Dear Readers, I hope you’ll forgive my second ‘science-y’ post in a row, but this report caught my attention today, and it has made me think about a possible hidden reason for the decline in numbers of many of our most familiar urban species, such as house sparrows and many pollinators. The study looked at the lungs of grey squirrels which lived in a number of London boroughs (Westminster, Greenwich, Haringey, and Richmond) and compared them with squirrels living in Surrey and Wales. The urban squirrels had a higher incidence of markers for lung disease, with those in Westminster showing the worst symptoms and those in leafy Richmond the least. In all, 13% of the urban squirrels sampled had diseases of the trachea, and 28% showed evidence of lung disease.
This rather begs the question of what air pollution is doing to the lungs of even more sensitive creatures, such as birds, which are notoriously sensitive to air-borne pollutants. Personally I think that the causes of urban wildlife loss are multifactorial, but it’s interesting to think of air-pollution as being another ingredient in the mix, alongside habitat degradation, lack of places to breed, noise and light pollution and the general increase in concrete and decrease in green space.
Also, we know that people living in the densest inner-city areas also have the highest incidence of asthma and other lung diseases, so the results aren’t that surprising. Previous papers have identified that other urban animals, including dogs and feral pigeons, also have higher levels of lung damage than their country cousins, and I especially feel for small dogs walking along the pavement and inhaling all those exhaust fumes which are pouring out at nose level. However, the authors of the study point out the need for longer-term studies that look at specific pollutants, so that action can be more targeted and so that we can go forward with better information.