Monkey populations in threatened forests are far more sensitive to damage to their habitat than previously thought, according to new research.
An analysis of monkeys living in Tanzania's Udzungwa Mountains suggests that the impact of external factors, such as human activity, on species numbers is felt in forests as large as 40 square kilometres.
Researchers also found that the health of monkey populations is closely related to the type of habitat found between forest fragments, rather than the distance that separates them.