December 4, 2013 — Need another reason to protect and value green spaces? Here’s an intriguing one: the benefits humans receive from being exposed to the microscopic organisms found in nature. In a paper published recently in the Proceedings of the National Academy of Sciences, University College London clinical microbiologist Graham Rook notes that such microorganisms, which he calls “Old Friends,” are an important part of our evolutionary history, and reduced exposure caused by distancing ourselves from the natural environment is likely one of the reasons behind the growing epidemic of immune disorders worldwide. Rook recommends policy makers and others factor in exposure to beneficial microbes when enumerating the services ecosystems provide to humans, and calls for stepped-up research “that will enable us to design urban green spaces that provide not only the psychological input to our brains but also an optimized microbial input to our immune systems.”

Photo by EMSL (Creative Commons | Flickr)