It is clear the that AGB stars can play a very significant role in the chemical evolution of a galaxy, especially a dwarf galaxy. A dwarf galaxy with an extended star formation history will likely be highly sensitive to the chemical enrichment created by the relatively slow and steady stellar winds from AGB stars. In small galaxies Supernovae may drive mass and metals entirely out of the galaxy, but stellar winds from AGB stars probably will not. The effect of AGB stars is likely to be dependent upon the time scale over which star formation occurred. The products of these stellar winds must be returned to the ISM on a time frame consistent with the subsequent star formation episodes in a galaxy to have an impact on the chemical evolution. From the lack of AGB stars in very metal poor systems it also seems likely that the [Fe/H] plays a role in the evolution of AGB star populations. It seems to be more difficult to produce metal poor AGB stars, and also to measure any effect in the abundance ratios that may come from them.
In this review I have just touched upon the connections that can be made between the AGB star properties of nearby galaxies and their star formation histories and metallicities. These results are likely to be placed on much more quantitative basis in the coming years as more and more wide-field near-IR and optical imaging and spectroscopic surveys are carried out for both nearby and more distant galaxies. It is clear that to sort out the complex and intertwined effects of star formation, stellar winds, supernovae explosions and their effect on the ISM we need to use information from a variety of sources that are sensitive to different time scales, and different physical processes. This means that we need to combine information from optical imaging (SFHs) and spectroscopy (abundances) with IR imaging and spectroscopy to get the full story.
I would like to thank Mike Irwin for useful conversations and letting me use his unpublished IR data. I would also like to thank the organisers for inviting me to this most interesting meeting, and NWO for funding my trip, through a VICI grant.