The US Endangered Species Act aims to recover threatened species and preserve their ecosystems, often through habitat management and restoration. In the face of climate change and phenological shifts, however, habitat management can seem futile. One of the most conspicuous effects of climate change is that many species are shifting in phenology, i.e., the timing of life history events. These shifts are assumed to have population-level effects on at-risk species, although it is less clear whether these effects are likely to be positive or negative. Here, we use a 27-year-long data set of Fender’s blue (Icaricia icarioides fenderi), an endangered butterfly, to investigate long-term changes in abundance and phenology at nine sites near Eugene, Oregon, USA. For Fender’s blue, day of peak flight activity consistently advanced at all sites from 1993 to 2019. At the same time, Fender’s blue populations increased at some sites and abundance was not changing at others. There was no association of population growth and advancement of peak flight activity. This suggests that although phenological shifts may be a “fingerprint” of climate change, they may not always be a cause for concern.

Implications for insect conservation Lessons from Fender’s blue butterfly are likely applicable to conservation of other at-risk butterflies. Despite a rapidly changing climate, at least some rare species can be conserved and recovered with appropriate habitat management.

《美国濒危物种法》旨在通过栖息地管理和恢复来恢复受威胁物种并保护其生态系统。然而，面对气候变化和物候变化，栖息地管理似乎徒劳无功。气候变化最明显的影响之一是许多物种的物候（例如生命历史事件的发生时间）正在发生变化。尽管尚不清楚这些影响可能是正面的还是负面的，但这些变化被认为对处于风险中的物种具有种群水平的影响。在这里，我们使用Fender蓝（Icaricia icarioides fenderi）长达27年的数据集），一只濒临灭绝的蝴蝶，研究美国俄勒冈州尤金附近9个地点的丰度和物候长期变化。对于Fender的蓝色，从1993年到2019年，所有站点的高峰飞行活动的日子一直持续增长。与此同时，Fender的蓝色种群在某些站点增加了，而其他站点的丰度却没有变化。人口增长与高峰飞行活动的发展没有关联。这表明，虽然物候变化可能是气候变化的“指纹”，但并非总是引起人们关注。

对昆虫保护的意义Fender的蓝蝴蝶的教训可能适用于其他高风险蝴蝶的保​​护。尽管气候变化迅速，但通过适当的栖息地管理，至少可以保护和恢复一些稀有物种。