Background Iguaçu National Park (INP) is known worldwide due to Iguaçu Waterfalls, being considered a World Natural Heritage by UNESCO. The INP is one of the last large forested extensions of inland Brazil that provides protection to the Atlantic Forest, one of the world’s biodiversity hotspots. However, its Natural Heritage status has been threatened by the construction and operation of the Baixo Iguaçu dam, agricultural and urban impacts on its boundaries and the increasing interest of the Brazilian government in re-opening of the “Colono road”, an old illegal road that crossed the interior of the park. Indeed, since benthic macroinvertebrates have been widely used for the environmental assessment of streams, records and abundance of their taxa under different seasonal periods may provide an additional dataset for biomonitoring of hydrographic systems in the face of current anthropogenic impacts on the INP boundaries and other similar streams on forest edges. New information In this study, we improved the sampling design of benthic macroinvertebrates and provided seasonal records covering distinct precipitation/temperature periods between 2016 and 2017 of a stream on the eastern edge of the Iguaçu National Park, Brazil. The records total 2,840 individuals distributed in 88 different taxa. The most abundant taxa were the Diptera subfamilies, Chironominae (n = 1,487) and Tanypodinae (n = 256), besides the Heterelmis genus (n = 152, Elmidae; Coleoptera). Diptera was the richest order in number of families (n = 8), while Leptophlebiidae (Ephemeroptera) was the richest taxonomic family in number of genera (n = 11). Aegla (Crustacea) and the Insecta genera, Heterelmis, Hexacylloepus, Noelmis, Phylloicus and Thraulodes, were recorded through all samplings. Twenty-five genera of Ephemeroptera, Plecoptera, Trichoptera (EPT) and Odonata were recorded during intermediate precipitation/temperature periods. Twenty-one of them were recorded in May 2016, with five genera standing out in abundance (Hydrosmilodon, Anacroneuria, Argia, Coryphaeschna, Americabaetis) and four (Needhamella, Tikuna, Simothraulopsis, Neocordulia) in December 2016. Four general taxa were exclusive of the lower precipitation/temperature period (August 2016), standing out in abundance were the Oxystigma (Odonata) and Corydalus (Megaloptera) genera. In March 2017 (higher precipitation/temperature period), four exclusive taxa were recorded, amongst them, the Chimarra (Trichoptera) genus. Furthermore, seasonal records demonstrated higher occurrences and abundance of macroinvertebrates during the intermediate and lower precipitation/temperature periods, besides a varied taxa composition throughout the year, with the presence of both sensitive and tolerant groups to environmental impacts. Our findings suggest that the number and composition of the local-stream macrobenthic fauna were influenced by the seasonal climatic regime. These changes should be considered in the limnological monitoring developed on the hydrographic systems of INP eastern edges to improve the assessment of environmental quality under different local seasonal conditions.

中文翻译：

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巴西伊瓜苏国家公园东缘溪流中大型底栖无脊椎动物的季节记录。


背景 伊瓜苏国家公园（INP）因伊瓜苏瀑布而闻名于世，被联合国教科文组织列为世界自然遗产。 INP 是巴西内陆最后的大型森林延伸区之一，为世界生物多样性热点之一的大西洋森林提供保护。然而，其自然遗产地位受到了拜索伊瓜苏大坝的建设和运营、对其边界的农业和城市影响以及巴西政府对重新开放“科洛诺路”（一条古老的非法道路）日益浓厚的兴趣的威胁。穿过公园的内部。事实上，由于底栖大型无脊椎动物已广泛用于溪流的环境评估，因此面对当前对 INP 边界和其他类似影响的人为影响，不同季节期间其类群的记录和丰度可能为水文系统的生物监测提供额外的数据集。森林边缘的溪流。新信息在这项研究中，我们改进了大型底栖无脊椎动物的采样设计，并提供了涵盖巴西伊瓜苏国家公园东缘一条溪流 2016 年至 2017 年不同降水/温度周期的季节记录。这些记录总共有 2,840 个个体，分布在 88 个不同的分类群中。最丰富的类群是双翅目亚科、摇蚊亚科 (n = 1,487) 和长足亚科 (n = 256)，此外还有异翅目属 (n = 152，Elmidae；鞘翅目)。双翅目是科数最丰富的目 (n = 8)，而细翅目 (Ephemeroptera) 是属数最丰富的分类科 (n = 11)。所有采样均记录了 Aegla（甲壳纲）和昆虫纲 Heterelmis、Hexacylloepus、Noelmis、Phylloicus 和 Thraulodes。 在中间降水/温度期间记录了蜉蝣目、蜉蝣目、毛翅目 (EPT) 和蜻蜓目 25 属。 2016 年 5 月记录到其中 21 个属，2016 年 12 月记录到的有 5 个属（Hydrosmilodon、Anacroneuria、Argia、Coryphaeschna、Americabaetis）和 4 个属（Needhamella、Tikuna、Simothraulopsis、Neocordulia）。 4 个一般类群被排除在外。在降水/气温较低的时期（2016 年 8 月），突出的是 Oxystigma (Odonata) 和 Corydalus (Megaloptera) 属。 2017年3月（降水量/气温较高的时期），记录了四个独有的类群，其中包括Chimarra（毛翅目）属。此外，季节性记录表明，除了全年不同的类群组成外，在中等和较低降水/温度期间，大型无脊椎动物的出现率和丰度更高，并且存在对环境影响敏感和耐受的群体。我们的研究结果表明，当地河流大型底栖动物的数量和组成受到季节性气候的影响。在 INP 东部边缘水文系统开发的湖泊学监测中应考虑这些变化，以改进对当地不同季节条件下环境质量的评估。