Pest Control – Rats
A new study led by professor Jonathon Richardson, at the University of Richmond, revealed that rising rat populations in cities are linked to a warming climate and the growth of cities.
Researchers analyzed public complaint and inspection data from 16 cities around the world. They found a strong link between rising rat numbers and three key aspects of the urban environment. These were: human population density, urbanization, and warming temperatures.
Of the 16 cities in the study, 11 had significant increases in rat numbers. Only three cities experienced decline.
The cities that experienced greater temperature increases saw larger increases in rat numbers. Those cities with more dense populations and more urbanization also had larger increases in rat numbers.
Richardson was very concerned about the link between climate warming and rat trends. When the temperatures increase, it may be expanding the seasonal activity periods for rats. He said, “Even an extra week or two of aboveground activity for wild rats can translate to one or two more reproductive bouts, accelerating population growth. Those working to manage rat populations will need to factor this climate-accelerated growth into their rat management planning.”
Rising global temperatures are beyond the control of individual cities. The study, however, did make it clear that cities need to:
- Invest more resources (budget and staff) to the problem.
- (a) Develop proactive rodent management plans that prioritize making the urban environment less conducive for rats (e.g. removing access to food waste).
(b) Enact and enforce regulations related to rodent exclusion in building
codes.
(c) Do timely removal of loose materials that rodents can use for harborage (e.g. clutter and debris).
(d) Devote more resources to lethal and nonlethal control, public education, and provide surveillance for areas of infestation across the city where intervention efforts are required.
- Start collecting systematic data on rodent activity and abundance rather than relying on public complaint data.
“Only by confronting the environmental factors that allow rats to thrive, and by giving municipal rodent managers the resources and tools they need, can we hope to rein in our growing rat problem,” Richardson said.
