WASHINGTON (Sept. 18, 2018) - A new study published in the peer-reviewed journal PLOS Biology reveals certain nonlethal methods are effective for managing predators in agricultural landscapes. Twenty-one authors from 10 nations reviewed 114 peer-reviewed scientific studies measuring the effectiveness of lethal and non-lethal methods for reducing carnivore predation on livestock, one of the main causes of conflict between predators and people. Livestock guardian dogs, livestock enclosures and fladry all were scientifically shown to be effective conflict deterrents. Many more methods - lethal and nonlethal alike - show promise but have not yet been studied in a scientifically defensible manner to determine if they are effective.
In addition to determining the effectiveness of three nonlethal tools, the authors of the study concluded that robust scientific research on carnivore management methods is urgently needed. Immense resources are spent globally each year to protect livestock from carnivores, but too often without science-based evidence that the methods work. Evidence of the effectiveness of a deterrent should be a mandatory prerequisite to large-scale funding, policy-making and implementation, according to their results. Their call included the need for a new coalition of scientists and managers to establish consistent standards for future research on method effectiveness.
Defenders of Wildlife is actively addressing the need for more scientific evaluation of the effectiveness of non-lethal methods. In 2017, Defenders published a scientific evaluation of the Wood River Wolf Project in Idaho that reported proactive, nonlethal methods resulted in a 90 percent decline in domestic sheep losses on public grazing allotments in Idaho's national forests, which are also home to wolves and other native predators. These methods included livestock guardian dogs, fladry, light and sound devices, livestock carcass disposal and human presence used across large-scale, open-range livestock grazing operations. They were then compared with adjacent sheep grazing allotments that relied on lethal instead of nonlethal management to control wolves and other predators.
Jennie Miller, a lead author of the study and senior scientist at Defenders of Wildlife, issued the following statement:
"Just as we rigorously and repeatedly test medicines, vehicles and other devices for their effectiveness, we should test carnivore management methods before deeming how and when they can be used effectively. Our study found that livestock guardian dogs, livestock enclosures and fladry are scientifically-sound management tools, and these methods can be used and promoted as reliable methods for deterring predators and protecting livestock. However, many other interventions, including predator lethal control and translocation but also newer methods like range riders and light-sound devices, need to be further tested to ensure they are effective before being recommended for widespread use. Ultimately, we want to avoid agencies and livestock owners investing substantial money and time in so-called solutions that might not be resolving carnivore conflicts.
"We call on the scientific and agricultural communities to hold carnivore management to the highest standards of scientific integrity. When scientists, policymakers and livestock producers come together to make wise regulations, we'll save money, time, livestock and carnivores alike."
Lily van Eeden, a lead author of the study and Ph.D. candidate at the School of Life and Environmental Sciences, University of Sydney, issued the following statement:
"Too often our current practices are based on habit and history, not evidence. Continuing with ineffective management has social and financial costs for the rural communities who bear the impacts of predator attacks on their livelihoods."
Ann Eklund, a lead author of the study and Ph.D. candidate at Grimsö Wildlife Research Station, Swedish University of Agricultural Sciences, issued the following statement:
"Quantifications of the effectiveness of carnivore management interventions are necessary to make their use efficient. As rigorous scientific evaluations are currently scarce we encourage animal owners, carnivore managers and researchers to collaborate to apply interventions in ways that allow for scientific evaluations. The field may then be able to move toward an evidence-based practice that can save time, money and the lives of both domestic animals and wild carnivores in the future."
Adrian Treves, a lead author of the study and professor at Nelson Institute for Environmental Studies, University of Wisconsin-Madison, issued the following statement:
"Nature is the legacy we leave to future generations so it's our moral duty -- and legal duty in most countries -- to preserve wild predators unimpaired for futurity. Our review is an effort to share global lessons with the broadest public and make progress in government policy and farmers' livelihoods."
The study was included four equal lead authors (in alphabetical order): Lily van Eeden, The University of Sydney; Ann Eklund, Swedish University of Agricultural Sciences; Dr. Jennie Miller, Defenders of Wildlife; and Dr. Adrian Treves, University of Wisconsin, Madison.
The study is available for open access review here.
A video by the lead authors about the study can be found here.