Natural areas going to the dogs

Human presence has changed the natural environment in many ways. One of the most important is the spread of species that do well in the presence of humans, many of which we tolerate and tacitly (or explicitly) encourage. Like Canis familiaris.

Last week, the Washington Post ran a short article describing research into the destructiveness of feral dogs in Brazil’s national parks and other natural areas: “The dog is one of the world’s most destructive mammals. Brazil proves it.”

It was found that the closer humans lived to a nature preserve, the more likely dogs had penetrated it.
But perhaps most striking? The dogs were neither feral nor domestic — but somewhere in between.
“All the dogs we detected had an ‘owner’ or a person that the animal has a bond with,” Paschoal said. “The species population increases following human populations, exacerbating their potential impact on wildlife.”

This is why many farms have dogs, to deter or kill small carnivores and other animals that would otherwise damage crops or kill small domesticates (especially chickens and other fowl). In communities where neutering and spaying are not practiced, large semi-feral dog populations often exist at the edges of human societies. They can rely upon discarded human foods during times when wild foods are scarce, which gives them a buffer that wild predators lack.

This process must have been important in the prehistoric past also. It may have contributed to a certain brittleness of human societies in the face of environmental change, since dogs would have reduced small herbivore biodiversity in the areas of human settlement, with longer-term consequences for forest and grassland plant community composition.