From Geoff Harding, Sydney, Australia
Plummeting wildlife populations, particularly of mammals and birds, must place the forests and savannahs of the world under increasing stress due to a lower rate of soil fertilisation by faeces and a lower rate of seed dispersal (26 September, p 16).
Considering the importance of forests and grasslands for carbon sequestration, it may become beneficial to take measures such as artificial fertilisation.
