Freshwater fish represent one-fourth of the world’s vertebrates and provide irreplaceable goods and services but are increasingly affected by human activities. A new index, Cumulative Change in Biodiversity Facets, revealed marked changes in biodiversity in >50% of the world’s rivers covering >40% of the world’s continental surface and >37% of the world’s river length, whereas <14% of the world’s surface and river length remain least impacted. Present-day rivers are more similar to each other and have more fish species with more diverse morphologies and longer evolutionary legacies. In temperate rivers, where the impact has been greatest, biodiversity changes were primarily due to river fragmentation and introduction of non-native species.

淡水鱼占世界脊椎动物的四分之一，提供了不可替代的商品和服务，但越来越受到人类活动的影响。一个新的指数，即生物多样性方面的累积变化，揭示了世界上50％以上的河流的生物多样性发生了显着变化，覆盖了世界40％以上的大陆表层和37％的世界河流长度，而世界上<14％河流长度受影响最小。当今的河流彼此之间更加相似，并且拥有更多的鱼类，其形态更加多样，进化遗迹也更长。在影响最大的温带河流中，生物多样性的变化主要是由于河流破碎和非本地物种的引入。