Dams and the fish fauna of the Neotropical region: impacts and management related to diversity and fisheries
Dams and the fish fauna of the Neotropical region: impacts and management related to diversity and fisheries
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DOI：
10.1590/s1519-69842008000500019
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发表时间：
2008-11-01
影响因子：
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通讯作者：
Gomes, LC.
中科院分区：
文献类型：
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作者：
Agostinho, AA.;Pelicice, FM.;Gomes, LC.
巴西几乎所有的水文盆地都建了水库。它们的用途包括为城市供水、灌溉，主要是发电。在该国的大河中有700多个大型水坝和相关水库。这些水库有利于地方和区域的经济发展，但它们也给河流的自然水文制度带来了严重的和不可逆转的变化，影响了生境质量和生物区系的动态。在蓄水区，主要影响是水体由静水向静水的转变，影响了包括鱼类在内的水生动物群。储集层的影响呈现相应的时空变化。在水库形成后，由于周围栖息地的合并，鱼类的丰富度通常增加，但丰富度随着水库的年龄而减少。然而，大坝下游的影响似乎与发生在水库内的影响相似或更强。大坝促进了流量控制，改变了洪水的季节周期。当水坝以梯级方式建造时，这些影响就会增强。因此，水坝深刻地影响了鱼类群落的组成和结构。最受影响的物种是嗜流动物和长距离候鸟，它们需要不同的栖息地来完成它们的生命周期。在严格管制的地区，迁徙物种种群可能会崩溃甚至消失。巴西为尽量减少渔网的影响而采取的管理行动历来包括修建鱼类通道、渔业控制和放养。这些行动的结果是可疑的和/或明显的失败。本文以巴西受水坝影响最严重的巴拉那河流域为研究重点。我们描述了受鸟类影响地区鱼类多样性变化和下降的一些规律。我们还讨论了对渔业和生态系统功能的负面影响。最后，讨论了水坝管理措施的重要性和成效，并提出了加强水坝影响下南美流域鱼类动物保护的建议。
Reservoirs have been built in almost all of the hydrographic basins of Brazil. Their purposes include water supply for cities, irrigation and mainly, generation of electricity. There are more than 700 large dams and associated reservoirs in the large rivers of the country. These reservoirs favor local and regional economic development, but they also bring serious and irreversible alterations in the natural hydrologic regime of rivers, affecting habitat quality and the dynamics of the biota. In the impounded area, the main impact is the change from lotic to lentic water, which influences aquatic fauna, including fishes. Impacts of reservoirs present relevant spatiotemporal variations. Immediately after reservoir formation, fish species richness usually increases due to incorporation of surrounding habitats, but richness decreases as reservoirs age. However, impacts downstream of dams appear to be similar or stronger than those that occur within the reservoir. Dams promote discharge control, altering the seasonal cycles of floods. These effects are augmented when dams are constructed in cascades. Therefore, dams profoundly influence composition and structure of fish assemblages. Most affected species are the rheophilics and long distance migratory that require distinct habitats to fulfill their life cycles. Populations of migratory species may collapse or even disappear in intensely regulated stretches. Management actions taken to minimize impacts of darns in Brazil historically considered construction of fish passages, fishery control and stocking. The results of these actions are questionable and/or with clear failures. In this paper, we give emphasis to the Parana River basin, the most affected by dams in Brazil. We describe some patterns in the alteration and decline in fish diversity in areas influenced by darns. We also discuss negative consequences in the fishery and ecosystems functioning. Finally, we argue the relevance and the Success of the management actions taken and present some suggestions to improve conservation of the ichthyofauna in South American basins influenced by dams.