Environmental variability across the landscape creates a mosaic of diverse habitats resulting in physical and behavioral differences in outmigrating salmon. We use juvenile salmon monitoring data and otolith strontium isotopes to track the expression and survival of different life history strategies in relation to dam operations, droughts and wet years, and water temperature.  Our research has highlighted that salmon are as diverse as the causes for their declines and that the within and among population variability in outmigration size and timing are critical for spreading risk and promiting population persistence in a changing climate. A particular focus at present is how water project operations and sustained droughts influence river temperatures for incubating winter run eggs and fry and quantifying temperature-dependent mortality and selection favoring adult spawn timing.