14
Apr
Winning the “War on Rats” Requires Community-Wide Systemic Change, Says New Study
(Beyond Pesticides, April 14, 2022) Over the last century, cities across the world have engaged in a “war on rats” that has failed to achieve meaningful results, and should consider a new paradigm for rodent management, according to a review of relevant literature published in Frontiers in Ecology and Evolution last month. As awareness regarding the widespread dangers of commonly used rodenticides increases, and states like California begin to rein in their use, the importance of alternative management approaches has grown. Reviewing over 100 studies on municipal rat management, the authors outline a path forward that embraces a systems approach and calls for a change in public expectations.
Since the early 1900s, municipal rat management has primarily focused on killing rats and removing their food, water and harborage, but data available on the efficacy of this approach is sparse. Successful programs, according to the literature, are often grant funded and time limited, or employ such substantial amounts of rodenticide that it carries significant risks regarding secondary poisoning of people and nontarget species.
Failures consistently note the ephemeral nature of rodent reductions. A 1909 study referenced in the review, from which the authors indicate much of present-day rodent management is based, discusses how Stockholm, Sweden removed over 700,000 rats over 10 years, but the total number of rats removed each year never decreased. “Despite several studies which successfully ‘won’ the war by relying extensively on rodenticide, the realities of management may have relegated much of this war to rat “farming” in which rats were harvested only to “regrow” and require repeat collection,” the study indicates.
The response to this ephemeral nature of rat reductions, and general ineffectiveness of municipal management campaigns is attributed to various reasons, including lack of interest within government or the public, the complexity of the problem, a dearth of information on cost-effective methodologies at a large scale, and an inability to change behaviors of residents and other members of the public contributing to rat problems.
The authors provide first a way to fix the current integrated pest management paradigm that calls for killing rats and reducing their food, water, and harborage. They suggest the implementation of large scale impact assessments and evaluation measures, and improving reduction strategies that incorporate a greater understanding of rat ecology. For example, the authors reference a study on the ecology of sewer-dwelling rats that determined that winter was the best time to implement control efforts as their population is lowest at that time.
Nonetheless, skeptical of the long-term success and sustainability of our continued “war on rats,” the authors propose a new paradigm for management – one that embraces a systems approach to the overall complexity of the issue. The difference is compared in metaphor to a sinking ship. The current paradigm, “uses a bucket to bail water out of a sinking ship (i.e., remove the rats) but acknowledges that this needs to be combined with methods to patch the holes from which the water entered,” the study says. An alternative approach, the researchers indicate, “considers the complex set of upstream determinants of why the holes were there in the first place might investigate how to effect change over the materials, engineering, and design of the ship, the policies that allowed the ship to be built that way, the behaviors of the crewmates that allowed the ship to fall into disrepair, the decisions of the captain which steered the ship into shallow water, or the policies which encouraged the ship to travel in dangerous weather conditions.”
Applied to rat management, a focus changes from killing rats to one that initially considers the reasons why rats are in an area in the first place. Such an approach would focus on improving the quality of life in low-income areas of degraded housing and other public amenities, rather than placing fines or penalties on rat activity. It also requires accepting that rat problems can be intractable “wicked problems.” Defined by reference in the study, wicked problems are those where a problem is always the symptom of another problem, and a problem that is unique. Rats are symptoms of other problems because they are always a factor of what the authors call “upstream determinants” like weak building codes or inadequate landscaping practices. Municipal rat problems are also always unique, with different outbreak sources, conditions, and goals, making clear best practices for rat management effectively impossible.
As a result, the authors say that the first step in a new paradigm for rat management is to map out the rat problem in the region, “to highlight, for example, where rats are considered problematic, who is vulnerable, who is resilient, what policies are in place to address them and do they work better in some areas, and which municipal departments and sectors of the urban environment are affected.” This new approach emphasizes the improvement of overall community health, rather than focusing on rats as symptoms of a problem that occurs in a vacuum. The study references work done to eliminate parasite transmission in Kathmandu, Nepal utilizing an ecosystem approach. With this work, community stakeholders came to together to map out the issue and zero in on areas where specific actions could be taken to address the problem. The community was able to successfully break transmission through different intervening actions – such as proper waste disposal, keeping livestock out of water bodies, and alterations to butchering practices.
The new paradigm proposed by researchers recognizes the complex reality of rodent management in large cities as a wicked problem that cannot be solved. “Instead,” as the authors indicate, “The problem can only be managed, making incremental gains in different aspects of the problem over time.”
While individuals can take ad-hoc protective measures to address rodent problems in and around their home, the study underscores the need for this issue to be dealt with comprehensively at a community-wide scale with an approach that does not focus solely on killing rats, but instead on achieving a set of specific, likely shifting outcomes agreed upon by the community. With advocacy from local residents, large cities will begin to shift toward this new, safer and more sustainable paradigm for rat management.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: Frontiers in Ecology and Evolution
