Black rats rainforest invasion 'speeded by deforestation'

By Matt McGrathEnvironment correspondent

Cutting down trees in rainforests facilitates the spread of invasive black rats, a study suggests.

The rodents normally avoid mature forests with large trees as they provide little in the way of cover.

But researchers, writing in Biotropica, say that logging makes rainforests more attractive for rats as fallen wood contains more insects which they eat.

Scientists are concerned that the invading black rats will be bad news for native mammals.

Sometimes called the ship rat, these rodents have spread around the world over the past 400 years, often causing the extinctions of native species and spreading disease.
Noisy trails

Much of their notoriety rests on the idea that black rats were the origin of bubonic plague, although recent research casts doubt on that notion.

Black rats have usually avoided older forests as they contain large trees which do not provide much in the way of ground level protection. They also tend to have leafy forest floors which are noisy for rats to run through, as they attract predators.

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