As if it wasn't already obvious, Google is focused on making your Google+ profile your main identity across all its services, with Blogger the latest to begin this transition. On its official Blogger blog, Google announced that users of Draft (Blogger's "testing ground") can now migrate from a Blogger profile to their Google+ profile, while everyone else will be able to "in the coming weeks." While more Google+ integration is sure to come, profile migration is the only link at this point.
There's a caveat for anyone who doesn't want to blog under their true identity, though -- just as Google+ doesn't yet allow pseudonyms, migrating over to a Google+ profile will eliminate your Blogger profile and let all your readers know who you really are. Google has no solution yet for this, only saying that "this integration may not work" for those that don't wish to use their real identity. Fortunately, switching is optional at this point, and Google is soon allow alternate names on Google+.