AAAAchooo! I don’t know about you but I have been waking up with a runny nose and my colleagues have been sneezing away in lab meetings and seminars. It is allergy time! You would think that one positive thing about living in cities would be reduced allergies- as we build up walls around plants and their pollen spewing abilities. Alas, while counterintuitive, that thought is mistaken. A high biodiversity of plants and trees actually helps prevent allergies. Yep, those country kids are sneezing less than city dwellers.
It turns out that there are different species of bacteria commonly found on flowering plants that, when on our skin, can help enhance our immune response and reduce inflammation due to allergies. Ilkka Hanski and colleagues tested teenagers in Finland- some living in urban areas, some in forested areas, and some on farms. They found that teens with allergy issues tended to live in areas with few flowering plants and that city teens had less immune-enhancing bacteria on their skin. That means that teens living on farms or near places with high plant biodiversity are protected against allergies by bacteria coming from those very plants that surround them! Amazing!
Does this mean that we all have to move to the boonies or farm country to be protected from allergies? No- we don’t have to go to the biodiversity, we have to bring the biodiversity to us! I have written other posts about urban biodiversity, but mostly as a way to provide habitat for insects and other creatures, like with the green roofs and green walls, but this new study is direct proof that not only does more plant biodiversity make us feel mentally better, it makes us physically better too! This study really opens the door to examining indirect links between biodiversity and our health- who knows how many other species of bacteria or fungi are associated with increased biodiversity and if they protect us from other immune disorders!
Hopefully, this and future studies like it will provide a case for increased urban biodiversity in a way conservation biologists haven’t realized. We can prove to urban planners and law makers that more trees, and different types of them, will help prevent children from developing allergies. In the mean time, get more native flowering plants in your yard and stop that sneezing!