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Aquatic species associated with regulated rivers are can be affected by human-altered flow regimes.

For example, the threatened Oregon spotted frog relies on aquatic habitats in all life history stages, and inundation patterns can have implications for population success. Federal researchers studied Oregon spotted frogs occupying wetlands along the Deschutes River downstream from two dams managed for irrigation water to examine the relationship between seasonally inundated habitat and monthly survival probabilities. Monthly survival was strongly associated with the extent and variability of inundated habitat, suggesting some within-season fluctuations at higher water levels could be beneficial. Seasonal survival was lowest in the winter when surface water was limited. At sites connected to the river, population growth was most strongly linked to adult survival, whereas population growth at the river-disconnected site was most strongly tied to survival in juvenile stages. This research identifies population effects of seasonally limited water and highlights conservation potential of enhancing survival of particularly influential life stages.

Rowe, J.C., Duarte, A., Pearl, C.A., McCreary, B., Haggerty, P.K., Jones, J.W., Adams, M.J., 2021, Demography of the Oregon spotted frog along a hydrologically modified river: Ecosphere, v. 12, no. 6, e03634,

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