An increasing number of wolf-dog hybrids threaten the genetic identity of European wolves and could drive local populations out of existence, according to a review written by more than 40 leading scientists. Writing in Frontiers in Ecology and Evolution, researchers agree that there is a major problem at hand but disagree on potential solutions.
Hybridization is the breeding of two distinct but closely related populations, in this case, dogs (Canis familiaris) and wolves (Canis lupus). This intermixing can deeply impact the genetic make-up, long-term survival, and evolution of the species. When it occurs as a natural process, it can often result in positive evolutionary adaptations, but when human-caused hybridization comes into play – whether intentional or accidental – it removes barriers between distinct populations and is generally seen as a threat for conservation.
As humans destroy wild habitats and bring feral dogs into closer proximity with wildlife, wolves are threatened by introduced genetic material encompassing thousands of years of domestic dog breeding that has limited evolutionary adaptations to survive in the wild. In short, interbreeding with dogs could force wolves to lose the very attributes that have helped them to survive for so long. Furthermore, interactions between domestic dogs and wolf populations increase the possibility for disease transfer between the taxa.
Here’s where it gets dicey. To mitigate hybridization, experts generally agree on adopting preventive, proactive and, when concerning small and recovering wolf populations, reactive interventions – but how they will achieve that remains a contentious issue. Some argue that the killing or sterilization of free-roaming dogs is a viable solution, while others contend that presents an ethical dilemma and feral dogs should instead be kept in a facility.
“We need to address this issue before wolf-dog hybrids backcross with wolves to the extent that wolf populations will be lost to hybrid swarms, and the conservation of wild populations will become unfeasible,” said ecologist lead author Valerio Donfrancesco, from the University of Exeter's Centre for Ecology and Conservation, in a statement.
Altogether, researchers agree that the general public needs to be made more aware of the issue to “encourage decision-makers to act.”
“The management of hybrids and wolf-dog hybridization should not be a taboo topic, especially within the scientific community,” said study co-author Paolo Ciucci, from the Sapienza University of Rome.
An estimated 17,000 wolves currently live in Europe, whose populations vary in size and are scattered across the continent, from Greece to Finland. Nearly all populations are either stable or increasing.