Data from: Historical citizen science to understand and predict climate-driven trout decline

Historical species records offer an excellent opportunity to test the predictive ability of range forecasts under climate change, but researchers often consider that historical records are scarce and unreliable, besides the datasets collected by renowned naturalists. Here, we demonstrate the relevance of biodiversity records developed through citizen-science initiatives generated outside the natural sciences academia. We used a Spanish geographical dictionary from the mid-nineteenth century to compile over 10 000 freshwater fish records, including almost 4 000 brown trout (Salmo trutta) citations, and constructed a historical presence–absence dataset covering over 2 000 10 × 10 km cells, which is comparable to present-day data. There has been a clear reduction in trout range in the past 150 years, coinciding with a generalized warming. We show that current trout distribution can be accurately predicted based on historical records and past and present values of three air temperature variables. The models indicate a consistent decline of average suitability of around 25% between 1850s and 2000s, which is expected to surpass 40% by the 2050s. We stress the largely unexplored potential of historical species records from non-academic sources to open new pathways for long-term global change science.

历史物种记录为检验气候变化下物种分布区预测模型的预测能力提供了绝佳契机，但学界普遍认为，除知名博物学家采集的数据集外，历史物种记录普遍稀缺且可靠性不足。本研究证实了非自然科学学术圈之外的公民科学（citizen-science）项目所产生的生物多样性记录的重要价值。本研究依托19世纪中期的西班牙地理辞典，整理得到超10000条淡水鱼类记录，其中包含近4000条褐鳟（Salmo trutta）的观测记录；并构建了覆盖超2000个10×10公里网格单元的历史存在-缺失数据集，该数据集的质量可与当代观测数据媲美。研究发现，过去150年间褐鳟的分布范围已出现显著缩减，这与全球普遍升温的时间节点高度吻合。本研究证实，仅依托历史记录以及3个气温变量的历史与当代数值，即可精准预测当前褐鳟的分布格局。模型结果显示，1850年代至2000年代间，褐鳟适生区的平均适宜度持续下降约25%，预计到2050年代这一降幅将超过40%。本研究强调，非学术来源的历史物种记录尚未得到充分挖掘，其可为长期全球变化科学研究开辟全新路径。