A major flood caused by a typhoon did not affect the population genetic structure of a river mayfly metapopulation.

Floods affect the population structure of organisms that inhabit streams. In recent decades, the scale of floods has become larger due to climate change. Under these circumstances, on 12 October 2019, the largest typhoon in the history of observation in Japan struck the Japanese Archipelago.

Seasonal modifications of longitudinal distribution patterns within a stream: Interspecific interactions in the niche overlap zones of two mayflies.

Niche differentiation between closely related species leads to differentiation of their habitats. Segregation based on slight differences in environmental factors, that is niche differentiation on the microhabitat scale, allows more species to inhabit a certain geographic space. Therefore, such fine scale niche differentiation is an important factor in the support of species diversity.