Nice story worth reading in New York Magazine by Ferris Jabr: Uptown Mice Are Different From Downtown Mice — NYMag. It discusses some work on evolution in urban environments, including a little bit about work starting to be done on gut microbes of rodents and how they might be affected by urban life.
Other things of note on this topic
- Carl Zimmer from July 2011 in the New York Times: Evolution Right Under Our Noses
- Brandon Keim on How city living is reshaping the brains and behaviour of urban animals
- Carl Zimmer from April 2013 on The Evolution of the Country Mouse and the City Mouse
And I am sure many others (not trying to be comprehensive here).
There are many reasons to be interested in this topic. One aspect of this I find of potential importance is in how microbes are evolving in respose to urban environments. Of course we know a lot about this in regard to some pathogens, but less in terms of the rest of the microbes out there. Now I note – this is a different angle than the normal work on microbial communities which has focused on the ecology of the such communities (e.g., comparing the types of microbes found in cities vs. other locations). The key questions here relate to what evolutionary changes have occurred in microbes (well, non pathogenic ones) in response to living in urban environments. I have very little work on this topic — and would love to know examples if people know of any.