Yes, dogs are adorable, but a new study shows that their feces and urine can have devastating effects on the environment. As you read it.
The research affirms that dogs, by relieving themselves in parks, can damage the ecosystem and generate a loss of biodiversity due to excessive fertilization. This pollution can unbalance the environment by favoring some plants over others.
The study, published this week in the journal Ecological Solutions and Evidencewas based on surveys of pet density over time in four nature reserves around Ghent, Belgium.
However, the researchers believe that this phenomenon is also relevant for natural areas in other cities in Europe and in the United States, where approximately 87 and 72 million dogs live, respectively.
What findings did the study reveal?
After analyzing the “natural effects” of dogs in four parks surrounding Ghent, Belgium, it was found that the dirty soil contained high concentrations of nitrogen and phosphorous, two powerful fertilizers that influence the environment.
“Nutrient inputs from canine urine and feces can have important effects on soil nutrient concentrations. Elevated concentrations of phosphorous and nitrogen are found in areas of many dog walkers and especially near walking trails, and stable isotope analyzes confirmed that dogs are the source,” the researchers wrote.
The amount of nutrients that could be released into the environment was assessed from an estimate of how often the dogs defecate and urinate, and how rich in phosphorous and nitrogen the faeces and urine are on average.
Assuming that the owners do not pick up the feces, dogs can deposit up to 11 kilograms of nitrogen and 5 kilograms of phosphorous per 1 hectare per year.
That means dogs could be pushing environments well past the “critical load,” which is the amount of nitrogen that can enter an ecosystem without affecting biodiversity. “For most ecosystems we work in, that level is 20 kg per hectare per year,” said Pieter De Frenne, a bioengineer at Ghent University and author of the study.
In addition, air pollution from agriculture and traffic contributes another 5 to 25 kg of nitrogen per 1 hectare per year to soil pollution.
“When there is an excess of available nitrogen in the soil, only a selection of competitive plants can cope,” De Frenne said. These plants then outgrow environmental conditions and suffocate other plants. “Orchids are a typical example. These are overcome and are lost from the ecosystem”, added the researcher.
“Higher nutrient levels lead to increased plant growth, primarily from a limited number of nutrient-demanding species,” the study says. These would take away available light from others, “causing loss of plant species and homogenization of plant communities,” the report stated.
It was also specifically described how dog urine has a negative effect on plant life due to the fact that canines often eat a lot of meat.
According to the researchers, this is because “dogs are carnivores and eat primarily a high-protein diet, and the concentrations of nutrients in the urine are relatively high.”
“Specifically, within urine patches (which contain nitrogen) deposition has a strong effect on plant biodiversity and ecosystem processes (eg, carbon and nutrient cycling) on a microscale,” the researchers noted.
What is the solution?
To reduce the burden on environments, park managers could introduce more off-leash dog areas with less sensitive ecosystems, De Frenne said.
Also, says the author, dog owners could try to encourage their dogs to relieve themselves before entering parks, or keep them on a leash to prevent the spread of contamination.
Finally, De Frenne comments that owners should pick up their dog’s feces, “because then 97 percent of the phosphorous and half of the nitrogen are removed.”