1. The Balbina hydropower dam in the Central Amazon basin, established in the Uatumã River in the 1980s, is emblematic for its socio‐environmental disaster. Its environmental impacts go far beyond the reservoir and dam, however, affecting the floodplain forests (igapó) in the downstream area (dam shadow), which have been assessed using a transdisciplinary research approach, synthesized in this review.
2. Floodplain tree species are adapted to a regular and predictable flood pulse, with high‐ and low‐water periods occurring during the year. This was severely affected by the operation of the Balbina dam, which caused the suppression of both the aquatic phase at higher floodplain elevations and the terrestrial phase at lower floodplain elevations (termed the ‘sandwich effect’).
3. During the period of construction and reservoir fill, large‐scale mortality already occurred in the floodplains of the dam shadow as a result of reduced stream flow, in synergy with severe drought conditions induced by El Niño events, causing hydraulic failure and making floodplains vulnerable to wildfires.
4. During the operational period of the dam, permanent flooding conditions at low topographical elevations resulted in massive tree mortality. So far, 12% of the igapó forests have died along a downstream river stretch of more than 125 km. As a result of flood suppression at the highest elevations, an encroachment of secondary tree species from upland (terra firme) forests occurred.
5. More than 35 years after the implementation of the Balbina dam, the downstream impacts caused massive losses of macrohabitats, ecosystem services, and diversity of flood‐adapted tree species, probably cascading down to the entire food web, which must be considered in conservation management.
6. These findings are discussed critically, emphasizing the urgent need for the Brazilian environmental regulatory agencies to incorporate downstream impacts in the environmental assessments of several dam projects planned for the Amazon region.

中文翻译：

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巴尔比纳水坝的阴影：亚马逊地区中下游洪泛区森林超过35年的下游影响的综合报告

1. 1980年代在Uatumã河中建立的亚马逊河中部巴尔比纳水电站大坝是其社会环境灾难的标志。它对环境的影响远远超出了水库和水坝，但是影响了下游地区的洪泛区森林（igapó）（水坝阴影），本评价使用综合的跨学科研究方法对其进行了评估。
2. 洪泛树种适应常规且可预测的洪水脉动，一年中会出现高水位和低水位的时期。这受到Balbina大坝运行的严重影响，导致高洪泛区高程的水生期和低洪泛区高程的陆生期受到抑制（称为“夹心效应”）。
3. 在施工和水库充填期间，由于溪流减少，大坝阴影的洪泛区已经发生大规模死亡，这与厄尔尼诺事件引发的严重干旱条件协同作用，导致水力衰竭，使洪泛区易受洪水影响。野火。
4. 在大坝运行期间，低地形高海拔地区的永久性洪水条件导致大量树木死亡。到目前为止，在超过125公里的下游河段中，有12％的伊加波森林已经死亡。由于在最高海拔地区抑制了洪水，因此发生了来自陆地（硬地）森林的次生树种的入侵。
5. 实施Balbina大坝后超过35年，下游影响造成了大型栖息地，生态系统服务以及适应洪灾的树种的大量损失，可能会蔓延到整个食物网，这在保护管理中必须加以考虑。
6. 对这些发现进行了严格的讨论，强调了巴西环境监管机构迫切需要将下游影响纳入对亚马逊地区计划的几个大坝项目的环境评估中。