构属性均存在显着差异。内陆社区最突出的是，三个真实多样性值的α多样性最高。有趣的是，红树林Rhizophora mangleL.是最主要的物种之一，在最靠近海岸的沼泽森林和最远离海洋的社区中都是如此。在最内陆的沼泽森林中，个体的基础面积和密度也达到了最大值。在检查过的沼泽森林中观察到的多样性和结构差异似乎与环境条件的对比有关，例如水盐度，到海岸线的距离以及乌苏马辛塔河的水文动态。我们强调的紧迫性，以节省R.轧车在距离海岸最远的沼泽森林的人群，由于其不寻常的栖息地的联系，这似乎是一个relictual条件。