  Recent observations, as well as theoretical studies, have suggested that
stellar cluster formation may depend on local and global environmental
properties. In particular, the fraction of stars that form within long-lived
bound clusters (\Gamma) may depend on environment, with indications that it may
be higher in the more extreme environments of high star-formation rate density
galaxies. How \Gamma varies has important implications on the use of clusters
to determine the star-formation histories of galaxies as well as our
understanding of the star-formation process itself. Previous studies have
estimated \Gamma over full galaxies, making it difficult to discern the
physical cause of the reported variations. Here, we use existing star cluster
catalogues and HST-WFC3 V and I images of the grand design, face-on spiral
galaxy M83 in order to see if and how \Gamma varies within a single galaxy. We
find that \Gamma decreases strongly as a function of galactocentric radius, by
a factor of ~5 over the inner ~6kpc, in agreement with recent theoretical
predictions and decreasing trends observed in the gas surface density of the
galaxy.
