Researchers found deforestation attract throngs of black rats as fallen wood provide them with more insects to eat. The deforestation-related invasion of black rats could be dangerous for native animals living in rainforest.
Black rats or ship rats have spread globally in the last 400 years. These rodents are often linked to disease spread and extinction of several native species. Towering trees in mature rainforests don't provide them with much cover. Scientists fear that the increasing practice of deforestation could result in black rat invasions.
The research team analyzed the deforestation at the island of Borneo. The common belief is that black rats stay within the urban areas. To test the hypothesis, the researchers tracked the movements of rats using spools of cotton thread attached to their backs. The team was able to track the exact trail each rat took in the forest floor.
Among the four rat species analyzed, the black rats preferred deforested areas the most. The disturbed forest floor provided more insects to eat. Plus, the fallen wood and increased undergrowth provide more cover for the rodents.
"Logging creates micro-environments that black rats love, helping them move in," said co-author Dr. Rob Ewers from the Imperial College London.
Black rat invasion could affect native mammals that would have to compete with them for food and other resources. Small mammals disperse important seeds across the rainforest, enabling it to grow. Larger animals also prey on small mammals. Black rat invasion could affect the rainforest's eco-system.
The more dead wood is left on deforested areas, the grander it is for the black rats. Effective clearing of cut up trees and connecting vines could prevent black rat invasion. The study was published in the journal Biotropica.
"This study sends a strong message for reducing the impact of logging by minimizing the damage to forest structure," added Ewers.
The researchers are preparing to track how fast the populations of black rats are growing and analyze their perceived impact. The team believes it is important to understand what would happen if black rats replace the small mammals living in rainforests.
Photo: Peter Blanchard | Flickr
