FunNature & AnimalWhy you shouldn't leave dog poop in the field

Why you shouldn't leave dog poop in the field

Could man’s best friend be nature’s worst enemy? This question has a very clear answer: it depends on the owner.

We have traditionally considered the needs of our canine companions as a ”fantastic natural fertilizer” – a perfect excuse to take the dog to the park or the field for a walk and take advantage of the ecosystem to save the task of collecting ”the little gift ” left behind by our furry little quadrupeds – but now new scientific research shows us that’s not the case. Dog feces and urine are not “so good” for nature.

An impact that was not being taken into account

The study in question, published in the journal Ecological Solutions and Evidence , has focused on knowing the effects of canine activity on soil fertilization . An impact that, to date, had not been documented in detail, unlike other effects of domestic dogs on wildlife such as direct mortality, disturbance or disease transmission. Specifically, they explain how two components of dog feces, nitrogen and phosphorus, are causing a truly polluting effect on semi-natural ecosystems , including forests, swamps, meadows or meadows, among others.

Good nutrients… but in the right measure

Nitrogen and phosphorus are essential nutrients in ecosystems, being one of the primary sources of food for plants. Yes, in adequate amounts.

The faeces and urine of domestic dogs contribute, as a whole, very high concentrations of nitrogen and phosphorus to the soil , something that scientists have been able to verify in areas with trails or paths frequented by these animals and their owners.

The high concentrations of these two nutrients have a strong negative impact on the diversity and function of the ecosystem with consequences such as the decrease in the richness of plant species or the effect on the niche of many threatened species.

How was the analysis done?

What this group of researchers from Belgium, led by Pieter De Frenne, did was to quantify the contributions of nitrogen and phosphorus that came from the urine and feces of dogs in places dedicated exclusively to the conservation of biodiversity . Specifically, nature reserves consisting of small patches of forests, wetlands and grasslands. To do this, they carried out 487 direct count censuses over a year and a half, collecting precise data on the abundance of dogs per hectare and per year. In addition, they carried out a rough estimate of nitrogen and phosphorus fertilization rates based on documentation of the concentrations of these nutrients in the dogs’ urine and feces.

The results indicated that the nitrogen and phosphorus fertilization rates of canines are very significant, amounting to an average of 11 kg of nitrogen (which is found in both urine and feces) and 5 kg of phosphorus (mainly in feces) per hectare. and year, respectively. Estimates show that these high levels of both macronutrients, in fact, can have a considerable influence on biodiversity and the functioning of ecosystems , as well as on the work carried out for their conservation and maintenance.

A new contribution to the management of natural spaces

A scientific study of these characteristics can have a direct application to avoid, as soon as possible, the impact of our activity and that of our domestic dogs on the semi-natural peri-urban ecosystems that we frequent. In it, the researchers propose a series of modifications in the management guidelines of these spaces to avoid the burden that is produced on the environment , the loss of biodiversity and, in addition, prevent inconveniences in the objectives of restoration and recovery of the environment, highlighting the importance of oligotrophic ecosystems (poor in nutrients), where there are plant species adapted to this type of soil.

Among the proposed measures are urging visitors to collect the feces of their pets responsibly – even in spaces surrounded by nature -. In this regard, campaigns in the media and in public education programs regarding the effect of soil fertilization on semi-natural peri-urban ecosystems can be key.

In addition, they raise the need to enforce the use of the leash more strictly (which has been seen to have a greater effect when there are legal reprimands for non-compliance with this rule), since this allows the concentration of excrement in areas reduced, reducing the damage to most of the ecosystem.

The alternative to this restrictive measure is the establishment of more specifically designed, fenced, off-leash dog parks in which dogs are allowed to roam free . Said alternative, together with the correct work of collection by the owners, would help to considerably reduce the impact on “natural” spaces.

How can both waste (faeces and urine) be collected?

It is clear that urine is not a simple waste to collect and although both feces and urine have a direct impact on the ecosystem due to their nutrient content, it is the former that contain the bulk of the nitrogen (56%) and the phosphorus (97%) deposited . For this reason, the study explains that removing feces using disposal bags and poop collection stations may be the measure of individual responsibility that considerably reduces the impact on soil nutrient levels.

Be responsible even in nature

It is not only a question of the ”health of the soil” and its good fertilization. Another reason why it is necessary to eliminate the faeces of our canine friends is to avoid infections by parasites that can be transmitted to other wild animals such as roe deer ( Capreolus capreolus ) or cattle and sheep. Parasites such as Neospora caninum , whose definitive host is dogs, can have an impact on these animals, causing abortions.

It is necessary to get rid of the saying “fantastic natural fertilizer” and “this is natural compost” and urge people who have dogs as pets to dispose of their solid fecal waste due to the impact that their waste has on the ecosystem . After all, it’s not just you and your dog, there are many more.

Despite being traveling companions for thousands of years, humans ( Homo sapiens ) and dogs ( Canis familiaris ) still have much to learn about our direct impact on the environment. This research is one more step that will contribute to the study of ecology.


De Frenne, P., Cougnon, M., Janssens, GPJ, & Vangansbeke, P. (2022). Nutrient fertilization by dogs in peri-urban ecosystems. Ecological Solutions and Evidence, 3, e12128.

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