Monitoring long-term changes in aquatic biodiversity requires the effective use of historical data that were collected with different methods and varying levels of effort. Aggregating data into different spatial scales can control for such differences and provide a robust framework for monitoring distribution trends. We used a quantitative, multi-scale assessment to evaluate the potential drivers of distribution change for 60 fish species at three spatial scales, using 503 unique sampling events conducted between 1931 and 2019 in a stream biodiversity hotspot (French Creek, Pennsylvania, U.S.A). Trends delineated at multiple scales demonstrated that only one cyprinid species consistently declined through time. In contrast, several species, particularly centrarchids (bass and sunfish), appeared to increase with time. However, evidence for species’ increases varied among the different spatial scales, and our observations suggest that differences in effort and detection across time periods may contribute to patterns of species increases. There was agreement among scales that agricultural land use, non-native brown trout ( Salmo trutta ), and anthropogenic barriers did not explain patterns in biodiversity change from the distribution trends in this study. The lack of species declines is likely due to the limited levels of historical impacts in the watershed compared with other locations in the region that experienced more acute pollution bottlenecks. Species increases were most prevalent for sportfish and baitfish species, suggesting that distribution increases were human mediated. Similar multi-scale assessments should provide more robust insight into patterns of biodiversity loss and distribution changes by maximizing the use of historical data.

中文翻译：

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多尺度鱼类分布的长期趋势评估降低了与历史数据集相关的不确定性

监测水生生物多样性的长期变化需要有效利用通过不同方法和不同努力水平收集的历史数据。将数据聚合到不同的空间尺度可以控制这种差异，并为监测分布趋势提供一个强大的框架。我们使用 1931 年至 2019 年在河流生物多样性热点（美国宾夕法尼亚州法国河）中进行的 503 次独特采样事件，使用定量、多尺度评估来评估 60 种鱼类在三个空间尺度上分布变化的潜在驱动因素。在多个尺度上描绘的趋势表明，随着时间的推移，只有一种鲤科鱼类持续下降。相比之下，几个物种，特别是centrarchids（鲈鱼和翻车鱼），似乎随着时间的推移而增加。然而，物种增加的证据在不同的空间尺度上有所不同，我们的观察表明，不同时期的努力和检测差异可能导致物种增加的模式。农业土地利用、非本地褐鳟 (Salmo trutta) 和人为障碍不能从本研究的分布趋势解释生物多样性变化的模式。与该地区经历更严重污染瓶颈的其他地点相比，该流域的历史影响水平有限，因此物种数量没有减少。运动鱼和诱饵鱼的物种增加最为普遍，这表明分布增加是人类介导的。