If you have a four-legged friend, you know it: it is mandatory to collect your dog’s feces in the city. But what about in nature? No more sidewalks to avoid or respect good manners… And yet dog poop is a real nuisance in the natural environment. Dog urine and feces contain high levels of nitrogen and phosphorus that harm plant biodiversity. That’s according to a recent study, which warns against this pollution that is all too often neglected.
The study, published in the journal Ecological Solutions and Evidence, took as its observation field four nature reserves around the city of Ghent, in Belgium. The researchers counted the number of dogs walking in these places and analyzed the impact of their droppings on the local flora. Result: Their urine and feces contain nutrients and leave an average of 11 kg of nitrogen and 5 kg of phosphorus per hectare of land per year, GEO reports. Nitrogen is in the urine and feces of dogs and phosphorus is only in the feces.
A level of pollution comparable to that of agriculture and industry
According to the study, this nutrient supply poses a threat to biodiversity. Indeed, since most ecosystems are naturally nutrient poor, this would lead to over-fertilization of the soil. What promotes the development of certain plants, such as nettles, to the detriment of other species, GEO specifies. The research also shows that the level of pollution from dog feces is comparable to that of agriculture and industry, ranging from 5 kg to 25 kg nitrogen.
The researchers observed 1,629 dogs in a year and a half, and a third of them were off-leash. If all these dog visitors had roamed freely, the results obtained could have been worse, according to the study: up to 175 kg of nitrogen and 73 kg of phosphorus per year along the trails.
“Atmospheric input of nitrogen from agriculture, industry and traffic rightly receives a lot of political attention, but dogs are completely neglected”regrets Professor Pieter De Frenne of Ghent University, who led the research.
Cleaning up and throwing away dog poop: an essential ecological gesture
According to the researchers, the situation in Belgium would be similar across Europe, which has nearly 87 million dogs. Suffice it to say that the level of pollution caused by their feces is far from negligible, but it is not inevitable. Picking up and taking out your dog’s feces would eliminate almost all of the phosphorus and half of the nitrogen, according to the study. “Urine is of course difficult to carry”, admits Pieter De Frenne. For that reason, managers of nature reserves could especially consider banning dog walking in these areas. However, previous research has shown that high nutritional levels can persist for up to three years after dogs are banned.
“Wherever you walk your dog, it is important to collect, bag and dispose of the droppings to ensure the continued protection of these wild areas for all of us to enjoy”said Rob Stoneman, director of landscape restoration at The Wildlife Trusts, in the UK and quoted by GEO.
Get out in the city or in the woods to protect your favorite hiking trails!