A font of potentially helpful sources, this database offers plenty of articles relating to the intersection of nature and urban life (and why nature is so important to urban life). Play around with search terms such as "nature" AND "urban environment" ; "urban wildlife" ; and "nature" AND "well-being."
Zoological Record is the world's oldest continuing database of animal biology, with a broad scope of coverage ranging from biodiversity and the environment to taxonomy and veterinary sciences. Basically, it's fancy.
