Death by a thousand cuts: Small local dams can produce large regional impacts in the Brazilian Legal Amazon

Freitas, Carlos; Mereles, Marcos de Almeida; Pereira, Diego Valente; Siqueira‐Souza, Flávia K.; Hurd, Lawrence E.; Kahn, James R.; Morais, Gilberto; Sousa, Raniere Garcez Costa

doi:10.1016/j.envsci.2022.07.013

Cited by 9 publications

(4 citation statements)

References 48 publications

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“…Even if effects of high fishing pressures are present, they may be more difficult to detect, because fishing is only one of several stressors on fish stocks in the Amazon (Castello & Macedo, 2016). Cumulative effects of fishing (Fabré et al., 2017), deforestation (Arantes et al., 2018), dam construction (Arantes et al., 2022; Freitas et al., 2022), mining (Araújo‐Flores et al., 2021), and climate change (Röpke et al., 2017) are among the many threats to biodiversity and ecosystem services in the region. Continuous data collection and analysis of longer time series are needed to unravel effects of fisheries from other synergistic factors on fish stocks and would allow for consistent estimates of stocks and development of effective fisheries management measures.…”

Section: Discussionmentioning

confidence: 99%

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Stable mean trophic level and decreasing fish size in Central Amazonian fishery landings

Matos,

Pereira,

Lopes

et al. 2023

Fisheries Management Eco

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Evaluating trends in fisheries, especially data‐limited small‐scale fisheries, is challenging. We used fish landings to evaluate changes in composition of fish landings in rivers of the Central Amazon, from a discontinuous historical 28‐year series of landings from different data collection systems in main ports of the city of Manaus, the largest consumer market in the region. Annual mean trophic level (MTL), fishing‐in‐balance index (FiB), and mean landed size (MSL) were estimated. MTL did not decline, FiB was positive in most years, and MSL declined. Relative catches of certain fish species were replaced by others at a similar trophic level, but mean body size declined over time. We conclude that fishing in the Central Amazon is not sustainable and would benefit from better management strategies.

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Section: Discussionmentioning

confidence: 99%

“…Cumulative effects of fishing (Fabré et al, 2017), deforestation (Arantes et al, 2018), dam construction (Arantes et al, 2022;Freitas et al, 2022)…”

Section: Discussionmentioning

confidence: 99%

Stable mean trophic level and decreasing fish size in Central Amazonian fishery landings

Matos,

Pereira,

Lopes

et al. 2023

Fisheries Management Eco

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“…SHPs may lead to the disappearance of fish species or the isolation of populations as occurs with large hydroelectric dams ( Kukuła & Bylak, 2022 ). In the Amazon Basin, thousands of small dams are operating and acting as physical barriers to fish movement ( Freitas et al, 2022 ). Blocking movement between upstream and downstream stretches, small dams can alter the composition and trophic structure of fish assemblages in Amazonian streams ( Sousa et al, 2018 ).…”

Section: Introductionmentioning

confidence: 99%

Impacts of river fragmentation on limiting individual dietary specialization of Amazonian predatory fish

Aguiar‐Santos

deHart

Forsberg³

et al. 2022

PeerJ

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Individual dietary specialization is one of the factors that promotes variation in resource use at the individual level. Here we used stable isotope analysis of multiple tissues with different turnover rates to examine the degree of individual specialization in two sub-populations of the predator Cichla temensis inhabiting both fragmented and undammed rivers within the Uatumã River basin of the Amazon. Our results showed that the undammed river provides better conditions to promote individual dietary specialization than the fragmented river. This study contributes to the understanding of how specific life history characteristics of populations of generalist predators are impacted by fragmentation within megadiverse environments such as the Amazon basin.

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“…The Brazilian government aims to supply three-quarters of its energy demand through this network of dams [3,4]. Although touted as one of the cleanest forms of energy generation in terms of greenhouse gas emissions [5], hydroelectric dams are known to have a suite of other hydrophysical and environmental impacts [1,[6][7][8][9][10]. Moreover, these hydropower systems may be even less "green" than generally assumed, given recent evidence that their reservoirs are important sources of methane (CH 4 ) and carbon dioxide (CO 2 ) emissions into the atmosphere.…”

Section: Introductionmentioning

confidence: 99%

Dams Pose a Critical Threat to Rivers in Brazil’s Cerrado Hotspot

Ferreira

Nogueira

Latrubesse

et al. 2022

Water

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Hydropower dams are touted as one of the cleanest forms of energy production, yet they are associated with severe environmental impacts on both the physical structure and functioning of river ecosystems. The threat is particularly acute in the Brazilian Cerrado—a biodiverse savanna region, spanning over 2 million km2, that concentrates the headwaters of several critical South American watersheds. Our study analyzed the current distribution of large and small hydroelectric plants in the Cerrado and focused on understanding their effect on land use changes. We also propose a Dam Saturation Index (DSI) to help spur more integrated planning for this region. Results indicate that the Cerrado river basins contains 116 (30%) of Brazil’s large hydroelectric plants and 352 (36%) of its small hydroelectric plants. Moreover, these plants spurred significant land use changes within a 5-km buffer of the dams, with over 2255 km2 of native vegetation cleared by 2000 and an additional 379 km2 in the ensuing 20 years, could reach ~1000 km2. Based on the historical anthropization process in the Brazilian savannas, we expect new crops, pastures, and urban equipment to be incorporated into this landscape, with different impact loads.

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Death by a thousand cuts: Small local dams can produce large regional impacts in the Brazilian Legal Amazon

Cited by 9 publications

References 48 publications

Stable mean trophic level and decreasing fish size in Central Amazonian fishery landings

Stable mean trophic level and decreasing fish size in Central Amazonian fishery landings

Impacts of river fragmentation on limiting individual dietary specialization of Amazonian predatory fish

Dams Pose a Critical Threat to Rivers in Brazil’s Cerrado Hotspot

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