Our already silent forests are dying.
Scientists have proved for the first time the alarming rates of decline in regeneration of native tree species that rely on kereru, or native pigeons, to disperse seeds.
In two forests, they have found regeneration has fallen by up to 84 per cent over two years. However, they fear the problem could be far worse in other areas in which bird populations are much lower.
Canterbury university plant ecology professor Dave Kelly said researchers were taken aback by their findings. “It was a surprise for us how big the effect was and how long it was lasting for.”
At one extreme, the researchers said regeneration of trees could fail completely, leaving forests full of dying adult trees and eventually lead to the collapse of mature forests.
Dr Kelly, with Landcare Research ecologist Debra Wotton, studied native taraire and karaka trees in two forests less than 100 hectares in size.
Taraire rely exclusively, and karaka almost exclusively, on kereru to disperse their fruit, which are too big for other smaller birds to eat.
Although it was already believed that falling populations of kereru were having an impact on seed dispersal, it was the first time the link has been proved and assessed.