Abstract In the northernmost of Rio Grande do Sul coastal plain, southern Brazil, the first comparative palynological study of the sedimentary profiles of two present-day Atlantic rainforests was conducted in Torres municipality: Pirataba forest (29°15′ S, 49°51′ W), 17 km from the coastline, and Faxinal forest (29°21′ S, 49°45′ W), 2 km from the coastline. Ten radiocarbon dates and additional grain influx diagrams allowed for a more accurate analysis. The results suggested that regional and local events affected the northern coastal plain vegetation. The inner coastal plain of the Pirataba site was characterized by a cold, dry regional climate and a small number of pioneer forest species at the end of the last glacial stage (24,000–10,000 bp ); a regionally variable temperature increase with slightly humid and dry phases in the early/mid-Holocene (10,000–6700 bp ); and regional high temperature and humidity, and expanding Atlantic rainforests, in the mid-Holocene (6700 bp onwards). Near the coastline in the Faxinal site, the following were detected: marine transgression and damage to herbaceous marsh plants, and elevated temperature in the mid-Holocene (7000–6700 bp); regional marine regression, gradual soil desalination and scarce herbaceous marsh in the mid/late Holocene (6700–3500 bp); and regional high temperature and humidity, with forest expansion over the desalinated herbaceous marsh in the late Holocene (3500 bp onwards). The Pirataba and Faxinal forests expanded because of the high temperatures, an even greater increase in regional rainfall, and improved soil conditions at the end of the late Holocene (1500 bp onwards). The hydrosere occurring due to a water reservoir in Faxinal highlights the importance of preserving the lacustrine bodies of the region as generators of coastal forests.

中文翻译：

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巴西南部南里奥格兰德州北部沿海平原过去 24,000 年的古环境

摘要 在巴西南部南里奥格兰德沿海平原的最北端，在托雷斯市对两个现今大西洋热带雨林的沉积剖面进行了第一次比较孢粉学研究：皮拉塔巴森林 (29°15′ S, 49°51′ W)，距海岸线 17 公里，Faxinal 森林（南纬 29°21'，西经 49°45'），距海岸线 2 公里。十个放射性碳日期和额外的谷物流入图可以进行更准确的分析。结果表明，区域和局地事件影响了北部沿海平原植被。皮拉塔巴遗址内沿海平原的特点是寒冷干燥的区域气候和末次冰期末期（24,000-10,000 bp）的少量先驱森林物种；全新世早期/中期（10,000-6700 bp）的区域性温度升高，略微潮湿和干燥；在全新世中期（6700 bp 以后），区域高温和高湿，以及大西洋热带雨林的扩张。在 Faxinal 遗址的海岸线附近，检测到以下情况：海洋入侵和对草本沼泽植物的破坏，全新世中期（7000-6700 bp）温度升高；全新世中/晚期（6700-3500 bp）的区域海洋回归、土壤逐渐淡化和稀少的草本沼泽；和区域高温高湿，在全新世晚期（3500 bp 以后），森林在淡化草本沼泽上扩张。Pirataba 和 Faxinal 森林因高温而扩大，区域降雨量增加更多，并在全新世晚期（1500 bp 以后）改善了土壤条件。由于 Faxinal 的一个水库而发生的水流突显了保护该地区湖泊水体作为沿海森林发电机的重要性。