Welcome: The Prince of Wales in Jameson Hall. (Listen to a pod cast).

The birth of the world's seven-billionth resident, marked symbolically on 31 October, offered a timely backdrop to the talk by the Prince of Wales at UCT on 5 November.

Prince Charles was addressing a packed Jameson Hall - the same venue in which is mounted a portrait of his great-uncle who in 1918, as Prince Edward, became UCT's first Chancellor; and where his grandmother, then known as Queen Elizabeth, received an honorary doctorate in 1947. But his talk was of another overflowing location - Earth.

Competing demands on the land, bring other consequences, said the Prince of Wales.

"What with the ever-growing need for more urban development and the pressure to produce more food, it is fast becoming difficult to maintain essential services such as the supply of clean water, and ultimately to protect those areas that are rich in the diversity of life and which, whether we like it or not, are actually vital if nature is to continue sustaining herself, and therefore, us."

But these concerns have local repercussions. The Prince turned, therefore, to the needs of rural farmers and local fisheries.

Both are under pressure, he explained. Farming families, ironically, are growing hungry, and many fisheries are overexploited or close to collapse.

These resources have to be properly governed and planned, with an eye on environmental sustainability, he urged. And international investment - deals for some 56 million hectares of land, much in sub-Saharan Africa, were announced in 2009 - has to be closely monitored.

"It seems to be absolutely essential, though, that such an investment is mindful of its impact on local communities and natural systems," the Prince of Wales said.

As has become a trademark, Prince Charles championed the cause of smallholders; specifically, in this case, those of Africa.

"I do not see small farmers as backward relics of the past," he said. "In fact, I see them as an utterly crucial cornerstone of the future, just as they are becoming in other parts of the world."