It turns out one man’s trash is another rat’s treasure. A former Buenos Aires landfill has turned out to be a great refuge for native rat species in Argentina, a new study finds.

For years, researchers have been studying just how many plants and animals really recolonize reclaimed landfills. Outside of Buenos Aires, a team of researchers focused on the return of rodents to a 500-hectare dump closed in 2004 after 25 years of use. To survey the animals, a research team used traps baited with a mixture of fat, rolled oats, peanut butter and raw meat to capture 433 rats in 2005 and 2006. They also surveyed plant communities, to see which habitats the rats preferred.

Overall, the researchers found that the closed landfill played “an important role in the recovery of almost all the native rodent species characteristic of the area,” they report in Urban Ecosystems. Four of six native rodent species returned to the site, while invasive commensal species that had dwelled in the working dump became less prevalent. They also found that, over time, rat populations were larger and more diverse in parts of the landfill that that had been closed the longest.

Although landfills can greatly alter soil composition, topography and plant cover, the authors conclude that abandoned dumps “can be used not only for recreational purposes, but also for the conservation of native fauna.” Levi Miller & David Malakoff | April 11, 2011

Source: Carballido, M., Arístide, P., Busch, M., Cittadino, E., & Gómez Villafañe, I. (2011). Are the closed landfills recovered habitats for small rodents? A case study in a riparian site, Buenos Aires, Argentina. Urban Ecosystems DOI: 10.1007/s11252-011-0167-6

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