In this study we aimed to understand the extent and spatial patterns of the fecal contamination in the urban parks of the City of Calgary for better management of the city parks. For the extent of the fecal contamination, according to our calculations, rate of fecal contamination of the public parks in the City of Calgary was close to 1.5 tons of dog feces per week. This amount of fecal material can be washed into rivers and streams by a heavy rain, contaminating the water downstream. Such a fecal contamination have not only serious direct effects on both public and wildlife health, but indirect effects through the increment of social conflict and an overall reduction of ‘wellness’ for people while in parks also; the combination of these effects may cause significant loss to the “commons” of the city.
Parks with off-leash bylaws seemed to have significantly larger amount of dog feces left unpicked by owners, suggesting that dog owners in the City of Calgary usually are more likely to clean up after their dogs if the dogs are on leash. This might be due to the increased awareness of their dogs defecating if they are on leash, or because of decreased sense of being observed by other park users when their dogs are unleashed (i.e. defecating dog is not in immediate proximity of its owner, a likely occurrence in off-leash park) thus feeling less social pressure to clean up after their dogs; a known factor contributing to fecal contamination [37]. Particular concern for park users may be that more dog feces were found near parking lots, leading to more exposure to people and dogs.
Our estimate of 19.04 dog feces per ha per week in off-leash parks in Calgary is within the range of dog fecal density reported from dog-friendly beaches in California where dogs were allowed off-leash, where the fecal densities were 2.1 ~ 4.9 dog feces per ha per day [14.7 ~ 34.3 per ha per week; 38]. Perhaps there is a tolerance level of the density of dogs or dog feces for dog owners in North America above which they start avoiding that park. It would be interesting to know if urban parks in other cities have similar dog fecal densities or if there are city features that influence the fecal contamination. Unfortunately, while there are many studies on parasitological concerns from dog feces in public areas [23, 39–43], studies on the dog feces itself are limited.
Few studies that record densities of dog feces were difficult to compare. g Rubel and Wisnivesky [19] studied the dog fecal contamination in the suburbs of Buenos Aires, Argentina, where most dogs (pets and stray) were free ranging. They found 177 dog feces in 1939.5 m2 (912.6 feces per ha) in the parks in middle-income neighborhoods and 315 dog feces in 3284.6 m2 (959 feces per ha) in the parks in low-income neighborhoods, and even higher densities of feces on sidewalks, seemingly much higher than the urban parks of the city of Calgary. However, because this study did not control the time it took for those feces to accumulate, their results cannot be directly compared. Another study in France surveyed urban parks and rural settlements, but these surveys were conducted along the paths in the parks and settlements and not by areas [20]. Similarly, a study in Naples, Italy, surveyed along the transects placed throughout the city [21].
While this study covered more parks than that of Rock, Graham [1], there are shortcomings. The socio-demographics of the neighborhoods surrounding each park were not assessed explicitly nor the activities of the park visitors studied. Part of the reason was that large parks such as Nosehill park and Fishcreek park straddle over several neighborhoods and are visited by people who do not resides in immediate neighborhoods of the parks, and are so large we could not make detailed observation of people. In fact, we had to omit small parks that were studied in Rock, Graham [1] as they were exceptionally small compared to the parks assessed in this study. However this study is rather complementary, assessing the patterns from different types of parks that provide important services to large number of people and dogs.
Management implications in urban planning
Based on our data, defining and enforcing leash bylaws for the parks is likely an effective method for reducing fecal contamination. However, dog owners often find the ability to walk dogs off-leash to be an important quality of a park [44], and their interests have to be balanced. Given the distribution of the feces within parks, to reduce the fecal contamination in public parks it is recommended to focus the efforts near parking lots and entrances, especially in off-leash parks. Designating areas near park entrances and parking lots as on-leash areas may have some effects. Studies by Jason and Zolik [45] indicated education of dog-owners as effective strategies for reducing dog fecal contamination. Educating dog owners, especially of those who visit off-leash parks, on how to properly dispose feces and the harms they can cause may be a simple and effective approach. Posting signs at the parking lots and entrances of the parks reminding dog owners to clean up after their dogs may have impacts as well.
Considering the potential problems associated with the policy regarding the pet dogs and their use of public parks, conceptual framework of assessing and designing local government’s policies on pets were proposed [46]. In 2021, the Calgary’s City Council approved changes to the bylaw on pet ownership, to take effect beginning in January of 2022. Among several changes, the new bylaw defines the maximum number of dogs a person can supervise in an off-leash park at six, increase the penalties for acts of nuisances including dog feces, and authority for the city to ban a repeated offenders from off-leash parks. As these new policies take effects, it will be interesting to assess the effects on the dog fecal contamination in the Calgary’s public parks. We hope there will be similar studies in future with consistent methodologies conducted in different cities across the world, so that we may see patterns of fecal contamination over different cities, countries, continents or cultures. Such patterns can then be used to identify cultural characteristics or policies associated with fecal contamination, patterns that are potentially useful for policy makers.