Local diversity in phenological responses of migratory lake sturgeon to warm winters

Rich intraspecific diversity in traits that shape responses to environmental conditions implies effects of climate change will differ within species or even populations. Nevertheless, few studies investigate how different groups respond climatic fluctuations, and most risk assessments rely upon species-wide generalizations. We studied among-year variation air temperature on the spring migratory phenology a metapopulation lake sturgeon Acipenser fulvescens waters connecting Lake Huron Erie Laurentian Great Lakes. Sturgeon here express multiple phenotypes all spawn either St. Clair River Detroit but their use after spawning more than 86 000 km2 accessible river habitat. Acoustic tracking over nine years (2012–2020) revealed mixed phenological late-winter temperatures, with three arriving at rivers earlier during warm one whose arrival was consistent across regardless temperature. Notably, two same overwinter lakes entered greater synchrony because advanced its while other did not. The results indicated weather could alter dynamics broader community, exemplify complexity hidden beneath broadscale generalizations species' response change.