  The interplay between stellar populations and gas in local starburst galaxies
is analyzed using images from the Hubble Space Telescope to map the ages of the
young stellar components and to isolate the contribution of shocks on spatial
scales ranging from a few tens of pc to ~1 kpc. The shocked gas represents a
small fraction of the total ionized gas in these objects, yet it can have
profound effects on the long-term evolution of the starburst, which may include
the triggering of new star formation.
