"On Matt Ridley: rational optimist. While agreeing with many of his reasons for being optimistic. There is one facet of his piece where I fear I am very much a party pooper.

"With the burgeoning human population and the creation of wealth that is going with it, especially in the Far East at this time, there are consequences on the downside that are very much impacting on the natural world. For instance, here in South Africa, 159 Rhinos have already been poached this year. Losses are currently running at two per day, principally from The Kruger National Park. Highly organised gangs include corrupt veterinarians and government officials. Huge sums of money are now involved, all for the stuff of fingernails!

"Elsewhere, in Borneo and Sumatra, vast areas of rainforest are being replaced by oil palm, very necessary I know for feeding more people, but catastrophic for the Orang Outang, a primate with which we share 95% of our genetic material.

"So when it comes to considering our inheritance to our children and grandchildren. I venture to predict they will be looking at a planet very much depleted of the biological diversity we see today. Certainly nothing like the amazing world my generation has had the privilege of knowing. They will of course have a record on film on what has gone."

David Fuller's view Thank you for reminding us of this. The poaching of these remarkable but endangered species is further evidence of how destructive and uncivilised the human race can be. I fear we may end up with rare and magnificent animals such as rhinos, tigers and the other big cats surviving only in open-range zoos in stable and developed countries where they can be bred and eventually returned to the wild, once countries which traffic in endangered animal parts show more responsibility towards other species.