Abstract：
Fishers possess detailed local ecological knowledge (LEK) which can be a valuable resource for tracking long-term environmental changes in less studied tropical rivers. Our goal was to investigate such changes in three clear water rivers in the Brazilian Amazon, focusing on hydrology, water quality and land cover. Additionally, we aimed to compare these changes among three rivers (Trombetas, Tapajós and Tocantins) representing a potential gradient of environmental changes. We interviewed 129 fishers (67 in Tapajós, 33 in Tocantins and 29 in Trombetas), and analyzed temporal series on land cover and hydrology respectively through maps produced by the project MapBiomas, and data from the Brazilian National Water Agency across the last 34 years (from 1985 to 2019). The complementary analyses of these three databases (mapping, hydrological data and fishers\' knowledge) revealed environmental changes in the studied rivers. The maps showed a gradient of anthropic changes on land cover, from the less altered Trombetas river, the moderately altered Tapajós and the more intensely changed landscape in the Tocantins River. Fishers from the Tocantins River reported a greater variety of negative changes in water quality related to anthropic actions, such as dams, deforestation, and pollution. Additionally, most fishers indicated hydrological changes making the Tocantins River drier in more recent years, which would cause negative effects on fish populations. In the Tapajós River, fishers mentioned more varied hydrological patterns and negative effects on water quality linked to mining activities, whereas in Trombetas fishers perceived increased floods. The changes mentioned by the interviewed fishers matched observed trends from hydrological data indicating a trend of increasing droughts in the more impacted Tocantins River. Fishers\' knowledge provided exclusive \'on the ground\' data to track long-term changes on local hydrology and water quality, as well as inform the effects of these changes on fish and fisheries.
摘要：
渔民拥有详细的当地生态知识（LEK），这可能是跟踪研究较少的热带河流长期环境变化的宝贵资源。我们的目标是调查巴西亚马逊河三条清澈河流的这种变化，专注于水文学，水质和土地覆盖。此外,我们的目标是比较三条河流之间的这些变化(Trombetas，Tapajós和Tocantins）代表环境变化的潜在梯度。我们采访了129名渔民(塔帕霍斯67名，33在Tocantins和29在Trombetas)，并通过MapBiomas项目制作的地图分别分析了土地覆盖和水文的时间序列，以及巴西国家水务局过去34年(1985年至2019年)的数据。这三个数据库的互补分析(映射，水文数据和渔民知识）揭示了所研究河流的环境变化。地图显示了土地覆盖的人类变化梯度，从改变较少的特隆贝塔斯河，Tapajós发生了适度的变化，而Tocantins河中的景观变化更为剧烈。来自Tocantins河的渔民报告说，与人类行为有关的水质出现了更多的负面变化，比如水坝，森林砍伐,和污染。此外,大多数渔民表示，近年来水文变化使得托坎廷斯河更加干燥，这会对鱼类种群造成负面影响。在塔帕霍斯河中,渔民提到了更多不同的水文模式和与采矿活动相关的对水质的负面影响，而在Trombetas，渔民认为洪水增加。采访的渔民提到的变化与水文数据中观察到的趋势相匹配，表明受影响更大的托坎廷斯河干旱增加的趋势。渔民的知识提供了独家的地面数据，以跟踪当地水文和水质的长期变化，以及告知这些变化对鱼类和渔业的影响。
